ANNOTATED BIBLIOGRAPHY
OF 40 BIRDS
IN THE
CALIFORNIA DESERT
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ANNOTATED BIBLIOGRAPHY
OF 40 BIRDS
IN THE
CALIFORNIA DESERT
by
Ralph W. Schreiber, PH.D.
Curator, Ornithology-
Los Angeles County Museum
of Natural History
900 Exposition Boulevard
Los Angeles, California 90007
Lib
for
Bureau of Land Management
Desert Plan Staff
1695 Spruce Street
Riverside, California 92507
Completed December 1978
Contract CA-060-CT8-000045
ANNOTATED BIBLIOGRAPHY OF 40 BIRDS IN THE CALIFORNIA DESERT:
1. BLACK-HEADED GROSBEAK (Pheucticus melanocephalus)
2. CACTUS WREN ( Campy lorhynchus brunneicapillus couesi)
3. CALIFORNIA THRASHER (Toxostoma redivivum)
4. COMMON NIGHTHAWK (Chordeiles minor)
5. DOWNY WOODPECKER (Pico ides pubescens turati)
6. FOX SPARROW (Passerella iliaca)
7. GRAY FLYCATCHER (Empidonax wrightii)
8. GREAT HORNED OWL (Bubo virginianus)
9. GREEN-TAILED TOWHEE (Pipilo chlorurus)
10. HAIRY WOODPECKER (Picoides villosus leucothorectic)
11. HOUSE FINCH (Carpodacus mexicanus)
12. LADDER-BACKED WOODPECKER (Picoides scalaris cactophilus)
13. LAWRENCE'S GOLDFINCH (Carduelis lawrencei
14. LESSER GOLDFINCH (Carduelis psaltria)
15. LONG-BILLED MARSH WREN (Cistothorus palustris)
16. LONG-EARED OWL (Asio otus)
17. MOUNTAIN BLUEBIRD (Sialia currucoides)
18. MOUNTAIN CHICKADEE (Parus gambeli)
19. NORTHERN BROAD- TAILED HUMMINGBIRD (Selasphorus platvcercus - S.p. platycercus)
20. NORTHERN GRAY-HEADED JUNCO (Junco c. caniceps)
21. NORTHERN ORIOLE (Icterus galbula)
22. PINON JAY (Gymnorhinus cyanocephalus)
23. PLAIN TITMOUSE (Parus inornatus)
24. POOR WILL (Phalaenoptilus nuttallii)
25. RED- TAILED HAWK (Buteo jamaicensis)
26. RED-WINGED BLACKBIRD (Agelaius phoeniceus)
27. RUBY- CROWNED KNINGLET (Regulus calendula)
28. RUFOUS- SIDED TOWHEE (Pipilo erythrophthalmus)
29. SAGE THRASHER (Oreoscoptes montanus)
30. SOLITARY VIREO (Vireo solitarius cassinii)
31. SONG SPARROW (Melospiza melodia)
32. TURKEY VULTURE (Cathartes aura)
33. VIOLET- GREEN SWALLOW (Tachycineta thalassina)
54. WESTERN BLUEBIRD (Sialia mexicana)
35. WESTERN FLYCATCHER (Empidonax d. difficulis)
36. WESTERN KINGBIRD (Tyrannus verticalis)
37. WESTERN MEADOWLARK (Sturnella neglecta)
38. WESTERN WHITE -THROATED SWIFT (Aeronautes saxatalis - A. s. saxatalis)
39. WILSON'S WARBLER (Wilsonia pus ilia)
40. YELLOW- RUMPED WARBLER (Dendroica coronata)
#
BLACK- HEADED GROSBEAK
Pheucticus melanocephalus
I TAXONOMY
A. Type description
AOU (1957) P. m. melanocephalus : Guiraca melanocephalus
Swainson, PTiil. Mag. , n. sTj I~7 no"! 6, June 1827, p. 538.
(Table land. Temiscaltipec = Temascal tepee, Mexico.)
P. m. maculatus : Fringilla maculata Audubon, Birds Amer.
Tfolio), vol. 4, 1837, pi. 373, Figs. 2-4. (Columbia River
[, Oregon].)
B. Current systematic treatments
Paynter (1970), recognizes four species in the genus
Pheucticus; two subspecies of melanocephalus , both of
which occur in California. Order: Passerif ormes ; Family:
Emberizidae ( Cardinal inae ) .
C. Synonomies of scientific nomenclature
P. m. melanocephalus : Dawson (1923), Hedymeles melanocephalus
melanocephalus. Ridgway (1901), zamelodia melanocephala.
) Grinnell and Miller (1944) , Habia melanocephala.
P. m. maculatus : Dawson (1923), Hedymeles melanocephalus
capital is. Grinnell and Miller (1944) , Coccoborus melano-
cephalus; Pitylus melanocephalus ; Guiraca melanocephala;
Goniaphea melanocephala; Zamelodia melanocephala micro-
rhyncha; Habia melanocephala; Z. m. maculata.
D. Synonomies of vernacular nomenclature
II DESCRIPTION
A. External morphology of adults
Dawson (1923), H. m. melanocephalus "Adult male in summer:
Head above and on sides, and narrowly across chin, glossy
black, area of black occasionally invaded by a supra- auricular
stripe of orange-tawny; a cervical ring, sides of neck,
throat, breast, and sides, rump, and interrupted stripes
connecting rump and cervix, orange- tawny. . . , paling on flanks
posteriorly to buckthorn brown; a touch or wash of the lighter
shade also on crissum, which is otherwise white; abdomen
narrowly white, middle of breast, axillars, and lining of
wings pure lemon-yellow; remaining upperparts black, inter-
rupted, as aforesaid, on back by tawny, and on wings by
>
Pheucticus melanocephalus (con't.)
broad white tips of median coverts, narrower white tips
of greater coverts and secondaries; basal portion of remiges,
nearly half on primaries, white: the 6th, 7th and 8th
primaries (reckoned from within) sharply edged with white
on the distal portion; rectrices black, the two outer
pairs broadly tipped and the 3rd pair touched with white
on inner web; tibiae black tipped with white. Bill dark
horn-color, lightening below; feet dark brown. Adult female:
Very different; pattern of male preserved only in yellow of
axillars and wing- linings, with touches of yellow on breast;
in general, above blackish, streaked with white; below
fulvous, streaked sharply and narrowly with blackish;
pileum blackish, separated by a coronal stripe of white
sharply flecked by black; lores and superciliary broadly
white; back black, broadly edged with whitish or fulvous;
white spotting of wings much restricted; the spots on tail
lacking; underparts chiefly whitish, clearest on chin,
throat (or else on sides of throat only), and abdomen;
elsewhere more or less suffused with pale ochraceous, most
intensely on breast, and sharply streaked with dusky."
P. melanocephalus maculatus: 'Similar to H. (P.) m. melano-
cephalus, but bill averages smaller; black of crown more
liable to invasion of tawny from behind, especially in post-
ocular stripe, and occasionally developing a median crown-
stripe." Ridgway (1901), detailed description of adult
males and females in summer and winter, including plumage,
soft parts, and measurements. Peterson (1961) "Male: Rusty
wings, and large pale bill... In flight shows black and white
wing and tail pattern, cinnamon rump. Female: Largely
brown; streaked. Breast washed with light brown (usually)
and lightly streaked on sides."
B. External morphology of subadult age classes
Dawson (1923), "resemble the adult female, but the ochraceous
element is stronger both above and below, and the lesser
wing-coverts are extensively edged with yellow." Ridgway
(1901), detailed description of young, including plumage
and soft parts.
C. Distinguishing characteristics
Interspecific - Peterson (1961), "Female Rose-breasted
Grosbeak (East) usually has a whiter, more streaked breast."
Intraspecific - Dawson (1923), "There is no doubt that coastal
specimens exhibit this ochraceous invasion of the cephalic
areas more frequently than do Rocky Mountain specimens; but
the latter do show individual examples of the same tendency,
and the grounds of separation are probably not valid."
•
•
0
Pheucticus melanocephalus (con't.)
I GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) Pheucticus melanocephalus in general: "Southern
British Columbia, southern Alberta, southern Saskatchewan,
and central Nebraska south to northern Baja California,
Guerrero and Oaxaca. Fossil, in the late Pleistocene of
California."
P. m. melanocephalus : "Breeds from southeastern British
Columbia (Okanagan Landing, Creston) , northwestern Montana
(Flathead Lake), southeastern Alberta (Walsh), southwestern
Saskatchewan (Maple Creek), northeastern Montana (Glasgow),
and northwestern North Dakota (Charleson) south through
eastern Washington and eastern Oregon to extreme eastern
California (White Mountains, Clark Mountain), central and
southeastern Arizona (Prescott, Huachuca Mountains) and the
Mexican Plateau to Guerrero (Amojileca) and Oaxaca (Cerro
San Felipe); east to central Nebraska (Greeley) and central
Kansas (east to Cloud and Harvey counties), western Oklahoma,
western Texas (Midland County), and Tamaulipas (La Joya de
Sal as)."
P. m. maculatus: "Breeds from southwestern British Columbia
XQuinsam Lake, Caquitlam) south along the Pacific coast to
northern Baja California (Sierra San Pedro Martir) ; east
in California to Owens Valley and the San Bernardino Moun-
tains." Dawson (1923), P. melanocephalus : "Western North
America from the plateau of Mexico north, in summer, to
eastern Kansas, southeastern Dakota, Montana, and British
Columbia; breeds throughout its range."
B. California distribution of the species
P. melanocephalus melanocephalus: Dawson (1923), "Restricted
to the portion lying east of the Sierra-Cascade Mountain
system... At least the Colorado River valley during migra-
tions; presumably the breeding bird in mountain ranges east
of the Sierras."
P. melanocephalus maculatus : Dawson (1923), "The Pacific
(!oast district of western North America, broadly; probably
includes eastern slopes of Sierra-Cascade system."
C. California desert distribution
Grinnell and Miller (1944), P. m. melanocephalus : "As
breeding, mountains of Mono and Inyo counties east of Owens
valley, extending south to eastern San Bernardino County.
Pheucticus melanocephalus (con't.)
In migration, Colorado River valley, Colorado and Mohave
deserts west to Twentynine Palms, and valleys of eastern
Inyo County . "
P. m. maculatus : "Breeds throughout State west of south-
east ern- Heserts and Owens Valley, with exception, apparently,
of coastal islands; in desert mountains of Mono and Inyo
counties replaced by H. (P.) m. melanocephalus . In migration
appears additionally on islands and in desert areas."
D. Seasonal variations in distribution
P. m. melanocephalus - AOU (1957), "Winters from southern
Sonora (Alamos), southern Chihuahua (Chihuahua), Nuevo
Leon (Mesa del Chipinque), and Louisiana (Shreveport, Monroe)
south to Guerrero and Oaxaca."
P. m. maculatus - AOU (1957), "Winters from southern Baja
California (La Paz), southern Sonora (Tesia), and southwestern
Chihuahua south to Oaxaca (Mitla)."
Dawson (1923), P. m. maculatus : "casual in winter in the San
Diegan district." Grinnell and Miller (1944), P. m. melano-
cephalus: "a common migrant on eastern deserts, appearing
in spring in mid-April and continuing through May." P. m.
maculatus: "Summer resident from early April to early
September. Migrations occur normally in late March and
April, and in late August and September; spring arrivel in
higher mountains and in northern California two to four
weeks later than in other sections, and migration continues
through May east of Sierran axis."
!V HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), P. m. melanocephalus : "Life zone
occupied for nesting, Upper Sonoran and Transition. . .Pinon
woodland primarily, but also mountain mahogany and, where
available, firs and rose and willow thickets, the latter
apparently preferred."
P. m. maculatus: "Life zones in summer, Lower Sonoran, Upper
SonorarTj and Transition. . .Riparian woodland, oak woodland
with associated shrubs, and open coniferous forests of
Transition and Upper Sonoran zones, especially where inter-
mixed with deciduous oaks. The range in habitat is thus
great and includes plant growths so diverse in type as
willows, black oaks, fruit orchards, and juniper trees.
Most favored is the willow-cottonwood association." Weston
(1947), "may ordinarily be found in the woodland or in riparian
*
Pheucticus melanocephalus (con't.)
I groves and thickets. . .Most often found in the open woods...
Along edges or transitions between grassland and woodland
or chaparral, grosbeaks are also common; but they enter
chaparral and grassland only infrequently and then only
in search of food." Small (1974), "for breeding, open coni-
ferous montane forest, riparian woodland, oak woodland
in foothills and lower mountain slopes; otherwise, woodland
patches and groves in lowlands." Miller (1951), Upper and
Lower Sonoran and Transition life zones. Austin (1968),
"in thickets of bushes, small trees, or willows which grow
along streams, around the edges of swamps, ponds, or damp
places, as well as on the edges of open woods, where the
sunlight filters down through the foliage, but almost always
not far from water or low ground."
B. Altitudinal range
Dawson (1923), "Ranging from 5000 feet up to 8500 feet,"
for P. m^ melanocephalus . "Range from near sea level at
least up to 7500 feet in Warner Mountains of Modoc County
and in southern Sierra Nevada," for P. m. maculatus.
C. Home range size
D. Territory requirements
Perch sites - Gander (1929), "seen perched on an electric
light wire." Weston (1947), "for singing perches, gros-
beaks appear to require fair visibility. . .best afforded by
open woods."
Courtship and mating sites - Weston (1947), "Courtship and
selection of mates occurs after the grosbeaks arrive on
their breeding grounds."
Nest sites - Dawson (1923), "Externally a bulky... airy
assemblage of interlaced twigs or dishevelled weed- stems,
or sometimes a generous mass of leaf-bearing twigs plucked
green. . .Placed at moderate heights in the larger bushes,
saplings, or small trees, chiefly those of the riparian
association. Weston (1947), "Nesting occurs most commonly
in streamside bushes and trees and in the live oaks of open
woods." Includes descriptions of six different nest sites
in Strawberry Canyon, Berkeley, California. In general:
"in deciduous bushes and trees bordering streams. . .Also
in bushes or trees away from stream courses in gardens,
dense brushland, closed woods and parklands. . .Placed in
trees and bushes, usually at a height of six to twelve
feet above the ground."
Pheucticus melanocephalus (con't.)
E. Special habitat requirements
Grinnell and Miller (1944), "Perhaps an important factor
is local diversity of plant growth and extensive 'edge'
conditions", for P. m. maculatus.
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Dawson (1923), "fruit in season, especially cherries and
f igs .. .codling moth, cankerworms, flower-beetles. .. scale
insects." Grinnell and Miller (1944), "food is varied and
the species may require several kinds of supply in the nest-
ing area. Insects and buds are sought in the foliage of
broad-leafed trees especially, and berries and other fruits
are taken in large quantity." Weston (1947), "Insects
and other animal matter eaten by grosbeaks amount to more
than the bulk of the vegetable food and should probably be
regarded as their main food." Fisk and Steen (1976), re-
port this species feeding on nectar from feeders in Arizona.
Ivor (1943), reported this species feeding upon ants (in
captivity) .
B. Foraging areas
Weston (1947), "The extensive peripheral foliage character-
istic of open woods is advantageous to grosbeaks in foraging
for food. . .Forage predominantly in trees... May occasionally
be seen flying out in midair in pursuit of insects. . .May
also frequent the ground in search of food."
C. Foraging strategies
Gander (1929), "from this perch it would make short fly-
catcher-like flights, presumably after insects."
D. Feeding phenology
Weston (1947) "A seasonal shift in food, probably due mainly
to change in availability. For several weeks after their
arrival on their summering grounds, grosbeaks fed mainly
on such soft succulent vegetable matter as leaf buds, flowers
and flower buds, as well as on early forming fruits. Worm-
like larvae of various lepidopterous insects were also con-
spicuous in the diet at this time. As the weeks passed, a
slow change was discernible. With the maturing of other
fruits, the grosbeaks resorted to them in turn and fruit
then became predominant in the diet. Early in the summer,
•
Pheucticus melanocephalus (con't.)
>with the disappearance of many of the fruits, the vegetable
diet shifted to one consisting mainly of seeds, found in
foraging about on the ground and in the bushes. Except
for the seasonal changes in the forms of lepidopterous in-
sects and the accompanying change in the diet, I noticed
no appreciable shift in the animal diet of the adult birds."
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Weston (1947), "The males arrive singly rather than in
flocks and are solitary for the few days preceding arrival
of females. They begin singing upon arrival. . .Males appeared
to be spaced, but I saw no conflicts between them until
after the arrival of females. . .Active competition among
males appeared to occur only in the presence of females
...Practically all local species of birds except predators
and other grosbeaks are tolerated at the nest." Kroodsma
(1974), comparison of species recognition behavior, with
regard to territoriality, with that of the Rose-breasted
ft Grosbeak.
C. Courtship and mating behavior
Weston (1947), "lone females arrived six days after the
males, and the grosbeaks engaged actively in courtship
soon after. Two or even three males would be singing and
flying about in the vicinity of one female, occasionally
chasing her... The only type of display seen was a nuptual
flight. Loud songs were uttered from some exposed perch
near a female and then the male would suddenly fly up and
out, performing a song- flight in the air above her. Flying
forth on a horizontal course, the male would circle out
from the summit of a tree, with the wings and tail spread,
uttering an almost continuous song. In the air for eight
to ten seconds, he would then fly back, usually to the
perch just vacated. . .During the early part of the season
the paired birds forage together, and at this time the
male is distinctly aggressive."
D. Nesting phenology
Dawson (1923), "May- June; one brood." Davis (1933), reports
in Butte. Co., California, the first date as 1 May; the last
date as 31 May; the average date as 15 May. Weston (1947),
^ "Construction of the nest takes from three to four days...
Building of the nest is done by the female."
Pheucticus melanocephalus ( c on * t . )
E. Length of incubation period Mr
Weston (1947) "Continuous incubation normally begins with
the laying of the next to last egg. Both sexes incubate
...Lasts 12 days; all eggs hatch within 24 hours."
F. Length of nestling period
Weston (1947), reports twelve days.
G. Growth rates
H. Post-breeding behavior
Weston (1947), "In the latter part of the season the young
follow the females, the males having left soon after nesting
is over. I have seen females feeding well grown young as
late as the early part of August."
I POPULATION PARAMETERS
A. Clutch size
Dawson (1923), reports three or four. Weston (1947) reports
from three to four in six nests, although has records of ^^
sets of two and five eggs. ^^
B. Fledging success
C. Mortality rates per age class
D. Longevity
Kennard (1975), reports record age of 6 years in 1938 when
trapped and released. Banded after hatching year in 1933.
Sex unknown.
E. Seasonal abundance
F. Habitat density figures
Gaines (1974), reported 123 and 158 territorial males per
square kilometer of clumped cottonwood and willow woodland
in Butte County, California; seventy-five territorial males
per square kilometer on floodplain gravel bar in Glenn and
Butte Counties, California, 1973; 130 per square kilometer
in clumped cottonwood and willow woodland, Glenn and Butte
Counties, California.
9
Pheucticus melanocephalus (con't.)
I INTERSPECIFIC INTERACTIONS
A. Predation
Stoner (1933), reports remains of this species in full spring
(male) plumage in nesting cavity of Western Burrowing Owls
near Benicia, California. Allen (1930), reported observa-
tions of Gray Squirrel examining nest of this species con-
taining two eggs. The squirrel was driven off by the adult
birds.
B. Competition
Weston (1947), "Wren-tits (Chamaea fasciata) were seen
picking at one occupied nest~j Bush-tits (Psaltriparus
minimus ) were seen foraging on a nest, a Pileolated Warbler
(Wilsonia pusilla) was seen standing on the rim of another
nest, and none caused any apparent alarm on the part of the
grosbeaks."
C. Parasitism
Payne (1976), reports this species as a host of Brown-
headed Cowbirds in California.
jX STATUS
A. Past population trends
Grinnell and Miller (1944), P. m. melanocephalus : "Summer
resident of restricted area in central eastern section of
State; common."
P. m. maculatus: "Common generally; in some areas abundant."
B. Present population status
Small (1974), "transient and summer visitor."
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
10
Pheucticus melanocephalus (con't.)
XI LITERATURE CITED
Allen, W. I. 1930. Do Gray Squirrels destroy eggs or young
birds? Condor 32:262.
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Austin, 0. L. , Jr. (Ed.) 1968. Life histories of North Amer-
ican cardinals, grosbeaks, buntings, townees, finches,
sparrows, and allies. Part 1. Bull. U.S. Nat. Mus. No.
237.
Davis, W. B. 1933. The span of the nesting season of birds
in Butte County, California, in relation to their food.
Condor 35:151-154.
Dawson, W. L. 1923. The birds of California. South Moulton
Co. , San Francisco.
Fisk, L. H. and D. A. Steen. 1976. Additional exploiters of
nectar. Condor 78:269-271.
Gaines, D. 1974. A new look at the nesting riparian avifauna
of the Sacramento Valley, California. Western Birds 5(3):
61-80.
Gander, F. G. 1929. Notes on the food and feeding habits of
certain birds. Condor 31:250-251.
Grinnell, J. and A. H. Miller, 1944. The distribution of
the birds of California. Pacific Coast Avifauna, No. 27.
Ivor, H. R. 1943. Further studies of anting by birds. Auk
60:51-55.
Kennard, J. H. 1975. Longevity records of North American
birds. Bird-Banding 46:55-73.
Kroodsma, R. L. 1974. Species-recognition behavior of terri-
torial male Red-breasted and Black-headed Grosbeaks
(Pheucticus). Auk 91:54-64.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. Vol.
50, No. 6.
Payne, R. B. 1976. The clutch size and number of eggs of
Brown-headed Cowbirds: Effects of latitude and breeding
season. Condor 78:337-342.
*
m
11
Pheucticus melanocephalus (con't.)
Peters, J. L. 1970. Checklist of birds of the world. Vol.
13. (R. A. Paynter, Jr., ed. ) Mus. Comp. Zool., Cambridge,
Massachusetts.
Peterson, R. T. 1961. Field guide to western birds. Houghton
Mifflin Co. , Boston.
Ridgway, R. 1901. The birds of North and Middle America.
Part 1. Bull. U.S. Nat. Mus. No. 50.
Small, A. 1974. The birds of California. Macmillan Co. ,
New York.
Stoner, E. A. 1933. Some subsistence items of Western Burrow-
ing Owls. Condor 35:204.
Weston, H. G. , Jr. 1947. Breeding behavior of the Black-
headed Grosbeak. Condor 49:54-73.
^
CACTUS WREN
Campylorhynchus brunneicapillus couesi
TAXONOMY
A. Type description
AOU (1957), Campylorhynchus couesi Sharp, Cat. Birds Brit.
Mus., 6, 1881, pp. 186 (in key), 196. (Larido [=Laredo] ,
Texas)
B. Current systematic treatments
Selander (1964) discussion of relationships within the
genus Campylorhynchus.
Paynter and Vaurie (1960) recognize ten species in the
genus, seven subspecies of brunneicapillus. Pas seri formes:
Troglodytidae.
Ridgway (1904), discussion of morphological characteristics
and geographic distribution in relation to systematic
treatment.
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), Heleodytes brunneicapillus
couesi; Campylorhynchus couesi; H. b. bryanti; H. b. anthonyi;
H. b. brunneicapillus ; H. af finis .
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), Brown-headed Wren; California
Cactus Wren; Brown- capped Cactus Wren; Bryant Cactus Wren.
II DESCRIPTION
A. External morphology of adults
Dawson (1923) "Pileum and nape warm brown... the former with
dusky mesial streaks; back and scapulars, broadly, pale
grayish brown, highly varied by mesial white in streaks
and stripes, and submesial dusky; f light-feathers. . .dusky,
spotted with white and brownish on outer webs, and broadly
with white on inner webs. .., tail. . .blackish, finely and
irregularly barred with pale grayish brown; concealed webs
of lateral rectrices chiefly black, the outermost pair
black and white barred throughout; the remaining pairs with
at least a subterminal band of white; a prominent superciliary,
continued to bill, white; post-ocular area clear brown;
cheeks mingled brown and white; underparts basally white,
immaculate on chin and upper throat, tinged with pale
9
Campy lorhynchus brunneicapillus (con't.)
cinnamon on belly and crissum; the sides of throat, lower
throat, and chest heavily spotted with black. . . ; breast,
sides of belly, sides, and crissum sharply and rather finely
spotted with black." Ridgway (1904), detailed description
of adults, including plumage, soft parts, and measurements.
B. External morphology of subadult age classes
Dawson (1923), "more sparingly spotted below, especially
on chest." Ridgway (1904), "Essentially like adults, but
paler markings of upper parts less sharply defined, pale
brownish buff or dull brownish white; pileum and hindneck
duller brown; outer webs of primaries and secondaries spot-
ted with pinkish buff instead of white, and blackish spots
on throat and chest much smaller, the former almost
immaculate. "
C. Distinguishing characteristics
Interspecific - Dawson (1923), "largest of American wrens;
highly varied (white- striped) upperparts and heavily black-
spotted underparts." Selander (1964) examination of the
genus Campy lorhynchus with a comparison of brunniecapillus
with other members of the genus.
Intraspecific -
EII GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), "Southern California, southern Nevada, south-
western Utah, western and south-central Arizona, southern
New Mexico, and central Texas south to southern Baja Calif-
ornia, Michoacan, and State of Mexico." C. b. couesi:
"Resident from southern California (Santa Paula, San Fernando,
Mohave, Little Owens Lake, Argus Mountains), southern Nevada
(Charleston, Sheep and Muddy Mountains), southwestern Utah
(Beaver Dam Mountains, Toquerville) , south-central Arizona
(Salt River Valley, Globe, Dos Cabezas) , southern New Mexico
(Silver City, San Marcial, Eagle, Tularosa, Carlsbad), and
central and central Texas (Pecos, San Angelo, Lomita, San
Antonio Range, Brownsville) south to northern Baja Calif-
ornia (Ensenada, Tijuana, El Valle de la Trinidad, eastern
base of the Sierra San Pedro Martir) , northern Sonora (Puerto
Libertad, Pesquiero, 12 miles west of Magdalena) , central
Chihuahua (Chihuahua) central Coahuila (Monclova) , Nuevo
Leon (Galeana), and northern Tamaulipas (Nuevo Laredo,
Matamoros) .
f
f
Campy lorhynchus brunniecapillus ( con ' t . )
B. California distribution of the species
Grinnell and Miller (1944), "Southeastern desert area... the
Colorado and Mohave deserts, north from Mexican boundary
to Inyo and Kern counties; and also most arid parts of
westward drainage slope from San Diego County northwest
to Ventura County."
C. California desert distribution
Dawson (1923), "Lower Sonoran deserts of southern California
. . .north to southern end of Owens Valley; also locally resi-
dent in the San Diego district north to Simi." Small (1974),
"Southeastern deserts (Colorado, Mojave, Sonoran) and
suitable arid habitats north coastal to Ventura County."
Miller (1951), Colorado Desert, Mojave Desert, San Diego,
Upper Kern Basin.
D. Seasonal variations in distributions
Anderson and Anderson (1973), "territory is used for mating,
nesting, and as a feeding ground for the young, and it is
also retained as a roosting area for the remainder of the
year..., Remained. .. throughout the winter with extremely
slight shifts in territory."
V HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), "Sharply defined as arid terrain
grown to thickets, patches or tracts of cactus of the larger,
branching types, or of stiff- twigged, thorny brush or small
trees. . .provide safe refuge. .. sites for nests that are
inaccessible to terrestrial maranders. .. required food,
insects, spiders and, in season, fruits. Besides cholla
and tuna cactuses, plants that are used... are yuccas of
the arborescent kinds, catclaw, mesquite, screw-bean, iron-
wood and palo verde." Small (1974), "deserts with suitable
cacti, yuccas, and shrubs for nesting, arid coastal hill-
sides, arid interior valleys." Miller (1951), Lower Sonoran
Life Zone.
B. Altitudinal range
Grinnell and Miller (1944), "from 180 feet below sea level,
as around Sal ton Sea, Riverside, and Imperial counties, up
to 5800 feet, in Argus Mountains, Inyo County."
Campy lorhynchus brunneicapillus (con't.)
C. Home range size
Anderson and Anderson (19 73) "estimate the average size of
a territory at 4.75 acres (1.9 ha), the minimum 2.9 acres
(1.16 ha), and the maximum 6.9 acres (2.76 ha)," Santa
Rita Experimental Range, Arizona.
D. Territory requirements
Perch sites - Anderson and Anderson (1957), "The male sang
from most of the available perches in his territory, such
as creosote bushes, chollas , mesquites, roof-tops, radio
antennas, windmills, and electric power poles and wires."
Courtship and mating sites
Anderson and Anderson (19 54), "territory is used for mating,
nesting, and feeding ground for the young, and it is also
retained as a roosting area for the remainder of the year. . .
territorialism probably assisted in maintaining the pair-
band."
Nest sites - Dawson (1923), "a cylindrical mass of dried
grasses, heavily lined with feathers; placed horizontally,
with entrance at one end, and well-shaded above; in top
of cholla cactus, yucca, or at base of sahuaro branch, or,
more rarely, in mesquite, or other desert shrub." Anderson
and Anderson (1963), "The use of a covered nest that obstructs
the direct rays of the sun is of considerable advantage...
If the roof ... completely shades the nest cavity, and if the
walls are sufficiently porous to permit air circulation,
the temperature of the inside of the nest approached the
standard shade temperatures." Anderson and Anderson (19 57)
"Cholla cacti were used almost exclusively ... Nest heights...
were limited to height of the chollas. Average height...
was from four to five feet... the nest, when placed in a
dense jumping cholla, is almost always at the outer surface
of the crown, the entrance pointing outward from the cholla."
Ricklefs and Hainsworth (1969), detailed discussion of en-
vironmental temperatures of nesting Cactus Wrens. Austin
(1974), consideration of nesting success in relation to
nest orientation.
E. Special habitat requirements
Dawson (1923), "local range nearly coincident with that of
Opuntia cacti. ..and the tree yuccas."
t
0
Campy lorhynchus brunniecapillus (con't.)
F. Seasonal changes in habitat requirements
Anderson and Anderson (1963) "In the normal desert habitat,
pools of water are seldom available for any useful length
of time. . . ; Provided a steady supply of water in a bird
bath saucer. . . ; Drinking by adult wrens from this pool
became noticeable in September, increasing to a high in
December and January. . . ; Evidently the insect food obtain-
able in the winter months does not have a sufficiently
high water content to satisfy the needs of the wrens...
As the days grew warmer the insect population increased,
and the wrens seldom came to drink.
V FOOD
A. Food preferences
Woods (1932), "fruit of the cultivated 'spineless' cactus
...sweet corn." Anderson and Anderson (1973) "white flowers
of the saguaros. . .The birds probed their bills deep into the
long corollas, apparently to obtain the nectar. . .Also cap-
tured any insects trapped in it. . . ; beetles and Hymenoptera
... grasshoppers. . .bugs. .. caterpillars. .. fruit pulp and weed
seeds. "
B. Foraging areas
Grinnell and Miller (1944), "Foraging, chiefly on the ground,
extends but a few rods radially from £nest sitesj ." Anderson
and Anderson (1973), "Foraged on the ground in autumn and
winter, picking up food from the surface and from low vege-
tation within reach. . .By the time nesting was well under way,
deciduous perennial vegetation leafed out. The wrens
spent less time now on the ground, and by midsummer they
foraged frequently in the palo verde and mesquite trees,
the cholla cacti and saguaros."
C. Foraging strategies
Anderson and Anderson (1963) "obtained relief from midday
summer sun by seeking the shade of bushes and trees. In
their search for food on the ground, they visited open
spaces for only short periods of time or avoided them al-
together." Bent (1948;, "approaches a leaf or other movable
object, inserts its bill carefully under one side, and raises
it up, meanwhile peering beneath it in readiness to seize
any small creature thus revealed."
Campylorhynchus brurmeicapillus (con't.)
D. Feeding phenology ^^
Ricklefs and Hainsworth (1968a) "as temperatures throughout
the environment become progressively hotter, birds select
relatively cooler microhabitats by shifting their foraging
location, and that after the minimum temperature reaches a
critical level of stress, activity decreases. . .This change
in behavior in the absence of changes in food availability
suggests that heat stress, rather than insect activity, is
the principle determinant of the behavior. . .During the
time of greatest heat stress. . .must rely exclusively on
water obtained from its food." Anderson and Anderson
(1973) "pushed the smaller debris aside, or turned it over
with their bills to facilitate their search for food. The)''
did not dig. "
E. Energy requirements
Ricklefs (1966) "The growth curves... are sigmoid in shape
and thus the rate of growth, and hense the required input
of energy, is highest during the middle of the growing
period and tails off toward both ends. It is possible
that while the growth rate is increasing and the parents
are becoming increasingly taxed, the energy resources of
the young are directed primarily to growth, and behavior
is limited to begging and defecation." 4^
VI REPRODUCTION
A. Age at first breeding
Anderson and Anderson (1962), "New nests were started at the
average age of 116.5 days [roosting nests]."
B. Territorial behavior
Anderson and Anderson (1963), "Once established, the adult
wren remains in its chosen territory for life; it mates for
life." Anderson and Anderson (1957), "Territorial intoler-
ance began at least in January. By February. .. the area
was usually cleared of other wrens. Females were most
active in driving out other females by chasing and fighting.
The male apparently kept out other males. Singing by the
male increased as the territory was secured."
C. Courtship and mating behavior
Anderson and Anderson (1957), "Since the sexes are identical
in coloration and size, sex discrimination must be by means
of distinctive behavior. . .Females are probably attracted
to males upon hearing the song. When they meet, there is a
Campylorhynchus bnmneicapillus ( con ' t . )
threatening display by the male, including the spreading
of his wings and tail, accompanied by a growling sound.
A female also displays and then she crouches. . .Pair- forma-
tion has not been observed." Anderson and Anderson (1960),
"Courtship feeding by the male occurred three to four times
a day [during incubation by the female"]."
D. Nesting phenology
Dawson (1923), "March, April- June, two broods." Anderson
and Anderson (I960), "Incubation was performed entirely
by the female. Partial incubation began the night after
the first egg was laid; daytime incubation was irregular
until the clutch was nearly complete. . .Hatching of eggs
was spread over a period of two or three days. . .Nestlings
are fed small fresh insects from the time they are hatched.
Feeding by regurgitation was not observed. . .The first egg
of the second brood was laid in from 0 to 13 days after
the fledging of the first brood."
E. Length of incubation period
Anderson and Anderson (1960), sixteen days. Asynchronous
hatching. Hensley (1959) "lasted 17 days in two nests."
F. Length of nestling period
Anderson and Anderson (1960) "average time which the nest-
lings spent in the nest was 20.9 days... range was from 19
to 23 days." Ricklefs and Hainsworth (1968b), "The develop-
ment of homeothermy. . . was investigated over the range of
ambient temperatures prevailing in their habitat during the
nesting season. Thermogenic responses develop later and
more slowly than in other species that have shorter nestling
periods." Hensley (1959), for six of the nests ranged from
17 to 20 days."
G. Growth rates
Anderson and Anderson (1962) "Young. . .attained the average
adult weight of 38.9 grams at about the age of 38 days."
Anderson and Anderson (1961). Growth and development
(morphological and behavioral) monitored daily from age
one day to age 18 days, including weights and measurements.
"Lowest weight on day of hatching was 2.6 grams ... Growth
of wings was slow up to the 5th day, at which time, the sheaths
pierced through the skin. Then the rate increased with the
increments to sheath length until the 13th day, after which
the rate dropped again. The tail feathers maintained a
steady rate of increase." Ricklefs (1975), detailed pre-
sentation of analyses of growth including age and body
weight growth; increase in linear measurements of the body,
Campy lorhyrichus brunneicapillus (con't.)
limbs and feathers; increase in body constituents with
resulting changes in the percentage composition of the
body and its caloric density; and increase in weight of
major body components and organs and their relative growth
rates with respect to the body as a whole. Ricklefs (1966)
comparison of behavioral development of Cactus Wren and
Curve-billed Thrasher nestlings.
H. Post-breeding behavior
Anderson and Anderson (1962), "The adult shared the feeding
duties for a short while. . .When the female began incubating
her next clutch of eggs, the male took care of the brood.
Exploratory pecking occurred as soon as the wrens were
fledged. Self- feeding began at about the age of 35 days. . .
They became independent of their parents at the age of
50 days. . .Adults broke up the family bond by gradually
ignoring the begging fledglings. . .Two instances of juvenile
wrens feeding fledglings of a latter brood were observed."
Anderson and Anderson (1957) , "required a covered roosting
nest in all months of the year. . .Usually by the end of the
breeding season some of the old nests had deteriorated;
others had been relinquished to the immature birds. The
adults selected new sites and built again."
VII POPULATION PARAMETERS
A. Clutch size
Dawson (1923), "4 or 5, rarely 6." Anderson and Anderson
(1960), "Eggs were laid at a rate of one a day. . .average
eggs per clutch was 3.41. . .Maximum number of broods raised
was three."
B. Fledging success
Anderson and Anderson (1963), "fledged 82 young from 27
successful broods, with an average of 6.83 per year."
Austin (1974), "orientation of the nest entrance appears
to have an effect on its success, apparently acting at the
nestling stage." Includes figures for hatching, fledging,
nestling, and nest success in relation to nest-entrance
orientation. Ricklefs (1968), of 39 young fledged from
14 nests, only 5 were lost after three to forty days
after fledging.
C. Mortality rates per age class
Anderson and Anderson (1973) "evidently the Cactus Wren's
most dangerous period is not in the egg or as a nestling.
It occurs after fledging."
0
Campy lorhynchus brunneicapillus ( con ' t . )
D. Longevity
Anderson and Anderson (1973), "The average age of seven
males in the Kleindale Road area was 737 days; 16 females
averaged 493 days. Five... in the Saguaro National Monu-
ment area lived for at least 4 years."
E. Seasonal abundance
Anderson and Anderson (1957), "never observed in such large
numbers [flocks of 6 to 30 or more as reported by Howell
(1916). Hensley (1959), twenty- two active nests found in
the intermountain desert plains in Organ Pipe Cactus National
Monument, Arizona. Anderson and Anderson (1973), "The
population peak, which was attained in late summer, was
produced entirely by the addition of immature birds that
had been raised in the vicinity. . .The population gradually
decreased as the immature birds left or vanished, reaching
its lowest point in winter."
F. Habitat density figures
Dawson (1923), "tend to colonize in loose association of
from ten to twenty pairs." Anderson and Anderson (1973)
Santa Rita Experimental Range: "Their population density
from 1953 to 1956, excluding the extralimital territories
0 . .., varied from 8.3 to 23.3 pairs per 100 acres (40.5 ha).
The average is 13.3 pairs Saguaro National Monument: 18
to 38 pairs per 100 acres.
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Anderson and Anderson (1963), "The most dangerous predator
was the house cat. Cats, Roadrunners, and snakes were
'mobbed' and followed by the wrens until they left. Shrikes,
although apparently innocuous, were harassed whenever they
appeared." Bond (1936), "At the nest site [Falco mexicanus]
was found. .. fresh feathers (but no corresponding pellet)
of a Northern Cactus Wren." Austin, Yensen, and Tomoff
(1972), describe a number of observations of snakes preying
upon nestlings (Gopher Snakes and Whipsnakes).
B. Competition
Anderson and Anderson (1963) "Although a direct competition
for nesting sites in cholla cacti, the Inca Dove appeared
to have little difficulty in maintaining its hold in the
vicinity. . . ; While feeding on the ground, the Cactus Wren
always gave way at the approach of Curved-billed Thrasher
...both vigorously defended their own breeding nests...
0
10
Campy lorhynchus bruimeicapillus (con't.)
attack the fledgling thrashers that strayed into their
vicinity. . .Most obvious evidence of conflict was the per-
sistent destruction of the roosting nests... by the Curve-
billed Thrashers. . .Recorded approximately 200 incidents
of total or partial destruction. .. from 1932 to 1961...
Thrashers did not attack breeding nests while they were in
use. . .Never defended [roosting nests] against attack. . .Young
[Cactus Wren and Thrasher] fledged sufficiently close to-
gether to be in competition for food." Re: Passer domesticus,
"observed no competition for cholla nesting sites. . . filled
a niche within the Cactus Wren territory that was not used
by the wrens."
C. Parasitism
Anderson and Anderson (1973) "Molothrus ater, observed
occasionally in the area, did not parasitize any of the
Cactus Wren. . .nests. "
IX STATUS
A. Past population trends
Grinnell and Miller (1944) "Completely resident, .. .numbers
sufficient only very locally such as to merit term 'common'
or 'abundant.'' Range on coastal slope of southern Calif-
ornia now much restricted as compared with condition in
1880 's and 1890' s, owing to- great reduction of requisite
habitat, as also, perhaps, in part, to the attentions of
egg collectors."
B. Present population status
Small (1974), "common resident." Anderson and Anderson
(1973), "weak intraspecific intolerance permits more ter-
ritorial 'compressibility' in years of surplus individuals.
Their population density is greater, not only because their
production is greater, but because the surviving surplus
is allowed to crowd in to nest."
C. Population limiting factors
D. Environmental quality: adverse impacts
Dawson (1923), "All proper desert areas west of San Gorgonio
Pass are being threatened sharply by human invasion. . .The
Cactus Wren has receded from many parts of the San Diego-
Ventura section already." Anderson and Anderson (1973;
"destruction of the Cactus Wren's habitat proceeds at an
alarming rate in the vicinity of the every- expanding south-
western desert cities."
11
t
Campylorhynchus brunneicapillus ( con ' t . )
E. Potential for endangered status
Anderson and Anderson (1963), "will probably be able to
maintain themselves in limited numbers within the resi-
dential sections of the rapidly expanding cities of our
southwest. "
12
Campy lorhynchus brunneicapillus (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Anderson, A. H. and A. Anderson. 1957. Life history of the
cactus wren. Part I: Winter and pre-nesting behavior.
Condor 59:274-296.
Anderson, A. H. and A. Anderson. 1959. Life history of the
cactus wren. Part II: The beginning of nesting. Condor
61:186-205.
Anderson, A. H. and A. Anderson. 1960. Life history of the
cactus wren. Part III: The nesting cycle. Condor 62:351-
369.
Anderson, A. H. and A. Anderson. 1961. Life history of the
cactus wren. Part IV: Development of nestlings. Condor
63:87-94.
Anderson, A. H. and A. Anderson. 1962. Life history of the
cactus wren. Part V: From fledging to independence.
Condor 64:199-212.
Anderson, A. H. and A. Anderson. 1963. Life history of the
cactus wren. Part VI: Competition and Survival. Condor
65:29-43.
Anderson, A. H. and A. Anderson. 1973. The cactus wren.
U. of Arizona Press, Tucson.
Austin, G. T. 1974. Nesting success of the Cactus Wren in
relation to nest orientation. Condor 76:216-217.
Austin, G. T. , E. Yensen and C. S. Tomoff . 1972. Snake pre-
dation on Cactus Wren nestlings. Condor 74:492.
Bent, A. C. 1948. Life histories of North American nuthatches,
wrens, thrashers and their allies. U.S. Nat. Mus. Bull.
195.
Bond, R. M. 1936. Some observations on the food of the
Prairie Falcon. Condor 38:169-170.
Dawson, W. L. 1923. The birds of California. South Moulton
Co., San Francisco.
Grinnell, J, and A. H. Miller. 1944. The distribution of birds
of California. Pacific Coast Avifauna No. 27.
13
Campy lorhynchus brunneicapillus ( con ' t . )
Hensley, M. M. 1959. Notes on the nesting of selected species
of birds of the Sonoran Desert. Wilson Bull. 71:86-92.
Howell, A. B. 1916. Some results of a winter's observations
in Arizona. Condor 18:209-214.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. , Vol.
50, No. 6.
Peters, J. L. 1960. Checklist of birds of the world. Vol.
9. (R. A. Paynter, Jr., and C. Vaurie, eds.) Mus. Comp.
Zool. , Cambridge, Massachusetts.
Ricklefs, R. E. 1966. Behavior of young Cactus Wrens and
Curve-billed Thrashers. Wilson Bull. 78:47-56.
Ricklefs, R. E. 1968. The survival rate of juvenile Cactus
Wrens. Condor 70:388-389.
Ricklefs, R. E. 1975. Patterns of growth in birds. III.
Growth and development of the Cactus Wren. Condor 77:
34-45.
Ricklefs, R. E. and F. R. Hainsworth. 1968a. Temperature
dependent behavior of the Cactus Wren. Ecology 49(2):
227-233.
Ricklefs, R. E. and F. R. Hainsworth. 1968b. Temperature
regulation in nestling Cactus Wrens: The development of
homeothermy. Condor 70:121-127.
Ricklefs, R. E. and F. R. Hainsworth. 1969. Temperature
regulation in nestling Cactus Wrens: The nest environ-
ment. Condor 71:32-37.
Ridgway, R. 1904. The birds of North and Middle America.
Part III. Bull. U.S. Nat. Mus. No. 50.
Selander, R. K. 1964. Speciation in wrens of the genus
Campy lorhynchus . Univ. California Publ. Zool. , No. 74.
pp. 135-140.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Woods, R. S. 1932. Acquired food habits of some native birds.
Condor 34:237-240.
*
#
CALIFORNIA THRASHER
Toxo stoma redivivum
I TAXONOMY
A. Type description
Toxo stoma r. redivivum - AOU (1957) Harpes rediviva Gambel,
Proc. Acad. Nat. Sci. Philadelphia, 2, no. 10, July- Aug.
(Dec. 5) 1845, p. 264. (near Monterey, in Upper California.)
B. Current systematic treatments
Hellmayr (1934) recognized 2 races of California Thrasher,
including T. r. redivivum; range listed as "Austral Zones
of California west of the high Sierra Nevada and South-
eastern deserts, from Monterey and Placer cos. through the
San Diego district to lat. 30 in Lower California
AOU (1957) considers the California Thrasher (2 races) a
member of the avian order Passeriformes, family Mimidae.
Grinnel and Miller (1944) give 2 races of California Thrasher
in California, Sonomae (Northern California Thrasher) and
redivivum (Southern California Thrasher; Mayr and Greenway
(1960) also list sonomae and redivivum as the only 2 races.
Specimens from the interior and southern localities were
formerly recognized as T. r. pasadenenae (Dawson 1923).
Engels (1940) gives very detailed study of relationships
within Toxo stoma. He states that redivivum is most closely
related to T. lecontei and T. dorsale.
Grinnell (1921) eliminated T. r. pasadenense as a race of
California Thrasher, leaving only T. r. recLTvivum in the
southern portion of the state.
Oberholser (1918) concluded that 3 races of California
Thrasher existed: T. r. redivivum (southern California);
T. r. sonomae (nortKern and central California); and T. r.
Kelvum (Baja California) .
C. Synonomies of scientific nomenclature
Hellmayr (1934), Harpes rediviva; Harporhynchus redivivus
Pasadenensis ; Toxo stoma rediviva helva; T. recLTvivum
helvolum; T. r. redivivum. Grinnell and Miller (1944)
list the previous names, with the addition of T. redivivum
pasadenense.
Toxostoma redivivum
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), Curve-billed Thrush; California
Mocking Bird; California Thrush; Sickle-bill Thrush; Calif-
ornia Mocking Thrush; Bowbill Thrush; California Sickle-
bill Thrush; Sickle-bill Thrasher; Pasadena Thrasher.
II DESCRIPTION
A. External morphology of adults
Ridgway (1907) gives detailed account of adult and subadult
plumages; "above plain deep grayish brown, the upper tail
coverts and tail more. . .brown. " Peterson (1961), "A large
dull gray-brown thrasher, with pale cinnamon belley and
under tail coverts; tail long, bill sickle- shaped. The eye
is dark brown." Robbins et al. (1966) --"note the eye stripe
and dark brown body, pale rusty below." Oberholser (1918),
"Brown of upper parts decidedly grayish; white of throat
with little or no tinge of buffy..."
B. External morphology of subadult age classes.
Ridgway (1907) noted young were "essentially like adults
but browner above. .. sometimes only slightly different."
C. Distinguishing characteristics
Interspecific - Peterson (1961), speaking of the California
Thrasher, "This is the only thrasher of this type in Calif-
ornia west of the desert divides."
Intraspecif ic - Ridgway (1907) "Sexes alike; male: wing
102.6 mm, length 284 mm, tail 129.7 mm and female: wing
100.6 mm, length 278 mm, tail 127.2 mm." Oberholser (1918)
gives detailed analysis of male and female characteristics
of several races.
ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) gives distribution of T. redivivum as, "Northern
California south to northern Baja California. "
AOU (1957) gives distribution of T. r. redivivum as, "Resi-
dent from central California (Point Lobos, Paicines, El
Portal, San Joaquin Valley) south to southwestern California
and northwestern Baja California (El Rosario, San Fernando,
western slopes of the Sierra San Pedro Martir)."
♦
♦
Toxo stoma r. redivivum (con't.)
Ridgway (1907) gives range of T. rediviyum as, "coast and
interior valleys of California and northern Lower California;
northward to Shasta Co., southward to San Quintin Bay, San
Fernando, and San Pedro Martir Mountains."
B. California distribution of the species
Peterson (1961), "Resident in California (west of Sierra,
deserts) from head of Sacramento Valley to N. Baja Calif-
ornia." Grinnell and Miller (1944) give California range
as--"coastal district from Monterey and San Benito counties
south to Mexican boundary, including east slopes of mountains
of southern California to limits of chaparral. .. locally on
floor of San Joaquin Valley; rediyivum and sonomae inter-
grade in Amador County." Small (1974), "generally west of
the Sierra-Cascade crest and west of the deserts; north to
Humboldt and Shasta counties; breeds." Dawson (1923) gives
California range as foothills and valleys west of the Sierra
Nevada. Grinnell (1917) concluded that the range of the
California Thrasher in California is determined by a narrow
phase of conditions in the chaparral association and within
the Upper Sonoran life- zone.
C. California desert distribution
Grinnell and Miller (1944) give several desert sightings,
including: near Hesperia, San Bernardino Co. ; San Gorgonio
Pass, and near Dos Palmas. Santa Rosa Mtns. , Riverside Co.
Grinnell and Swarth (1913) called them fairly common in
the foothills near Banning and Cabezon, but were never
seen out in the brush of the lower valleys. Found breeding
near Colton, San Bernardino Co. (Willett (1953). Although
little mention was given of this species desert distribution,
it is apparently resident in the Little San Bernardino
Mountains, with records from May (Willett 1951). A sparse
population occurs on the western half of Joshua Tree National
Monument, centering in the scrub oak and manzanita thickets
of the Little San Bernardino Mtns. and extending east to
Pinyon Wells; also noted in juniper and willow thickets
of Little Morongo Canyon (Miller and Stebbins 1964). The
California Thrasher has been found nesting on the desert
side of the San Gabriel, San Bernardino, and San Jacinto
Mountains (Bent 1948). Hanna (1936) recorded a rare nesting
of this thrasher on the desert side of the San Bernardino
Mountains: on 3 May 1936 near Hesperia, San Bernardino
County. Pemberton (1916) found this species nesting near
LeConte's Thrashers near Cabezon, Riverside Co.
D. Seasonal variations in distribution
Grinnell and Miller (1944) call this species a permanent
resident throughout its range in California.
Toxo stoma r. redivivum (con't.)
IV HABITAT
A. Biotopic affinities *
Peterson (1961) reported chaparral, foothills, valley thickets,
parks, gardens, as normal habitat. Grinnell and Miller
(1944;, "Chaparral of various types; chamise, ceanothus,
baccharis and sages. .utilization of informally kept gardens
which offer cover." Small (1974), "lowland and coastal
chaparral, riparian woodland thickets." Grinnell (1908)
found the species over much of the Upper Sonoran Chaparral
belt of the San Bernardino Mtns. Grinnell (1917) concluded
that the California Thrasher is best adapted to life in the
Upper Sonoran Zone (chaparral) of California.
B. Altitudinal range
"Altitudes of occurrence from near sea level... up to 5,500
ft. in the San Bernardino Mtns. (Grinnell and Miller 1944)."
Dawson (1923), " a fairly uniform distribution up to about
6,000 ft." Seen at 4,900 ft. in the San Jacinto Mtns.
(upper limit) by Grinnell and Swarth (1913). Noted in the
scrub oak belt between 3,500 and 5,500 ft. in the San Bernar-
dino Mtns. (Grinnell 1908). Willett (1933) noted this
thrasher up to 5,000 ft. in southern California mountains.
Grinnell (1917), "While sharply delimited. . .at the upper
edge of Upper Sonoran, the California Thrasher is not so
closely restructed at the lower edge of this zone." 0
C. Home range size
Sargent (1940) found that thrashers defended a 0.75 acre
territory all year long (Los Angeles Co.).
D. Territory requirements
Perch sites - Dawson (1923), "Song requires the topmost
bough of ceanothus or scrub oak." Although it spends much
time on the ground, this bird perches on the highest bush
or tree to sing. (Martin et al. 1951). Male thrashers seen
singing from palms, radio towers, rooftops, and tall trees
by Sargent (1940) in Los Angeles County .
Courtship and mating sites - Bent (1948) states that the
top of trees and bushes are common song posts.
Nest sites - Peterson (1961), "nest a twiggy cup in a bush."
Dawson (1923), "nest. . .placed at moderate heights in bushes
or trees, or well concealed in thickets." Nests are usually
placed within a few feet of the ground, well inside a large
bush or scrubby tree, according to Bent (1948). Hanna (1936)
found a nest on the Mohave Desert (near Hesperia) 2 ft. high
in Artemisia tridentata. Grinnell (1917), 'The nests... are
located in dense masses of foliage, from 2 to 6 ft. above ^
9
0
Toxo stoma r. redivivum (con't.)
the ground, in bushes which are usually part of its typical
chaparral habitat. In onl}^ exceptional cases is the nesting
site located in ac..tree."
E. Special habitat requirements
Engels (1940) states the redivivum is rather strictly limited
to the upper Sonoran life zone; occupies the chaparrel.
Grinnell (1917), "The California Thrasher is unquestionably
delimited in its range in ultimate analysis by temperature
conditions. "
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Dawson (1923) lists beetles, ants, grubs, berries, and seeds.
Engels (1940) notes the taking of spiders, grubs, and crickets
The animal diet consists primarily of beetles, ants and
other Hymenoptera, moths and caterpillars, and spiders and
myriapods; plant food includes poison-oak, laurel sumac,
elderberry and various other berries, buckthorn, oak, wheat,
and sorghum (Martin et al. 1951). Bent (1948) states the
vegetable matter slightly exceeds animal matter in the
diet. Grinnell (1917) stated that 59% of the diet was plant
food and 41% animal food.
B. Foraging areas
Dawson (1923), "it seeks its food chiefly on the ground...
among the leaves." Engels (1940), "all species of Toxo stoma
do much of their foraging on the ground"; gives detailed
account of foraging behavior. Martin et al. (1951) also
described the usually feeding area as the ground around
manzanito and other chaparral on hill slopes. California
Thrashers, "dig and whish the bill in leaf litter and
humous layers beneath or at the edge of chaparral" (Miller
and Stebbins 1964). In a Los Angeles County study, Sargent
(1940) noted all foraging on the ground except for trips
to a balcony feeder. Grinnell (1917) stated that over
two- thirds of the foraging is done on the ground.
C. Foraging strategies
"When feeding on the ground, this species. . .holds their
tail. .. erect. . .digs with curved beak rather than scratching
with its feed (Robbins et al. 1966). "Engels (1940) states
that the feet are not used for scratching; redivivum digs
with the bill, using it like a pick, or as a tool with which
to whish litter from side to side. Bent (1948) states that
most of its animal food is obtained by raking away fallen
Toxo stoma r. redivivum (con't.)
leaves or by digging in the soil." Salt (1953) described
this thrasher as a member of the ground-insect foraging
guild in Los Angeles County. Cander (1931) notes that
"during the ten minutes or so that I watched (feeding),
it tried some 15 or 20 different spots, all within the
radius of 4 or 5 feet... the beak served... for digging in
the soft sand..." Grinnell (1917) noted that, "...the long
curved bill, is used to whish aside litter, and also to
dig..."
D. Feeding Phenology
The percentage of plant food and animal food in this species'
diet is nearly equal in winter, summer and fall; in spring,
however, animal matter accounts for 97% of the diet (Martin
et al. 1951).
E. Energy requirements
Moist food, and possibly at times berries, make unnecessary
the seeking of water... has made it possible for this thrasher
to penetrate the marginal type of chaparral of the Monument
(Joshua Tree) (Miller and Stebbins 1964). Dawson (1965)
notes that California Thrashers may loose 4.7% of their
body weight per day through evaporative water loss.
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
"Members of rival pairs faced each other bill to bill...
occasionally rising in an attack. .. chases varied from a
few feet in length to a complete circuit of the yard."
(Sargent 1940)
C. Courtship and mating behavior
"Song includes a great variety of phrases, many repeated"
(Robbins et al. 1966). The birds apparently remain paired
throughout the year (Bent 1948). Male thrashers were ob-
served singing and chasing females in November: male singing
continued all year (Sargent 1940). Lack (1942) states that
California Thrashers maintain a loose pair-bond during
winter and may thus mate for life.
D. Nesting phenology
Dawson (1923) gives season as March to June, with 1 or 2
broods raised. In southern California, breeds mainly in
March and April; set taken in December (Los Angeles County)
-
0
f
I
#
Toxo stoma r. redivivum (con't.)
(Willett 1933) . Breeding season of December to May given
for interior southern California by Wheelock (1904;. In
Los Angeles Co. , breeds mainly in March and April (Grinnell
1898) ; he also noted a set taken in January. Egg- laying
in Joshua Tree National Monument given as March and April
(Miller and Stebbins 1964). Bent (1948) gives California
egg dates as 15 December to 27 June, with the height of
the season in April. Sharp (1907) gives the breeding season
as 18 February to 13 June, with 2 or 3 broods being raised
( San Diego Co. ) .
E. Length of incubation period
Wheelock (1904) gives incubation period is 14 days; both
adults assist in incubation and feeding of young. Bent
(1948) also gives a 14 day incubation period.
F. Length of nestling period
"The young thrashers leave the nest when 12 to 14 days old,
but are fed by the adults for some time after (Bent 1948).
G. Growth rates
Wheelock (1904) summarizes general development; are fed
regurgitated food until fourth day, whole items thereafter.
H. Post-breeding behavior
First young of the year are forced out of the nesting terri-
tory by adults when a new nest rs constructed (Sargent 1940)
VII POPULATION PARAMETERS
A. Clutch size
Eggs (2-4) pale blue, speckled (Peterson 1961). Reed
(1904) gives clutch of 3-4 eggs. Dawson (1923), eggs 3
or 4. Bent (1948) cites clutch as 2-4, usually 3. In San
Bernardino County, Hanna (1936) gives an average clutch as
3.07, with 83% of all nests containing 3 eggs (range = 2-4).
B. Fledging success
In Los Angeles County, Sargent (1940) reported the fledging
of 5 young from 4 nests.
C. Mortality rates per age class
Sargent (1940) noted the taking of nestlings by house cats.
Toxostoma r. redivivum (con't.)
D. Longevity
Linsdale (1949) recaptured a California Thrasher 6 years
after it was banded in California.
E. Seasonal abundance
F. Habitat density figures
California Thrashers are most abundant in the foothill and
mesa regions of southern California (Willett 1933) . Jehl
(1978) reported a breeding population of 2 territorial males
on a 20 ha (49.42 acre) scrub oak-desert chaparral study
area in Imperial Co., California. Gaines (1975) found a
population of 3 territorial male thrashers on a 13.70 ha
study area in "serpentine chaparral" in Napa Co. , California.
Ill INTERSPECIFIC INTERACTIONS
A. Predation
Bent (1948) recounts the taking of a California Thrasher
by a Sharp- skinned Hawk. He also notes the loss of eggs
and young by skunks, banded racers, lizards, cats, and per-
haps, the Scrub Jay. House cats were the chief enemies
of this species in a study in Los Angeles County by Sargent
(1940). Allen (1943) noted the attack of a Sharp-skinned j±
Hawk on a thrasher near Berkeley in November. Edwards
(1919) describes the taking of thrasher eggs by jays in
southern California.
B. Competition
"Only the. . .LeConte' s (Thrasher) overlaps any part of this
bird's U.S. range" (Robbins et al. 1966). Bent (1948)
feels that the California Thrasher is able to drive most
other species from a food source, including the Scrub Jay.
California Thrashers were able to successfully compete with
Mockingbirds for nesting sites in a study in residential
Los Angeles County (Sargent 1940).
C. Parasitism
Friedmann (1963) does not list this thrasher as a victim
of cowbird parasitism.
IX STATUS
A. Past population trends
"Common resident below the Transition Zone in Southern Calif-
ornia" (Grinnell 1915). Earlier, Grinnell (1898) called the
species a common resident in Los Angeles County. Called, "one gp
of our common residents," by Sharp (1907) in Escondido, San
Diego Co.
Toxostoma r. redivivum (con't.)
B. Present population status
Grinnell and Miller (1944) reported them permanently resi-
dent; common under favorable conditions in many parts of
range. Small (1974) called this species a common resident
in California. Miller and Stebbins (1964) describe a resi-
dent, but sparse, population at Joshua Tree National Monu-
ment.
C. Population limiting factors
"In general, both high mountains and deserts constitute
effective barriers to its spread" (Bent 1948). Grinnell
(1917), "An explanation of this restricted distribution
(of the California Thrasher) is probably to be found in the
close adjustment of the bird... to a narrow range of environ-
mental conditions."
D. Environmental quality: adverse impacts
Grinnell and Miller (1944) note that--"informally kept
gardens. .. compensate in limited fashion for some of the
reduction in natural habitat brought about by clearing
of chaparral." Storer (1933) also felt that clearing
of chaparral had reduced needed thrasher habitat in Calif-
ornia.
E. Potential for endangered status
10
To xo stoma r. redivivum (con't.)
XI LITERATURE CITED
Allen, A. S. 1943. Additional notes on the birds of a Berkeley
hillside. Condor 45:149-157.
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bent, A. C. 1948. Life histories of North American nuthatches,
wrens, thrashers, and their allies. U.S. Nat. Mus. Bull.
195:1-475.
Davis, J. 1952. A second November nest of the California
Thrasher. Condor 54:116.
Dawson, W. L. 1923. The birds of California. Vol. 2. South
Moulton Co. , San Francisco.
Dawson, W. R. 1965. Evaporative water losses of some Australian
parrots. Auk 82:106-108.
Edwards, H. A. 1919. Losses suffered by breeding birds in
Southern California. Condor 21:65-68.
Engels, W. L. 1940. Structural adaptations in thrashers
(Mimidal: Genus Toxo stoma) with comments on interspecific
relationships. Univ. California Publ. Zool. 42:341-400.
Friedmann, H. 1963. Host relations of the parasitic cowbirds.
U.S. Nat. Mus. Bull. 233. 276 pp.
Gaines, D. A. 1975. Thirty-ninth breeding bird census. Am.
Birds 29:1129-1130.
Gander, F. F. 1931. Thrasher psychology. Condor 33:73.
Grinnell, J. 1898. Birds of the Pacific slope of Los Angeles
County. Pasadena Academy Sci. No. 11:1-52.
Grinnell, J. 1898. The biota of the San Bernardino Mountains.
Univ. California Publ. Zool. 5:1-170.
Grinnell, J. 1915. A distributional list of the birds of
California. Pacific Coast Avifauna No. 11. 217 pp.
Grinnell, J. 1917. The niche-relationships of the California
Thrasher. Auk 34:427-433.
Grinnell, J. 1921. The "Pasadena" Thrasher not a recognizable
race. Condor 23:165.
11
Toxo stoma r. redivivum (con't.)
Grinnell J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna. No. 27.
608 pp.
Grinnell, J. and H. S. Swarth. 1913. An account of the birds
and mammals of the San Jacinto area of southern California.
Univ. California Publ. Zool. 10:197-406
Hanna, W. C. 1936. California Thrasher nesting on Mohave
Desert. Condor 38:220.
Hellmayr, C. E. 1934. Catalogue of birds of the Americas
Part 7. Field Mus. Nat. Hist. Zool. Ser. Publ. 330,
Vol. 13.
Jehl, J. R. , Jr. 1978. Forty-first breeding bird census.
Am. Birds 32:105.
Lack, D. 1940. Pair- formation in birds. Condor 42:269-286.
Linsdale, J. M. 1949. Survival in birds banded at the Hastings
Reservation. Condor 51:88-96.
Martin, A. C. , H. S. Zim, and A. L. Nelson. 1951. American
wildlife and plants. McGraw-Hill Book Co. , New York.
500 pp.
Mayr, E. and J. C. Greenway, Jr. Editors. 1960. Checklist
of birds of the world. Vol. 9. Mus. Comp. Zool., Cambridge,
Mass. 506 pp.
Miller, A. H. and R. C. Stebbins. 1964. The lives of desert
animals in Joshua Tree National Monument. Univ. California
Press, Berkeley. 452 pp.
Oberholser, H. C. 1918. A revision of the races of Toxo stoma
redivivum (Gambel). Auk 35:52-61.
Pemberton, J. R. 1916. Nesting of the LeConte Thrasher.
Condor 18:219-221.
Peterson, R. T. 1961. A field guide to western birds. 2nd
Edition Houghton Mifflin Co., Boston. 366 pp.
Reed, C. A. 1904. North American birds eggs. Doubleday, Page
& Co., New York. 356 pp.
Ridgway, R. 1907. The birds of North and middle America.
Part 4. Bull. U. S. Nat. Mus. No. 50.
Robbins, C. S. , B. Bruun and H. S. Zim. 1966. Birds of North
America. Western Publ. Co., Wisconsin. 340 pp.
12
Toxostoma r. redivivum (con't.)
Salt, G. W. 1953. An ecological analysis of three California
avifaunas. Condor 55:258-273.
Sargent, G. T. 1940. Observations on the behavior of color-
banded California Thrashers. Condor 42:49-60.
Sharp, C. S. 1907. The breeding birds of Escondido. Condor
9:84-91.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Storer, T. I. 1933. Relations between man and birds in Calif-
ornia. Condor 35:55-59.
Wheelock, I. G. 1904. Birds of California. A. C. McClurg
and Co. , Chicago. 578 pp.
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna. No. 21. 204 pp.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles Co. Mus. Zool. Ser. 6:1-39.
Woods, R. S. 1939. The California Thrasher as a mimic. Condor
4i:30.
I
COMMON NIGHTHAWK
Chordeiles minor
»
•
I TAXONOMY
A. Type description
AOU (1957), Chordeiles virginianus hesperis Grinnell,
Condor 7, no. 6, Nov. 22, 1905, p. 170 (Bear Lake, 6700
feet, San Bernardino Mountains, California).
B. Current systematic treatments
Selander (1954) recognizes five subspecies, giving detailed
description of morphology and ranges (minor, hesperis,
henryi , howelli, sennetti) .
Peters (1940), recognizes four species in the genus Chordeiles,
C. minor composed of 8 subspecies (minor, hesperis, sennetti,
howelli, henryi , aserriensis, chapmani , vicmus , gundlachii) .
Caprimalgiformes: Caprimalgidae.
C. Synonomies of scientific nomenclature .
AOU (1957) Chordeiles virginianus hesperis Grinnell
D. Synonomies of vernacular nomenclature
Dawson (1923), Bull-bat. Grinnell and Miller (1944) Pacific
Virginia Nighthawk.
II DESCRIPTION
A. External morphology of adults
Peterson (1961), "slim-winged, gray or gray-brown. . .broad
white bar across pointed wing. . .male has white bar across
notched tail; white throat." Ridgway (1914) detailed des-
cription of adult, including plumage, soft parts and
measurements. Dawson (1923), "Mottled, black, gray, and
ochraceous and with white in patches; above, black pre-
dominating, especially on crown and back, mottling falling
into indistinct bars on upper tail-coverts and tail... a
large inverted V-shaped throat patch white, the chest,
in sharp contrast, chiefly black." Adult female similar
but lacking white band, possessed by male, on notched tail.
Selander (1954), in areas where night hawks necessarily
are restricted to one or a few habitats, .. .a correspondingly
narrow range of variation, while more environmentally diverse
regions are. . .able to support a wider range of color and
pattern types."
Ghordeiles minor ( con ' t . ) ^^
B. External morphology of subadult age classes ^
Ridgway (1914), "Much like the adult female but without a
wall defined (if any) white throat-patch, the chin and
throat being buffy barred or transversely spotted with
dusky- -usually, however, with more or less of an indication
of the throat-patch of adults in the form of a less heavily
spotted or barred (sometimes immaculate) buffy or whitish
A- shaped area across middle of throat; gentle cast of upper
parts decidedly paler, on account of more numerous and
smaller pale markings, the wing-coverts especially having
pale grayish or buffy grayish largely predominating, and
barring of under parts less sharply defined."
C. Distinguishing characteristics
Interspecific - Peterson (1961), larger than lesser night-
hawk. White in wing further away from tip. Flies high
in the air.
Intraspecif ic -
III GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) "Breeds from northern Washington (east of the
Cascade Mountains) and southeastern British Columbia (Trail,
Cranbrook) south to northwestern California (rarely to
Humboldt Bay) , in interior of California from the Sierra
Nevada to the San Bernardino Mountains, and through western
Montana, northwestern Wyoming (Yellowstone Park) , and Idaho
to central Nevada (Sharp) and central Utah."
B. California distribution of the species
Small (1974), "Cascades, Sierra Nevada, and in the Transi-
tion Ranges, the San Bernardino Mountains." Dawson (1923),
"Summer resident in high Transition and Boreal zones in
northern California from the Warners to the Coast, and south
through the Sierras and adjacent highlands to Tulare County.
Also in the San Bernardino Mountains.
C. California desert distribution
Miller (1951) San Bernardino region. Grinnell and Miller
(1944) San Bernardino Mountains; Lone Pine, Cottonwood
Lakes. Death Valley (Inyo County); Pasadena, Los Angeles
County.
•
♦
•
Chordeiles minor (con't.)
D. Seasonal variations in distribution
AOU (1957): "Winter range unknown; presumably in South
America. Recorded in migration in Colorado (Estes Park),
Kansas (Hamilton), New Mexico (Tres Piedras), Texas (Brown-
wood), Louisiana, Campeche, and Nicaragua." Small (1974),
"summer visitor (California) and transient, April to end
of October."
IV HABITAT
A. Biotopic affinities
Peterson (1961), "Treeless plains to mountains, open pine
woods." Small (1974), "coniferous forest of Transition and
lower Canadian Life Zones." Dawson (1923). "high Boreal
and Upper Transition zones." Miller (1951) Transition,
Canadian, and Hudsonian zones. Grinnell and Miller (1944),
"open type of coniferous forest with exposed, usually rocky
or gravelly ground for 'nest sites. ' Most frequent asso-
ciated trees: yellow pine, white fir, and lodge-pale pine."
B. Altitudinal range
Dawson (1923) "July 5, 1911, charging above over the melting
snowbanks at the Cottonwood Lakes (el. 11,000 ft.)... Dr.
Grinnell took eggs at an altitude of 9000 feet on San
Gorgorio Peak." Selander (1954) "altitudinally from tree
line down to the lower limits of the Upper Sonoran Zone."
C. Home range size
Armstrong (1965) thirteen neighboring nighthawk breeding
home ranges in the center of Detroit, Michigan included
on the average 10.4 ha total area. . .variation in home range
size seems best explained by birds settling thickly where
flat roofs are numerous. . .and by birds not settling at all
where roofs are scarce, and by home ranges next to such
unoccupied areas expanding into them and/or at the expense
of neighbors who must defend their entire boundaries.
D. Territory requirements
Perch sites - Rust (1947) "When mated, the^ male selects
a roost in a nearby tree."
Courtship and mating sites - Dawson (1923), description
of aerial courtship flight of male.
Nest sites - Dawson (1923)"... on bare ground, often among
rocks, sometimes upon a flat rock, or on the gravel roof
of a tall building. .. eggs. . .practically invisible to the
Chordeiles minor (con't.)
searching eye even though they rest upon the bare ground
or upon an exposed and lichen- covered rock ledge." Rust
(1947) "low foothills or the extreme ends of the lower ridges
or benches in opening not far from trees... on low flats
or pasture land free from dense grass or thick weed beds...
female invariably selects the nesting area."
E. Special habitat requirements
Gaccamise (1974), "feeding is generally done on or near the
territory. . .an effective means of minimizing. .. time and
energy required to travel to distant feeding sites, pro-
viding that territories with sufficiently high concentra-
tions of food were available." Cowles and Dawson (1951),
"The fact that insects are more abundant near sources of
water may serve to restrict Nighthawk populations to nearby
areas, thus indirectly limiting them to nesting sites within
flying distance to water.
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Dawson (1923), "One Nighthawk stomach under examination gave
up seventeen species of beetles at one time. Another,
nineteen entire grasshoppers. Another, parts of thirty-
eight. But if the Bullbat has a speciality, it is flying
ants." Caccamise (1974), "often one or two species of insects
made up 90-100% of the total food weight. .. flying ants often
make up a large proportion of the diet... are probably selected
over most other foods. Knowlton and Harmston (1943) "Four
stomachs were examined; one contained nine winged grasshoppers."
Blake (1941) "known to feed on termites."
B. Foraging areas
Small (1974), "forages over lakes, valleys, meadows, and
rivers." Grinnell (1944) "broad, open fly-ways, over moun-
tain meadows, lakes, larger stream courses, and lower valleys
adjacent to mountains."
C. Foraging strategies
Caccamise (1974), "opportunistic feeders, taking that food
which is most abundant and most easily captured (on the wings).
...may seek... areas where there are high concentrations of
insects..." Armstrong (1965) "active, catching flying
insects, mostly during twilight and night."
♦
Chordeiles minor ( con ' t . )
D. Feeding Phenology-
Rust (1947) "The gathering of the nesting Nighthawks from
the various nesting locations from all directions for the
evening feeding was found to be remarkably regular. . . shortly
after males leave for feeding, they are followed by incubat-
ing females, which leave their eggs for a brief period and
join the feeding group... if a large swarm of insects is
found, all the nighthawks present over the area will con-
centrate in a close group and move in small circles in a
rather slow flight. . .when insufficient food has been obtained
in the air, they will do some feeding on the ground or in
the vicinity of their nesting sites.
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Weller (1958), "the territory. .. seemed well defined and
clearly outlined by his flight pattern during the hen's
I period of incubation. . .another male frequented an adjacent
area, and some chasing occurred when either male strayed
into the other's territory."
C. Courtship and mating behavior
Dawson (1923) "After much preliminary shifting and many
emphatic bayards he suddenly casts himself head long down
the air in a great parabola of flight. As he turns sharply
and at break-neck speed, he produces a bud booming' daw-w' . "
D. Nesting phenology
Dawson (1923), June, one brood. Weller (1958), reports
that second clutches occur. "The male assumed the respon-
sibility for feeding the young of the first brood while
the female incubated the second clutch."
E. Length of incubation period
Rust (1947), 18-19 days.
F. Length of nestling period
♦
Rust (1947), young are able to move around in nesting area
after latching. "At the age of 18 days they are able to fly
short distances and can fly well at the age of 25-30 days,
although the primaries are not yet fully developed."
Chordeiles minor (con't.)
G. Growth rates
Rust (1947), measurements of primaries and total length of
young up to age 30 days.
H. Post-breeding behavior
Hansen (1950) observed flocks of up to 75 individuals from
20 initially (July through September) , discusses daily
east-west movements in mornings and evenings (Hovenweep
Nat. Monument, Colorado) ... feeding flocks, not migrants.
Rust (1947) "as soon as the young nighthawks are able to
fly well, they begin to appear among the adult birds at
feeding time... at certain times in the summer... the young
congregate in a large flock in fairly close formation and
exercise and feed just above the ground. . .adults also have
a group flight, in which they engage several evenings before
the migration flight. .. similar to that of the young but
at much greater heights."
VII POPULATION PARAMETERS
A. Clutch size
Rust (1947), mostly 2 eggs, sometimes one egg.
B. Fledging success
4
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
Grinnell and Miller (1944), "Summer resident within breeding
ranges, elsewhere detected sparingly as a transient, chiefly
in September and October."
F. Habitat density figures
Dawson (1923), "While not at any time strictly gregarious,
favorable conditions are likely to attract considerable
numbers... to a given spot... seen dozens of birds at one
time winging noiselessly. . .over the tranquil waters of an
inland lake, and on several occasions companies from one
to two hundred. .. over a well-watered pasture." Evidence
that large numbers are not limited to migration. Snyder
(1950), reports density of breeding birds in coniferous
forest in Colorado as 5 per 40 ha. (average) .
♦
Chordeiles minor (con't.)
Selander and Preece (1951), "In desert areas where trees
or other such roosting sites are not available. . .birds do
not congregate in large roosting flocks. In such regions
...feed in small groups and at sunset have been observed
to fly low over the ground and scatter before alighting
to roost for the night." Rust (1947), "four sets of eggs
or nests were found in one pasture of twenty acres; two
sets were found on a low ridge 210 yards apart and two
nests were found on a low hillside 52 yards apart."
VIII INTERSPECIFIC INTERACTIONS
A. Predation
B. Competition
Caccamise (1974), "the breadth of habitat utilization of
C. minor is decreased within the sympatric distribution
while that of C. acutipennis seems unchanged. .. the presence
of C. acutipennis precludes use of lowland habitats by C.
minor within sympatric distribution. . .C. minor spends more
time excluding C. acutipennis from its territories than
excluding members of its own species. .. the divergence in
#food niches between sexes is greater for C. minor than for
C. acutipennis." Detailed discussion of competitive re-
la tTolisT:iips~~wTth acutipennis.
C. Parasitism
IX STATUS
A. Past population trends
Grinnell and Miller (1944) "Summer resident within breeding
range; elsewhere detected sparingly as a transient, chiefly
in September and October. In metropolis, common; even
'abundant' in some favored places."
B. Present population status
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
♦
Chordeiles minor ( con ' t . )
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Armstrong, J. T. 1965. Breeding home range in the Nighthawk
and other birds. Ecology 46:619-629.
Bent, A. C. 1940. Life histories of North American cuckoos,
goatsuckers, hummingbirds and their allies. U.S. Nat.
Mus. Bull. No. 176.
Blake, C. H. 1941. Termites taken by birds. Auk 58:104.
Caccamise, D. F. 1974. Competitive relationships of the Com-
mon and Lesser Nighthawks. Condor 76:1-20.
Cowles, R. B. and W. R. Dawson. 1951. A cooling mechanism of
the Texas Nighthawk. Condor 53:19-22.
Dawson, W. L. 1923. The birds df California. Vol. II. South
Moulton Co., San Francisco.
Grinnell, J. and A. H. Miller. 1944. The distribution of
birds of California. Pacific Coast Avifauna No. 27.
Hansen, C. G. 1950. Notes on flights of the Nighthawk.
Condor 52:40-41.
Knowlton, G. F. and F. C. Harms ton. 1943. Grasshoppers and
crickets by Utah birds. Auk 60:589-591.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. 50:
531-624.
Peters, J. L. 1940. Checklist of birds of the world. Vol.
IV. Mus. Comp. Zool., Cambridge, Massachusetts.
Peterson, R. T. 1961. Field guide to western birds. Houghton
Mifflin Co., Boston. 309 pp.
Ridgway, R. 1914. The birds of North and Middle America.
Part VI. Bull. U.S. Nat. Mus. No. 50.
Rust, H. J. 1947. Migration and nesting of Nighthawks in
northern Idaho. Condor 49:177-188.
Selander, R. K. 1954. A systematic review of the booming
nighthawks of western North America. Condor 56:57-82.
Chordeiles minor (con't.)
Selander, R. K. and S. J. Preece. 1951. Cock roosts of Night-
hawks. Condor 53:302-303.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Snyder, D. P. 1950. Bird communities in the coniferous forest
biome. Condor 52:17-27.
Weller, M. W. 1958. Observation on the incubation behavior
of a common Nighthawk. Auk 75:48-59.
•
f
#
♦
DOWNY WOODPECKER
(Picoides pubescens turati)
I TAXONOMY
A. Type description
Picus turati - AOU (1957) Malherbe, Monogr. Picidees, vol.
1, 1860, P. 125 (vol. 3, pi. 29, figs. 5-7). (California
. . .non loin de Monterey = near Monterey, California.)
B. Current systematic treatments
AOU (1957) calls this species Dendrocopos pubescens turati
(Malherbe) and a subspecies of the Downy Woodpecker.
Fisher (1902) called it Dryobates pubescens turati , founded
on Picus turati of Malhebe. This species was synonymized
to Picoides by Morony, et al. (1975; after the genus
Dendrocopos recognized by Peters (1948).
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944) in describing Dryobates pubescens
turati , "Picus gardineri ; Picus gairdneri; Picus meridionalis ;
Picus turati; Dryobates turati ; Picus pubescens gairdneri,
part; Picus pubescens ; Dryobates pub"escens; Dendrocopus
pubescens; Dendrocopus gairdneri; Dryobates pubescens
oreoecus, part; Dryobates pubescens gairdneri, part.
Peters (1948), "Dendrocopos pubescens turati."
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944) in describing the Willow Downy
Woodpecker, "Gairdner Woodpecker, part; Little Georgian
Woodpecker; Downy Woodpecker; Batchelder Woodpecker; part;
Willow Woodpecker."
II DESCRIPTION
A. External morphology of adults
Peterson (1969), "Note the white back, small bill... clear
white back. .. spotted with white on wings; males with a small
red patch on back of head; females, without." Udvardy
(1977), "Black forehead, crown, and bridle across the eyes
contrast with white face, underparts, and central part of
back; wings checkered black and white. Male has red patch
on nape." Dawson (1923), reports similar to D. villosus
orius but smaller with darker underparts - reTer to that
description. Length 146-158 (5.75-6.25); tail 55 (2.165);
bill 16 (.63); tarsus 16.1 (.63).
B. External morphology of subadult age classes
Picoides pubescens turati (con't.)
C. Distinguishing characteristics
Interspecific - Peterson (1969) reports Ladder-backed Wood-
pecker has black and white striped back while Downy has a
white back. Hairy Woodpecker is a larger bird, especially
the bill. Hairy has no spots on outer tail feathers.
Robbins, Bruun, Zim (1966;, "Barred outer tail feathers
when sizable are diagnostic (they are rarely unbarred like
Hairy' s). May be mistaken for a sapsucker, whose white
stripe is on the wing, not the back." Udvardy (1977), "A
smaller version of the Hairy Woodpecker, with bill propor-
tionately shorter and more slender and with barred outer
tail feathers."
Intraspecific - Bent (1939), "Smaller than D. p_. gairdneri,
with smaller feet; underparts lighter; the elongated super-
ciliary patch and rectal stripe extending over sides of
neck, pure white, instead of smoky white of gairdneri ; tertials
always more or less spotted with white. .. differs from (D.
£. pubescens) in having much less white on the wings, tKe
coverts and tertials of pubescens being conspicuously and
often heavily marked with white."
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) in describing P. pubescens, "From southeastern
Alaska, southwestern Mackenzie, northern Alberta, central
Saskatchewan, northern Manitoba, James Bay, southern Quebec,
Anticosti Island, and Newfoundland south to southern Calif-
ornia, central Arizona, northern New Mexico, south-central
Texas, and the Gulf coast from Louisiana to Florida.
Recorded in England (Dorset, 1836; Gloucester, 1908)."
In describing P. p_. turati , "Breeds from north-central
Washington (Okanagan County) southward along the east slopes
of the Cascades through southwestern Oregon (Josephine,
Jackson, and Klamath counties), the greater part of Calif-
ornia west of the Sierra divide (except the humid coast belt
from Mendocino County northward), including the deserts,
and west-central Nevada in the valleys of the Treckee, Carson,
and Walker Rivers."
B. California distribution of the species
Grinnell and Miller (1944), "Life-zone, characteristically
Upper Sonoran, but at margins of general range. . .Transition. "
Lists numerous site and specimen records throughout the
birds' California rctnge. Small (1974), "Length of state
except eastern slope of Sierras from Lake Tahoe south and
entire eastern and southeastern desert areas." Miller
(1951) gives various California area locations. Grinnell
(1915) gives California locations, also. Dawson (1923),
»
#
♦
Picoides pubescens turati (con't.)
"resident in Upper Sonoran and Transition zones of California,
except in extreme northwestern and northeastern sections
and in the desert mountains." Mailliard (1918) found them
in Yosemite Valley.
C. California desert distribution
Small (1974) says they are NOT found in eastern and south-
eastern desert areas. Grinnell and Miller (1944) give the
life-zone as "characteristically Upper Sonoran." Grinnell
(1902), "Breeds chiefly in Upper Sonoran zone west of the
Sierran divide, except in the extreme northwest humid coast
belt." Various sites are given. Willett (1933) also gives
locations.
D. Seasonal variations in distribution
Grinnell (1915) reported it as being characteristically
associated with willow growths of the valleys in breeding
season. Also, that there is a more widely distributed
winter population, locally. Grinnell (1902) also reported
it as breeding chiefly in Upper Sonoran west of the Sierras.
Dawson (1923), "...in winter it may make. .. excursions into
the desert."
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), "Markedly restricted to riparian
soft-woods, willow and cottonwood. . .Thus the lowland stream-
bottoms constitute the main theaters of activity. . .Possibly,
available water is a factor for presence. But there is some
invasion of the oak belts, locally, even of tracts of coni-
fers; and deciduous orchard trees, notably apple, satisfy
the birds' needs." Small (1974), "Riparian woodlands."
Miller (1951) found them in Lower Sonoran and Transition
zones and in coastal forest. Bent (1939), "Downy Woodpeckers
were seen most often close to streams and in orchards. '
Peterson (1969), "Broken or mixed forest, woods, willows,
poplars, river groves, orchards, shade trees." Robbins,
Bruun, Zim (1966), "Seen in suburbs, orchards, shade trees,
and woods." Udvardy (1977), "Broken or mixed forests; often
found in conifers but feeds and nests chiefly in young
deciduous trees. Also frequents orchards, city parks, and
suburban areas." Dawson (1923), "...chiefly confined to
deciduous timber, and shows a great preference for wooded
bottoms and the borders of streams. Willow trees are every-
where its most natural associations." Bendire (1895), "It
is partial to rather open and cultivated country, inter-
spersed here and there with small woods and orchards; and
to scattering trees and shrubbery of river and creek bottoms,
Picoides pubescens turati (con't.)
the shade trees along country roads, and along the edges
of clearings. . .it does not seem to care for burnt tracts."
B. Altitudinal range
Grinnell and Miller (1944) give altitudes of nesting from
near sea level to 6,100 feet.
C. Home range size
D. Territory requirements
Perch sites - Bendire (1895), "In winter, they dig shallower
excavations in dead trees, old stumps, or fence posts in
some sheltered situation, in which they spend the nights,
and to which they retire in stormy weather."
Courtship and mating sites - Bendire (1895) reported that
males drum on resonant dry limbs to attract females.
Nest sites - Grinnell and Miller (1944), "Markedly restricted
to riparian soft-woods, willow and cottonwood. . . some inva-
sion of oak belts. .. tracts of conifers, and deciduous orchard
trees, notably apple. . .Branches of boles of these trees
must be far advanced in decay to be excavatable for nest or
shelter purposes." Small (1974), ". . .nest. . .on the trunks
...of small trees." Grinnell (1915) reported them as being
associated with willow growths in the breeding season.
Peterson (1969), "In hole in tree." Udvardy (1977), "...
nests chiefly in young deciduous trees... in a hole in a
dead tree." Dawson (1923), "A hole excavated by the birds
in tree, usually deciduous, as willow, cottonwood, alder,
and the like; at moderate heights." Bendire (1895) reported
nest at 4-20 feet from ground and usually no higher. Prefers
apple, cherry, pear oak, maple poplar, alder, linden, ash,
willow and magnolia, especially in dead limbs.
E. Special habitat requirements
Grinnell and Miller (1944), "possibly, available water is
a factor for presence." Bendire (1895), "Its breeding
sites seem to be confined to deciduous trees, preferably
dead ones, or old stumps." Ligon (1970) reports that they
need standing dead timber to breed.
F. Seasonal changes in habitat requirements
Grinnell (1915) reported them as being associated with willow
growths during breeding. Dawson (1923) reported that areas
of increased insect density were required to feed the young
birds during nestling season since the adults do not have a
large foraging range then.
t
0
Picoides pubescens turati (con't.)
V FOOD
A. Food preferences
Bendire (1895) reported that the food was similar to the
Downy Woodpecker's diet, i.e., larvae and eggs of insects,
occasionally berries and seeds. He also reported that
they eat ants and spiders and raw meat.
B. Foraging areas
Small (1974), "Forage. . .on the trunks... of small trees."
In Bent (1939), "Their forage places included the limbs
or small trunks of willow, alder, cottonwood, sycamore,
valley oak, blue oak, digger pine, and yellow pine trees."
Udvardy (1977), ".. .feeds. . .chief ly in young deciduous
trees. ' Dawson (1923), "Foraging expeditions are regularly
undertaken into neighboring groves of live oak or pine,
and... to apple orchards."
C. Foraging strategies
Udvardy (1977), "...the male is larger than the female and
has a longer, stronger bill and chisels deep into wood,
whereas the female pries under the bark with her shorter
bill. Thus, a pair shares the food resource without com-
peting with one another." Bendire (1895), "It begins near
the roots and carefully scans every cranny as it hops along,
looking now at one side and then on the other." Kisiel
(1972) discusses how Hairy and Downy Woodpeckers divide
the resources by feeding on different species of trees.
D. Feeding phenology
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Bendire (1895), "Each pair of birds lay claim to a certain
range, and intruders on this are driven away." Kilham (1962)
describes defense of territories against others of the same
species.
t
Picoides pubescens turati (con't.)
C. Courtship and mating behavior
Bendire (1895) reported that males drum on limbs and
attract females. Both sexes build nest and care for young.
Kilham (1962) also described drummings and tapping as well
as displays used in courtship. Both sexes take part in
nest building and incubation. He also describes preening
and other courtship-related activities (1972), as well
as saying they maintain year-round pair bonds.
D. Nesting phenology
Willett (1933) reported breeding to start in April and
May. Dawson (1923), "Nesting - April-May; one brood.
Young are hatched some time in May." Bendire (1895) reports
nesting starts in mid-April in southern California.
E. Length of incubation period
Dawson (1923), "12 days." Bendire (1895), "about 12 days."
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
Dawson (1923), "One brood." Bendire (1895) reported one
brood, normally. Young are also cared for after they leave
the nest.
VII POPULATION PARAMETERS
A. Clutch size
Willett (1933) reports 5 and 7 egg clutches. Bent (1939)
reports 3-6 eggs, more commonly 4 or 5, sometimes 7.
Peterson (1969; reports 4-7, as does Udvardy (1977).
Dawson (1923) reports 4 or 5, 7 of record. Bendire (1895),
"Four or five eggs... one laid daily."
B. Fledging success
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
Neff (1928) describes them as being more abundant within a
given area in winter than in summer, presumably because they
tend to associate only in pairs in the other seasons.
»
Picoides pubescens turati (con't.)
F. Habitat density figures
Koplin (1969) reports that density changes as the amount
of prey items change due to fire and floods. E.g., there
is a fifty-fold increase in response to insect increase
after a fire. Short (1971) states that these birds need
smaller territories than Hairy Woodpeckers, and thus have
denser populations.
VIII INTERSPECIFIC INTERACTIONS
A. Predation
B. Competition
Ligon (1973) reports competition for food with White-headed
Woodpeckers in Idaho, and (1970) competition for nesting
sites with the Red-cockaded Woodpeckers.
C. Parasitism
IX STATUS
A. Past population trends
w
Grinnell (1902) reported this species as a "common resident
in suitable localities almost throughout the State," and
(1915) as a "common resident locally, chiefly in Upper
Sonoran Zone west of the Sierran divide except in the ex-
treme northwest humid coast belt." Willett (1933) reported
it as a common resident in willow regions of lower country.
B. Present population status
Grinnell and Miller (1944) reported it as permanently resi-
dent. Locally common with about normal marginal vagrancy
in autumn. Small (1974) reported it as a resident. Ligon
(1970) feels that there are more of this species in open
pinelands now than previously.
C. Population limiting factors
Grinnell and Miller (1944) and Ligon (1970) both report
that if diggable wood (especially standing dead timber)
is reduced, so is the bird population.
t
D. Environmental quality: adverse impacts
Grinnell and Miller (1944), "Repeatedly, elimination of all
such diggable wood is a given neighborhood has been observed
to be followed by disappearance of the birds." Ligon (1970)
reports that they need dead standing timber to breed, and re-
peated fired reduce this.
Picoides pubescens turati (con't.)
E. Potential for endangered status
•
Picoides pubescens (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957." Checklist of North
American Birds. 5th Edition. American Ornithologists'
Union. The Lord Baltimore Press, Inc. Baltimore, Mary-
land. 691 pp.
Bendire, C. 1895. Life histories of North American birds.
Volume 2. Smithsonian Contributions to Knowledge #985.
Smithsonian Institution. Washington, D.C. 518 pp.
Bent, A. C. 1939. Life histories of North American Wood-
peckers. Smithsonian Institution. United States National
Museum Bulletin #174. U.S. Gov't. Printing Office, Wash-
ington. 334 pp.
Dawson, W. L. 1923. The birds of California. Volume Two.
South Moulton Company. San Diego. 1432 pp.
Fisher, W. K. 1902. The Downy Woodpeckers of California.
The Condor. 4(3): 68-70.
Grinnell, J. 1902. Checklist of California birds. Pacific
Coast Avifauna #3. Cooper Ornithological Club. Santa
Clara, California. 98 pp.
Grinnell, J. 1915. A distributional list of the birds of
California. Pacific Coast Avifauna #11. Cooper Ornith-
ological Club. Hollywood, California. 217 pp.
Grinnell, J. and A. H. Miller. 1944. The distribution of
the birds of California. Pacific Coast Avifauna Number
27. Cooper Ornithological Club. Berkeley, California.
608 pp.
Kilham, L. 1962. Reproductive behavior of Downy Woodpeckers.
Condor 64:126-133.
Kisiel, D. S. 1972. Foraging behavior of Dendrocopos villosus
and D. pubescens in Eastern New York State. Condor 74:
393-399.
Koplin, J. R. 1969. The numerical response of woodpeckers
to insect prey in a subalpine forest in Colorado. Condor
71:436-438.
Ligon, J. D. 1970. Behavior and breeding biology of the Red-
cockaded Woodpecker. Auk 87:255-278.
Ligon, J. D. 1973. Foraging behavior of the White-headed
woodpecker in Idaho. Condor 90:862-869.
10
Picoides pubescens (con't.)
Mailliard, J. 1918. Early autumn birds in Yosemite Valley.
Condor 20:11-19.
Miller, A. 1951. An analysis of the distribution of the birds
of California. University of California Publications in
Zoology. Vol. 50, #6, pp. 531-644.
Morony, J. J. Jr., W. J. Bock, J. Farrand, Jr. 1975. Reference
list of the birds of the world. The American Museum of
Natural History, New York. 207 pp.
Neff, J. A. 1928. A study of the economic status of the common
woodpeckers in relation to Oregon Horticulture. Free Press
Print, Marionville, Mo. 68 pp.
Peters, J. L. 1948. Checklist of birds of the world. Vol.
VI. Harvard University Press, Cambridge. 259 pp.
Peterson, R. T. 1969. A field guide to western birds.
Houghton Mifflin Company. Boston. 366 pp.
Ridgway, R. 1914. The birds of North and Middle America.
Part VI. Bull, of the U.S. Nat'l. Museum. Gov't. Print-
ing Office. Washington, D.C. 882 pp.
Robbins, C. S. , B. Bruun, H. S. Zim. 1966. Birds of North
America. Western Publishing Company, Inc. Racins, Wiscon-
sin. 340 pp.
Short, L. L. 1971. Systematics and b avior of some North
American woodpeckers, Genus Picoides (Aves) . Bull, of
the Am. Mus. of Nat'l. Hist. vol. 145: Article 1, pp. 1-118.
Small, A. 1974. The birds of California. Winchester Press.
New York. 310 pp.
Udvardy, M. D. F. 1977. The Audubon Society Field Guide to
North American Birds. Alfred A. Knopf, Inc. New York.
855 pp.
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna #21. Cooper Ornitholo-
gical Club, Los Angeles, California. 204 pp.
t
0
$
FOX SPARROW
Passerella iliaca
I TAXONOMY
A. Type description
AOU (1957), Passerella iliaca: Passerella Swainson, Nat.
Hist. Class. Birds, vol. 2, July 1, 183/, p. 288. Type
by monotypy, Frinqilla iliaca Merrem.
Passerella iliaca zaboria Oberholser, Journ. Washington
Acad. Sci., Jb, no. 11, Nov. 15, 1946, p. 388. (Circle,
Alaska. )
P. i. sinuosa Grinnell, Univ. California Publ. Zool., 5,
no. 12, Mar. 5, 1910, p. 405. (Drier Bay, Knight Island,
Prince William Sound, Alaska.)
P. i. schistacea described as, P. schistacea Baird, in
B"aird, Cassin, and Lawrence, Rep. Expl. and Surv. R. R.
Pac, vol. 9, 1858, pp. xl, 488, 490. (Head of the Platte =
South fork of Platte River, about 25 miles east of the
northeastern corner of Colorado, in Nebraska.)
P. :L. canescens Swarth, Proc. Biol. Soc. Washington, 31,
no. 40 . , Dec . 30 , 1918, p. 163. (Wyman Creek at 8250 feet
altitude, east slope of White Mts., Inyo County, California.)
P. i. megarhyncha described as, P. megarhyncha Baird, Cassin
and Lawrence, Rep. Expl. and Surv. R.R. Pac. , vol. 9. 1858,
pp. xl, 925. (Fort Tejon, [Kern County, California].)
P. i. monoensis J. Grinnell and T. I. Storer, Condor, 19,
no. 5, Sept. 25, 1917, p. 165. (Mono Lake Post Office,
altitude 6500 feet, Mono County, California.)
P. i. stephensi Anthony, Auk, 12, no. 4, Oct. 1895, p. 348.
"CJTahquitz ValleyJ San Jacinto Mts., California.)
B. Current systematic treatments
AOU (1957) places the species P. iliaca in the Order Passeri-
formes, Family Frinqillidae, Subfamily Emberizinae, with 18
subspecies. Mayr and Short (1970): "The Fox Sparrow is
highly variable. Its variation has been treated by Linsdale
(1928a, b), by Oberholser (1946), and by Behle and Selander
(1951). Distinctive races include the insular unalaschensis
and insularis, as well as various continental races. The
Fox Sparrow seems closely related to P. melodia." Martin
(1977) discusses Fox Sparrow relationships to other emberizids
according to song. Linsdale (1928) suggests that Passerella
and Melospiza properly belong in the same genus, as does
Paynter (,1964) while Parkes (1954) maintains they should
be separate.
Passerella iliaca (con't.)
C. Synonomies of scientific nomenclature
AOU (1957) lists the two synonomies as above. Grinnell and
Miller (1944): for sinuosa, P. i. townsendi, part; P. i.
unalaschensis, part; P. i. insuTaris, part; P. ^L. meruToides,
part; for me g" ar hync hu s , P. schistacea, part; P. townsendi
var. megarhynchus , part; P. schistacea var. megarhynchus ,'
part; P. i. mariposae; P. i. monoensis, parti for cane sc ens,
P. _i. schistacea: for stepKensi, P. schistacea, part; P.
townsendi var. schistacea, part;_F. townsendi var.
megarhyncha, part; P. megarhyncha, part; P. stephensi, part:
ana for several others they say, "Inability to verify racial
identity of many early records of Fox Sparrows renders a
complete listing of names futile."
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), sinuosa: "Oregon Finch, Townsend
Sparrow, Shumagin Fox Sparrow, Kodial Fox Sparrow, Yakutat
Fox Sparrow." Schistacea, monoensis, "Inability to verify
racial identity. . . " Megarhynchus : "Large-beaked Sparrow,
Slate-colored Sparrow~ Thick-billed Sparrow, Thick-billed
Fox Sparrow, Yosemite Fox Sparrow, Mono Fox Sparrow."
Canescens: "Slate-colored Fox Sparrow, Inyo Fox Sparrow,
StepheniT: "Slate-colored Sparrow, Thick-billed Sparrow, ^k
Stephens ' Sparrow."
II DESCRIPTION
A. External morphology of adults
Dawson (1923), P. _i. sinuosa, "Similar to P. I. insularis,
but still darker (as compared with unalascKensis) and less
rufescent." P. i. schistacea, "Somewhat similar to P. _i.
_i. but rufous spots somewhat smaller with tail longer -
nearly equal to wing; rufous element in plumage greatly
reduced; pattern of upper plumage entirely blended; streaking
of underparts about equal in quantity but slightly dusky
or brownish instead of red. Color of upperparts, brownish
gray; more rufuscent, dull cinnamon brown, in upper-tail
coverts and exposed surfaces of wings and tail; below white,
sharply streaked, especially on the chest and sides with
spots of dark brown; streaks tend to confluence on sides
of throat; those of the sides are prolonged and enlarged
posteriorly. Bill slightly smaller and darker, feet darker
than iliaca. " "P. i, canescens, "From schistacea, canescens
may be dit terentTated by ics decidedly more grayish colora-
tion. A dubious candidate for nomenclatural recognition,
albeit the tendency toward grayishness does exist." P. _i.
monoensis, "Similar to P. i. schistacea, but slightly grayer
and with much stouter bill - comparable in this regard to ^^
Passerella iliaca (con't.)
P. i_. fauva, which is a much browner bird. Monoensis is
possibly the lightest of the recognizable forms of iliaca.
' The affinities of monoensis are with mariposae, and it pro-
bably does not deserve nomenclatural distinction from it."
P. i. stephensi, "Similar to P. i^. mariposae in coloration,
"But size averaging slightly larger and bill at maximum of
development, relatively enormous.
Bent (1968) in a description of the western mountain sub-
species of P. iliaca says, "In these nine races the tail
is at least (rarely)" equal to and usually longer than the
wing. Grays predominate in their coloration, increasingly
so from north to south, and the rather pale uniform gray
head and back contrasts with the dull reddish-brown wings
and tail. The spots and streaks of the underparts are
dull. The bill is large and somewhat swollen, increasingly
so from east to west in the California forms. ' Baird et al .
(1905): "General aspect of upper parts foxy-red the ground-
color and the sides of the neck being ashy; the interscapular
feathers each with a large blotch of fox-red; this color
glossing the top of the head and nape; sometimes faintly,
sometimes distinctly; the rump unmarked; the upper coverts
and surface of the tail continuous fox-red. Two narrow
white bands on the wing. Beneath with under- tail coverts
and auxillars, clear white, the sides of the head and throat,
the jugubum, breast, and sides of body, conspicuously
blotched with fox-red. Sometimes the entire head above is
continuously reddish."
B. External morphology of subadult age classes
C. Distinguishing characteristics
Interspecific - Robbins et al. (1966) comments that Western
Fox Sparrows are deeper brown or gray-brown than eastern
races. Peterson (1961): "The many races can be divided
into three types: (1) bright rusty Fox Sparrows; (2) dark-
brown headed with darker bills; (3) gray-headed with large
yellowish bills. The only race identified readily is the
Yukon Fox Sparrow (zaboria) ." Ridgway (1915) provides a
key to some of the races. ' Phillips et al . (1964) state that
the study of the variation of the races has been thrown off
track by failure of investigators to take into account
seasonal wear, which causes color variations. Wolf son (1955)
mentions Linsdale's study (1928) in which individual varia-
tion in bone size was found to be slight when compared to
geographic variation. Gabrielson and Jewett (1940) state
that trying to identify races in the field is hopeless due
to the variation, and close relation of subspecies.
Passerella iliaca (con't.)
Intraspecific - Robbins et al. (1966): "This may be confused
with Hermit Thrush except for the yellow lower mandible and
slightly notched tail." Peterson (1961): "Larger than the
House Sparrow. Hermit Thrush has a similar reddish tail,
but is thin-billed and spotted rather than stripped."
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) Passerella iliaca: "Northern Alaska, northwestern
and central eastern Mackenzie, northern Manitoba, northern
Ontario, northern Quebec, and northern Labrador south on
the Pacific coast to northwestern Washington; in the moun-
tains to southern California, central Nevada, central Utah,
and central Colorado; and to central Alberta, central
Saskatchewan, southern Manitoba, central Ontario, southern
Quebec, and Newfoundland."
P. i. zaboria: "Breeds from northwestern and interior Alaska,
northern Yukon, northwestern and central eastern Mackenzie,
and northern Manitoba south to northern British Columbia,
central Alberta, and central Saskatchewan, and southern
Manitoba."
P. i. sinuosa: "Breeds in the Kenai Peninsula and Prince
William Sound districts (25 miles north of Valdez, Cordova)
and on Middleton Island, south central Alaska."
P. i_. schistacea: "Breeds from southeastern British Columbia
and southwestern Alberta south through the mountains of
northern Idaho, north-central and eastern Oregon, and western
Montana, to north-central and northeastern Nevada, south-
western Wyoming, and central Colorado."
P. _i. canescens: "Breeds in central Nevada and extreme
central eastern California (White Mountains).
P. i. megarhyncha: "Breeds in mountains from southwestern
Uregon south through central and northern California and
the Sierra Nevada of California to lat. 37° N. ; locally to
west-central Nevada in the Tahoe district."
P. i. monoensis : "Breeds in the Mono district on the east
"Flank of the central Sierra Nevada in California; locally
in adjoining Mineral County, Nevada."
P. i. Stephen si : "Breeds in the southern Sierra Nevada of
"CalTfornia ana in the high mountains in southern California
(Mount Pinos, San Gabriel, San Bernardino, and San Jacinto
mountains. "
f
#
Passerella iliaca (con't.)
Phillips et al. (1964): "Fox Sparrows nest clear across the
northern part of the continent and extend southward in the
west to the Rockies of Colorado and Utah and to the high
mountains of southern California." They consider P. i^.
zaboria an eastern bird due to tail size and coloration,
but list Alaska as its breeding range. P. i^. schistacea
is the only race regularly occurring in Arizona. Banks
(1970) lists three subspceies that nest in Oregon; megarhyncha,
fulva and schistacea. He reported megarhyncha and fulva
both breeding in one locality. Gabriel son and Jewett (1940)
list these races for Oregon; altivagans, unalaschcensis ,
insularis, sinuosa, annectens, townsendi, fuliginosa, "
schi s tac ea , ""rul va , mariposae.
B. California distribution of the species
Small, (1974) lists P. iliaca as breeding in Klamath Moun-
tains, Cascades, Warner Mountains, Sierra Nevada, northern
inner Coast Range, higher Basin and Ranges Mountains, Mount
Pinos in Ventura County, Transverse and Peninsular Ranges
to Mount San Jacinto, Riverside County.
Grinnell and Miller (1944): P. i^. sinuosa, "In winter, all
sections of the state except areas east of Sierran brushlands;
not yet reported in mid-winter from northern humid coastal
strip; found in migration in northeastern plateau district."
P. i. megarhynchus , "As breeding, Siskiyou Mountains, southern
Cascade range, and Sierra Nevada south to Kings River Canyon,
Fresno County, and Kearsarge Pass, Inyo County, but exclu-
sive of Mono Lake Basin. Summer residents of Trinity Alps
of northern Trinity County and southern Siskiyou County
and of Siskiyou Mountains are, so far as known in varying
degree intermediate toward P. jL. brevicauda. In winter
chiefly southern districts west of deserts, from Tehachapi
Mountains southward; extends to Santa Cruz and Santa Catalina
islands; also occurs commonly northward as far as Shasta
County, but not east of Sierra Nevada nor in humid coastal
belt north of Marin County." P. i. schistacea, "In winter
chiefly southern California west of deserts, But also sparsely
north along Sierra Foothills to Tehana County; recorded like-
wise from San Francisco Bay region. Migrates along Sierra
Nevada and through Modoc and Inyo regions." P. i. monoensis,
"Breeds along eastern flank of Sierra Nevada, extending from
northern Alpine County south through Mono County to southern
rim of Mono Lake Basin. In winter, known from vicinity of
Coulterville, Mariposa County, in western foothills of the
Sierra and from scattered localities in coastal southern
California, including Santa Catalina and San Clemente Islands."
P. _i. canescens, "As breeding, White Mountains of Mono and
Tnyo Counties, from 8000 fo 9000 feet. In winter, known from
Santa Barbara and Los Angeles counties; once recorded from
the Colorado River valley." P. i. stephensi, "As breeding,
Passerella iliaca (con't.)
Pacific drainage of southern Sierra Nevada from southern
Fresno County, south of Kings River, south through Tulare
County; Mount Pinos in Kern and Ventura counties; and San
Gabriel, San Bernardino and San Jacinto Mountains. In
winter, detected occasionally in Santa Barbara and Los
Angeles Counties in foothills and lower mountains."
Dawson (1923): P. i. sinuosa, "Winter resident, apparently
well distributed, But no records from southeastern portion
of the state." P. i. schistacea, "Scattered records of occur-
rence in fall aricl winter in interior and southern California
await differentiation from those attributable to P. i. fulva."
P. i. megarhyncha, "Winters commonly in the San DTegan dis-
trict north to Fort Tejon, Kern County, and west to Santa
Barbara." P. i. canescens, "Breeds in the White Mountains of
California. Winter range undefined." P. i. monoensis,
"Breeds in high transition in Mono Lake region. Winter
range unknown." P. i. stephensi, "Breeds in the higher
mountains of soutHern California from about latitude 36° in
the Sierras. Winter range unknown, presumably the mountains
of Lower California."
Grinnell (1928) discusses the distribution of the races in
lower California.
C. California desert distribution
Grinnell and Miller (1944): P. i. sinuosa, does not breed.
In winter reported in Kern County, Los Angeles County, San
Bernardino County, Riverside Valley in San Jacinto Mountains,
Riverside County. P. i. schistacea, migrant and winter
visitant. Reported in Kern, Los Angeles, San Bernardino,
San Diego, Inyo and Riverside Counites. P. i. megarhynchus ,
breeds in Inyo County. Winter records from Kern, Los Angeles ,
Riverside, San Diego and San Bernardino Counties. P. i.
monoensis, does not breed in the desert. Winter records
from Los Angeles, Inyo, Riverside Counties. P. i^. stephensi
breeds mostly to the north in California. Winter records
from Los Angeles and Kern Counties.
Willett (1951) does not list Fox Sparrows in this publication
on the birds of the southern California deserts.
D. Seasonal variations in distribution
AOU (1957), P. i. zaboria, "Winters chiefly east of the Great
Plains from eastern Kansas and southern Iowa south to southern
Texas, Louisiana, Mississippi, Alabama, and northern Georgia;
rarely west to Washington, central and southern California,
southern Arizona and Colorado." P. i_. schistacea, "Winters
from northern interior California, central Arizona and north-
ern New Mexico south through southern California to northern
t
Passerella iliaca (con't.)
Baja California, southern Arizona and western Texas." P.
i_. sinuosa, "Winters from southwestern British Columbia
south through western Washington, western Oregon and Cal-
ifornia to northwestern Baja California." P. ±. canescens,
"Winters in southern California, northern Baja California,
and southern Arizona." P. i_. megarhyncha, "Winters in low-
lands of central and southern California and northwestern
Baja California." P. i^. monoensis, "Winters in central
interior and southern coastal California and northwestern
Baja California." P. i. stephensi, "Winters at lower eleva-
tions in southern California. "
Stewart et al . (1974) did a study on age ratios of migrating
Fox Sparrows in central California.
IV HABITAT
A. Biotopic affinities
Bent et al. (1968), "schistacea seems to prefer willows and
rose thickets along the streams in more open country, but
in general most abundant close to the foothills of the moun-
tains," in Oregon. In Montana the same race prefers "the
thickest and most impenetrable willow thickets in the
valleys. In northern Nevada. . .common in the Transition
Zone, especially on rocky slopes..." megarhynchus inhabits
"tracts of Ceanothus cordulatus and manzanita, either in. . .
large brush fields or in large clumps... in broken forest.
To less extent. . .aspen thickets and stream side willow and
alder tangles in the mountains..." Monoensis " prefers
brush composed of Manzanita and ceanothus . . . stream side thickets
of willow and wildrose and low aspen scrub with associated
forbs about springs and meadows." Stephessi "occupies in
summer, chin apin and ceanothus brush; less commonly
brakes, willow thickets, and gooseberry brushes about moun-
tain streams and spring." Grinnell and Miller (1944);
sinuosa, "wide variety of chaparral cover or underbush of
forest and woodland, but preference is shown for in land
areas, and hence the. . .birds occupy semi-arid chaparral of
lower Mountain slopes." Schistacea, "inland chaparral,
prevailingly of somewhat arid character as with other races
that winter in the interior." Megarhynchus , "tracts of
ceanothus cordulatus and manzanita. . .aspen thickets and
streamside willow and alder tangles in the mountains."
monoensis, "in summer brush composed of manzanita and ceanothus
...streamside thickets of willows and wild rose and low aspen
scrub. . .about springs and wet meadows." Canescens, "thickets
of aspens and birches, with dense ground cover of rose,
gooseberry or alder, along streams..." Stephensi, "in summer,
chinquapin and ceanothus brush; less commonly brakes, willow
| thickets and gooseberry about mountain streams and springs."
Passerella iliaca (con't.)
B. Altitudinal range
• Bent et al. (1968), canescens - above 8,000 feet. Schistacea
- breeds in lowlands and at higher altitudes.
C. Home range size
D. Territory requirements
Perch sites -
Courtship and mating sites -
Nest sites - Bent et al. (1968), "Nest locations are either
above ground in the rugged, thorny bushes or sunk in the
ground at their bases. Schistacea "prefers to nest in
willow thickets, next in dense wild rose bushes. . .Their
nests are generally placed some little distance above ground,
rarely. . .greater than 3 feet, and are invariably well hidden."
Megarhyncha nests were found on the ground near Lake Tahoe
and some were 2-3 feet up in Ceanothus bushes.
E. Special habitat requirements
Oberholser (1974) describes one essential condition for Fox
Sparrow breeding; a good supply of dense shrubs for cover.
Southwestern racer often find this in Ceanothus.
F. Seasonal changes in habitat requirements
Peterson (1961): "In winter, woodland under growth, chaparral,
parks, gardens." Oberholser (1974) reports Fox Sparrows
to inhabit wooded bottomlands along rivers and creeks after
migrating south in the fall.
V FOOD
A. Food preferences
Bent et al . (1968) refer to all races eating insects.
Gabrielson and Jewett (1940) write that Fox Sparrows feed
largely on seeds. Oberholser (1974) lists food items as:
ragweed, smartweed, and other seeds, and berries.
B. Foraging areas
Bent et al . (1968) states that a requirement of all Fox
Sparrows is leaf litter in which to forage. Gabrielson and
Jewett (1940): "They feed largely on the ground."
*
^ Passerella iliaca (con't.)
C. Foraging strategies
Robbins et al. (1966): "It feeds by scratching, towhee-
fashion, with both feet." Gabrielson and Jewett (1940)
write that they feed by scratching vigorously on the ground
to uncover seeds.
D. Feeding phenology
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Martin (1977) states that song appears to function more as
a distant threat. Close threats consisted of "chirping
calls" and posturing, followed by vigorous winging after
the intruder is driven away.
t
C. Courtship and mating behavior
Martin (1977) describes males as being extremely vociferous
and singing throughout spring and summer. Females may, at
times, produce song but softer and more imcomplete. The
messages encoded in the songs are believed to be sex, location,
possession of territory, aggressive and sexual, individual
identity.
D. Nesting phenology
E. Length of incubation period
Bent et al. (1968), schistacea - 12 to 14 days.
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
VII POPULATION PARAMETERS
A. Clutch size
Peterson (1961) - 4 to 5. Gabrielson and Jewett (1940) -
3 to 4.
A B. Fledging success
10
Passerella iliaca (con't.)
C. Mortality rates per age class
D. Longevity
Kennard (1975) in a study of band returns found the oldest
recorded Fox Sparrow to be 9 years, 9 months.
E. Seasonal abundance
F. Habitat density figures
Fill INTERSPECIFIC INTERACTIONS
A. Predation
B. Competition
C. Parasitism
Friedmann (1963), "Fox Sparrow is an infrequent victim of
the Brown-headed Cowbird. Only in one place has anyone
considered it a common host... in Montana.
IX STATUS
A. Past population trends
Wolf son (1955) reports finding Fox Sparrows in Pleistocene
deposits in California.
B. Present population status
Hayward et al . (1976) note a decline in the population of
Fox Sparrows in Utah from the 1920 ' s and 30' s.
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
11
Passerella iliaca (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union. Baltimore, Maryland. 691 pp.
Baird, S. F. , T. M. Brewer and R. Ridgway. 1905. A history
of North American land birds. Vol. II. Little, Brown,
and Co. , Boston.
Banks, R. C. 1970. The Fox Sparrow on the west slope of the
Oregon Cascades. Condor 72:369-370.
Bent, A. C. and collaborators. 1968. Life histories of North
American cardinals, grosbeaks, buntings, towhees, finches,
sparrows and allies. Part three. Smithsonian Inst. U.S.
Natl. Mus. Bui. No. 237.
Dawson, W. L. 1923. The birds of California. Vol. 1. South
Moulton Co., San Francisco
Friedmann, H. 1963. Host relations of the parasitic cowbirds.
U.S. Nat. Mus. Bui. 233.
| Gabrielson, I„ N. and S. G. Jewett. 1940. Birds of Oregon.
" Oregon State College, Corvallis. 650 pp.
Grinnell, J. 1928. A distributional summation of the ornith-
ology of lower California. Univ. Calif. Publ. Zool. Vol. 32.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna. No. 27.
608 pp.
Hayward, C. L. , C. Cottam, A. M. Woodbury and H. H. Frost.
1976. Birds of Utah. Great Basin Naturalist Memoirs, No. 1.
Hines, J. Q. 1963. Birds of the Noatak River, Alaska. Condor
65:410-425.
Kennard, J. H. 1975. Longevity records of North American
birds. Bird-Banding 46:55-73.
Linsdale, J. M. 1928. The species and subspecies of the
fringillid genus Passerella Swainson. Condor 30:349-351.
Martin, D. J. 1977. Songs of the Fox Sparrow. I. Structure
of song and its comparison with song in other Emberizidae.
Condor 79:209-221.
| Mayr, E. and L. L. Short. 1970. Species taxa of North American
F birds. Publ. Nuttal Ornithol. Club 9:1-127.
12
Passerella iliaca (con't.)
Oberholser, H. C. 1974. The bird life of Texas. Vol. 2.
Univ. of Texas Press, Austin.
Parkes, K. C. 1954. Notes on some birds of the Adirondack
and Catskill mountains, New York. Ann. Carnegie Mus.
33:149-178.
Paynter, R. A. 1964. Generic limits of Zonotrichia. Condor
66:277-281.
Peterson, R. T. 1961. A field guide to western birds. Houghton
Mifflin Co., Boston. 366 pp.
Phillips, A., J. Marshall and G. Monson. 1964. The birds of
Arizona. Univ. of Ariz. Press, Tucson. 212 pp.
Ridgway, R. 1915. A manual of North American birds. Fourth
Edition. J. B. Lippincott Co., Philadelphia. 653 pp.
Robbins, C. S., B. Bruun and H. S. Zim. 1966. Birds of North
America. Western Publ. Co., Wisconsin. 340 pp.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Stewart, R. M. , L. R. Mewaldt and S. Kaiser. 1974. Age ratios
of coastal and inland fall migrant passerines in central
California. Bird-Banding 45:46-57.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. No. 6. 39 pp.
Wolfson, A., Ed. 1955. Recent studies in avian biology. Univ.
of 111. Press, Urbana. 479 pp.
*
GRAY FLYCATCHER
Empidonax wrightii
I TAXONOMY
A. Type description
Empidonax wrightii - AOU (1957) Baird, in Baird, Cassin,
and Lawrence, Rep. Expl. and Surv. R. R. Pacific, vol. 9,
1858, p. 200. (El Paso, Texas.)
B. Current systematic treatments
AOU (1957) describes the Gray Flycatcher as a member of the
avian Order Pas serif ormes, Suborder Tyranni, Superfamily
Tyrannoidea, and Family Tyrannidae; this species is mono-
typic. This species was called Empidonax griseus in the
fourth edition of the AOU Check-list (1931), while the name
E. wrightii was used for the Dusky Flycatcher, which is
called E. oberholseri in the fifth edition.
Hellmayr (1927) felt that E. wrightii, E. griseus, E. pulverius,
E. fulvipectus, and E. trepidus were alT races of tHe same
species; did not want to employ trinominals- until more
breeding information was gathered. He called E. griseus
the "Gray Flycatcher," and E. wrightii the "Wright's Fly-
catcher."
Johnson (1963) concluded that griseus is synonymous with
wrightii, with the former being dropped from useage. He
stated that a complex and sometimes bewildering nomenclature
has surrounded these flycatchers. For years, wrightii and
oberholseri were considered the same species (E. obscurus) .
C. Synonomies of scientific nomenclature
Hellmayr (1927) gives Empidonax obscurus. Grinnell and
Miller (1944) add E. canescens.
D. Synonomies of vernacular nomenclature
Hellmayr (1927), Wright's Flycatcher. Dawson (1923) adds
Little Gray Flycatcher.
II DESCRIPTION
A. External morphology of adults
Ridgway (1907) gives detailed description of plumages;
| above plain olive, tail deep grayish brown, two distinct
" wing bands, lower mandible pale, iris brown, legs and feet
Empidonax wrightii (con't.)
brownish black, has a dull white eye ring. Peterson (1961),
"...the lower mandible is more abruptly flesh-colored and
...the back is gray with scarcely a hint of olive or brown."
Johnson (1963) gives a detailed description of plumages,
molts, and age determination in Gray Flycatchers. Russell
and Woodbury (1941), "The long narrow bill, almost com-
pletely yellow mandible, nearly completely white belly,
and the... almost obsolete eye ring help in identification."
B. External morphology of subadult age classes
"Young essentially like adults, but wing bands more buffy
...and under parts more whitish" (Ridgway 1907). Johnson
(1963) discussed methods of age determination in this
species; "the tips of the juvenile rectrices in wrightii
differ in shape from those of the adult in being pointed
or rounded." Russell and Woodbury (1941) found that, "In
young birds... the white outer web of the outer tail feathers
is distinctive."
C. Distinguishing characteristics
Interspecific - Hellmayr (1907), "Similar to E. hammondii,
but... bill much longer, and coloration of anterior under ^^
parts paler." Peterson (1961) states that this species
is similar to Dusky and Hammond Flycatchers. . .can be safely
identified on the breeding grounds by habitat." Phillips
et al. (1964) describes methods of distinguishing this
species from other small f lycatchers--"This species does
not jerk the tail, but dips it slowly and evenly downward
...This in combination with its white wing-bars, pale gray
color, and frequent occurrence in open country, makes
identification possible in the field."
Intraspecific - Ridgway (1907), sexes alike; adult male--
length 129 mm; wing 69.5 mm; tail 62.6 mm and adult female--
length 130 mm; wing 67.4 mm; tail 60.6 mm.
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
A0U (1957), range of species "Breeds from central Oregon,
southwestern Idaho, southwestern Wyoming, northeastern
Utah, and central Colorado, south to central eastern Calif-
ornia (Inyo Mountains), southern Nevada, central Arizona,
and central western New Mexico." Hellmayr (1927) gives
range of E. wrightii as "Western United States, breeding
from soutHern British Columbia and southwestern Saskatchewan
south to southern California (San Gabriel, San Bernardino,
San Jacinto, and Santa Rosa Mountains), Arizona, New Mexico,
and western Texas, and east to eastern base of Rocky Moun-
tains, wintering from northern to southern Mexico."
•
Empidonax wrightii (con't.)
B. California distribution of the species
Grinnell and Miller (1944) gives the California distribu-
tion of the Gray Flycatcher as "In general, as breeding,
higher Mountain masses of the State; at north, from Warner
Mountains, Modoc County, west through Shasta, Siskiyou
and Trinity regions as far as south Fork Mountain, on
Trinity-Humboldt county line... south from Mount Shasta...
over entire Sierra Nevada to their southern terminus near
Tulare-Kern County line; to eastward, on White Mountains,
in Mono and Inyo counties; recurs on various isolated,
higher ranges of southern California; Mount Pinos, San
Gabriel, San Bernardino, San Jacinto, and Santa Rosa moun-
tains." Small (1974) lists this species California range
as "breeds in northeastern Basin and Ranges Region from
Modoc County south to Inyo County; some of population
winters in southern California." Willett (1933) describes
this species as a summer resident of upper Transition and
Boreal zones of mountains, south to San Jacinto and Santa
Rosa ranges.
C. California desert distribution
Grinnell and Miller (1944) list records of transient Gray
Flycatchers, which include--Death Valley (26 April); near
Needles, San Bernardino Co. (19 February); Palm Springs and
Cottonwood Springs, Riverside County (April). Johnson et al,
(1948) found Gray Flycatchers only as late spring migrants
in the Providence Mountains. Grinnell (1914) collected a
male Gray Flycatcher near Needles (lower Colorado River
Valley) on 19 February; he seldom saw the species in this
area. Wauer (1964) found Gray Flycatchers breeding in the
pinon- juniper woodlands of the Panamint Mountains in Death
Valley (5,000-6,000 feet elevation). Van Rossem (1922)
states that the Gray Flycatcher, after passing through the
San Diegan district on spring migration, breeds in the
desert mountain ranges of California (lists several speci-
mens taken in the White Mountains, Mono and Inyo counties).
Van Rossem (1911) noted Gray Flycatchers wintering near the
Sal ton Sea (January-March). Miller and Stebbins (1964)
called this species a spring migrant (only) in Joshua Tree
National Monument. Willett (1951) found Gray Flycatchers
migrating and wintering on the deserts of southern Calif-
ornia. Hollister (1908) noted a single Gray Flycatcher
near Needles in April in a study of the birds of that region,
D. Seasonal variations in distribution
A0U (1957) states that Gray Flycatchers migrate, in winter,
to southern California (Ventura, Needles), central Arizona,
southern Coahuila, and central Tamaulipas south to southern
Empidonax wrightii (con't.)
Baja California, Jalisco, Michoacan--in migration to
western Texas. In California, Grinnell and Miller (1944)
give the seasonal status of this species as "on breeding
ground, summer resident, April to September. . .elsewhere,
a spring transient, sparse; in autumn apparently passes
over the southward lowlands nearby or quite unobserved."
Small (1974) described seasonal status as "transient and
summer resident, April to October." Bent (1963) stated
that Gray Flycatchers are found north to southern California
and south to Central America during winter. He gives date
of fall departure (for much of California population) as
5 November, and early April as date of spring arrive!.
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), "Most characteristic, green
chaparral with trees scattered through it; in other words,
mixed brushland and trees, either deciduous or coniferous
ones... green manzanita and chinquapin, with scrub black-
oaks, or scattering red or white firs, or lodgpole pines,
or Jeffery pines. .. there is no apparent attraction to
water." Small (1974) gives breeding habitat in California
as "pinon- juniper woodland, mixed Great Basin sagebrush and
pines, arid forests." Van Rossem (1936) found that the
summer distribution of Gray Flycatchers in Nevada closely
coincides in altitude with that of the yellow pine. In
Arizona, Swarth (1904) found this species most abundant
below 5000 feet, favoring the foothill regions covered with
scrub oak, madrona, and manzanita. Grinnell and Swarth
(1913) found Gray Flycatchers breeding between the lowest
edge of the Transition Zone up to the higher slopes of the
San Jacinto Mountains of California. Johnson (1965) found
these flycatchers in "pinon-juniper where scattered ponderosa
pine and clumps of mountain mohogany were subdominant"
(breeding) .
B. Altitudinal range
Grinnell and Miller (1944) give altitudes of occurrence in
California as from 4,000 to 11,300 feet. Van Rossem (1936)
notes the regular occurrence of this species from 7,500
to 10,000 feet in Nevada. Willett (1933) found two species
from 5,500 to 9,000 feet in California. Johnson et al.
(1948) found Gray Flycatchers between 5,000 and 6,400 feet
during spring migration (May) in the Providence Mountains,
California. Grinnell (1908) noted this species breeding
at 10,000 feet in Mono County, California.
£
I
♦
Empidonax wrightii (con't.)
C. Home range size
Russell and Woodbury (1941) found that during the breeding
season, Gray Flycatchers usually stayed within 100 yards
of the nest tree.
D. Territory requirements
Perch sites - Hoffmann (1924) noted Gray Flycatchers singing
from small pines in dry, open woodland of Oregon. Bent
(1963) recounts the use of small twigs as perch sites while
feeding.
Courtship and mating sites - Johnson (1963) describes court-
ship sites as "the male on a horizontally placed branch
5-20 feet above the ground. The female perches nearby."
Nest sites - Dawson (1923), "placed in upright crotch in
bushes, or settled upon branch of evergreen sapling."
Grinnell (1908) gave an average nest height of 7.5 feet
in the San Bernardino Mountains. Nest sites included
willow, Cottonwood, black oak, incense cedar, tamarack
pine, fir, buckthorn, manzanita, and mountain mahogany;
nest heights ranged from 2 to 40 feet. Johnson (1963;,
"the nests of this species are often placed on horizontal
branches of trees as high as 20 feet above the ground (mean
height of 17 nests, 12.5 feet)." Walker (1914) found Gray
Flycatchers nesting in sagebrush in Oregon.
E. Special habitat requirements
Grinnell and Miller (1944), "The essential elements appear
to be low-growing thickets for nesting and much of the foraging,
and near by high singing posts and lookout stations."
Grinnell (1908) found this species was confined to the less
arid parts of the San Bernardino Mountains, but were not
dependent upon a nearby water source for breeding. In
southern Nevada, Johnson (1965) found that considerable
open ground characteristically occurred on occupied terri-
tories of this species.
F. Seasonal changes in habitat requirements
Peterson (1961), "Breeds in sagebrush, pinon, junipers.
In winter, willow thickets, brush." In winter, Small (1974)
states that Gray Flycatchers move into riparian woodlands
from their woodland and sagebrush breeding grounds. Russell
and Woodbury (1941) state that after nesting, Gray Flycatchers
move into sagebrush habitat (August and later).
Empidonax wrightii (con't.)
V FOOD
A. Food preferences
Russell and Woodbury (1941) found that in Arizona and Utah,
the food consisted entirely of insects. It varied in size
from tiny beetles to large butterflies, and included grass-
hoppers, wasps, moths, and ant-lions.
B. Foraging areas
In the San Bernardino Mountains of California, Grinnell
(1908) found Gray Flycatchers foraging from willow thickets
of canyon bottoms, all the way up into the upper reaches
of tall pines. Hollister (1908) noted a Gray Flycatcher
feeding 'among the higher creosote bushes along a dry wash"
during April near Needles, California.
C. Foraging strategies
Oberholser (1974) states that in Texas "It frequently
perches atop a bush or low tree from where it flycatches."
Salt (1953) lists the Gray Flycatcher as a member of the
"air" foraging guild. Bent (1963) recounts the taking of
insects from beneath leaves of trees.
D. Feeding phenology
Bent (1963) stated that very little information is available
on food habits and phenology, which "probably does not
differ materially from that of other western Empidonaces. "
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Oberholser (1974), "Song on the breeding territory is
vigorous..." Johnson (1963) stated that males of wrightii
defend territories both intra- and interspecifically. In
disputes between wrightii and oberholseii, the former was
usually the dominant bird.
C. Courtship and mating behavior
Wheelock (1944) describes courtship, which lasts for about
2 weeks before nest-building begins. Grinnell (1908) des-
cribes the singing of this species during breeding ^^
Empidonax wrightii (con't.)
"jumble of twitters, with rising and falling inflection...
which reminded me of... the Black Phoebe." Johnson (1963)
gave a detailed account of courtship and mating behavior,
which includes a male solicitation display, a female soli-
citation display (wing- fluttering prior to copulation),
and extensive flight songs.
D. Nesting phenology
Wheelock (1904) gives California breeding season as 15 June
to 15 July. Russell and Woodbury (1941) found that 2 broods
are usually raised in a season (Utah and Arizona); nesting
season extends from mid-May until August. Bent (1963) gives
California egg dates as: 65 records, 27 May to 18 July;
33 records, 14 June to 24 June, indicating the height of
season.
E. Length of incubation period
Dawson (1923) gives a 13 day incubation period. Wheelock
(1904) states that incubation is shared by both adults, and
lasts 13-14 days. Johnson (1963) found the incubation
period of wrightii to be 14 or 15 days, with the female
performing all duties of incubation. Russell and Woodbury
(1941) list a 14 day incubation.
F. Length of nestling period
Wheelock (1904) states that young are ready to leave the
nest after about 2 weeks from hatching. Russell and Wood-
bury (1941) found that young usually fledge in 16 days;
young are then fed an additional 14 days after fledging
by their parents.
G. Growth rates
Wheelock (1904) found that young are fed by regurgitation
for the first few days after hatching. Russell and Wood-
bury (1941) reported that at one week of age, nestlings are
about one- third grown and that major feather development
has begun. They found that the feathers were near complete
growth by 11 days of age.
H. Post-breeding behavior
Following breeding, much of the California population of
Gray Flycatcher migrates to Mexico (Bent 1963); birds do
winter in southern California.
Empidonax wrightii (con't.)
II POPULATION PARAMETERS
A. Clutch size
Peterson (1961), "Eggs (3-4) white." Wheelock (1940)
lists a clutch size of 3-5 eggs. Bent (1963) gives an
average clutch as 3 or 4 eggs, sometimes 2.
B. Fledging success
Johnson (1963), "The fates of 25 eggs from. . .nine nests
were as follows: 12 hatched, 10 stolen by predators, and
3 infertile" (California).
C. Mortality rates per age class
Bent (1963) reported that "There is a high mortality among
the young... due to sudden and severe wind and storms during
the nesting season."
D. Longevity
E. Seasonal abundance
Peterson (1961) called the Gray Flycatcher a "sparse" winter
visitor in southern California. Grinnell and Miller (1944),
"On breeding ground. . .common, even abundant for a flycatcher,
Elsewhere, a spring transient, sparse."
F. Habitat density figures
Wheelock (1904) reports finding 4 nests within a radius of
a quarter mile or less in California pine forest. Willett
(1933) calls this species "most plentiful between 6,500
and 9,000 feet" in California. Grinnell (1908) stated that
there were "not less than 3760 Gray Flycatchers in the San
Barnardino Mountains" during breeding season; called their
abundance "remarkable." About 8 breeding territories of
Gray Flycatchers were found in an 800 x 600 yard plot in
Nevada Co., California; the area was dominated by sagebrush
and scattered yellow pine (data calculated from Johnson
1963). Haislip (in Friedmann et al . 1977) found a breeding
population of about 25 pairs per 100 hectares in Oregon.
a Empidonax wrightii (con't.)
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Grinnell (1908) felt that chipmunks and jays destroyed
nests in the San Bernardino Mountains. Pierce (1916) also
noted the taking of eggs by chipmunks in these mountains.
Bent (1963) recounts the destruction of eggs by chipmunks,
snakes, weasels, and other predators.
B. Competition
Johnson et al. (1948) found that Gray and Hammond flycatchers
occupy the same habitat (pinon- juniper) during spring migra-
tion in the Providence Mountains of California. In areas
of sympatry, Johnson (1963) concluded that Gray and Dusky
(E. oberholseri) flycatchers avoided direct competition
tKrough ecological separation (different foraging and nest-
ing sites). Beaver and Baldwin (1975) feel, however, that
"It remains to be demonstrated that competition for food
between E. wrightii and E. oberholseri is eliminated by
habitat cTif terences when in sympatry."
C. Parasitism
Friedmann et al. (1977), in recounting the first published
records for this species as a cowbird host--"It appears
that the Gray Flycatcher is a regular host choice of the
Brown-headed Cowbird in central Oregon, and probably is
more affected elsewhere than the absence of published records
would indicate." They noted that 20 to 30% of Gray Fly-
catcher nests were parasitized in an Oregon study.
IX STATUS
A. Past population trends
Grinnell (1908) found this species to be very abundant as
a breeder in the San Bernardino Mountains. In the San
Jacinto Mountains, Grinnell and Swarth (1913) called Gray
Flycatchers "abundant breeders."
B. Present population status
Johnson and Garrett (1974), "A major recent southwestward
extension of breeding range in California, into formerly
unoccupied woodland of mature single-leaf pinyon. . .from. . .
Tulare County, and from Clark Mountain, eastern San Bernar-
dino County."
•
•
10
Empidonax wrightii (con't.)
C. Population limiting factors
Bent (1963) felt that the Gray Flycatcher is "confined
mainly to the foothills and slopes of the various mountain
ranges, at elevations varying with latitude."
D. Environmental quality: adverse impacts
E. Potential for endangered status
11
Empidonax wrightii (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. 5th edition. American Ornithologists'
Union, Baltimore, MD. 691 pp.
Beaver, D. L. and P. H. Baldwin. 1975. Ecological overlap
and the problems of competition and sympatry in the Western
and Hammond's flycatchers. Condor 77:1-13.
Bent, A. C. 1942. Life histories of North American flycatchers,
larks, swallows, and their allies. U.S. Nat. Mus. Bull.
179:1-555.
Dawson, W. L. 1923. The birds of California. Vol. 2. South
Moulton Co., San Francisco.
Dickey, D. R. and A. J. Van Rossem. 1922. The Gray Flycatcher
in the White Mountains of California. Condor 24:137.
Friedmann, H. , L. F. Kiff and S. I. Rothstein. 1977. A further
contribution to knowledge of the host relations of the
parasitic cowbirds. Smithsonian Contrib. Zool. No. 235.
75 pp.
Grinnell, J. 1908. The biota of the San Bernardino Mountains.
Univ. California Publ. Zool. 5:1-170.
Grinnell, J. 1914. An account of the mammals -and birds of the
lower Colorado Valley. Univ. California Publ. Zool. 12:
51-294.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27. 608 pp.
Grinnell, J. and H. S. Swarth. 1913. An account of the birds
and mammals of the San Jacinto area of southern California.
Univ. California Publ. Zool. 10:197-406.
Hellmayr, C. E. 1927. Catalogue of birds of the Americas and
the adjacent islands. Part 5. Field Mus. Nat. Hist. Zool.
Ser. Publ. 242, Vol. 13.
Hoffmann, R. 1924. Song of the Gray Flycatcher. Condor.
26:195
Hollister, N. 1908. Birds of the region about Needles, Cal-
ifornia. Auk 25:455-462.
Johnson, N. K. 1963. Biosystematics of sibling species of
flycatchers in the Empidonax hammondii-oberholseri-wrightii
complex. Univ. California Publ. Zool. 66: 79-238.
12
Empidonax wrightii (con't.)
Johnson, N. K. 1965. The breeding avifaunas of the Sheep and
Spring ranges in southern Nevada. Condor 67:93-124.
Johnson, D. H. , M. D. Bryant and A. H. Miller. 1948. Verte-
brate animals of the Providence Mountains area of California.
Univ. California Publ. Zool. 48:221-376.
Johnson, N. K. and K. L. Garrett. 1974. Interior bird species
expand breeding ranges into southern California. Western
Birds 5:45-56.
Miller, A. H. and R. C. Stebbins. 1964. The lives of desert
animals in Joshua Tree National Monument. Univ. California
Press, Berkeley. 452 pp.
Moore, R. T. 1940. Notes on middle American Empidonaces.
Auk 57:349-389.
Oberholser, H. C. 1920. Empidonax griseus in Nevada. Auk
37:133.
Oberholser, H. C. 1974. The bird life of Texas. Vol. 2.
Univ. Texas Press, Austin.
Peterson, R. T. 1961. A field guide to western birds.
Houghton Mifflin Co., Boston. 366 pp.
Phillips, A. R. 1939. The type of Empidonax wrightii. Auk
56:311-312.
Phillips, A. R. 1944. Some differences between Wright's and
Gray Flycatchers. Auk 61:293-294.
Phillips, A., J. Marshall and G. Monson. 1964. The birds of
Arizona. Univ. Arizona Press, Tucson. 212 pp.
Pierce, W. M. 1916. More bird notes from Big Bear Valley,
San Bernardino Mountains. Condor 18:177-182.
Ridgway, R. 1907. The birds of North and Middle America.
Part 4. Bull. U.S. Nat. Mus. No. 50.
Rowley, J. S. 1939. Breeding birds of Mono County, California.
Condor 41:247-254.
Russell, H. N., Jr. and A. M. Woodbury. Nesting of the Gray
Flycatcher. Auk 58:28-37.
Salt, G. W. 1953. An ecological analysis of three California
avifaunas. Condor 55:258-273.
13
Empidonax wrightii (con't.)
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Swarth, H. S. 1904. Birds of the Huachuca Mountains, Arizona.
Pacific Coast Avifauna No. 4. 70 pp.
Swarth, H. S. 1924. Notes upon certain summer occurrences of
the Gray Flycatcher. Condor 26:195-197.
Van Rossem, A. 1911. Winter birds of the Salton Sea region.
Condor 13:129-137.
Van Rossem, A. J. 1936. Birds of the Charleston Mountains,
Nevada. Pacific Coast Avifauna No. 24. 65 pp.
Walker, A. 1914. Nesting of the Gray Flycatcher in Oregon.
Condor 16:94.
Wauer, R. H. 1962. A survey of the birds of Death Valley.
Condor 64:220-233.
Wauer, R. H. 1964. Ecological distribution of the birds of
the Panamint Mountains, California. Condor 66:287-301.
Wheelock, I. G. 1904. Birds of California. A. C. McClurg
and Co. , Chicago. 578 pp.
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna No. 21. 204 pp.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. No. 6. 39 pp.
Yaich, J. A. and E. J. Larrison. 1973. Nesting record and
behavioral observations on the Gray Flycatcher in Washing-
ton. Murrelet 54:14-16.
GREAT HORNED OWL
Bubo virginianus
I TAXONOMY
A. Type description
AOU (1957) B. v. pacificus Cassin, Illustr. Birds California,
Texas, etc., pt. 6, (Sept. 12) 1854, p. 178. (The West -
Sacramento, California.)
B. v. pallescens Stone, Amer. Nat., 31, no. 363, Mar. 1,
1897, p. 237. ("Watson Ranch, 18 miles southwest of San
Antonio , Texas . )
B. Current systematic treatments
Peters (1940), recognizes eleven species in the genus Bubo;
sixteen subspecies of the species virginianus. Order:
Strigiformes; Family: Strigidae.
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), B. y. pacificus: Strix virginiana;
Bubo magelannicus ; B. y. arcticus; B. y. subarcticus; B.
subarcticus; Asio magellanicus ; A. m. pacificus; A."""m.
icelus; B. y. icelus; Bubo horriEilis; B. y. elacKistus.
B. y. pallescens: B. y. subarcticus; B. y. pacificus; Asio
magellanicus pallescens.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), B. y. pacificus: Pacific Horned
Owl; Western Great Horned Owl; Western Horned Owl; Horned
Owl; Dusky Horned Owl; California Horned Owl. B. y. pallescens
Western Horned Owl; Pacific Horned Owl; Desert Horned Owl.
II DESCRIPTION
A. External morphology of adults
Ridgway (1914), detailed description of adults and young of
B. v. virginianus and comparisons with pallescens and
pacificus, including plumage, soft parts! and measurements.
Peterson (1961), "the only large N. American owl with ear
tufts, or 'horns. ' Heavily barred beneath; conspicuous
white throat-collar. In flight, as large as our largest
hawks; dark (most races), looks neckless, large-headed."
Dawson (1923), B. y. pacificus: "Adult: Ear tufts conspi-
cuous, two inches or more m length, black, bordered with
I ochraceous; entire upperparts dusky or blackish, finely
barred and mottled with prevailing whitish and ochraceous,
Bubo virginianus (con't.)
the latter color predominant on each feather basally; wing-
quills and tail faintly broad-barred; facial disc ochraceous,
sharply bordered by blackish laterally, feathers whitish and
black-tipped centrally, borders before and over eye blackish;
a broad white space on chest; feathers of remaining under-
parts tawny or ochraceous tawny at base, changing to white
on terminal portions (in very variable amount;, finely and
heavily barred with dusky brown; the sides of breast spotted
with the same color; the toes pale tawny, nearly immaculate;
iris bright yellow. Bill and toe-nails bluish black."
B. y. pallescens: "Similar to B. y. pacificus, but much
paler, the ochraceous tawny element largely replaced by white,
sometimes nearly wanting below, the barring of underparts
usually narrower and finer."
B. External morphology of subadult age classes
Ridgway (1914), detailed description of plumage and soft
parts. Dawson (1923), "Young: Above and below ochraceous,
barred with dusky. Chicks are covered with white down."
C. Distinguishing characteristics
Interspecific - Peterson (1961), "Long-eared Owl is much
smaller. . .with lengthwise, streakings, rather than cross-
wise barrings, beneath. 'Ears' closer together."
Intraspecific - Ridgway (1914), B. y. pacificus: "Similar
to B. y. pallescens but darker throughout, the feet more
heavily mottled with dusky, the face usually with more
decided tinge or suffusion of tawny; slightly smaller."
II GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), "America, exclusive of West Indies, from the
limit of trees in the Arctic to the Straits of Magellan."
B. y. pacificus: "California west of Great Basin and desert
areas (exclusive of northern humid coast belt) south to
lat. 30° N. in northwestern Baja California and east to
extreme western central Nevada (Tahoe area)." B. y. pallescens
"Arid regions of southeastern California (from Inyo district) ,
southern Nevada (Clark County), southern Utah (Virgin River),
northern New Mexico, and north-central Texas south to extreme
northeastern Baja California, northern Sonora (Hermosillo) ,
Chihuahua, Durango, Coahuila, Nuevo Leon, and northern
Tamaulipas.
"
•
•
f
Bubo virginianus (con't.)
B. California distribution of the species
Grinnell and Miller (1944), B. v. pacificus: "In general,
that major portion of State lying west of the Great Basin
and southeastern deserts, and east of the northern and
central humid coast belt; north from Mexican line in San
Diego County to Oregon line in central Siskiyou County; at
extreme north, specimens of this race at hand... from South
Fork Mountain and Weaverville, Trinity County, and from
Boggs Creek and near Weed, Siskiyou County. Range includes
all of Sierra Nevada, Great Central Valley and enclosing
foothills, and southern coast range belt northwest on the
seacoast through Monterey County and interiorly to Alameda
and Contra Costa counties." B. y. pallescens: "In general,
Colorado and Mohave deserts. North from Mexican line in
Imperial County to Argus and Panamint Mountains, in Inyo
County... and even, apparently, to Benton, Mono County...
West from valley of Colorado River, Needles to Pilot Knob. . .
to south end of Sal ton Sea, Imperial County... and to Victor-
ville, San Bernardino County." Dawson (1923), B. v. pacificus
"(chiefly contained within California). — California, except
the southeastern portion, the humid coastal strip (narrowly)
north of Latitude 35, and (possibly) the extreme northeastern
portion, north into south-central Oregon, east to San Fran-
cisco Mountains, Arizona, south to northern Lower California."
B. y. pallescens: "Resident along the Colorado River, in
the Imperial Valley, and in wooded portions of the Colorado
and Mohave Deserts, To a limited degree also in the desert
ranges."
C. California desert distribution
Grinnell and Miller (1944), B. y. pacificus: reported from
Escondido and Sorrento, San Diego County. B. y. pallescens:
reported from Death Valley; Yermo and Twentynine Palms,
San Bernardino County; San Fernando, Pasadena, and San Antonio
Canyon, Los Angeles County; Buena Vista Lake, Kern County.
Also, "west from valley of Colorado River, Needles to Pine
Knob... to south end of Salton Sea, Imperial County... and to
Victorville, San Bernardino County."
D. Seasonal variations in distribution
AOU (1957), no seasonal variations noted.
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), B. y. pacificus: "Of wide variety;
perhaps most usual, woodland especially of oaks, or broken
type of forest, with open ground included or adjacent. But
Bubo virginianus (con't.)
also, cliff- sided canyons; broad washes if with trees such
as cottonwood and sycamore containing old hawks' nests;
in fact, almost any locality affording sheltered daytime
roosting places and nesting sites up from the level ground,
whether in trees or in rock walls." B. v. pallescens:
"In different places: rock-walled canyons; pmon- and juniper-
clothed mountain sides; riparian lowlands where grow cotton-
woods and willows of large size; desert washes with bluff -
like sides; desert mesas supporting large-sized tree-yuccas."
Small (1974), "broken woodland of oaks or coniferous-deciduous
forest, thickly-wooded canyons, desert, riparian woodland."
Miller (1951), Upper and Lower Sonoran, Transition and
Canadian life zones.
B. Altitidinal range
Grinnell and Miller (1944), B. y. pacificus: "occurs from
near sea level up regularly, at least m summer, to 7000
feet, exceptionally to 10,500 feet." B. y. pallescens:
"from 200 or more feet below sea level, in Death Valley
and around Salton Sea, up to at least 6200 feet, in Pana-
mint Mountains, Inyo County."
C. Home range size
Fitch (1947) "Several times a pair was seen at dusk making
a flight of a quarter of a mile or more across open fields
to hunt on a wooded ridge opposite the one where they had
roosted for the day." Baumgartner (1939), concerning birds
in New York: "In no case did the size of the feeding range
have a radius exceeding one- fourth of a mile in any direc-
tion from the nest, but obviously the individual character-
istics of the topography and the availability of food in
the immediate vicinity are important factors determining
the range." Craighead and Craighead (1956), report ranges
of four nesting pairs in Wyoming, 1947: 0.62 sq. mi. (1.8
mi. max. diam.); 0.45 sq. mi. (1.4 mi. max. diam. ) ; 1.10
sq. mi. (1.6 mi. max. diam.); 1.11 sq. mi. (1.6 mi. max.
diam. ) .
D. Territory requirements
Perch sites - Cushing (1939), "was seen at night perched
upon a telephone pole." Fitch (1947), "Horizontal limbs
of larger Digger pines provide perch sites during the night
hours of activity. . .The perches used in actual hunting are
lower, so that prey may be more readily detected and pur-
sued at close range... Such perches atop rock piles. .. fence
posts, stumps, and logs." Bent (1938), "A favority perch
of the bird is the roof of a building."
Courtship and mating sites -
•
f
Bubo virginianus (con't.)
Nest sites - Fitch (1947), reports sites of six nests:
"25 feet above ground, in depression on top of digger pine
stub... 15 feet above ground, on bole of cottonwood growing
in stream bed... 45 feet above ground and about 25 feet
out on horizontal limb; an old gray squirrel nest taken
over... 50 feet above ground in Digger pine, in a shallow
depression of trunk where a large limb had broken off. . .
65 feet above ground in crotch of main trunk of Digger
pine. . .On ground, sheltered by edge of a large boulder."
Dawson (1923), "A cranny or inaccessible ledge of cliff,
or a deserted nest of Swainson Hawk, Western Redtail,
Yellow-billed Magpie, or Western Crow. . .Rarely in hollow
trees." Baumgartner (1938), "In the deserts of the South-
west cactus plants take the place of trees and horned owls
often occupy old nests among the thorny branches."
E. Special habitat requirements
Grinnell and Miller (1944), "the requisite elements of the
habitat seem to be shaded shelter and places for nesting,
out of reach of terrestrial marauders --niches in cliffs,
or other birds' nests in trees."
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Cunningham (1960), Examination of pellets collected on the
U. of California campus, Los Angeles and in the Santa Monica
Mountains showed the following prey items: Neotoma fuscipes,
Thomomys bottae, Mus musculus , Micro tus calif ornicus,
Reithrocfontomys megalotis, Perognathus sp., Dipodomys agilis,
Peromyscus sp . , Notiosorex crawfordi, Sylvilagus sp . ,
Sorex ornatus, Scapanus latimanus , Rattus sp. , and un-
identified birds. Fitch (1947), lists remains of mammals,
birds, reptiles, amphibians, and invertebrates found in
654 pellets collected in Madera County, California. Craig-
head and Craighead (1956), "In 1942 mammals were 40.5 per-
cent and birds 59.6 percent of the Horned Owl diet; in
1948 mammals were 62.1 percent and birds 29.7 percent."
B. Foraging areas
Craighead and Craighead (1956), "Their food is largely
crepuscular or nocturnal animals. . .Are present in all types
of country that support their prey... The large mature wood-
lots which furnished more extensive and perhaps better
hunting grounds, and were thus intimately related to food
availability. "
Bubo virginianus (con't.)
C. Foraging strategies
Bent (1938), "While this owl usually remains hidden during
the day and does most of its hunting at night, it can see
well enough to do some by day, if necessary." Rhodes and
Duke (1977), examination of gastric motility and pellet for-
mation. "The muscular stomach of the Great Horned Owl
appears to be the site of initial proteolysis; chemical
separation of soft tissues from hair and bone is completed
there. . .Gastric motility is also essential for evacuating
fluid from the stomach after chemical digestion is complete,
and for ferming and egesting the pellet."
D. Feeding phenology
Craighead and Craighead (1956), "The increased activity
of pheasants at the time of dispersion from protective winter
roosting areas to crowing territories, when protective
cover is at a minimum, made the Ring-necked Pheasant more
vulnerable to the Horned Owl at this period. It is signi-
ficant that this increased vulnerability of adult Ring-
necked Pheasants occurs at a time when other prey popula-
tions are at or near a seasonal low."
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Miller (1930), B. y. pacificus: "Bubo hoots from a point
within his chosen territory. Within that territory he gen-
erally responds quickly to the note of a supposed invader.
Calls from without his estates do not bring him to the spot
though they may rouse him to send out his own challenge.
The male bird is the more aggressive and is recognized by
the deeper voice and more regular cadence." Baumgartner
(1939), "holds a definite territory throughout the nesting
season. .. In many cases the male takes up his station...
before the period of courtship and mating begins."
C. Courtship and mating behavior
Bent (1938), "So little is known of the courtship of these
big birds." Baumgartner (1938), "Hooting of the males
becomes conspicuous about a month before mating begins.
Active courtship and mating apparently last less than two
weeks. .. Hooting of the males has a three-fold function--to
express physical vigor and vitality; to warn other males
of their territorial rights; and to attract a mate... The
hooting of the female is chiefly limited to the mating and
nesting season."
•
•
•
t
Bubo virginianus (con't.)
D. Nesting phenology-
Davis (1933), reports, in Butte County, California, the
first date as 8 February; the last date as 1 March; the
average date 18 February. Dawson (1923), "February- April;
one brood." Baumgartner (1938), reports average dates of
completed first sets of eggs throughout the U.S. and Canada.
E. Length of incubation period
Hoffmeister and Setzer (1947), report 34 to 35 days for
four observed. Baumgartner (1938), "normally begins with
the laying of the first egg... No indisputable data on the
exact length of the incubation period has been found. . .
At least twenty-six and probably nearer thirty days."
F. Length of nestling period
Hoffmeister and Setzer (1947), "By the forty-fifth day,
the young owls are able to fly short distances and thus
are able to leave the site of the nest permanently. At
this time they are about three- fourths grown."
I G. Growth rates
Hoffmeister and Setzer (1947), regularly recorded weights
of 4 developing young (graph included). ' During the first
four weeks of postnatal growth, each owl gained in weight,
daily, an average of 33-1/3 grams or an increase of 11.1
per cent... From the beginning of the fifth week until the
time the young left the nest, the three owls gained on the
average only 12.7 grams or approximately 1.6 percent in
weight daily."
H. Post-breeding behavior
Craighead and Craighead (1956), "young of the previous
year were a very small proportion of the spring population.
As nesting patterns became fixed, immature ... owl s were haras-
sed constantly and buffeted from one territory to another. . .
Once settled, they developed a range that often was limited
by those of other neighbors." Errington (1932), "were apt
to station themselves in the fall in the near neighborhood
of old stick nests (hawk or crow) which they would appro-
priate in the spring."
VII POPULATION PARAMETERS
A. Clutch size
| Fitch (1947), reports three nests with three eggs; also
three nests with one, two, and three nestlings. Dawson
(1923), "2 or 3, rarely 4; rounded ovate, white, luster-
less, granular."
Bubo virginianus (con't.)
B. Fledging success
Craighood and Craighood (1956), report in Michigan 50%
(1942) and 27% (1948) fledgling success (fledglings per
eggs laid). In Wyoming: nest success was 89% (fledglings
per eggs laid) in 1947.
C. Mortality rates per age class
Craighead and Craighead (1956), report from studies in
Michigan: 33% (1942) and 21% (1948) of the clutches were
incomplete and nests receiving no eggs; 55% (1948) of the
eggs were destroyed, infertile, or failed to hatch; there
was 50% (1942) and 40% (1948) mortality in the nest after
hatching. In Wyoming in 1947: 25%, of the clutches were
incomplete or nests failed to receive eggs; 11% of the
eggs were destroyed, infertile, or failed to hatch; no
mortality of nestlings was observed.
D. Longevity
Kennard (1975) reports a record age of 12 years, 8 months
in 1939. Age and sex unknown when banded in 1927.
E. Seasonal abundance ^P
Baungartner (1939), reports observed nesting populations
(one to three pairs per square mile) with winter populations
seemingly equally dense, since he observed that resident
birds generally remain in the nesting vicinity throughout
most of the year.
F. Habitat density figures
Franzreb (1975), reports 14.3 breeding pairs per 100
hectares at Thomas Creek, White Mountains, Arizona, summer,
1973. Fitch (1947), reports census of individuals in 2000
acre area, Madera County, California. Seven counts from
1938 to 1947 revealed from 14 to 25 individuals. Baumgartner
(1939), "In optimum range the decided territorial require-
ments of the males probably determine the nesting density.
Populations in such areas seem to average from one to three
pairs of nesting owls to the square mile. Over most of
the range of the species the nesting density is much lighter."
m Bubo virginianus (con't.)
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Hoechlin (1976), reports the remains of two adults at one
nest of the California Golden Eagle. Miller (1952), re-
corded the reactions of a number of species (prospective
prey) to imitated hoots of this owl. Killpack (1951),
found the following remains in a nest in Uintah County,
Utah: Short-eared Owl, young muskrat, adult jackrabbit,
Ring-necked Pheasant, Black-billed Magpie, Morning Dove,
domestic pigeon, American Coot. Placed emphasis upon large
size of these items. Fox (1948), reports a young owl of
this species feeding on a garter snake (Thamnophis sirtalis
inf ernalis) . Carnie (1954) reports remains of seven indivi-
duals in nests of Golden Eagles, 1947-1952, in central
California. Wiley (1975), reports predation on young Red-
shoulder Hawks.
B. Competition
•
•
Wiley (1975), discusses interactions between this species
and other raptors nesting in close proximity with Horned
Owls. Cooper's Hawks vigorously attacked the adult owls.
Red- shoulder Hawks were not observed to attack the owls,
but the young hawks were preyed upon. American Kestrels
regularly attacked the owls. "A pair of Cooper's Hawks,
Accipiter cooperi, attempted to use a Great Horned Owl nest
after the owl nest had failed. The owl began nesting
activity in a stick nest that Cooper's Hawks had built
the previous year."
C. Parasitism
Fitch (1947), reports the half-grown young in one nest
were attacked by small blood -sucking flies (Eusimulium
clarum) .
IX STATUS
A. Past population trends
B. Present population status
Small (1974), "resident."
C. Population limiting factors
Baumgartner (1939), "Horned Owl populations are limited
chiefly by human molestation and man-made changes in their
environment that result in a scarcity of cover and less
10
3ubo virginianus (con't.) ^A
frequently a lack of nesting sites and sufficient food."
Craighead and Craighead (1956), "Lack of extensive wooded
areas, rather than food supply, apparently was the factor
limiting the Horned Owl population."
D. Environmental quality: adverse impacts
E. Potential for endangered status
•
11
A Bubo virgin! anus (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Baumgartner, F. M. 1938. Courtship and nesting of the Great
Horned Owls. Wilson Bull. 50:274-285.
Baumgartner, F. M. 1939. Territory and population in the
Great Horned Owl. Auk 56:274-282.
Bent, A. C. 1938. Life histories of North American birds
of prey. Part 2. Bull. U.S. Nat. Mus. No. 170.
Carnie, S. K. 1954. Food habits of nesting Golden Eagles
in the coast ranges of California. Condor 56:3-12.
Craighead, J. J. and F. C. Craighead, Jr. 1956. Hawks, Owls
and Wildlife. Stackpole Co., Pennsylvania.
Cushing, J. E. , Jr. 1939. The relation of some observations
upon predation to theories of protective coloration. Condor
41:100-111.
#
Cunningham, J. D. 1960. Food habits of the Horned and Barn
Owls. Condor 62:222.
Davis, W. B. 1933. The span of the nesting season of birds
in Butte County, California, in relation to their food.
Condor 35:151-154.
Dawson, W. L. 1923. The birds of California. South Moulton
Co. , San Francisco.
Errington, P. L. 1932. Studies on the behavior of the Great
Horned Owl. Wilson Bull. 44:212-220.
Fitch, H. S. 1947. Predation by owls in the Sierran foothills
of California. Condor 49:137-151.
Fox, W. 1948. Horned Owl feeding on Garter Snake. Condor
50:46.
Franzreb, K. E. 1975. Avian densities in a mixed-coniferous
forest, Thomas Creek, White Mountains, Arizona. Western
Birds 6:101-105.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
^ birds of California. Pacific Coast Avifauna, No. 27.
12
Bubo virginianus (con't.)
Hoechlin, D. R. 1976. Development of Golden Eaglets in south-
ern California. Western Birds 7:137-152.
Hoffraeister, D. F. and H. W. Setzer. 1947. The postnatal
development of two broods of Great Horned Owls (Bubo
virginianus) . Univ. Kansas Publ., Mus. Nat. Hist"I 1: 157-
1737
Kennard, J. H. 1975. Longevity records of North American
birds. Bird-Banding 46:55-73.
Killpack, M. L. 1951. Short- eared Owl eaten by Horned Owl.
Condor 53:262.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. Vol. 50,
No. 6.
Miller, L. 1930. The territorial concept in the Horned Owl.
Condor 32:290-291
Miller, L. 1952. Auditory recognition of predators. Condor
54:89-92.
Peters, J. L. 1950. Checklist of birds of the world Vol. IV.
Mus. Comp. Zool., Cambridge, Massachusetts.
Peterson, R. T. 1961. Field guide to western birds. Houghton
Mifflin Co., Boston.
Rhoades, D. D. and G. E. Duke. 1977. Cine radio graphic studies
of gastric motility in the Great Horned Owl (Bubo virginianus) .
Condor 79:328-334.
Ridgway, R. 1914. The birds of North and Middle America. Part
6. Bull. U.S. Nat. Mus. No. 50.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Wiley, J. W. 1975. Relationships of nesting hawks with Great
Horned Owls. Auk 92:157-159.
f
GREEN- TAILED TOWHEE
Pipilo chlorurus
I TAXONOMY
A. Type description
AOU (1957), Fringilla chlorura Audubon, Orn. Biogr. , vol.
5, 1839, p. 336. (No locality given = about 20 miles south-
west of Blackfoot, Idaho.)
B. Current systematic treatments
Sibley (1955), discussion of the characteristics illustrating
the close relationship with both P. ocai and P. erythrophthalmus
(color pattern, ecological preferences, pattern of song,
coloration and pattern of markings of the eggs), concluding
that C. chlorura and P. ocai are congeneic and that chlorura
should" be placed in tHe genus Pipilo.
Paynter (1970), recognizes chlorurus as a monotypic species
in the genus Pipilo, which is divided into seven species.
Passeriformesl Emberizidae (Emberizinae) .
C. Synonomies of scientific nomenclature
► Dawson (1923), Oberholseria chlorura. AOU (1957), Chlorura
chlorura; Fringilla chlorura. Ridgway (1901), Oreospiza
chlorura. Grinnell and Miller (1944), Embernagra blandingiana;
E. chlorura; Atlapes chlorurus; Oberholseria chlorura zapolia.
D. Synonomies of verncular nomenclature
Dawson (1923), Green-tailed Finch; Blanding's Finch. Grinnell
and Miller (1944), Blanding Finch; Green Finch; Green-tailed
Bunting.
II DESCRIPTION
A. External morphology of adults
Dawson (1923), "Sparrow size; chestnut crown, white throat;
greenish coloration of upper parts, especially tail and
wings. . .Adults (sexes alike): Crown and occiput rich chest-
nut; forehead blackish gray, with whitish loral spot on
each side; cheeks mingled gray and white; a short malar
streak white, and a narrow, sharply defined sub-malar streak
dark gray; remaining upperparts olive-gray, tinged more or
less with bright olive-green. Wings and tail with brighter
greenish edgings. .. ;bend of wing, axillars, and under coverts
yellow; chin and throat white, sharply defined and with con-
j^ vex posterior outline; sides of head and neck and remaining
P underparts neutral gray, clearing to white on abdomen, tinged
Pipilo chlorurus (con't.)
with buffy or brownish on sides, flanks, and crissum;
under tail-coverts clear cream-buff. Bill blackish above,
paler below; legs brown, toes darker; irides cinnamon."
Peterson (1961), "rufous cap and conspicuous white throat
...plain olive-green back, gray breast." Ridgway (1901),
detailed description of adult male and female, including
plumage, soft parts, and measurements.
B. External morphology of subadult age classes
Dawson (1923) "Immature birds are brown above, tinged with
greenish and streaked with dusky, but with wings and tail
much as in adult. Nestlings show greenish on wings alone,
and are otherwise finely streaked above and below."
Ridgway (1901), detailed description of plumage.
C. Distinguishing characteristics
Interspecific - Dawson (1923), "chlorura possesses no color
character not found in at least one other member of the
genus Pipilo; and the very fact that this bird has these
characters in common with the others would seem to designate
it as a typical and central member of the genus, rather than
an aberrant form" Peterson (1961), "Brown Towhee is browner,
has buff throat." ^
Intraspecific -
I GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
Dawson (1923), "Western United States and northern Mexico;
breeding from central Oregon and south central Montana to
western Texas and southern California." AOU (1957), "Breeds
from southwestern and central Oregon. . . southeastern Washing-
ton (Blue Mountains), southern Idaho, southwestern Montana...
and northwestern, central, and southeastern Wyoming (Yellow-
stone Park, Wheatland) south through the interior mountains
to southern California (San Jacinto Mountains), southern
Nevada (Charleston Mountains), central Arizona (San Fran-
cisco Mountains, White Mountains), and southern New Mexico
(Black Mountains, Sacramento Mountains) .. .Casual north to
Saskatchewan. .. and east to Massachusetts. . .New Jersey...
Virginia. .. South Carolina. . .and Louisinna." Ridgway (1901)
"Mountain districts of Western United States, from more
eastern Rocky Mountain ranges to Coast Range of California;
north to central Montana and Idaho and eastern Washington;
south at least in winter, Lo States of Guanajuato, Durango
. . . , and Sinaloa. . .middle Mexico, and to southern extremity
of Lower California."
Pipilo chlorurus (con't.)
B. California distribution of the species
Dawson (1923), "Summer resident in high Transition, chiefly
east of the Sierran divide, from the Warner Mountains south
to the desert ranges and the San Jacinto Mountains. Also
breeds, northwesterly, at least to Sissons..., and south-
westerly to Mt. Pinos..., and south centrally along the
western slopes of the Sierras. Abundant during migrations
easterly; and recorded variously in the northern Coast
Range south to Mendocino County, Sierra Nevada south through
Mt. Pinos and Transverse Ranges to Mt. San Jacinto in Penin-
sular Ranges; Great Basin south through mountains of Inyo
County." Grinnell and Miller (1944), "As breeding, northern
coast ranges, west to interior Humboldt County and south
to northern Mendocino County; Cascade Mountains, Sierra
Nevada, and high ranges of southern California west to
Mount Pinos and southeast to Mount San Jacinto; mountains
and high plateaus of Great Basin region from Modoc County
south through Inyo County."
C. California desert distribution
Grinnell and Miller (1944), recorded at the following
localities: Palm Springs, Riverside County, Mount Water-
man, Los Angeles and Pasadena, Los Angeles County; Watch
Creek, San Diego County.
D. Seasonal variations in distribution
Dawson (1923) "Has occurred in winter in the San Diegan
district. . .wintering from southern portion of its breeding
range south to Cape San Lucas and Guanajuato." AOU (1957),
"Winters from southern California (Los Angeles, Casually),
southern Arizona (Fort Mohave, Gila River Valley), and
western and southern Texas (Sierra Blanca, Brownsville)
south to southern Baja California (San Jose del Cabo),
Jalisco, Guanajuato..., Morelos (Cuernavaca) , Nuevo Leon
(Galeana) , and Hidalgo (Metztitlan) ; occasionally north
to central California (Marysville) ; in migration to western
Kansas and western Oklahoma (Cimarron County)." Small
(1974), "winter visitor in small numbers in southern Calif-
ornia." Grinnell and Miller (1944), "In winter, chiefly
Pacific slope north to Los Angeles County, exceptionally
as far as Sacramento Valley." Willett (1912), 'Summer
resident of the mountains from 5000 to 9000 feet altitude.
Occurs occasionally along the base of the mountains during
migrations. Winters in small numbers at least as far north
as San Bernardino."
Pipilo chlorurus (con't.)
IV HABITAT
A. Biotopic affinities
Peterson (1961), "dry brushy mountain slopes, low chaparral,
open pines, sage, manzanita." Small (1974), "for breeding,
mountain chaparral, otherwise, lowland thickets and oases."
Grinnell and Miller (1944), "Chaparral types occurring in
the Transition and Boreal zones. Most commonly this essen-
tial cover is composed of snow bush (Ceanothus cordulatus)
and manzanita, or, eastwardly, of Artemisia tridentata and
Purshia. Forest is avoided; only scattered trees within
the brushland are tolerated, but they may be used as song
posts. The brush cover is typically low (2 to 4 feet) and
spreading, affording runways between plants and underneath
the foliage. Within forested areas, the places occupied
are comparatively dry and well insulated; in the Great
Basin region the lower, warmer flats are avoided even though
grown to sage brush." Miller (1951), Transition and Canadian
life zones.
B. Altitudinal range
Grinnell and Miller (1944), "breeding localities range from
2500 feet, as at Nevada City, Nevada County, .. .up to 10,000
feet in the white Mountains, Mono County."
C. Home range size
Austin (1968) reports that no information is available.
D. Territory requirements
Perch sites - Grinnell and Miller (1944), "scattered trees
within the brushland. . .may be used as song posts."
Courtship and mating sites -
Nest sites - Dawson (1923). "Low in bushes, especially
sage (Artemsia tridentata) , often well concealed, .. .of
twigs, weed-stems, pine needles, etc. ; lined with rootlets,
grasses, or, rarely, horse hair."
E. Special habitat requirements
F. Seasonal changes in habitat requirements
?
Pipilo chlorurus (con't.)
f V FOOD
A. Food preferences
Grinnell, Dixon, and Linsdale (1930), "when berries of
amelanchier bushes. . .were turning reddish but were not yet
at all ripe, the green- tailed towhees were seeking these
eagerly and eating them" Austin (1928) reports them feed-
ing on weed seeds, insects, alfalfa weevil, third-instar
Mormon crickets, cracked corn, bread crumbs, birdseed,
rolled oats.
B. Foraging areas
Grinnell and Miller (1944) "The sphere of activity is low,
foraging taking place on the ground in the leaf litter and
in the tangle of branches."
C. Foraging strategies
Austin (1969) "scratching not unlike that of other kinds
of towhees." Grinnell and Storer (1924), "the combination
of conical bill, long tail, short wings, and stout legs
and feet, proclaim the Green- tailed Towhee to be adapted
for foraging beneath brush patches."
^ D. Feeding phenology
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
C. Courtship and mating behavior
D. Nesting phenology
Dawson (1923), "Season: May- July; two broods."
E. Length of incubation period
F. Length of nestling period
G. Growth rates
Austin (1968), "Almost no information is available on
parental' care or development of nestlings."
Pipilo chlorurus (con't.)
H. Post-breeding behavior
Austin (1968), "Prior to fall migration proper, there is an
up-mountain scattering of birds after the breeding season,
and immatures are prevalent among these wanderers. . .There
is also evidence of downshape scattering of individuals
in late summer."
VII POPULATION PARAMETERS
A. Clutch size
Dawson (1923), "3 or 4; palest bluish or grayish white,
finely and almost uniformly sprinkled or spotted with light
reddish brown... and purplish gray."
B. Fledging success
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
Huey (1942), "perhaps the most generally distributed winter ^^
visitor. While never in concentrated numbers, it was found
singly in almost every place where vegetation was dense
enough to give it shelter" (Oregon Pipe Cactus National
Monument, Arizona).
F. Habitat density figures
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Austin (1968), "while no evidence of predation has come to
my attention, probably adults as well as eggs and young
of this low-nesting bird occasionally fall prey to mammalian
predators. "
B. Competition
C. Parasitism
Henshaw (1875), recorded a cowbird egg in a nest of this
species in Fort Garland, Colorado. Rockwell (1908), re-
corded this species as a host of Molothrus ater obscurus
in Mesa County, Colorado. Mitchell (1898), reports this
species as parasitized in San Miguel County, New Mexico.
t
Pipilo chlorurus (con't.)
!X STATUS
A. Past population trends
Grinnell and Miller (1944), "Present in three seasonal roles
common summer resident from May to early September in moun-
tains, especially those of the interior; winter visitant
rarely, in coastal southern section; transient there and
elsewhere, except along northwest coastal strip; migrants
are most numerous in the interior."
B. Present population status
Small (1974), "Transient and summer visitor, April to
October."
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
Pipilo chlorurus (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Austin, 0. L. , Jr. 1968. Life histories of North American
cardinals, grosbeaks, buntings, towhees, finches, sparrows,
and allies Part 1. U.S. Natl. Mus. Bull. No. 237.
Dawson, W. L. 1923. The birds of California. South Moulton
Co., San Francisco.
Grinnell, J., J. Dixon and J. M. Linsdale. 1930. Vertebrate
natural history of a section of northern California through
the Lassen Peak region. Univ. California Publ. Zool. Vol.
35.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27.
Grinnell, J. and T. I. Storer. 1924. Animal life in the Yose-
mite. Contr. Mus. Vert. Zool. Univ. California.
Henshaw, H. W. 1875. Report upon the ornithological collec-
tions. U. S. Geographical Surveys West of the 100th Meri-
dian. Vol. V., Chap. III.
Huey, L. M. 1942. A vertebrate faunal survey of the Oregon
Pipe Cactus National Monument, Arizona. Trans. San Diego
Soc. Nat. Hist., vol. 9, pp. 353-376.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool., Vol.
50, No. 6.
Mitchell, W. I. 1898. The summer birds of San Miguel County,
New Mexico. Auk 15:309.
Peters, J. L. 1970. Checklist of birds of the world. Vol.
10. (R. A. Paynter, Jr., ed.) Mus. Comp. Zool., Cambridge,
Massachusetts.
Peterson, R. T. 1961. Field guide to western birds. Houghton
Mifflin Co., Boston.
Ridgway, R. 1901. The birds of North and Middle America.
Part 1. U.S. Natl. Mus. Bull. No. 50.
Rockwell, R. B. 1908. An annotated list of the birds of Mesa
Co., Colorado. Condor 10:169.
e
~
t
Pipilo chlorurus (con't.)
Sibley, C. G. 1955. The generic allocation of the Green-
tailed Towhee. Auk 72:420-423.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Willett, G. 1912. Birds of the Pacific slope of southern
California. Pacific Coast Avifauna No. 7.
~
•
HAIRY WOODPECKER
Picoides villosus leucothorectic
I TAXONOMY
A. Type description
Dryobates villosus leucothorectis - AOU (1957) Oberholser,
Proc. U.S. Nat. Mus . , 40 , June 3 , 1911, P.. 597 (in key),
608. (Burley, New Mexico)
B. Current systematic treatments
AOU (1957) calls this species Dendrocopos villosus
leucothorectic (Oberholser) and a subspecies of the Hairy
Woodpecker. Oberholser (1911) called it Dryobates villosus
leucothorectic. Morony, et al. (1975) synonymized this
species to Picoides after Dendrocopos, the genus recognized
by Peters (1948;.
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), "Dryobates villosus hyloscopus,
part.", in describing Dryobates villosus leucothorectis .
Grinnell (1902), describing Dryobates villosus hyloscopus,
"Dryobates villosus harrisi, part, Picus harrisi, Picus
# villosus, Picus villosus harrisi, Dendrocopus harrisi."
Peters (1948), "Dendrocopos villosus leucothorectic."
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), "Cabanis Woodpecker, part.;
White-breasted Woodpecker; Hairy Woodpecker, part.", in
describing the White-breasted Hairy Woodpecker. Dawson
(1923), "Southwestern Hairy Woodpecker. Arizona Hairy
Woodpecker."
II DESCRIPTION
A. External morphology of adults
Dawson (1923), "Males average: wing 126.8 (4.99); tail 79.4
(3.126); bill 30.8 (1.21); tarsus 21.5 (.846). Females
smaller." In describing D. v. orius, a similar race differ-
ing only by being slightly larger than D. y. leucothorectis,
which also has pure white underparts, "Adult male: Above , in
general, black, glossy (at least) on head and nape, paling,
brownish dusky, on quills; nuchal feathers slightly lengthen-
ed, the anterior ones scarlet-red, forming a short nuchal
band; nasal tufts dingy white; a narrow white superciliary
and a broad white rictal stripe, curving upward and some-
times nearly meeting fellow on hind nape (rarely connecting
with white of back) ; a black area included on side of head
»
Picoides villosus leucothorectic (con't.)
continuous with nape; a black malar stripe broadening behind;
a lengthened white patch down middle of back, connecting
with sides of rump, or not; one to several rounded spots
of white on middle wing-coverts, or not; primaries (except
usually the first) and the outer secondaries marked with
angular white spots on outer webs and with large rounded
spots on the inner webs, the spots tending to fall into
bars on the closed wing; the two outer pairs of tail-feathers
white on exposed portion, and the succeeding pair chiefly
white on outer web and tip. Bill and feet plumbeous; iris
reddish brown. Adult female: Like male, but without red
on head." Peterson (1969), "Note the white back, large
bill... clear white back. .. spotted with white on wings; males
with a small red patch on back of head; females, without."
Udvardy (1977), "White head with black crown, eyemask, and
'whiskers. ' Male has red patch at base of crown; light
underparts; white back; black wings with white spots. Tail
black with white outer tail feathers. Female similar, but
lacks red patch."
B. External morphology of subadult age classes
Dawson (1923) in describing D. v. orius, a similar race,
"Like adult, but crown, instead of nape, red (scarlet,
grenadine red, grenadine, or even yellowish) ; the forehead
and often the crown finely spotted with white."
C. Distinguishing characteristics
Interspecific - Peterson (1969), "Other woodpeckers have
white rumps or white bars on the back, but the Downy and
the Hairy are the only common woodpeckers with clear white
backs... The Hairy is like a magnified Downy: bill is especially
large in relation to Downy' s little bill. Downy at close
range shows spots on outer tail feathers. Northern Three-
toed Woodpecker of boreal forests may have white back."
Robbins, Bruun, Zim (1966), "Easily confused with. . .Northern
Three- toed Woodpecker, which has barred sides and a much
narrower white eye stripe."
Intraspecific - In Bent (1939), "...much like D. v. monticola
but decidedly smaller; wing coverts practically always with-
out white spots." Dawson (1923), "Adults: Similar to D^ y.
orius, but slightly smaller; the underparts pure white. A
very dubious race. Bendire (1895), "...it is distinguish-
able from the former (D. villosus) by its plain back or much
less spotted wing coverts and tertials, and from D. v.
harrisii by its lighter-colored underparts and somewKat
smaller size. "
•
*
#
#
Picoides villosus leucothorectis (con't.)
I GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) in describing P. villosus, "Central Alaska,
middle Yukon, central Mackenzie, northern Manitoba, James
Bay, south- central Quebec, and Newfoundland south to north-
ern Baja California, Mexico, central Texas, the Gulf coast,
southern Florida, the Bahama Islands, and through the moun-
tains of Central America to western Panama."
In describing P. y. leucothorectis, "Resident in the White
Panamint, Coso, Grapevine, and Clark mountains in south-
eastern California, the higher mountains in southern Nevada
and southern Utah, Arizona (except southwestern deserts,
and mountains in southeastern part) western and central
New Mexico, and the Guadalupe Mountains in western Texas."
B. California distribution of the species
Grinnell and Miller (1944), "Life-zones, Upper Sonoran to
Hudsonian." Small (1974), "Length of state except Central
Valley and deserts of the eastern and southeastern portions."
Miller (1951) found them in Inyo Mountains. Grinnell (1915),
gives various California locations and found this to be the
representative race in the White and Panamint mountains,
in Mono and Inyo Counties, and gives additional locations
(1918). Mailliard (1918) found them in Yosemite Valley.
Willett (1953) also gives various locations. Dawsbn (1923),
"...at least the White and Panamint Mountains, ... the bird
is decidedly more abundant in the northern and more elevated
portions of its range."
C. California desert distribution
Small (1974) says that this species is not found in eastern
and southeastern deserts. Grinnell (1902) says it is found
"chiefly in Transition south and east of the northern humid
coast belt." Miller (1940) found them at Clark Mountains.
Wauer (1962) found them in Death Valley during winter.
D. Seasonal variations in distribution
Small (1974), if the winters are not too severe, "Resident
species such as... Hairy Woodpeckers can remain in the mon-
tane forests in considerable numbers." Grinnell (1915)
reported as "more widespread throughout winter through the
interior valleys west of the Sierras." Willett (1933)
reported as "quite numerous in oak regions during severe
winters..." In Bent (1953), "Breeds commonly throughout
the pine belt, often ascending higher in summer. . .About
Picoides villosus leucothorectic (con't.)
the middle of June, the young leave their nests, and soon
make a partial migration downward towards the lower border
of the pine belt.1 Peterson (1969), "...mainly in moun-
tains in southwest United States. .. Some down-mountain drift
in winter." Dawson (1923), "In summer the bird ranges up
to timberline, a little above the normal breeding level;
and in winter it visits the live oaks and the sycamores or
even takes a turn through the chaparral." Bendire (1895),
"It is practically a resident wherever found, and its breed-
ing range is coextensive with its geographical distribution.
In winter it is often met with in the valleys adjacent to
mountain ranges, to which it retires in summer to breed;
but these vertical migrations, if they may be called so,
are never very extended."
IV HABITAT
A. Biotopic affinities.
Grinnell and Miller (1944), "Broken or scattering forest.
Has been found associated with pinon, juniper, white fir,
foxtail, limber and hickory pines, mountain mahogany, cotton-
wood and aspen." Also gives life-zones as Upper Sonoran
to Hudsonian. Small (1974), "Montane forest to Transition
Life Zone; also broken and mixed coniferous and deciduous
forest. Two Hairy Woodpeckers are also found in relatively
pure stands of Black Oak (Oak Woodland) in dry valley floors
and on small mesas. Miller (1951) found these in Upper
Sonoran, Transition, Canadian, and Hudsonian Zones, pinon-
juniper formations, riparian woodlands, coastal forest,
montane forest, and subalpine forest. Peterson (1969),
"Montane forests, woodlands, river groves." Robbins, Bruun,
Zim (1966), "Fairly common, especially in mature deciduous
or mixed woods." Udvardy (1977), "Deciduous trees; coniferous
stands, especially in montane forests and river groves."
Dawson (1923), "...favorate resorts are old burns and the
edges of clearings, logged-off areas, open, rangy woods,
and interrupted groves.
B. Altidudinal range
Grinnell and Miller (1944) reported 6200 to 9000 feet as
altitudes of capture of specimens. Bendire (1895), reported
it up to 10,000 feet.
C. Home range size
D. Territory requirements
»
Perch sites -
•
Picoides villosus leucotherectic (con't.)
Courtship and mating sites - Bendire (1895) reported that
males drum on resonant dry limbs to attract females.
Nest sites - Peterson (1969), "In holes in tree stub."
Udvardy (1977), "...eggs on wood chips in a previously used
tree hole or newly excavated cavity. Dawson (1923), says
nests are excavated in trees such as dead firs or pines and
sometimes living alders. The nest height is from 4 to 80
feet from the ground and about 10 inches deep.
E. Special habitat requirements
Ligon (1970) reports that they need standing dead timber
to breed.
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
In Bent (1939), reports of "small black beetles. . .wood
ants. . .woodbo ring larvae, caterpillars, moth pupae, other
insects and mast." Dawson (1923) reports worms and larvae
from trees. Nearly half of the food is larvae of wood-
boring beetles (Cerambycidae and Buprestidae) , the rest
being caterpillars, wild raspberries and blackberries, cornel
berries, acorns, pits of the evergreen cherry. Bendire
(1895), "...food, which consists principally of injutious
larvae and eggs of insects, varied occassionally with a
diet of small berries and seeds, ... .pinon nuts, pine seeds,
and acorns." Also, around slaughterhouses, small bits of
meat and fat.
B. Foraging areas
Bendire (1895) and Dawson (1923) both give examples of the
trees upon which these birds feed and which include apple
trees, oaks, willows, etc.
C. Foraging strategies
Udvardy (1977), "Woodpeckers secure their food by hammer-
ing holes through bark and then extracting grubs with their
extremely long, flexible tongues." Bendire (1895) describes
the feeding behavior of these birds (chiseling at trees
with bill while hanging on with sharp claws and using tail
as support), and the use of the tongue. Kisiel (1972)
discusses how Hairy and Downy Woodpeckers divide the resources
by feeding on different species of trees. Neff (1928),
reports that they tunnel for insects and probe with their
tongues for the larvae.
Picoides villosus leucothorectic (con't.)
D. Feeding phenology ^^
Dawson (1923) reports wild blackberries and raspberries are
eaten in summer and acorns, cornel berries, and pits of the
evergreen cherry are eaten in winter. Bendire (1895) reports
the birds eating pinon nuts, pine seeds, and acorns in
winter and insect eggs and larvae and berries at other times.
Also, some fat and meat from slaughtered animals in winter.
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Dawson (1923) reports strong defense of the nest, especially
by the male. Bendire (1895; reports that they drive other
species of woodpeckers from their feeding grounds. Kilham
(1960) reports that males and females have separate fall
and winter territories, and "mark" them by drumming.
C. Courtship and mating behavior
Bendire (1895) described the male drumming which he believed
was to attract a female. He thought they remained paired
for life. The female incubates the eggs as well as the
male, and both build the nest. Carpenter (1919) believes
they remain mated for a number of years as well as Willard
(1918). Kilham (1960) reports that the female may attract
the male by drumming in her fall and winter territory and
join him in display flights.
D. Nesting phenology
Willett (1933) reported as breeding mostly in April and May.
Dawson (1923) reported incubation to begin from the last
week in March to the last of May. Bendire (1895) reported
that mating season begins in March (latter part). Eggs are
laid in April -May.
E. Length of incubation period
Bendirc (1895), "2 weeks."
F. Length of nestling period
Bendire (1895) "about 3 weeks."
G. Growth rates
Picoides villosus leucothorectic (con't.)
H. Post-breeding behavior
Dawson (1923) reported only one brood is raised per season.
Bendire (1895), reported that they care for the young for
some time after they have left the nest.
VII POPULATION PARAMETERS
A. Clutch size
Willett (1933) reported clutches of 3 and 4 eggs. Bent (1939)
reported clutches of the same amount. Peterson (1969),
"Eggs (3-6)." Udvardy (1977), "3-6 eggs." Dawson (1923)
reported 4 or 5. Bendire (1895), 3-6, commonly, 4.
B. Fledging success
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
Neff (1928) found them more abundant in a given area in
winter. During the other seasons, they tend to associate
^ only in pairs or singly.
F. Habitat density figures
Koplin (1969) reports that density changes as the amount of
prey items change due to fire and floods. For example, there
is a 50-fold increase in response to insect increase due
to a fire. Neff (1928), "The Hairy Woodpeckers are not
especially companionable and seem to prefer the more secluded
timber or the wooded mountain sides. . .Generally, they work
in pairs... Only during the winter months do they venture
in any numbers." Short (1971), "The Hairy Woodpeckers re-
quire much larger territories. . .hence their populations
are less dense than those of pubescens and nuttallii."
VIII INTERSPECIFIC INTERACTIONS
A. Predation
B. Competition
Bendire (1895), "It does not live in harmony with smaller
species of its own kind, and drives them away, when they
•
encroach on its feeding grounds." Ligon (1970) reports
competition for nesting and foraging sites with the Red-
cockaded Woodpecker.
Picoides villosus leucothorectic (con't.)
C. Parasitism
IX STATUS
A. Past population trends
Grinnell (1902), reported it as "a common resident in suit-
able localities throughout the State." Grinnell (1915)
reported it as a common resident in the Canadian, Transition,
and high Upper Sonoran zones except in northwest humid coast
belt. Willett (1933) reported it as a common resident
of mountains and less common in lower country.
B. Present population status
Grinnell and Miller (1944) reported it as permanently resi-
dent. Numbers usually small and individuals wisely scatter-
ed. Small (1974) reported it as a resident. Ligon (1970)
believes the numbers are now greater in open pine land than
previously.
C. Population limiting factors
Ligon (1970) reports that reduced standing dead timber
decreases the population.
D. Environmental quality: adverse impacts
Ligon (1970) reports that they need dead standing timber
to breed, and repeated fires reduce this.
E. Potential for endangered status
♦
Picoides villosus (con't.)
FXI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American Birds. 5th Edition. American Ornithologists'
Union. The Lord Baltimore Press, Inc. Baltimore, Mary-
land. 691. pp.
Bendire, C. 1895. Life histories of North American birds.
Volume 2. Smithsonian Contributions to Knowledge #985.
Smithsonian Institution, Washington, D.C. 518 pp.
Bent, A. C. 1939. Life histories of North American wood-
peckers. Smithsonian Institution. United States National
Museum Bulletin #174. U.S. Gov't. Printing office.
Washington. 334 pp.
Carpenter, N. K. 1919. Evidence that many birds remain
mated for a number of years. Condor 21:28-30.
Dawson, W. L. 1923. The birds of California. Volume Two.
South Moulton Company. San Diego. 1432 pp.
Grinnell, J. 1902. Checklist of California birds. Pacific
Coast Avifauna #3. Cooper Ornithological Club. Santa
Clara, California. 98 pp.
Grinnell, J. 1915. A distributional list of the birds of
California. Pacific Coast Avifauna #11. Cooper Ornith-
ological Club. Hollywood, California. 217 pp.
Grinnell, J. 1918. Seven new or noteworthy birds from east-
central California. Condor 20:86-90.
Grinnell, J. and A. H. Miller, 1944. The distribution of the
birds of California. Pacific Coast Avifauna Number 27.
Cooper Ornithological Club. Berkeley, California. 608 pp.
Kilham, L. 1960. Courtship and territorial behavior of hairy
Woodpeckers. Auk 77:259-270.
Kilham, L. 1972. Reproductive behavior of White-breasted
Nuthatches. Auk 89:115-129.
Kisiel, D. S. 1972. Foraging behavior of Dendrocopos villosus
and D. pubescens in eastern New York State. Condor 74:
393-399.
Koplin, J. R. 1969. The numerical response of woodpeckers to
insect prey in a subalpine forest in Colorado. Condor 71:
436-438.
10
Picoides villosus (con't.)
Ligon, J. D. 1970. Behavior and breeding biology of the Red-
cockaded Woodpecker. Auk 87:255 278.
Mailliord, J. 1918. Early autumn birds in Yosemite Valley.
Condor 20:11-19.
Miller, A. H. 1940. A transition island in the Mohave Desert.
Condor. 43:161-163.
Miller, A. 1951. An analysis of the distribution of the birds
of California. University of California Publications in
Zoology. Vol. 50, #6, pp. 531-644.
Morony, J. J. Jr., W. J. Bock, J. Farrand, Jr. 1975. Reference
list of the birds of the world. The American Museum of
Natural History. New York. 207 pp.
Neff, J. A. 1928. A study of the economic status of the com-
mon woodpeckers in relation to Oregon Horticulture. Free
Press Print, Marionville, Mo. 68 pp.
Oberholser, H. C. 1911. A revision of the forms of the Hairy
Woodpecker (Dryobates villosus CLinnaeusj) . Proc. U.S.
Nat . Mus . , vol. 40, pp. 595-621 .
Peters, J. L. 1948. Checklist of birds of the world. Vol.
VI. Harvard University Press. Cambridge. 259 pp.
Peterson, R. T. 1969. A field guide to western birds.
Houghton Mifflin Company. Boston. 366 pp.
Ridgway, R. 1914. The birds of North and Middle America.
Part VI. Bull, of the U.S. Nat'l. Museum. Gov't. Print-
ing Office. Washington, D. C. 822 pp.
Robbins, C. S. , B. Bruun, H. S. Zim. 1966. Birds of North
America. Western Publishing Company, Inc. Racins, Wiscon-
sin. 340 pp.
Short, L. L. 1971. Systematics and behavior of some North
American Woodpeckers, Genus Picoides (Aves). Bull, of the
Am. Mus. of Nat'l. Hist, vol"! 145: Article 1, pp. 1-118.
Small, A. 1974. The birds of California. Winchester Press.
New York. 310 pp.
Udvardy, M. D. F. 1977. The Audubon Society Field guide to
North American birds. Alfred A. Kropf, Inc. New York.
855 pp.
11
Picoides villosus (con't.)
Wauer, R. H. 1962. A survey of the birds of Death Valley.
Condor. 64:220-233.
Willard, F. C. Evidence that many birds remain mated for
life. Condor 20:167-170.
Willett, G. 1933. A revised list of the birds of Southwestern
California. Pacific Coast Avifauna #21. Cooper Ornithol-
ogical Club. Los Angeles, California. 204 pp.
*
♦
♦
t
HOUSE FINCH
Carpodacus mexicanus
I TAXONOMY
A. Type description
AOU (1957), Fringilla frontalis, in Long, Exp. Rocky Moun-
tains, vol. 2~, 1823, p. 40 (note). (Arkansas River near the
mountains = near Colorado Springs, Colorado.)
B. Current systematic treatments
Howell, Paynter, and Rand (1968), recognize twenty-one
species of the genus Carpodacus ; twelve subspecies of the
species mexicanus . Order: Pass eri formes; Family:
Fringillidae (Carduelinae) .
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), Fringilla frontalis; Erythrospiza
frontalis; Carpodacus frontalis; Carpodacus familiaris;
C. rhodocolpus; C. jE. rhodocolpus; C. IT. frontalis; C.
dementis; C. mexicanus obscurus; C. m. dementis; C. m.
solitudinus ; C. m. grinnellii.
V D. Synonomies of vernacular nomenclature
Dawson (1923), Crimson-fronted Finch; Burion; California
Linnet. Grinnell and Miller (1944), Crimson-necked Finch;
Crimson- fronted Purple Finch; Purple House Finch; California
Purple Finch; Domestic Purple Finch; Red Linnet; House
Linnet; Linnet; Red-fronted Linet; California House Finch;
Crimson House Finch; San Clemente House Finch; Grinnell
House Finch; Desert House Finch.
II DESCRIPTION
A. External morphology of adults
Dawson (1923), "Adult male in highest spring plumage: Head
and neck all around, throat, and breast, broadly, and rump,
rich red (carmine, light carmine, or napal red), or, rarely,
tinged with orange; upper back more or less tinged with the
same shade...; remaining upperparts, wings, and tail brownish
gray, or fuscous; margins of feathers vaguely paler; remain-
ing underparts whitish finely streaked with brownish gray. . .
Bill horn-color; feet and legs dark brown. In autumn, the
reds duller (grayer), more blended, and more widely diffused;
the intensity of red, especially, reduced on crown, where
varied by darker centers to feathers (pure only on forehead) ;
Carpodacus mexicanus (con't.)
the wings with many edgings of pinkish, or brownish buffy,
not present in spring. In this plumage the appearance of
C. m. frontalis very closely approximates that of C. purpureus
. . .Adult female in spring: Above dull grayish brown, streaked
with darker; below dull white, sharply and finely streaked
with grayish brown or dusky; wings and tail grayish brown
without distinguishing marks. Adult female in fresh fall
plumage: Above, plumage more blended; wings with some mar-
ginings of lighter (buffy gray); below, streaks broader and
less distinct by reason of buffy edgings." Ridgway (1901),
detailed description of C. m. mexicanus with comparison
with frontalis, including plumage, soft parts, and measure-
ments. Michener and Michener (1931), discussion of color
variation in the plumage of males--based upon observations
during banding activities. Peterson (1961;, "Male: Near
size of House Sparrow, brownish with bright red breast,
forehead, stripe over eye, and rump. . .Female: Sparrow-like;
gray-brown above; underparts streaked with dusky; face with-
out strong stripings, bill stubby."
B. External morphology of subadult age classes
Dawson (1923), "resemble the female parent, but are more
finely streaked with dusky below, and more heavily margined
by brownish buffy, especially on wing-coverts and tertials."
C. Distinguishing characteristics
Interspecific - Dawson (1923), "red never so widely diffused
above as in C. purpureus californicus) . . .Female not certainly
distinguishable from that ot Purple Finch in autumn, but
upper plumage rather more blended and grayer, less olivaceous."
Peterson (1961), male: "Resemble males of Purple and Cassin's
Finches (which do not nest about buildings); is brighter
red. Some are almost orange. Narrow dark stripes on flanks
and belly are best distinction."
Intraspecific - Ridgway (1901), "Smaller than C. m. mexicanus
and C. m. rhodocolpus, but larger than C. m. sonoriensis and
C. m. ruberrimus ; in coloration, the adult male intermediate
"Between the first named and the rest in extent of the red,
this being less restricted and less sharply defined and less
intense than in C. m. mexicanus, the crown, occiput, and
back often tingecl with red, but rarely to the same extent
as in C. m. rhodocolpus; C. m. sonoriensis, and C. m. ruber-
rimus; female rather grayer and more distinctly streaked
above than that of C. m. mexicanus."
♦
t
Carpodacus mexicanus (con't.)
I GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
Dawson (1923), "Western United States from Oregon, southern
Idaho, and southern Wyoming, east upon the plains to Kansas,
and south throughout Lower California and to southern border
of the tableland of Mexico." C. m. frontalis: As above,
excepting the southern half of Lower California and the
southern portion of old Mexico." AOU (1957), "Breeds, and
largely resident, from southwestern and south-central British
Columbia (Victoria, Williams Lake, Okanagan Landing), central
western and southern Idaho (Moscow, Boise, Pocatello), central
northern and southeastern Wyoming (Big Horn Valley, Tarring -
ton), and western Nebraska (Kimball County, Haigler) south
through California, including the northern Channel Islands,
to central Baja California (Todos Santos Islands, Cedros
Island, Santana) , central Sonora (Tiburon Island, San Pedro
Martir Island, Oposura) , northwestern Chihuahua (Chihuahua),
and western and south-central Texas (Boquilla, Somerset,
Austin). Introduced in Hawaii, and on Long Island, New York,
where now (1956) breeding in southern Nassaw and southwestern
Suffolk counties; breeding also in Greenwich Township,
Fairfield County, southwestern Connecticut."
B. California distribution of the species
Dawson (1923), "Abundant resident throughout the State below
Transition." Grinnell and Miller (1944), "Breeds in all
sections of State, exclusive of high montane areas and
coastal islands from Santa Barbara Island southward, where
replaced by the race dementis; of but scattered occurrence
within northwest coastal belt. Life-zones, Lower Sonoran
and Upper Sonoran; locally in Transition." Keeler (1890),
"In California it resorts chiefly to the valleys, both
of the coast and interior region, but it occurs in the
mountains to the height of at least three thousand feet."
C. California desert distribution
Smyth and Coulombe (1971) report this species frequenting
desert springs for drinking, Upper Carrizo Spring, Riverside
County.
D. Seasonal variation in distribution
AOU (1957), "In winter to the Gulf coast of southern Texas.
Casual north to Alberta (Topaz Lake) and Montana (Santon
Lake), east to northeastern Texas (Fort Worth), and south
to southern Sonora (Chinobampo) ." Grinnell and Miller (1944),
Carpodacus mexicanus (con't.)
"Wanders to some degree, especially in late summer, but
definite migratory movements not apparent. Evidently de-
parts in winter from some higher points in breeding range,
especially along eastern flank of Sierra Nevada." Salt
(1952), "Throughout much of their range house finches move
up into the mountain valleys in the late summer after the
breeding season and return to the lowlands with the onset
of colder weather." Keeler (1890), "Its distribution in
winter does not differ essentially from its summer range,
as its migrations are caused merely by local influences,
such as scarcity of food or a cold spell."
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), "Open places and sunshine are
favored and in the foothill districts, great interior valleys
and coastal plains the House Finch is the predominant
avian species in fields and orchards, and about scattered
trees and ranch buildings." Small (1974), "open woodland,
edges of forest, woodland, and chaparral; desert cities,
towns, suburbs, gardens, parks, farms, ranches, agricultural
land, savannah." Miller (1951), Upper and Lower Sonoran
and Transition life zones.
B. Altitudinal range
Grinnell and Miller (1944), "Altitudes of nesting range
from -200 feet as in Death Valley, Inyo County, up rarely
to 8000 feet, as at Mammoth, Mono County. . .May occur even
higher in late summer."
C. Home range size
Gullion (1960), "highly mobile species, capable of moving
considerable distances from one food supply to another."
D. Territory requirements
Perch sites - Salt (1952), "Any structure will do: the ridge
pole of a house, a telephone pole, or the top of a tree."
Courtship and mating sites -
Nest sites - Thompson (1960a), "in dense foliage and often
build in ivy under the eaves of a building, if such a site
is available. In the absence of dense foliage or a man-made
structure, they may nest in crannies on cliffs." Robertson
(1931a), "The loose bark of the blue gum seems to have been
designed especially for Linnets ... to nest in. They build
m
Carpodacus mexicanus (con't.)
i behind slabs of bark on the trunks or larger limbs, or in
accumulations of bark in the crotches." Dawson (1923),
"nest almost anywhere ... Caught in vines, or placed on timbers,
under cornices, in bird-boxes, mail boxes." Bergtold (1913),
"in vines about houses, in sheltered corners and awnings
of buildings. . .in any place of vantage about a building
...In globes, when partly broken, surrounding incandescent
lamps.
E. Special habitat requirements
Grinnell and Miller (1944), "Habitat--Remarkably varied,
the following apparent requirements being met by a great
diversity of situations: (l) water, at least within a fairly
wide daily cruising radius, fruits perhaps forming a satis-
factory substitute; (2) open ground of limited or great
extent thus affording growths of low seed-producing plants,
especially composites; (3) sources of fruits and berries
during part of year (possibly not essential); (4) trees,
cliffs and earth banks, or man-made structures for roosting
and placement of nests above ground in sites often partly
enclosed. These requisites are not met in forest associa-
tions or continuous chaparral, although they may be found
in woodland formations, in forest and chaparral edges and
on treeless plains and deserts; low temperatures in summer
i and high rainfall and heavy wet fogs either hold low the
number of individuals or seem to account for the absence
of the species in some areas."
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Thompson (1960a) "primarily seedeaters. . .but they also eat
fruit, and are considered a pest by fruit growers. . .Ripe
thistle. . .other composites." Fisk and Steen (1976), report
this species feeding on nectar (at feeders in California).
Bergtold (1913), "will eat almost anything vegetable, though
it prefers seeds."
B. Foraging areas
Thompson (1960a) "Large numbers. . .are attracted to fields
of blooming and fru
and radi sh( Raphanus
C. Foraging strategies
of blooming and fruiting wild mustard (Brassica campestris)
sativus) in the spring."
#
Salt (1952), "either forage directly on the ground, or they
may pick the seeds and flowering heads from the plants while
hanging onto the stems or branches."
Carpodacus mexicanus (con't.)
D. Feeding phenology-
Salt (1952), "rely throughout the year more on ground feed-
ing...During the breeding season about three-fourths of their
food consists of seeds of annual grasses and forbs...As in
some other fringillids, the food preferences of this species
changes from one species of plant to another during the
course of the growing season, depending upon the time at
which the seeds develop." Bergtold (1913), "In winter when
the ground is unusually deeply covered by snow, these birds
wander far and wide over the prairie and vacant city lots,
eating weed seeds."
E. Energy requirements
Partin (1933), detailed study of daily and seasonal fluctua-
tions in body weight; adult males and females and young.
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Thompson (1960a), 7!In early spring when pairs are forming,
aggressive behavior reaches a peak. Increasingly, males ^^
become intolerant of other males perched near them. Males,
when they have secured a mate, defend the area around the
female... The peak of aggressive activity continued through
the selection of a nest site and the construction of the
nest, but it begins to wane by the time the nest is com-
pleted. The area around the nest is defended rather sporadi-
cally and weakly. Vigorous displays are rarely observed
in territorial defense. Usually the defender merely flies
to a perch near the intruder and sits until the latter moves
away." Thompson (1960b), detailed discussion of agressive
behavior.
C. Courtship and mating behavior
Thomspon (1960a), "The first evidence of pair formation in
captive House Finches is billing, accompanied by soft
twittering. . .Later the male accompanies this mock feeding
with regurgitating movements of the throat, but no food
passes into the female's open mouth... The female usually
begins to big from the male. . .At about the time of nest
building, the male actually feeds the female regurgitated
material .. .Copulation in the House Finch normally occurs
at the invitation of the female."
^
•
Carpodacus mexicanus (con't.)
D. Nesting phenology
Davis (1933), reports in Butte County, California the first
date as 16 April; the last date as 9 May; the average date
as 28 April. Dawson (1923), "March to July; 2 or 3 broods."
E. Length of incubation period
Evenden (1957), "The average incubation period for the 11
nests was 13.27 days. . .Extremes of 12 and 14 days." Berg-
told (1913), "The average length of incubation is 14 days."
F. Length of nestling period
Evenden (1957) "residence of individual young varied from
11 to 19 days within one nest, with nest averages ranging
from 13.2 to 17.0 days; the overall average was 15.1 days."
Bergtold (1913), "The young remained about fourteen days
in the nest."
G. Growth rates
Evenden (1957), "it was noted that growth rates varied from
young to young, nest to nest, month to month, and year to
year." Keeler (1890), "The growth of the young bird is
# rapid and constant. In ten days the chord of the culmen
had grown from four to eight millimeters, the gape had
increased from five and a half to eleven millimeters, and
the tarsus from five to fourteen millimeters."
H. Post-breeding behavior
Thompson (1960a), "It is not known what happens to the young
just after they leave the nest, but they probably do not
join large feeding flocks during the several weeks when they
are fed by both parents. Later on juveniles and adults
may assemble where food is plentiful..." Austin (1968),
"With the close of the nesting season in late summer, house
finches of all ages begin to gather in flocks and search
out the larger tracts of maturing weeds, whence they flush
and circle in clouds."
VII POPULATION PARAMETERS
A. Clutch size
Evenden (1957), "completed clutches averaged 4.4 eggs."
Thompson (I960), "The nests examined in Strawberry Canyon
averaged 4.7 eggs per clutch, with a range of three to
•
six."
Carpodacus mexicanus (con't.)
B. Fledging success
Evenden (1957), "There was a 52 per cent fledging success
based on 110 eggs laid, and a 70 per cent fledging success
based on 80 young hatched."
C. Mortality rates per age class
Bergtold (1913), "Over forty per cent of the eggs laid were
ultimate failures, the largest factor in the loss being
destruction of the eggs and young by the English Sparrow
...About ten per cent loss is caused by late spring storms,
climatic conditions lasting but a short time."
D. Longevity
Michener and Michener (1933), report ages of birds based
upon banding records. Of known-age individuals when first
banded, recaptured individuals, 7 males were 4 years and 8
months old; two were 5 years and 7 months old; one female
was 6 years and 8 months old. Of individuals whose ages
were not known when first banded (as adults), five were
at least 5-1/2 years old; one was at least 6-1/2 years old;
two were at least 8-1/2 years old.
E. Seasonal abundance
Austin (1968), "Even in the mildest regions of coastal
California, the numbers of the house finch are distinctly
less in winter, though some remain throughout the year in
almost all localities."
F. Habitat density figures
Gaines (1974), reports 35 territorial males per square kilo-
meter in clumped cottonwood and willow woodland, Glenn and
Butte Counties, California.
IIII INTERSPECIFIC INTERACTIONS
A. Predation
Bond (1936), reported two pellets of the Prairie Falcon
containing remains of this species, San Luis Obispo, Calif-
ornia. Evenden (1957), "Neighborhood cats accounted for
almost the entire loss of young." Sumner (1928), reports
a headless immature in the nest of Screech Owls."
•
Carpodacus mexicanus (con't.)
B. Competition
Evenden (1957), "Competition between House Finches and House
Sparrows for nesting sites was particularly strong early
in the season." (Sacramento, California). Thompson (1960a),
"It is more often the somewhat larger and heavier House
Sparrow which wins fights between the two species." Berg-
told (1913), "The loss of nests, eggs and young of the House
Finch through direct destruction by the English Sparrow is
very large. It was 16% in some of the nests studied...
the English Sparrow overcomes, and is superior to, the House
Finch in the biologic struggle."
C. Parasitism
Hanna (1933), reports on incident of the nest of this species
containing 3 eggs of the finch and one of the Dwarf Cowbird.
The nest was deserted. A nest of a Black Phoebe contained
four eggs of the House Finch and one of the phoebe; the
phoebe at this time was building a new nest a few feet away.
Robertson (1931b), reports finding cowbird eggs in the nests
of this species. Evenden (1957), "Brown-headed Cowbirds
(Molothrus ater) were present but did not parasitize finch
nests in this area."
X STATUS
A. Past population trends
Grinnell and Miller (1944), "Permanent resident. Abundant
generally, except in situations marginal from the standpoint
of zone and habitat."
B. Present population status
Small (1974), "common resident."
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
10
Carpodacus mexicanus (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Austin, 0. L. , Jr. 1968. Life histories of North American
cardinals, grosbeaks, buntings, towhees, finches, sparrows,
and allies. Part 1. Bull. U.S. Nat. Mus. No. 237.
Bergtold, W. H. 1913. A study of the House Finch. Auk 30:
40-73.
Bond, R. M. 1936. Some observations on the food of the Prairie
Falcon. Condor 38:169-170.
Davis, W. B. 1933. The span of the nesting season of birds
in Butte County, California, in relation to their food.
Condor 35:151-154.
Dawson, W. L. 1923. The birds of California. South Moulton
Co. , San Francisco.
Evenden, F. G. 1957. Observations on nesting behavior of the
House Finch. Condor 59:112-117.
Fisk, L. H. and D. A. Steen. 1976. Additional exploiters of
nectar. Condor 78:269-271.
Gaines, D. 1974. A new look at the nesting riparian avifauna
of the Sacramento Valley, California. Western Birds 5(3):
61-80.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna, No. 27.
Gullion, G. W. 1960. The migratory status of some western
desert birds. Auk 77:94-95.
Hanna, W. C. 1933. House Finch parasitized by Dwarf Cowbird
and Black Phoebe nests occupied by House Finch. Condor
35:205.
Keeler, C. A. 1890. Observations on the life history of the
House Finch (Carpodacus mexicanus frontalis) . Zoe 1:172-
176.
Michener, H. and J. R. Michener. 1931. Variation in color of
male House Finches. Condor 33:12-19.
<~
T
11
Carpodacus mexicanus (con't.)
Michener, H. and J. R. Michener. 1933. Ages of House Finches
trapped during February, 1933, at Pasadena, California.
Condor 35:183-185.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. Vol.
50, No. 6.
Partin, J. L. 1933. A year's study of House Finch weights.
Condor 35:60-63.
Peters, J. L. 1968. Checklist of birds of the world. Vol.
10. (T. R. Howell, R. A. Paynter, Jr., and A. L. Rand,
eds.). Mus. Comp. Zool., Cambridge, Massachusetts.
Peterson, R. T. 1961. Field guide to western birds. Houghton
Mifflin Co. , Boston.
Ridgway, R. 1901. The birds of North and Middle America.
Part 1. Bull. U.S. Nat. Mus. No. 50.
Robertson, J. McB. 1931a. Birds and eucalyptus trees. Condor
33:137-139.
Robertson, J. McB. 1931b. Some changes in the bird life of
western Orange County, California. Condor 33:204-205.
Salt, G. W. 1952. The relation of metabolism to climate and
distribution in three finches of the genus Carpodacus.
Ecological Monographs 22:121-152.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Smyth, M. and H. N. Coulombe. 1971. Notes on the use of desert
springs by birds in California. Condor 73:240-243.
Sumner, E. L. , Jr. 1928. Notes on the development of young
Screech Owls. Condor 30:333-338.
Thompson, W. L. 1960a. Agonistic behavior in the House Finch.
Part I: Annual cycle and the display patterns. Condor
62:245-271.
Thompson, W. L. 1960b. Agonistic behavior in the House Finch.
Part II: Factors in aggressiveness and sociality. Condor
62:378-402.
I
-
♦
•
LADDER-BACKED WOODPECKER
Picoides scalaris cactophilus
TAXONOMY
A. Type description
Dryobates scalaris cactophilus - AOU (1957) Oberholser,
Proc. U. S. Nat. Mus., 41, June 30, 1911, P. 140 (in key),
152. (Tucson, Arizona)
B. Current systematic treatments
Oberholser (1911) split Dryobates scalaris into 15 sub-
species, one of which was D. _s. cactophilus. AOU (1957)
calls this same species Dendrocopos scalaris cactophilus
(Oberholser), and a subspecies of the Ladder-backed Wood-
pecker. Morony, et al. (1975) synonymized this species
to Picoides after the genus Dendrocopos recognized by Peters
(194SJ;
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944) in describing Dryobates scalaris
cactophilus, "Dyctiopicus lucasanus ; Picus scalaris, part;
Dryobates scalaris; Dendrocopus scalaris; Dryobates scalaris
bairdi ; Dryobates scalaris lucasanus ; Dendrocopus lucasanus ;
Dryobates scalaris yumanensis; Dryobates scalaris mojavensis. "
Grinnell (1915), "Dryobates~~Tucasanus. " Peters (1948),
"Dendrocopos scalaris cactophilus."
*TT"
•
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), in describing the Cactus Ladder-
backed Woodpecker, "Barred Woodpecker; Arizona Woodpecker;
Ladder-backed Woodpecker, part; Texan Woodpecker, Mojave
Ladder-backed Woodpecker." Peterson (1969), "Mexican Wood-
pecker."
II DESCRIPTION
A. External morphology of adults
Peterson (1969), "The only black and white "zebra-backed"
woodpecker with a black and white striped face in the arid
country. . .Males have red caps." Robbins, Bruun, Zim (1966),
"Note the distinct black and white on side of head."
Dawson (1923), "Adult male: Extreme forehead and nasal
tufts snuff-brown, shading into sooty brown of forehead,
thence through black of crown, narrowly tipped with scarlet-
red and broadly subtipped with white, to nearly pure scarlet-
red on sides of occiput and nape, the fore-crown thus speckled
with white and red in varying proportions; cervix (narrowly),
Picoides scalaris cactophilus (con't.)
upper tail-coverts, and tail from above, black; back and
wings sooty brown or brownish dusky, heavily and equally
barred or spotted with white, the spotting of wings involv-
ing flight-feathers arranged in rows, equivalent to bars
when in repose; sides of head and neck, including super-
ciliaries and remaining underparts, pale buffy brown fading
to white on sides and crissum; included area of sides of
head black, invaded by malar streaks of buffy brown or
whitish; the sides of breast sharply and heavily spotted
with brownish black; the sides, flanks, and crissum indis-
tinctly barred with dusky; the under (outer) feathers of the
folded tail equal-barred black-and-white. Bill and feet
dusky horn-color; iris brown. Adult female: Like male, but
without red on crown or nape, glossy black instead, shading
to sooty brown on forehead; forehead sometimes sparingly
speckled with white. Length of adult male: 158.75-184.2
(6.25-7.25); wing 104 (4.09); tail 60.8 (2.39); bill 22.7
(.89); tarsus 18.1 (.71). Females' average slightly less."
B. External morphology of subadult age classes
Bent (1939), assumes young are hatched naked (as in other
woodpeckers). Juvenile plumage is acquired before young
leaves the nest, and is like that of an adult male, but the
sexes are not alike. Male: Forehead, sides of occiput, and
nape are uniform black. Crown is scarlet, more or less
dotted with white. Female: has much less scarlet on crown.
In both, back is barred with dull black and grayish white.
Underparts are "vinaceous-buff , " faintly spotted on the
sides and flanks. Plumage is softer and markings are not
as clearly defined as in adult." Dawson (1923), "Young
male: Like adult male, but nape and sides of occiput black,
the red carried forward and prevailing on crown; plumage
softer and pattern slightly blended. Young female: Like
young male, but red of crown somewhat reduced."
C. Distinguishing characteristics
Interspecific - Peterson (1969) ,"Nuttall ' s Woodpecker is
found only in California, west of Sierra, not in the desert.
There are minor differences in the amount of black on upper
back, pattern on face. Downy Woodpecker has white back.
Robbins, Bruun, Zim (1966), r,Told from Gila and Golden-
fronted by the dark rump, finely spotted sides, and lack
of white wing patch in flight." Udvardy (1977), "Zebra-
backed like Nuttall1 s Woodpecker, but with slightly smaller
black ear patch and face stripe, usually separated from
black of nape and back of white band. Male s red cap
usually more extensive than Nuttall' s."
•♦
Picoides scalaris cactophilus (con't.)
A Intraspecific - Bent (1939), "Much like D. _s. eremicus, but
J smaller, particularly the tail and bill; lower surface lift-
er, laterally almost always streaked with black; upper parts
lighter - the black bars on back and scapulars narrower;
wing quills with larger spots and broader bars on white;
outer long rectrices with exterior webs barred throughout
with black; black bars on posterior lower surface narrower."
As compared with D. _s. symplectus, "slightly larger, with
black bars on back, etcT, decidedly broader."
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) in describing P. scalaris, "From southeastern
California, southern Nevada, southwestern Utah, and southern
Colorado south through Mexico (including Baja California,
the Tres Marias Islands and Cozumel Island, Quintana Roo)
to Chiapas and British Honduras."
AOU (1957) in describing P. _s. cactophilus. "Resident in
the desert areas of southeastern California, southern Nevada,
southwestern Utah, central Arizona, central New Mexico, and
western Texas, south to the Colorado River Delta, in north-
eastern Baja California, to about lat. 20°N. in Sonora (in-
a eluding Tiburon Island), Chihuahua and northern Durango."
B. California distribution of the species
Grinnell and Miller (1944), lists numerous site and specimen
records throughout the birds' California range. States,
in general, Colorado and Mojave deserts. Life- zone, Lower
Sonoran, Small (1974), "Colorado and Mohave deserts." Miller
(1951) gives locations. Bendire (1895) reported that a
mated pair was found in San Gorgonio Pass and also some in
the Colorado desert.
C. California desert distribution
Grinnell and Miller (1944), "Colorado and Mojave deserts"
Lower Sonoran life-zone. Small (1974) also give this.
Grinnell (1902) reported them as common to deserts of the
southeastern corner of California, recorded west to Hesperia
and San Gorgonio Pass. Grinnell (1915) reported them as a
"common resident locally on the Lower Sonoran deserts of
southeastern California," and goes on to give various
localities. Willett (1933) gives locations, especially
in the Colorado Desert. Bent (1939) reports that this species
frequents the deserts or borders of deserts and lower slopes
of the mountains in the Sonoran Zone. Dawson (1923), "The
southeastern deserts, broadly; hence, occasionally invading
Picoides scalaris cac tophi lus (con't.)
the domain of nuttalli through Walker and San Gorgonio
Passes." Carter (1937) reported them at Twentynine Palms.
Hoffmann (1922) found them near Banning.
D. Seasonal variations in distribution
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), "Almost any kind of desert
terrain providing fair- sized shrubby vegetation and also
diggable woody stems or trunks of sufficient diameter for
nesting excavations. . .commonly by the trunks of tree-yucca
...cottonwood and willow. . .also telegraph poles." Small
(1974), "Low and high deserts, pinon- juniper woodlands."
Found also in desert scrub. Miller (1951) found them in
the Lower Sonoran areas, desert scrub, pinon- juniper forma-
tions and riparian woodlands. Peterson (1969;, "Deserts,
canyons, cottonwoods, arid brush,
Bruun, Zim (1966), "Fairly common
mesquite, less common in cactus."
and their borders; also mesquite,
and scrub oaks." Bendire (1895),
and river bottoms."
prairie groves." Robbins,
in deciduous woods and
Udvardy (1977), "Deserts
pinon- juniper woodland,
It prefers the lowlands
B. Altitudinal range
Grinnell and Miller (1944) states that they are found from
200 feet below sea level to 6,000 feet and up to 6800 feet
as a vagrant. Bendire (1895), "...rarely found at alti-
tudes above 4000 feet."
C. Home range size
D. Territory requirements
Perch sites
Courtship and mating sites
Nest sites - Grinnell and Miller (1944) state that almost
any type of desert terrain containing fair- sized shrubby
vegetation and diggable woody stems or trunks of sufficient
diameters will do. Bent (1939) repeats findings of nests
being from 2-30 feet off the ground in cavities in various
wooden structures and plants. Peterson (1969), "In hole
in tree, post, yucca, agave." Udvardy (1977), "...in the
tall (up to 30 feet high) dry stalk of a century plant or
agave; occasionally in a hole chiseled in a yucca, a cotton-
wood tree, or even a fence post." Dawson (1923), "Nest: A
ff
•
♦
♦
Picoides scalaris cactophilus (con't.)
hole at moderate height in giant cactus, Joshua- tree, willow,
or other tree." Also, the dried stalks of the agave and
lesser yucca and willows, as well as mesquite and telephone
poles. Bendire (1895), reported that it prefers mesquite
trees.
E. Special habitat requirements
Dawson (1923), "...requires something of more ample girth
for a nesting site (than creosote or cholla).
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Bent (1939) reports larvae of woodboring beetles, coddling
moths, and other Lepidoptera. Udvardy (1977) reports larvae
of the agave beetle. Dawson (1923) reported that they eat
the ripened fruit of the giant cactus. Bendire (1895)
reports this also.
B. Foraging areas
Grinnell and Miller (1944) state that foraging occurs in
trunks of the tree-yucca, trunks or dead flower stalks of
other yuccas, cottonwood and willow trunks, telegraph poles,
cactus clumps, various bushes and desert trees such as
mesquite, palo verde, and ironwood. Udvardy (1977) reports
century plant flower stalks. Austin (1978) has found that
males and females forage in different areas (on different
species of plants) , and that the species they feed on change
during the year. Females feed mainly on mesquite throughout
the year, while males switch between cholla, mesquite, and
others.
C. Foraging strategies
Bent (1939) reports that it gleans larvae from trunks and
branches of trees, usually at low elevations on small trees,
shrubs, cacti. Also, it sometimes feeds on the ground.
D. Feeding phenology
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
r
Picoides scalaris cactophilus ( con ' t . )
C. Courtship and mating behavior
D. Nesting phenology
Dawson (1923), "Season: March 25-May, rarely June." Bendire
(1895), "...full sets of fresh eggs are sometimes found by
the middle of April... but (usually) the first week of May."
E. Length of incubation period
Bendire (1895), "about 13 days."
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
Dawson (1923), "One brood." Bendire (1895), one brood,
rarely two, maybe.
VII POPULATION PARAMETERS
A. Clutch size
Bent (1939) gives clutch size as 2-6 eggs, usually 4 or 5. ^
Peterson (1969), and Udvardy (1977), say 4 or 5. Dawson
(1923), usually 4. Bendire (1895), 2-5, usually 4 or 5.
B. Fledging success
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
Bendire (1895), reports gregariousness in winter. In
December, 1885, flocks of 4-12 birds were encountered fre-
quently at 3,000 feet.
F. Habitat density figures
Bendire (1895) reported flocks of 4-12 on plains at 3,000
feet in December, 1885.
VIII INTERSPECIFIC INTERACTIONS
A. Predation
e
Picoides scalaris cac tophi lus ( con ' t . )
| B. Competition
Bent (1939) reports that in the regions where it is found,
there are no other species of woodpecker. Gila Woodpeckers
and Mearn's Gilded Flickers replace it in giant cactus
(Saguaro) regions. Short (1971) saw conflicts between these
and Nuttall's Woodpeckers.
C. Parasitism
IX STATUS
A. Past population trends
Grinnell (1902) reported them as "common resident in deserts
of southeastern corner of the State." Grinnell (1915)
reported them as a "common resident locally on the Lower
Sonoran deserts of southeastern California." Willett (1933)
reported them as a common resident of the Colorado Desert
west to San Gorgonio Pass.
B. Present population status
♦
Grinnell and Miller (1944) reported that they are permanently
resident and common with the degree of abundance dependent
on availability of nest sites. Small (1974) reported them
as resident.
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
#
Picoides scalaris (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American Birds. 5th Ed. American Ornithologists' Union.
The Lord Baltimore Press, Inc. Baltimore, Maryland. 691
pp.
Austin, G. T. 1976. Sexual and seasonal differences in forag-
ing of Ladder-backed Woodpeckers. Condor 78(3) : 317-323.
Bendire, C. 1895. Life Histories of North American Birds.
Volume 2. Smithsonian Contributions to Knowledge #985.
Smithsonian Institution. Washington, D.C. 518 pp.
Bent, A. C. 1939. Life Histories of North American Woodpeckers.
Smithsonian Institution. United States National Museum
Bulletin #174. U.S. Government Printing Office. Washington,
D.C. 334 pp.
Carter, F. 1937. Bird life of Twentynine Palms. Condor 39:
210-219.
Dawson, W. L. 1923. The Birds of California. Volume Two.
South Moulton Company. San Diego. 1432 pp.
Grinnell, J. 1902. Checklist of California Birds. Pacific
Coast Avifauna #3. Cooper Ornithological Club. Santa
Clara, California. 98 pp.
Grinnell, J. 1915. A distributional list of the Birds of
California. Pacific Coast Avifauna #11. Cooper Ornith-
ological Club. Hollywood, California. 317 pp.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
Birds of California. Pacific Coast Avifauna Number 27.
Cooper Ornithological Club. Berkeley, California. 608 pp.
Hoffmann, R. 1922. Field notes from Riverside and Imperial
Counties, California. Condor 24:101.
Miller, A. 1951. An analysis of the distribution of the birds
of California. University of California Publications in
Zoology. Vol. 50, #6, pp. 531-644.
Morony, J. J., Jr., W. J. Bock, J. Forrand, Jr. 1975. Refer-
ence list of the birds of the world. The American Museum
of Natural History. New York. 207 pp.
Oberholser, H. C. 1911. A revision of the forms of the Ladder-
backed Woodpecker (Dryobates scalaris ^WoglerJ ) . Proc. U.S.
Nat. Mus., vol. 41, pp. 139-lW.
c
<*
Picoides scalaris (con't.)
Peters, J. L. 1948. Checklist of birds of the world. "Vol.
VI. Howard University Press. Cambridge, 259 pp.
Peterson, R. T. 1969. A field guide to western birds.
Houghton Mifflin Company. Boston. 366 pp.
Ridgway, R. 1914. The birds of North and Middle America.
Part VI. Bull, of the U.S. Nat'l Museum. Gov't. Printing
Office. Washington, D.C. 882 pp.
Robbins, C. S. , B. Bruun, H. S. Zim. 1966. Birds of North
America. Western Publishing Company, Inc. Racine, Wiscon-
sin. 340 pp.
Short, L. L. 1971. Systematics and behavior of some North
American Woodpeckers, Genus Picoides (Aves). Bulletin of
the American Museum of Natural History. Vol. 145: Article
1, pp. 1-118.
Small, A. 1974. The birds of California. Winchester Press.
New York. 310 pp.
Udvardy, M. 0. F. 1977. The Audubon Society Field Guide to
North American Birds. Alfred H. Knopf, Inc. New York.
855 pp.
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna #21. Cooper Ornitholo-
gical Club. Los Angeles, California. 204 pp.
£
«
LAWRENCE'S GOLDFINCH
Carduelis lawrencei
I TAXONOMY
A. Type description
AOU (1957) Spinus lawrencei: Carduelis lawrencei Cassin,
Proc. Acad. Nat. Sci. Philadelphia, no. 3^ Sept. -Oct.
(Dec. 7), 1850, p. 105, pi. 5. (Sonoma and San Diego, Calif-
ornia. )
B. Current systematic treatments
Mayr (1968), recognizes C. lawrencei as a monotypic species
in a genus in which there are twenty- four species. Passeri-
formes: Fringillidae (Carduelinae) .
C. Synonomies of scientific nomenclature
Dawson (1923), Astragalinus lawrencei. Small (1974), Spinus
lawrencei. Grinnell and Miller (1944) , Chrysomitris
lawrencei; C. lawrencii; Astragalinus lawrencii.
D. Synonomies of vernacular nomenclature
DESCRIPTION
A. External morphology of adults
Dawson (1923), "Adult male in spring: General color neutral
gray, paling on underparts posteriorly; pileum, face, and
throat, narrowly, black; breast dark yellow..., everywhere
sharply outlined against the surrounding gray; rump yellow;
back touched with yellow centrally; the wings black, heavily
edged with yellow; the tertials bordered with white; tail
black, the three or four outermost pairs of feathers heavily
blotched with subterminal white on inner web. Bill light;
feet brownish. Adult male in autumn: as in spring, but
back and sides of hind neck brownish olive. Adult female
in spring: Like male in spring but without black on head
and throat; duller. In autumn: Above brownish olive."
Ridgway (1901), detailed description of adult male and female,
including plumage, soft parts, and measurements. Peterson
(1961), yellow wing-bars. Male: Gray-headed, with black
face. . . ; some yellow on breast and rump. . .No seasonal change.
Female: Lacks black face. Gray color, 2 yellow wing bars.
»
Carduelis lawrencei (con't.)
B. External morphology of subadult age classes
Dawson (1923), "Young birds are like adult female in autumn,
but yellow element is almost or quite confined to wing,
where also largely replaced by buffy brown edgings; breast
faintly streaked. ' Ridgway (1901), "Similar to adult female,
but colors duller, with yellow, especially on breast, less
distinct, and under parts obsoletely streaked."
C. Distinguishing characteristics
Interspecific - Peterson (1961), "only U.S. goldfinch with
a black chin. ..2 yellow wing-bars distinguish it (female)
from other goldfinches."
Intraspecific -
III GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), "Breeds in California west of the Sierra Nevada
(Hyampom southeast to Santa Rosa Mountains) and in northern
Baja California (Sierra Juarez, Sierra San Pedro Martir) .
Dawson (1923), "California and northern Lower California;
in winter east to Arizona (but chiefly at Colorado Valley
points) and New Mexico (Fort Bayard). ' Ridgway (1901),
'California and northern Lower California (breeding south
to San Pedro Martir Mounta'ins) ; in winter to Arizona."
B. California distribution of the species
Dawson (1923), "Of very local occurrence in summer west of
the Sierras, perhaps chiefly in the southwestern coast
districts, but also north through Great Valley to McCloud
River, in Shasta County and east to Weldon, Kern Co.,
Raymond, Madera Co., and Oroville, Butte Co.; breeding,
chiefly in Upper Sonoran life zone; perhaps casual breeder
in Lower Sonoran (Indian Wells, Colorado Desert...). Per-
haps casual on Catalina Island, but a regular breeder on
Santa Cruz Island." Small (1974), "West of Cascades and
Sierra Nevada and south of the northern mountains; coast-
wise (from about Sonoma County) and interiorly south through
Central Valley to Mexican border."
C. California desert distribution
Grinnell and Miller (1944), "Breeds in coastal districts
from Sonoma County south to Mexican boundary and interiorly,
west of Cascade- Sierran axis, from Shasta and Trinity counties
southward; extends eastwardly through mountains of southern
r
Carduelis lawrencei (con't.)
j California onto western edge of Mohave Desert in vicinity
of Victorville. . . In winter... in moderate numbers in coastal
southwestern California and in Coachella, Imperial, and
Colorado River valleys." Recorded at following sites:
Weldon and Mt. Pinos, Kern Co. ; Hesperia, Grapevines, and
Twentynine Palms, San Bernardino Co.; Azusa, Los Angeles,
and Pasadena, Los Angeles Co.; Escondido, Volcan Mts., and
San Diego, San Diego Co.; Mecca, Riverside Co.; March and
the Alamo River near Brawley, Imperial Co. Carter (1937),
noted several among the Lesser Goldfinches at Twentynine
Palms. Miller (1951), Kern Basin and San Diego.
D. Seasonal variations in distribution
AOU (1957), "Winters from north-central California (San
Francisco, Margsville) , central Arizona (Fort Mohave, near
Prescott, Phoenix, Paradise), and southwestern and central
southern New Mexico (Fort Bayard, Las Cruces) south to
northern Baja California (20 miles south of San Quintin,
Cocopah Mountains), northern Sonora (Tecoripa), and western
Texas (El Paso). Dawson (1923), "Winters irregularly in
San Diego district and east of the desert divide to the
Colorado River." Grinnell and Miller (1944), "Summer resi-
dent from April through September. A small part of the
population remains through winter in the breeding range;
I also appears then in otherwise unoccupied areas southeast-
r wardly/'
IV HABITAT
A. Biotopic affinities
Peterson (1961), "open oak or oak-pine woods, dry chaparral,
edges." Small (1974), "riparian woodland, oak woodland,
open forest, montane forest of a more arid nature, pinon-
juniper woodland." Grinnell and Miller (1944), "as breeding,
usually oak woodland and open or broken forest of the arid
Transition Zone. Coutlee (1968), "restricted to wooded
areas bordering permanent water sources." Miller (1951),
Upper and Lower Sonoran and Transition life zones.
B. Altitudinal range
Grinnell and Miller (1944) "nesting stations extend(s) from
near sea level as at Laguna Beach, Orange County, up to
6500 feet, as in the San Bernardino Mountains; vagrants
have been taken up as high as 8500 feet."
»
Home range size
Coutlee (1966), reports territories about 10-15 meters in
diameter.
Car duel is lawrencei (con't.)
D. Territory requirements \
Perch sites - Jaeger (1947), "on creosote twigs." Gander
(1930) "Some fifty or more roosted nightly in a large
clump of lemonade berry bush (Rhus integrifolia) in the center
of a grassy patch in a nearby canyon" (January and February,
East San Diego). Coutlee (1968) 'singing loudly from the
tops of the trees." Linsdale (1950), "the whole flock
would fly up to a fence or to a nearby, isolated blue oak."
Courtship and mating sites -
Nest sites - Dawson (1923), "A rather loosely woven cup of
highly varied materials, --grasses, wool, weed- stems, and
feathers; placed at any height in a cypress tree, or at
moderate height (2 to 15 feet) in weeds, artemesia, elder-
berry bush, or small tree, as live oak."
E. Special habitat requirements
Grinnell and Miller (1944), "Water sources probably are
necessary." Linsdale (1950), "Birds that feed so exclu-
sively on dry seeds as the goldfinches do apparently have
greater need for water to drink than other kinds. Between
feeding periods they assemble at watering places where they
drink, sing, bathe, preen, rest, and sun themselves." ^
F. Seasonal changes in habitat requirements
Linsdale (1950), "We see the species in winter in the
chamisal and where there is water along intermittent creeks.
In spring it ranges over open ground where abundant small
seeds are produced. In the nesting season the birds go
to the hills where there are oaks. Linsdale (1957), "Search
for particular kinds of seeds takes the bird to varied kinds
of habitat."
V FOOD
A. Food preferences
Culbertson (1946) reports birds feeding on seed fleas or
jumping galls (Neuroterus slltatorius) . Examination of
droppings of the birds revealed only the hulls of the
galls, suggesting that the birds feed only upon the insects
inside. Ortega (1945), observed feeding on one egg of two
in a Mourning Dove's nest. Gander (1930), "seen feeding
daily on the seeds of the greasewood ( Ad eno stoma fascicu-
latum) . " Linsdale (1950) 'special predilection for seeds of
the Boraginaceae." Coutlee (1966) 'feed almost exclusively
on seed-bearing chaparral plants, although a few insects ^^
(mostly Aphidae) may be taken during the breeding season."
Carduelis lawrencei (con't.)
J B. Foraging areas
Grinnell and Miller (1944), "Grassland, growths of tall
annuals, and chaparral are plant formations where suitable
and workable seed supplies may be found, often at some
distances from the nest." Linsdale (1957) "It is fitted
to live where the seeds it eats and the water it requires
may be far from the trees where it nests."
C. Foraging strategies
Linsdale (1957) "They search in flocks for patches of low
herbaceous plants and shrubs that bear seeds."
D. Feeding phenology
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Dawson (1923), "colonize to some extent. .. found as many
m as ten nests at once in two adjoining trees." Coutlee
(1966), "is much less active in his defense than is the
male psaltria. He often sings while perched near the nest
when he comes to feed the female. No elaborate circling
flight displays or song flights are given... The territory
is usually defended solely by high intensity singing if a
strange male enters it. In only a few instances was a
resident Lawrence's male seen to fly toward a strange male."
Includes detailed analysis of vocalizations and comparisons
with C. psaltria. Linsdale (1950), reports incidents where
resident males did chase: "The male was quick to chase other
males. The female pursued other females and sometimes
strange males. "
C. Courtship and mating behavior
Coutlee (1968), "initially large flocks. . .break up as each
male becomes less tolerant of other males and spends more
and more time singing loudly from the tops of the trees...
Noisy groups of five or six individuals are common in the
tops of oaks" (mixed males and females). Coutlee (1966),
"The male lawrencei are subordinate to the females and
approach them only hesitantly. .. It is... the female who
initiates billing and courtship feeding by flying to and
perching near the male. . .Feeding of the female by the male
is continued throughout nesting. Coutlee (1971), detailed
analysis of vocalizations.
Carduelis lawrencei (con't.)
D. Nesting phenology
Dawson (1923), "Extreme dates: Shandon, April 8, 1916, 5
fresh eggs; Claremont, July 5, 1903, 4, inc. begun... In
the more elevated stations of southern California, the
seasons may be prolonged into June, or even July."
E. Length of incubation period
Coutlee (1966), "The female is in almost continuous attendance
of the nest during the 12-13 days of incubation." Shepardson
(1915), "lasts from ten to twelve days."
F. Length of nestling period
Linsdale (1950), "the young birds hatched on July 2... they
left on the 13th or 14th day after hatching." Coutlee
(1966), "The young remain in the nest for 12-15 days before
fledging." Shepardson (1915), "the young birds remain in
the nest about two weeks." Linsdale (1957), description
of nestling period up to 11 days after hatching, whereupon
the young fledged.
G. Growth rates
Coutlee (1966), description of the development of vocal-
izations and motor patterns in hand-reared birds.
H. Post-breeding behavior
Coutlee (1966), "By the end of the first week or so after
fl edging. .. the young birds accompany the adults to foraging
areas and are fed whenever they give the insistent begging
calls. These small family groups do not return to the
nesting territory and remain together until the end of the
season when large flocks are again formed as migration
begins."
VII POPULATION PARAMETERS
A. Clutch size
B. Fledging success
C. Mortality rates per age class
D. Longevity
Carduelis lawrencei (con't.)
W E. Seasonal abundance
Culbertson (1949), "a flock of about thirty continued to
appear everyday" (August, Fresno, California). Gander
(1930), reports small flocks of from eight to twenty,
January and February, East San Diego. Linsdale (1950),
"From 50 to 200. . .were present daily for nearly a month,
beginning in the middle of March." Coutlee (1966), "Both
the Lesser and Lawrence's Goldfinches are highly social
and form loose flocks of 20-30 birds during the non-
reproductive season. . .May include members of both species
of goldfinches or even of other passerines."
F. Habitat density figure
Dawson (1923), "found as many as ten nests at once in two
adjoining trees."
VIII INTERSPECIFIC INTERACTIONS
A. Predation
♦
Coutlee (1968), "Jays, squirrels, and cowbirds were chased
from nest sites."
B. Competition
Coutlee (1966), "Since nest sites are often similar in both
species (C. lawrencei and C. psaltria) , some interspecific
competition is apparent."
C. Parasitism
Friedmann (1943), reports one nest containing four eggs of
the goldfinch and one of the Dwarf Cowbird (Gilroy, Calif-
ornia) ; another clutch containing one egg of the goldfinch
and two of the cowbird (collected in Ventura Co., California).
IX STATUS
A. Past population trends
Grinnell and Miller (1944), "Fairly common in general, but
numbers often variable from year to year in any given locality,
and distribution notably discontinuous and movements erratic. '
Willett (1912), "Common summer resident of the mesas and
foothills up to 7000 feet... Rare in winter."
Carduelis lawrencei (con't.)
B. Present population status
Small (1974), "resident in southern half of the state; summer
visitor elsewhere." Linsdale (1950), "the population of
Lawrence Goldfinches is greater now than it was before the
development of agriculture in its range and that probably
its range has been extended somewhat by that development."
C. Population limiting factors
Linsdale (1950), "the kind and amount of seeds produced each
year are important in determining the numbers of goldfinches
and the length of their stay."
D. Environmental quality: adverse impacts
E. Potential for endangered status
*
Carduelis lawrencei (con't.)
I LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Carter, F. 1937. Bird life at Twentynine Palms. Condor
39:211-219.
Coutlee, E. L. 1966. The comparative behavior of Lawrence's
and Lesser Goldfinches. Ph.D. Thesis Univ. Claifornia,
Los Angeles.
Coutlee, E. L. 1968. Comparative breeding behavior of Lesser
and Lawrence's Goldfinches. Condor 70:228-242.
Coutlee, E. L. 1971. Vocalizations in the genus Spinus.
Animal Behavior 19:556-565.
Culbertson, A. E. 1946. Lawrence Goldfinches feed on jump-
ing galls. Condor 48:40.
Dawson, W. L. 1923. The birds of California. South Moulton
Co., San Francisco.
Friedmann, H. 1943. Further additions to the list of birds
known to be parasitized by the cowbirds. Auk 60:350-356.
Gander, F. F. 1930. Notes on winter bird roosts. Condor
32:64.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27.
Jaeger, E. C. 1947. Use of creosote bush by birds of the
southern Calif ornian deserts. Condor 49:126-127.
Linsdale, J. M. 1950. Observations on the Lawrence Goldfinch.
Condor 52:255-259.
Linsdale, J. M. 1957. Goldfinches on the Hastings Natural
History Reservation. Amer. Midi. Nat. 57:1-119.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. Vol.
50, No. 6.
Ortega, J. L. 1945. Lawrence Goldfinch eating egg of Mourning
Dove. Condor 47:41.
10
Carduelis lawrencei (con't.)
Peters, J. L. 1968. Checklist of birds of the world. Vol.
13. (E. Mayr, ed. ) Mus. Comp. Zool. , Cambridge, Massachu-
setts.
Peterson, R. T. 1961. Field guide to western birds. Houghton
Mifflin Co., Boston.
Ridgway, R. 1901. The birds of North and Middle America.
Part 1. U.S. Natl. Mus. Bull. No. 50.
Shepardson, D. I. 1915. Nesting habits of Lawrence's Gold-
finch. Oologist 32:58-60.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Willett, G. 1912. Birds of the Pacific slope of southern
California. Pacific Coast Avifauna No. 7.
LESSER GOLDFINCH
w Carduelis psaltria
I TAXONOMY
A. Type description
AOU (1957), Spinus psaltria hesperophilus ; Astragalinus
psaltria hesperophilus Oberholser, Proc. Biol. Soc. Washing-
ton, 16, Sept. !v, 1903, p. 116. (San Bernardino, Calif-
ornia. )
B. Current systematic treatments
Mayr (1968), recognizes twenty- four species in the genus
Carduelis; five subspecies in the species psaltria (witti,
hesperophila, psaltria, j ouyi , columbiana) . Pas seri formes:
Fringillidae (Carduelinae) .
C. Synonomies of scientific nomenclature
Dawson (1923), Astragalinus psaltria hesperophilus. Peter-
son (1961), Spinus psaltria. Grinnell and Miller (1944),
Chrysomitris psaltria; C. mexicanus; also under subspecies
ari zonae.
| D. Synonomies of vernacular nomenclature
Dawson (1923), Green-backed Goldfinch. Peterson (1961),
Dark-backed Goldfinch. Grinnell and Miller (1944), Arkansas
Siskin; Western Goldfinch; Arkansas Finch; Arkansas Gold-
finch; Mexican Goldfinch; Arizona Goldfinch.
II DESCRIPTION
A. External morphology of adults
Dawson (1923), "Adult male (no seasonal change): Pileum,
broadly, glossy black; sides of head and upper parts olive-
green, .. .more yellow on rump, sometimes faintly streaked
with darker, or blackish, on back; upper tail-coverts chiefly
black; wings black; the middle and greater coverts and tertials
(variably) tipped with white; both webs of inner primaries
crossed about midway with white, forming a conspicuous
blotch in flight; tail black, the two or three outermost
pairs of feathers extensively white on inner web; underparts
lemon-yellow, paling posteriorly, shading on sides. Bill
horn-color; feet and legs brownish. Adult female: Like male
but much paler and duller, without black. Above dull olive
...; below olive-yellow, paling posteriorly." Peterson
(1961), "Male: a very small finch with a black cap, black or
greenish backs and bright yellow underparts; bold white marks
on wings. The black cap is retained in winter. . .Female:
Very similar to female American Goldfinch but smaller, more
greenish; had dark rump."
Carduelis psaltria ( con ' t . )
B. External morphology of subadult age classes
Dawson (1923), "Immature males are like adult females but
brighter, with early indications of black cap."
C. Distinguishing characteristics
Interspecific - Dawson (1923), "coloration not definitely
gray, and chin not black, as distinguished from A. (G.)
lawrencei . " Peterson (1961), "The black cap is retained
(by males) in winter (male Americans become brownish and
lose caps) .. .American Goldfinch always shows white near
rump. Summer male has yellow back."
Intraspecific -
III GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), Spinus psaltria in general: "Southwestern
Washington, western Oregon, northeastern California, northern
Nevada, northern Utah, northern Colorado, northwestern Okla-
homa, and central Texas south through Mexico, Central America,
and northwestern South America to northwestern Peru, central
Colombia (San Agustin) , and northern Venezuela. Introduced
in western Cuba (Habana, Banza) . " C. p_. hesperophilus :
"Resident from southwestern Washington (Vancouver) , western
Oregon (Portland; Coos County), northeastern California
(Modoc County), northern Nevada (Santa Rosa Mountains),
and northern Utah (Tooele, Morgan, and Uintah Counties)
south through California and central Arizona (Flagstaff,
Grand Canyon) to southern Ban a California (Sierra de la
Laguna) and southern Sonora (Guirocoba) , Casual to eastern
Oregon (Riverside), south-central New Mexico (San Antonio),
and northwestern Durango." Dawson (1923), C. p^ hesperophilus
"Southwestern United States from central northern Texas,
northern Colorado, southern Idaho, and southern Oregon, south
through Mexico to northern South America."
B. California distribution of the species
Dawson (1923), C. p_. hesperophila: "An abundant breeder
below the Transition zone and locally within that zone;
most abundant along the southern coasts and in the central
interior; rare or wanting in the humid Northwest; apparently
absent from the central region east of the Sierras, at least
above the head of Owens Valley and its tributaries (White
Mountains above Bishop. . . , Hilton Creek, Long Valley. . . ,
near Mammoth Camp...), although reappearing in Lassen and
Humboldt Counties (Goose Lake. . . , Surprise Valley. . . , Eagle-
ville...); of local distribution in the deserts; of limited
#
•
Carduelis psaltria (con't.)
occurrence on some of the Santa Barbara Islands (Santa
Cruz) and casually on the Farallons." Grinnell and Miller
(1944), "The entire State, except small districts in high
mountains and heavily timbered areas; may appear even in
such places as a vagrant, especially in late summer. Most
abundant and most continuously distributed in southern
and central California west of the Sierra Nevada."
C. California desert distribution
Dawson (1923), "of local distribution in the deserts."
Grinnell and Miller (1944), recorded in following areas:
Buena Vista Lake, south fork of Kern River, and Walker Basin,
Kern Co. ; Los Angeles, Los Angeles Co. ; Cabezon, Riverside
Co. ; Escondido and San Diego, San Diego Co. ; Inyo, Panamint,
Grapevine and Argus Mountains, Owens and Death Valleys,
Inyo Co.; Mecca, Riverside Co. Carter (1937), reports
various sized flocks and individuals often observed at
Twentynine Palms, California. Miller (1951), Kern Basin,
San Diego, Inyo, Modoc, Mojave regions and Channel Islands.
D. Seasonal variations in distribution
Grinnell and Miller (1944), "probably leaves northeastern
section in winter." Willett (1912), "Abundant summer resi-
dent of the Mesa and foothill regions and up to 3000 feet
in the mountain canyons. Less common in the lower country
and up to 6400 feet in the mountains. In winter, distributed
in flocks over the whole lower country."
IV HABITAT
A. Biotopic affinities
Small (1974), "riparian woodland, open forest, savannah,
open areas with trees nearby." Peterson (1961), "open
brushy country, open woods, wooded streams, gardens."
Grinnell and Miller (1944), "Open terrain with scattered
trees or bushes. Brush land may be occupied if open land
and edge situations are present in the vicinity. Of the
four members of the genus Spinus , . . . shows the widest range
of tolerance with respect to rainfall, humidity and temper-
ature. It appears to be the most water- seeking of all the
gold finches. Miller (1951), Lower and Upper Sonoran
and Transition life zones. Coutlec (1966), breed mainly
in chaparral and oak woodland. . .Found in dry chaparral to
distances of as much as one-half mile from water." Linsdale
(1957), "In the dry seasons these birds concentrate about
supplies of water in streams and springs."
#
Carduelis psaltria (con't.)
E. Altitudinal range 4P
Grinnell and Miller (1944), "extends from -200 feet at
Mecca, Riverside County, up to 9800 feet on Mount Tallac,
Eldorado County; probably does not breed much above 6500
feet, as in San Bernardino Mountains and at Mono Lake."
Dixon (1943), one observed in September, Kings Canyon
National Park, at 11,000 feet.
C. Home range size
Coutlee (1966), reports territories about 30 meters in
diameter.
D. Territory requirements
Perch sites - Jaeger (1947), "on creosote twigs." Coutlee
(1968), "stations himself near the top of a tall tree and
makes himself conspicuous by perching in the open and utter-
ing occasional short songs.
Courtship and mating sites - Coutlee (1968), "As courtship
progresses, the following flights develop into high- inten-
sity chasing flights, the male following the female at a
distance of two meters or less and the two birds darting
rapidly in and out through dense foliage." Mb
Nest sites - Dawson (1923), "Placed at any height but usually
moderate, and in almost any host, --tree or bush or even
rank weeds; live oaks and sycamores favorites; ... of twisted
grasses and weed fibers, deeply capped, lined with fine
grasses or horsehair; settled firmly into concealing bunch
of leaves or branching twigs, or sometimes artfully incorpor-
ated with immediate setting."
E. Special habitat requirements
Linsdale (1957) "Availability of water is important in the
nesting season and afterward when water becomes scarce.
The distribution of water helps determine where the gold-
finches live."
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Dawson (1923), "96 per cent. .. consists of weed- seed. . .Napa
Thistle. Gander (1929), reports feeding on seeds of various
species of Eucalyptus in Balboa Park, San Diego. Coutlee
(1966) "feed almost exclusively on seed-bearing chaparral
Carduelis psaltria (con't.)
plants, although a few insects (mostly Aphidae) may be
taken during the breeding season." Linsdale (1957),
"plant materials, including buds, leaves, fruits, and
seeds. "
B. Foraging areas
Grinnell and Miller (1944), "Activity centers near the
ground in foraging- -on low-growing composites, for example,
the seed heads on bush tops; seldom, as with the American
Goldfinch and Pine Siskin, does it feed in the crowns of
trees. "
C. Foraging strategies
Dawson (1923), Napa Thistle: "cracks each brittle shell
and, aided no doubt by its tongue, extracts. .. the starchy
kernel." Ross (1924), "while seeding a batchelor button
head, bent the slight stem to a horizontal position. When
through with it, the bird reached deliberately out with
one foot and grasped a nearby spray and pulled it under his
feet on the original stem and ate from the new supply of
seeds." Linsdale (1957), "forage in flocks through most
of the year. They move through the bushes and trees that
provide the major part of their food, and they sometimes
t concentrate on the lower herbaceous plants."
D. Feeding phenology
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Coutlee (1966), "he perches atop the highest branches of
the trees within his territory. . .and gives very loud ad-
vertising song. . .Although given at fairly regular intervals
throughout the day, song is characteristically triggered by
song from other males or the presence of another male near
the territory. If a strange male enters the territory,
the resident male flies toward it with the ' song flight
display'." Includes detailed analysis of vocalizations
and comparisons with _C. lawrencei .
Carduelis psaltria (con't.)
C. Courtship and mating behavior
Coutlee (1966), "small flocks broke up into pairs over a
period of only one week. After this time they were found
perching or flying in pairs, the male and female usually
about a meter apart. . .Repeated chasing between the two
members of a pair. .. characterizes the initial stages of
courtship. . .This, in turn is replaced by 'billing as
members of the pair become more tolerant of one another. . .
Billing develops into true 'courtship feeding' in which
the female actually takes regurgitated food from the males
bill. . .Feeding of the female by the male is continued
throughout nesting." Coutlee (1971), detailed analysis of
vocalizations .
D. Nesting phenology
Dawson (1923), "April to June, or occasionally in autumn;
two or three broods." Grinnell and Miller (1944), "In
south and west-central California, occasionally nests in
fall."
E. Length of incubation period
Dawson (1923), "lasts eleven or twelve days." Coutlee
(1966) "continuous incubation is begun before the clutch
of three to five eggs is complete. .. the female is in almost
continuous attendance at the nest during the 12-13 days of
incubation. "
F. Length of nestling period
Coutlee (1966), "the young remain in the nest for 12-15
days before fledging. '
G. Growth rates
Coutlee (1966), description of development of vocalizations
and motor patterns in hand-reared birds.
H. Post-breeding behavior
Coutlee (1966), "By the end of the first week or so after
f ledging. . . the young birds accompany the adults to foraging
areas and are fed whenever they give the insistent begging
calls. These small family groups do not return to the
nesting territory and remain together until the end of the
season when large flocks are again formed as migration
begins. "
Carduelis psaltria (con't.)
[I POPULATION PARAMETERS
A. Clutch size
Dawson (1923), "4 or 5, ovate, pale bluish green, unmarked."
B. Fledging success
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
Dawson (1923), after Carpodacus mexicanus, "possibly the
most abundant numerically of the breeding birds of central
and western California. . .about thirty million of them per
annum in California." Carter (1937), "around April 27, 1934,
flocks of 2 or 3 dozen frequented beds of a small yellow
composite in the swamp." Coutlee (1966), "Both the Lesser
and Lawrence's Goldfinches are highly social and form
loose flocks of 20-30 birds during the non- reproductive
season. . .May include members of both species of goldfinches
or even of other passerines."
F. Habitat density figures
Gaines (1974), reports 35 and 43 territorial males per
square kilometer in clumped cottonwood and willow woodland,
Butte County, 1972 and 1973, respectively.
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Coutlee (1968), "On one occasion a Cooper's Hawk called
and alighted in an area where psaltria nests were abundant.
About 20 psaltria gathered in a loose flock about the
hawk- -both in the same tree and in adjacent trees--and
gave continual, drawn-out Hawk calls. . .Jays, squirrels,
and cowbirds were chased. . .usually both male and female
participating. "
B. Competition
Coutlee (1966), "There is some competition for nest sites
(with C. lawrencei) probably due in part to the highly
social nature of both species and their attraction to nest
building activities."
•
•
Carduelis psaltria ( con ' t . )
C. Parasitism
Piath (1919), reports an average of 61% of the nests examined
held young infested with larvae of Protocaliphora azurea;
a total of 13 nests examined. Woods (1930) , "founaT. .
incubating three of its own eggs and one of the cowbird's
(Molothrus a tea) . The eggs were later abandoned before
they had hatched . "
IX STATUS
A. Past population trends
Grinnell and Miller (1944), "Resident, but there is consid-
erable local movement and vagrancy. .. common to abundant."
B. Present population status
Small (1974), breeding resident.
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
♦
Car due lis psaltria (con't.)
LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Carter, F. 1937. Bird life at Twentynine Palms. Condor 39:
211-219.
Coutlee, E. L. 1966. The comparative behavior of Lawrence's
and Lesser Goldfinches. Ph.D. Thesis, U. California,
Los Angeles.
Coutlee, E. L. 1968. Comparative breeding behavior of Lesser
and Lawrence's Goldfinches. Condor 70:228-242.
Coutlee, E. L. 1971. Vocalizations in the genus Spinus.
Animal Behavior 19:556-565.
Dawson, W. L. 1923. The birds of California. South Moulton
Co. , San Francisco.
Dixon, J. S. 1943. Birds of the Kings Canyon National Park
area of California. Condor 45:205-219.
Gaines, D. 1974. A new look at the nesting riparian avifauna
of the Sacramento Valley, California. Western Birds 5:
61-80.
Gander, F. F. 1929. Notes on the food and feeding habits of
certain birds. Condor 31:250-251.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27.
Jaeger, E. C. 1947. Use of creosote bush by birds of the
southern Californian deserts. Condor 49:126-127.
Linsdale, J. M. 1957. Goldfinches on the Hastings Natural
History Reservation. Amer. Midi. Nat. 57:1-119.
Peters. J. L. 1968. Checklist of birds of the world. Vol.
10. (E. Mayr, ed. ) Mus. Comp. Zool. , Cambridge, Massachu-
setts.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool., Vol.
50, No. 6.
Peterson, Ri T. 1961. Field guide to western birds. Houghton
Mifflin Co., Boston.
10
Carduelis psaltria (con't.)
Plath, 0. E. 1919. Parasitism of nestling birds by fly larvae. f
Condor 21:30-38.
Ross, R. C. 1924. More birds that grasp objects with the feet.
Condor 26:226-227.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Willett, G. 1912. Birds of the Pacific slope of southern
California. Pacific Coast Avifauna No. 7.
Woods, R. S. 1930. Two more victims of the Cowbirds. Condor
32:126.
♦
LONG-BILLED MARSH WREN
Cistothorus palustris
TAXONOMY
A. Type description
AOU (1957), Telmatodytes palustris plesius: Cistothorus
palustris plesius Oberholser, Auk, 14, no. 2, Apr. 1897,
p^ 188. CFort Wmgate, N [ew] . M [exico] . ) . Telmatodytes
palustris aestuarinus: T. p. aestuarinus Swarth, Auk, 34,
no. T, July (June 30), T91/, p~] 310. (Grizzly Island, Solano
County, California.)
B. Current systematic treatments
Paynter and Vaurie (1960), recognize four species in the
genus Cistothorus; eleven subspecies of palustris. Passeri-
f o rme s: Troglodyti dae .
Ridgway (1904), discussion of morphological characteristics
and geographic distribution in relation to systematic
treatment.
C. Synonomies of scientific nomenclature
C. p_. plesius, Grinnell and Miller (1944): Troglodytes
palustris; Telmatodytes palustris plesius, Cistothorus
palustris paludicola, Telmatodytes palustris paludicola.
C. p_. aestuarinus: Telmatodytes palustris paludicola; C.
p_. paludicola.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), C. p_. plesius: Tule Wren,
Western Marsh Wren. C. p_. aestuarinus: Tule Wren; Suisun
Marsh Wren.
Dawson (1923), C. £. aestuarinus: Swarth' s Marsh Wren, San
Joaquin Marsh Wren. C. p. plesius: Interior Marsh Wren.
II DESCRIPTION
A. External morphology of adults
Dawson (1923), C. p_. plesius: "Adult: Crown blackish; fore-
head warm brown. . .color sometimes spreading superficially
over entire crown; hind-neck and scapulars a lighter shade
of brown; rump bright brown; a triangular patch on back
blackish, with prominent white stripes and some admixture
of brown, wings and tail fuscous or blackish on inner webs,
brown with black bars on exposed surfaces; upper and under
•
•
Cistothorus palustris (con't.)
tail-coverts usually more or less distinctly barred with
dusky; sides of head whitish before, plain brown or punctate
behind; a white superciliary line; underparts white, tinged
with ochraceous buff across breast, and with pale cinnamon-
brown on sides, flanks, and crissum. Bill blackish brown
above, paler brown below; feet and legs brownish."
C. £. aestuarinus: "Like T. (C. ) p_. paludicola, but larger and
somewhat darker; like T. I"C. ) £. plesius m size, but much
darker . "
C. £. paludicola; "Similar to T. (C. ) £. plesius, but smaller
and with coloration decidedly barker."
Ridgway (1904), detailed description of adults including
plumage, soft parts, and measurements, as compared with
T. £. palustris.
B. External morphology of subadult age classes
Ridgway (1904) concerning T. £. palustris: "Essentially like
adults, but pattern of coloration less distinct, the pileum
and hindneck uniform dull blackish, the back very indistinctly,
if at all, streaked, and the whitish superciliary stripe
less distinct (sometimes nearly obsolete)."
C. Distinguishing characteristics
Interspecific - Phillips (1975) "Short-billed Marsh Wren...
has these upper tail coverts boldly barred and the crown
streaked with whitish, not solidly dark." Peterson (1961),
"known from other small wrens with white eye stripes by
the white stripes on back."
Intraspecific - Phillips (1975) "The migratory eastern races
...lack the faint dusky bars on the upper tail-coverts."
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), Telmatodytes palustris: Central British Columbia,
northern Alberta, south-central Saskatchewan, southern
Manitoba, southern Ontario, southwestern Quebec, southern
Maine, and eastern New Brunswick south to northern Baja
California, south-central Mexico, the Gulf coast, and
southern Florida.
T. £. plesius: "Breeds from central British Columbia (Tachick
Take, Springhouse, Lac la Hache, Okanagon Landing), central
*
•
Cistothorus palustris (con't.)
tand eastern Washington (Loomis, Kettle Falls, Spokane),
Idaho (Lake Pend d Oreille) , western Montana (Forine, Swan
Lake, Big Lake), northwestern Wyoming (Tower Falls), north-
eastern Utah (Jensen), northwestern Colorado (Lag), south-
eastern Wyoming (Laramie, Torrington, Cheyenne), and south-
western Nebraska (Pine Bluffs, Crescent Lake Refuge) south
to northeastern and central eastern California (Tule Lake,
Pitt River, Rolands Marsh, Lake Tahoe), central Nevada
(Yerington, Ruby Lake), south-central Utah (Margsvale),
central New Mexico, and southwestern Texas (El Paso, Pena
Creek)."
T. £. aestuarinus: "Resident in Sacramento, San Joaquin,
and Imperial valleys of California, and the Colorado River
Valley from southern Nevada (Search light, St. Thomas) south
to southern California (Sal ton Sea, Alamo Duck Preserve),
northern Baja California (Cerro Prieto, mouth of the Hardy
River), northwestern Sonora (Colorado River Delta), and south-
western Arizona (Mittry Lake, California Swamp).
B. California distribution of the species
#
Grinnell and Miller (1944), C. palustris plesius: "As breed-
ing, northeastern plateau region, in Modoc, eastern Siskiyou
and Lassen counties, and Tahoe area.
C. p. aestuarinus: "Sacramento and San Joaquin valleys from
at least Glenn and Butte counties south to Kern County,
and Imperial Valley and valley of lower Colorado River,
in Imperial County."
C. California desert distribution
Dawson (1923), C. p. plesius: "interior birds, breeding at
high levels east or the Sierras, are obliged to retire in
winter to. .. southeastern deserts, and the. . .overflowed
margins of the Colorado River and 'New' River. . .Many spill
over at this season into the San Diego district."
Small (1974), "for breeding, coastally, length of state:
also Central Valley, Imperial Valley and Modoc Plateau.
D. Seasonal variation in distribution
AOU (1957), T. p_. plesius: "Winters throughout breeding
range and south to southern California (including Santa
Cruz and San Nicolas Islands), southern Baja California
(San Jose del Cabo), Michoacan, Mexico, central Veracruz,
and southern Texas (San Antonio, Fort Brown, Corpus Christi)."
•
Cistothorus palustris (con't.)
T. £. aestuarinus: "Found in winter in southern Utah." [
Dawson (192 J), C. p. aestuarinus: "Winters irregularly
south to the San Diego district." Small (1974), "some
withdrawal of birds from northeastern section during fall
and winter."
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), C. p. plesius; "Typically,
especially in nesting season, thick tracts of tall, straight-
stemmed marshland vegetation as comprised of cattail, tule,
and bulrush."
C. p. aestuarinus: "Fresh- water or brackish marshland,
typically as grown to beds of cattail, tule, or bulrush."
Similar to C. p_. plesius. Small (1974), "fresh-water marshes,
ponds, streams, and lakes grown with cattail, tule, bulrush."
Miller (1951), Lower and Upper Sonoran and Transition Life
Zones.
B. Altitudinal range
Grinnell and Miller (1944), C. p. plesius: "altitudes
to 6200 feet."
4000
C. £. aestuarinus: "altitudes of known nesting stations,
all below 500 feet."
C. Home range size
Verner (1965a) , C. p_. plesius: in Washington, 2500-9600 square
feet. Welter (1935), "A single monogamous male occupied a
territory of from 13,000 to 15,000 square feet... In the
grass association this was extended to approximately 30,000
square feet." Kale (1965), comparison of mean territory
sizes among study areas and in different years.
D. Territory requirements
Perch sites - Kale (1965) "down in the dense grass or near
the tops of tall dead flower stalks remaining from the pre-
vious year's crop of Spartina." Miller (1906), "cattail
blade or a dead stalk.
Courtship and mating sites - Verner (1965a), "After establish-
ing a breeding territory the male begins building "courting"
nests. . .grouped in a small area. . .Number of nests. . .ranges
from one partial to four or five complete nests... As the
season progresses more courting centers are built, often
overlapping others. Most songs are delivered from the court-
ing center and little foraging is done there."
*
Cistothorus palustris (con't.)
Nest sites - Grinnell and Miller (1944) "Nests. . .above water,
a greater measure of security against terrestrial marauders
being thus probably secured. ' Verner (1965a) "usually
placed in cattails (preferably in stands of moderate density),
but occasionally. .. in bulrushes. A colony. . .placed their
nests in the Spiraea, no cattails being available. Nest
height... in direct relation to the height of supporting
cover."
E. Special habitat requirements
Verner and Engelsen (1970), "cattail is the preferred nest-
ing cover only if it has standing water. The importance
of water could be in protection of the nest from predation
and/or provision of a highly important food source.
F. Seasonal changes in habitat requirements
Grinnell and Miller (1944) C. p_. plesius: "In migrations
and in winter any sort of low vegetation growing in water
or on damp ground suffices for foraging and concealment. . .
In its winter range, when its elevated and interior summer
grounds are largely uninhabitable, this wren finds in southern
California the wet season on, with. . .plenteous fresh water
and the lush plant growths that are to its liking." Verner
i and Engelsen (1970), "Bulrush typically grows in deeper
water than cattail. .. Selection favored those males whose
territories contained some bulrush because they were less
likely to be forced to abandon their territories in mid-
season." [See "Special habitat requirements"]] Swarth
(1917) "Especially numerous winter visitant in the San
Diegan district of southern California. In this region
summer is the dry season, a period of such excessive aridity
that birds with the needs... of the marsh wrens are closely
limited as to habitat, being restricted to extremely cir-
cumscribed areas about the few suitable permanent streams
and sloughs. In winter this is all changed. Abundant
rains often transform what were dry fields and pastures
into ponds and marshes."
V FOOD
A. Food preferences
Verner (1964) "an almost exclusively animal diet, especially
aquatic forms and terrestrial forms with aquatic life stages."
Welter (1935), "There is no actual selection of types of
insects by the species but the food taken depends upon its
predominance and accessibility. Beetles. . .aquatic larvae
. . .Coleoptera and Diptera." Miller (1906), insects, their
egg and larvae."
Cistothorus palustris (con't.)
B. Foraging areas
Verner (1965b), "normally forage on or near the marsh floor."
Verner (1964), "Much food for Seattle young was obtained
from willow thickets. .. the importance of bulrushes for for-
aging may result from their being more thoroughly broken
down during the winter than is cattail, thus allowing more
light to penetrate to the water surface and promoting higher
production there... The greater proportion of foraging took
place in it [bulrush]." Welter (1935) "Much of the food is
obtained near or from the surface of the water. . .Upon the
stems and leaves of the cattails and other plants."
C. Foraging strategies
Verner (1965b) "For an insectivorous species. .. food species
would be less active, hence less conspicuous, at lower temper-
atures. They would also be more easily seen in bright
than in dull light... The most efficient period for a Marsh
Wren to forage is probably during the afternoon, when ambient
temperature reaches a maximum." Welter (1935), "The elong-
ated bill and natural agility of the bird are important."
D. Feeding phenology
Verner (1965b) "Young birds were fed on larger and larger
items as they grew older, whereas the adults continued to
eat very small items, such as aphids and mites." Welter
(1935), "By the time the birds arrive in the spring there
is an abundance of insect food. . .As the season advances
insect food becomes more plentiful."
E. Energy requirements
Verner (1965b), "If it takes adult wrens nearly half their
available time just to meet their own energetic demands,
they must be seriously pressed to feed four or five young
as well... Must also store enough energy to pass the night
...Enough energy must be stored to meet unexpected exigencies
during the night, such as sudden temperature drops or dis-
turbance from a roost."
VI REPRODUCTION
A. Age at first breeding
f
e
Cistothorus palustris (con't.)
B. Territorial behavior
Verner (1965a), C. p. plesius: "territorial limits were
largely determined by the distribution of marsh vegetation,
and birds utilized all of the areas they occupied." Welter
(1936) "A male approaching too closely to the boundary of
another's area is challenged by the song of the rightful
owner. . .Several song perches are selected in different parts
of the territory and the owner continues to go from one to
another singing enroute." Kale (1965), "T. p_. griseus
delimits his territory by singing at one end of it for
several minutes and then moving to the other end and singing
there."
C. Courtship and mating behavior
Verner (1965a), "After establishing a breeding territory
the male begins building "courting' nests. . .Female approaches
a male's territory, he immediately flies toward her, deliver-
ing a rapid valley of songs with his tail cocked. . .Female
examines and often enters one nest after another, being
escorted to each by the male... Male practically ceases singing
during courtship, resorting instead to display. . .After a
female selects a mate, she either selects one of his courting
nests for breeding and lines it... or she initiates a new
nest, which is constructed chiefly by the male... A day or
two before laying begins or shortly thereafter. .. shifts to
another part of his territory. . .and starts building a new
courting center from which he advertises for additional
mates." Verner (1964) discussion of polygamy in different
populations in Washington State. Welter (1936), description
of courtship by male and a discussion of the song of the
male.
C. Nesting phenology -■
Verner (1965a), "high degree of synchrony in the initiation
of nest construction by males. . .males build a number of nests
that are never used for breeding purposes. . .breeding nests
differ from non-breeding nests by having a substantial
lining." Welter (1936) description and discussion of mul-
tiple nests built by the male."
E. Length of incubation period
Verner (1965a), "Eggs. . .deposited at a rate of one per day...
Incubation performed solely by the female." Mean incubation
ranged from 14 to about 17 days near Seattle, Washington.
Kale (1965) range of 12-14 days for 35 nests; mean of 13.1
days .
Cistothorus palustris (con't.)
F. Length of nestling period
Verner (1965a), "undisturbed nest often contained young 15
or 16 days old. . .continued to feed fledglings for 12 or
more days." Kale (1965) reports 12 or 13 day. "If left
undisturbed the young may remain in the nest 13-15 days."
G. Growth rates
Welter (1935), "The average weight for the newly arrived
wren is 0.87 of a gram but by the end of the twelfth day
this has been increased to an average of 11.08 grams. During
this time the gain is from 1 to 1.7 grams per day... During
the period of greatest feather growth the gain in weight
drops off markedly." Includes graph of weigth vs. age in
days.
H. Post-breeding behavior
Verner (1965a), "As the young aged and became progressively
more dependent the males' rates of singing and nest build-
ing once again increased. Welter (1935), "The family group
remains together for some time and it is not unusual in
mid- September to see four, five, and six birds of an age
still keeping together. The young do not remain in the
territory of their parents but wander from place to place."
VII POPULATION PARAMETERS
A. Clutch size
Verner (1965a), reports six as average; range of 4-8 eggs.
B. Fledging success
Kale (1965), "The number of eggs fledged in 1958 was 74
out of a total of 178 laid, or a nesting success of 42%>.
In 1959, 86 eggs fledged out of 421 laid, or a nesting
success of only 20%. In 1960. .. success of 7%. In 1961...
15%."
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
Grinnell and Miller (1944), C. p_. plesius: "summer resident
in elevated northeastern corner of State; winter visitant
(September to March) in southern half, chiefly; transient
there and elsewhere."
'
-
Cistothorus palustris (con't.)
•
C. p_. aestuarinus : "Subject to fall and winter wandering
of some individuals considerably out of breeding range."
Welter (1935) "There is no marked exodus of birds from the
marsh at a given time in the fall... As the time of departure
approaches, there is an apparent flocking together of young
birds, usually near the water's edge. . .Twenty- five or thirty
birds may be observed together feeding near the surface of
the water. The next day the numbers may be greatly reduced
and in a short time only a few birds remain." Swarth (1917),
"In winter. . .plesius is perhaps the most abundant of any
form of the species, occurring in numbers over a large
part of the state. . .May occasionally be found in winter at
any point along the coast... both on the deserts and in the
San Diegan region."
F. Habitat density figures
Welter (1935), "In an area 400 by 650 feet... eight males
took up residence." Kale (1965), "The ecological density
of 45-56 pr/ha (18-23 pr/acre) represents the number of
birds in relation to the available wren habitat." Com-
parison of different methods of calculating population
densities.
i'TII INTERSPECIFIC INTERACTIONS
W A. Predation
Bond (1939), six remains found in pellets of Barn and
Horned Owls at Petroglyph Cliffs, California. Welter
(1935), "The chief enemies. . .are some of the smaller mammals
that reside in the marsh... No specific case has been observed
but the appearance of the nest leads one to this conclusion
...Hawks and owls have a poor chance of adding this species
to their diet as they are never very conspicuous and can
easily hide in the dense vegetation." Kale (1965), reports
Rice Rat, racoon, and mink prey on eggs and young (Georgia).
Suspect Fish Crows and Boat-tailed Grackles.
B. Competition
Dawson (1923) "had constructed a sham nest hard against a
completed structure of the Yellow-headed Blackbird, and
to the evident retirement of its owner." Welter (1935)
"it is apparently not unusual to find a colony of [bumble
bees] in a nest of this species." Allen (1914), describes
destruction of fifty-one nests of Red-winged Blackbirds.
•
10
Cistothorus palustris (con't.)
C. Parasitism
Welter (1935), flea (Ceratophyllus garei) and louse (Philop-
terusm. mirinotatus) recorded; hTppobascid flies observed.
"The alimentary tracts of more than fifty birds were examined
carefully without obtaining a single cestode or nematode."
IX STATUS
A. Past population trends
Grinnell and Miller (1944), "Common to even abundant where
conditions of habitat are most favorable."
B. Present population status
Small (1974), "common resident but some withdrawal of birds
from northeastern section during fall and winter."
C. Population limiting factors
Kale (1965), "discussion of factors which may possibly limit
the wren population (food, high tides, predation, terri-
toriality and social behavior).
D. Environmental quality: adverse impacts
E. Potential for endangered status
r
r
11
Cistothorus palustris (con't.)
kXI LITERATURE CITED
Allen, A. A. 1914. The Red-winged Blackbird: A study in the
ecology of a cat-tail marsh. Abst. Proc. Linn. Soc. N.Y.
pp. 43-128.
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bond, R. M. 1934. Observations on raptorial birds in the
Lava Beds - Tule Lake region of Northern California.
Condor 41:54-61.
Dawson, W. L. 1923. The birds of California. South Moulton
Co. , San Francisco.
Grinnell, J. and A. H. Miller. 1944. The distribution of
birds of California. Pacific Coast Avifauna No. 27.
Kale, H. W. 1965. Ecology and bioenergetics of the Long-
billed Marsh Wren in Georgia Salt marshes. Publ. Nut tall
Ornithological Club No. 5.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. Vol.
50, No. 6.
Miller, R. F. 1906. Long-billed Marsh Wren (Telmatodytes
palustris) in Philadelphia County, Pennsylvania. Oologist
23:117-124.
Peters, J. L. 1967. Checklist of birds of the world. Vol.
12. (D. Snow, ed.) Mus. Comp. Zool., Cambridge, Massachu-
setts.
Peterson, R. T. 1961. Field guide to western birds. Houghton
Mifflin Co., Boston.
Phillips, A. R. 1975. Why neglect the difficult? Western
Birds 6(3):69-86.
Ridgway, R. 1904. The birds of North and Middle America.
Part III. Bull. U.S. Nat. Mus. No. 50.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Swarth, H. S. 1917. A revision of the marsh wrens of Calif-
ornia. Auk 34:308-318.
12
Cistothorus palustris ( con ' t . )
Verner, J. 1964. Evolution of polygamy in the Long-billed
Marsh Wren. Ecology 18:252-261.
Verner, J. 1965a. Breeding biology of the Long-billed Marsh
Wren. Condor 67:6-30.
Verner, J. 1965b. Time budget of the male Long-billed Marsh
Wren during the breeding season. Condor 67:125-139.
Verner, J. and G. H. Engelsen. 1970. Territories, multiple
nest building, and polygyny in the Long-billed Marsh Wren.
Auk 87:557-567c
Welter, W. A. 1935. The natural history of the Long-billed
Marsh Wren. Wilson Bull. 42:3-34.
'
<
t
•
♦
#
LONG -EARED OWL
Asio otus
TAXONOMY
A. Type description
AOU (1957), Asio otus tuftsi Godfrey, Can. Field-Nat., 61,
no. 6, Nov. -Dec. TW1 (Feb. 13, 1948), p. 196. (South Arm,
Last Mountain Lake, Saskatchewan.)
B. Current systematic treatments
Peters (1940), recognizes six species in the genus Asio;
three subspecies of the species otus. Order: Strigif ormes;
Family: Strigidae.
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), Otus wilsonianus; Otus vulgaris
wilsonianus; Otus brachyotus var. wilsonianus; Asio americanus ;
Nyctalops wilsonianus; Asio wilsonius; Asio otus wilsonianus.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), American Long-eared Owl.
DESCRIPTION
A. External morphology of adults
Ridgway (1914), detailed descriptions of adults and young,
including plumage, soft parts, and measurements. Peterson
(1961), A slender, medium-sized, grayish owl with long ear
tufts... Face dark rusty." Dawson (1923), "Adult: Above
finely mottled white and dusky, with apparently half -concealed
ochraceous on subterminal margins of feathers, the design
broadened on wings, --ochraceous, white, and dusky in patches;
the wing-quills and tail distinctly barred--dusky with
ochraceous basally, dusky with gray terminally; ear-tufts
conspicuous, an inch or more in length, black centrally,
with white and ochraceous edges; facial disc tawny; region
about base of bill, or at least chin, white; blackish about
eyes on inner sides, the edges, especially on forehead,
finely mottled with black and white; tibiae, tarsi, and feet
pale tawny, immaculate; remaining underparts white, ochraceous,
and dusky, in bold, free pattern, and upper breast distinctly
and heavily streaked, the sides and flanks distinctly barred,
the belly exhibiting a combination of the two types; lining
of wing pale tawny, unmarked basally, save for a dusky patch
on tips of coverts, heavily barred distally. Bill and toe-
nails blackish. The folded wings exceed the tail, and the
bill is nearly concealed by black and white bristles."
Asio otus (con't.)
B. External morphology of subadult age classes *
Ridgway (1914), detailed description of plumage and soft
parts. Armstrong (1958), description of plumage changes
as observed regularly to 59 days of age. Dawson (1923),
"Everywhere, except on head and linings of wings, finely
barred dusky and gray or ochraceous."
C. Distinguishing characteristics
Interspecific - Peterson (1961), "much smaller than Horned
Owl, streaked lengthwise, rather than barred, beneath.
'Ears' closer together, toward center of forehead, giving
a different aspect. .. Screech Owl is smaller, has shorter
ears, lacks rusty face... In flight, Long-eared Owl's ear
tufts are depressed; then grayer color, habitat distinguish
it from Short-eared Owl."
Intraspecific -
III GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), "British Isles, western Europe from lat. 66°N. ,
Siberia from lat. 60°N. , and Japan south to the Azores, m
Canary Islands, Morocco, Tunisia, southern Europe, Palestine, ^
Afghanistan, the Himalayas, Manchuria, Korea, and Formosa;
southern Alaska, southern Mackenzie, southern Manitoba,
central Ontario, southern Quebec, and Nova Scotia south to
northwestern Baja California, southern Arizona, Oklahoma,
Arkansas and Virginia." A. £. tuf tsi: "Breeds from southern
Mackenzie (Fort Simpson, Fort Providence) , central British
Columbia (Nulki Lake), and Saskatchewan south to southern
California (including Catalina Island), northwestern Baja
California (to lat. 30°N.), southern Arizona (Bates Well.
Pima County, Santa Rita Mountains), New Mexico (Santa Fe),
and western Texas."
B. California distribution of the species
Grinnell and Miller (1944), "Entire length of State east
of northern humid coast belt; three centers of abundance,
in northeastern Great Basin territory, in central valleys,
and in San Diegan district. Peripheral stations: northern-
most in coast belt, Bodega and Sebastopol, in Sonoma County
. . .Northeasternmost, Goose Lake and Surprise Valley, Modoc
County... to eastward on southern deserts, chiefly or perhaps
entirely." Dawson (1923), "Locally resident, chiefly in
interior valleys, on the oak-covered foothills, and along
wooded streams of the Upper Sonoran zone, south (at least
formerly) to San Diego. Sparingly resident on the Santa
Barbara Islands... An occasional invader of the higher moun-
tains."
•
Asio otus (con't.)
C. California desert distribution
Grinnell and Miller (1944), "in winter: Mohave River near
Yermo, San Bernardino County. . .Palm Springs, Riverside County
...Palo Verde, Imperial County." Dawson (1923), "Numbers
augmented in winter, at least in San Diego district and on
the edges of the deserts."
D. Seasonal variations in distribution
AOU (1957), Asio otus in general: "In winter south to Egypt,
Iraq, northwestern India, and southern China, and to Baja
California, central Mexico, Texas, and Florida. Fossil,
in the Pleistocene of California and Nuevo Leon." A. o.
tuftsi: "Winters from southern Canada south to Northern
Baja California, Sonora (Tiburon Island), and Durango."
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), "Typically, bottomlands grown
to tall willows and cottonwoods; but also, west of Sierran
divides, belts of live oaks, especially as paralleling stream
courses." Armstrong (1958), "either coniferous or deciduous
nesting habitats." Small (1974), "riparian woodlands and
stands of live oaks along watercourses." Miller (1951),
Lower and Upper Sonoran and Transition life zones."
B. Altitudinal range
Grinnell and Miller (1944), "ranges normally up to 2000 feet
west of Sierras, up to 7000 feet east of Sierra Nevada;
exceptionally has reached 9000 feet on San Jacinto Peak,
Riverside County. . ..and 10,500 feet on White Mountains, Mono
County."
C. Home range size
Craighead and Craighead (1956), during nesting season in
Wyoming, 1947, reported ranges of three nesting pairs:
0.13 sq. mile (maximum diameter of 0.7 mile); 0.41 sq.
mile (maximum diameter of 1.0 mile); 0.10 sq. mile (maximum
diameter 0.5 mile).
D. Territory requirements
Perch sites - Marti (1976), "It does require small, dense
trees for nesting and roosting." Randle and Austing (1952),
"roosted at a height of six to twelve feet, close to the
♦
•
Asio otus (con't.)
trunk. In three places where the owls had a choice between
trees taller than twenty feet and those smaller than fifteen /
feet in contiguous groves they chose the smaller trees."
Peterson (1961), "Usually seen 'frozen' close to trunk of
dense tree."
Courtship and mating sites -
Nest sites - Armstrong (1958), "Nests in Michigan have been
recorded from ground level to a height of 40 feet." Dawson
(1923), "Usually a deserted nest of crow, magpie, heron,
etc.; sometimes in rock-rifts or even on the ground...
Nests regularly in live oaks and evergreens."
E. Special habitat requirements
Udvardy (1958), "The only bird that in North America is
largely dependent on the deciduous woods is Asio otus."
Grinnell and Miller (1944) "Open land productive of mice is
requisite, as also presence of old nests of crows, hawks
or magpies for breeding purposes."
F. Seasonal changes in habitat requirements
Wilson (1938), "During the late summer, fall and winter
months they inhabited the coniferous woods and during their
nesting and brooding seasons from March until June, they
were found in the hard woods." (Michigan)
*
V FOOD
A. Food preferences
Errington (1932), "Total vertebrate kills from pellets and
stomachs (quantitative data) amount to 3273: juvenile cotton-
tail, 1; Norway rat, 3; meadow mouse, 2732: deer mouse,
497; shrew, 14; small bird (mostly finches), 26." Graber
(1962), "The detailed record of pellet contents. .. indicates
that Long-ears usually consume voles and deer mice entirely,
while house mice are more often only partly eaten." (Illinois).
Marti (1976), "feed upon small, nocturnal mammals that live
in open lands, i.e., farmlands, grasslands, marshes and
deserts." Includes detailed discussion of diet.
B. Foraging areas
Marti (1976), "This is a strictly nocturnal species. . .and
apparently feeds almost exclusively in open lands." Getz
(1961), Washtenow County, Michigan: "fed primarily on the
meadow vole, and hunted in an old- field habitat. They
apparently did not utilize a near-by marsh, although it
Asio otus (con't.)
t
contained more voles than the old field. The use of the old
field appears to be related to a lesser amount of cover in
this habitat than in the marsh. Timbered areas nearer
the roost than the old field and having a greater abundance
of small mammals were not utilized. . .Therefore, apparently
prefer open, grassy areas to timbered areas."
C. Foraging strategies
Marti (1976), "compared to many other North American owls
this species has rather light wing-loading, which indicates
efficiency of hunting on the wing." Dawson (1923), "strictly
nocturnal in habit."
D. Feeding phenology
Errington (1932), reports the following from analysis of
pellets and stomachs: Fall, winter, early spring, 1929-30,
99.66% mammals, 0.34% birds; Late spring, early summer,
1930, 87.62% mammals, 12.38% birds; Late summer, 1930,
92.6% mammals, 7.4% birds; Fall and early winter, 1930,
99.24% mammals, 0.76% birds; Late winter and early spring,
1931 , 100% mammals, (Wisconsin). Graber (1962), ''With the
passing of winter into spring, there was a marked increase
in frequency of house mice and least shrews in pellets at
both roosts."
E. Energy requirements
Graber (1962), "Standard (basal) rate: 26 kcal . /bird/day
(105 kcal. /ig. /day ) , aviary existence: 109 kcal . /bird/day
(357 kcal ./kg. /day) , natural existence: 159 kcal . /bird/day
(532 kcal. /kg. /day)."
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Bent (1938), "is normally so inactive and retiring during
the daytime that we have learned very little about its
behavior, except what we have seen of it when its nest or
brood of young is disturbed." Dawson (1923), describes in-
dividuals feigning prey capturing as a method of distracting
attention from the nest.
♦
•
Asio otus (con't.)
C. Courtship and mating behavior
Armstrong (1958), "The courtship pattern consisted of
competitive calling, aerial performance, non-competitive
calling, nest selection and copulation. . .Flights were
sporadic and irregular and consisted of turning, twisting,
diving, and wing slaps. An owl would suddenly disappear
in a swoop or dive to the pines, and on several occasions,
a cracking noise was heard, evidently made with the wings
slapping each other."
D. Nesting phenology
Dawson (1923), "February -May; one brood."
E. Length of incubation period
Armstrong (1958), "lasted from 23 to 26 days... from 22 to
26 days."
F. Length of nestling period
Armstrong (1958), "When young were 25 or 26 days old, their
wings were developed sufficiently to permit them to leave
the nest." Whitman (1924), "The oldest left the nest when
about four weeks old, but the younger ones... began crawling
around in the branches long before they could fly."
G. Growth rates
H. Post-breeding behavior
Wilson (1938), "offspring remained with the parents until
January of the next mating season when all but the mated
adults disappeared."
VII POPULATION PARAMETERS
A. Clutch size
Whitman (1924), reports a nest containing four eggs and two
newly hatched young. Dawson (1923), "3 to 6; subsperical,
white (or not infrequently red-spotted with nest-marks).
B. Fledging success
Craighead and Craighead (1956), report in Wyoming, 1947:
93% nesting success based upon number of fledglings (8)
per total eggs laid.
'
Asio otus (con't.)
. C. Mortality rates per age class
Craighead and Craighead (1956), report for Wyoming, 1947:
7% of the clutches were incomplete or nests failed to re-
ceive eggs; 77o of the eggs were destroyed, infertile, or
failed to hatch; no mortality in the nest after hatching
was observed.
D. Longevity
E. Seasonal abundance
F. Habitat density figures
Randle and Austing (1952), "Where more than one bird was
found in the same group of trees, roosting was communal.
In one place twenty- seven birds flushed from a clump of
four fifteen-foot pines. In a second place five birds
were in a twelve- foot pine and sixein two neighboring
trees. On another occasion eight were discovered in two
intermingling trees."
rill INTERSPECIFIC INTERACTIONS
A. Predation
m Marti (1976), detailed analysis of prey items of this species.
Armstrong (1958), examination of predation on mouse popula-
tion near nesting sites of this species in Michigan. Sutton
(1926), reports this species preying upon Ruffed Grouse in
Cameron County, Pennsylvania. "It seems hardly possible
that so light a creature as the Long- eared Owl should cus-
tomarily kill creatures so much heavier than itself."
B. Competition
Wilson (1938), "Occupied and hunted the same areas used by
Marsh Hawks (Circus hudsonius), and the Red- shouldered Hawk
Buteo lineatus)." (Michigan)
C. Parasitism
IX STATUS
A. Past population trends
Grinnell and Miller (1944), "Resident within State, but with
markedly irregular wanderings of individuals and groups. In
general, numbers are so large as to warrant term common,'
even 'abundant' locally. Reduction of late years is apparent,
in the main probably as result of clearing of bottomlands for
farming . "
•
Asio otus (con't.)
B. Present population status
Small (1974), "resident but populations shift about in
unknown pattern."
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
•
Asio otus (con't.)
kXI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Armstrong, W. H. 1958. Nesting and food habits of the Long-
eared Owl. Michigan State University Publications of the
Museum, Biological Series, Vol. 1, No. 2.
Bent, A. C. 1938. Life histories of North American birds of
prey. Part 2. U.S. Nat. Mus. Bull. No. 170.
Craighead, F. C, Jr. and J. J. Craighead. 1956. Hawks,
owls and wildlife. Stackpole Co., Pennsylvania.
Dawson, W. L. 1923. The birds of California. South Moulton
Co., San Francisco.
Errington, P. L. 1932. Food habits of southern Wisconsin
raptors. Condor 34:1-186.
Getz, L. L. 1961. Hunting areas of the Long- eared Owl.
Wilson Bull. 73:79-82.
Graber, R. R. 1962. Food and oxygen consumption in three
species of owls (Strigidae). Condor 64:473-487.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27.
Marti, C. D. 1976. A review of prey selection by Long-eared
Owl. Condor 78:331-336.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. Vol. 50.
Peters, J. L. 1940. Checklist of birds of the world Vol. IV.
Mus. Comp. Zool. , Cambridge, Massachusetts.
Peterson, R. T. 1961. Field guide to western birds. Houghton
Mifflin Co., Boston.
Randle, W. and R. Austing. 1952. Ecological notes on Long-
eared and Saw-whet Owls in southwestern Ohio. Ecology 33:
422-426.
Ridgway, R. 1914. The birds of North and Middle America.
Part 6. U.S. Nat. Mus. Bull. No. 50.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
10
Asio otus (con't.)
Sutton, G. M. 1926. Long-eared Owl capturing Ruffed Grouse.
Auk 43:236-237.
Udvardy, M. D. F. 1958. Ecological and distributional analysis
of North American birds. Condor 60:50-66.
Whitman, F. N. 1924. Nesting habits of the Long-eared Owl.
Auk 41:479-480.
Wilson, K. A. 1938. Owl studies at Ann Arbor, Michigan. Auk
55:187-197.
i
•
MOUNTAIN BLUEBIRD
Sialia currucoides
I TAXONOMY
A. Type description
Sialia currucoides - AOU (1957) Motacilla s. Sylvia Curru-
coides "Borkh," Bechstein, in Latham, Allgem. Ueb. Vogel,
vol. 3, pt. 2, 1798, p. 546, pi. 121. (Virginien = western
America.) .
B. Current systematic treatments
AOU (1957) considers this species a member of the avian
Order Passeriformes, Family Turdidae (Thrushes, Solitaires,
and Bluebirds) ; listed as monotypic.
Peters (1964) lists the Mountain Bluebird as a member of
the Subfamily Turdinae, Family Musicapidae; also considered
monotypic
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), Sialia arctica. Ridgway (1907)
adds, Erythaca arctica; Sylvia arctica; Sialia macroptera.
r D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), Arctic Bluebird; Rocky Mountain
Bluebird.
II DESCRIPTION
A. External morphology of adults
Ridgway (1907) gives detailed description of plumages and
measurements of all age classes and sexes. Describes adult
male as "above plain rich turquoise. . .bill, legs, and feet,
black; iris, dark brown." Miller and Stebbins (1964),
"A bluebird without any rich brown areas... Male light azure
blue above and below, except belly, which is white.
B. External morphology of subadult age classes
Ridgway (1907) details subadult plumages — "Young male...
light brownish gray or drab-gray. .. indistinctly streaked
with white. Young female, similar to the young male, but
blue of wings and tail much duller." Wheelock (1920),
"Young: Grayish, indistinctly streaked or mottled with
white; wings and tail blue."
#
Sialia cur rue o ides ( con f t . )
C. Distinguishing characteristics
Interspecific - Peterson (1961), "Similar species: (l)
Other bluebirds have red breasts. (2) Male Blue Crosbeak
has a thick bill, brown wing bars. (3) Male Indigo Bunting
is smaller, very much darker."
Intraspecific - Ridgway (1907) states that the female is
"plain mouse gray or smoky gray, sometimes faintly tinged
with greenish blue. .. turquoise or light cerulean blue."
Adult male-- length 169 mm; wing 117 mm; tail 72 mm, and
female-- length 166 mm; wing 112 mm; tail 68 mm. Miller
and Stebbins (1964), "Male light azure blue. . .Female dull
brownish with pale, dull blue rump, tail, and wings."
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) gives the range of the Mountain Bluebird (Sialia
currucoidesj as "Breeds from central Alaska, southern Yukon,
southern Mackenzie, southern Saskatchewan, and southwestern
Manitoba south along eastern slopes of the coast ranges,
and in the Sierra Nevada and the Rocky Mountains to north-
western and central southern California (South Yolla Bolly
Mountains. Mt. Sanhedrin, Panamint Mountains, San Bernardino
Mountains) central and southeastern Nevada, northern Arizona,
southern New Mexico, western Oklahoma, Colorado, western
Nebraska, South Dakota, and northeastern North Dakota.
Winters from southern British Columbia and western Montana
south to northern Baja California, Sonora, southern Chihuahua,
Guanajuato, central Nuevo Leon, and southern Texas; extending
to the Pacific coast and offshore islands, and to western
Kansas, western Oklahoma, and western Texas." Peters (1964),
"Breeds from central Alaska, southern Yukon, southern Mackenzie,
and southwest Manitoba south in the mountains to southern
California, northern Arizona, southern New Mexico, and in
plains of Dakotas; winters from southern British Columbia
south to Baja California, Sinaloa, Michoacan, Guanajuato,
Nuevo Leon, and southern Texas."
B. California distribution of the species
Grinnell and Miller (1944) list range as "Breeds along
Cascade — Sierra Nevada Mountain system and on high plateaus
and mountains to eastward from Warner Mountains south to
Panamint Mountains, Inyo Co. ; also in inner northern coast
ranges from Siskiyou Co. south to Mt. Sanhedrin, Mendocino
Co. , and in San Bernardino Mountains of southern California.
In winter, throughout state at lower levels." Small (1974)
gives range as "for breeding, Sierra Nevada and Cascades,
K
♦
Sialia currucoides (con't.)
Warner Mountains, inner Coast Range south to Mendocino
County, San Bernardino Mountains; in winter sometimes com-
mon in San Joaquin Valley, Carrizo Plain in eastern San
Luis Obispo County, Antelope Valley, and Imperial Valley."
Wheelock (1920), On the higher Sierra Nevada, from Mt.
Shasta to the San Bernardino Mountains."
C. California desert distribution
Grinnell and Miller (1944) summarize winter desert records,
including — Death Valley, Twentynine Palms, Needles, and
Brawl ey. At Joshua Tree National Monument, Miller and
Stebbins (1964) called this species a "Winter visitant in
moderate numbers. Recorded from: Upper Covington Flat,
March 10; Quail Spring, January 27; Twentynine Palms, Nov-
ember 16... March 24." Willett (1951) stated that although
they do not remain to breed, these bluebirds are found on
southern California deserts during winter. Wauer (1964)
found Mountain Bluebirds breeding in the limber pine asso-
ciation between 8,000 and 9,000 feet in the Panamint Moun-
tains, Death Valley. Gilman (1935) noted the presence of
this bluebird in Death Valley (Furnace Creek Ranch; Eagle
Borax Works) from January to mid- April. Carter (1937)
noted Mountain Bluebirds, often in mixed flocks of Western
Bluebirds, at Twentynine Palms between January and mid-
March. Van Rossem (1911) noted this species near the Sal ton
Sea during winter. Lamb (1912) discovered only four Moun-
tain Bluebirds between December and March on the Mohave
Desert near Daggett (San Bernardino Co.). During winter
in the lower Colorado Valley, Price (1899) found these
bluebirds to be "Common about alfalfa fields in the river
bottom." Grinnell (1904) noted this species wintering near
Palm Springs, Riverside Co. Near Victorville during winter,
Mailliard and Grinnell (1905) encountered several flocks of
these bluebirds "out on the desert quite a distance from
the (Mojave) river."
D. Seasonal variations in distribution
Grinnell and Miller (1944) found in California that "Winter
occurrence in lowlands irregular as to date and variable
from year to year; noted chiefly from November to March."
Small (1974) gives seasonal status in California as "summer
visitor in mountains and northeastern plateau; winter visitor
in some lowland areas." In California, Willett (1933)
noted "Breeds in higher mountains, mostly on eastern slope,
south to San Bernardino Range; more or less common in lower
country in winter."
Sialia currucoides (con't.)
IV HABITAT I
A. Biotopic affinities
In California, Grinnell and Miller (1944) give habitat
as "Widely open terrain, the ground covered with short
grass, alpine turf, stunted or widespread bushes, or even
rock shingle. At Joshua Tree during winter, Miller and
Stebbins (1964) noted Mountain Bluebirds on "open desert."
B. Altitudinal range
In California, altitudes of known nesting range from 4,000
to 12,000 feet (Grinnell and Miller 1944J.
C. Home range size
In Montana, Power (1966) found "The smallest territory...
was only approximately 100 yards wide, while other terri-
tories had no clear boundries, and the resident bluebirds
occasionally flew. ..from their nests, up to about one-
quarter mile away."
D. Territory requirements
Perch sites - "Perches may be provided by rocks, bush tops,
or scattered trees or small or moderate stature" (Grinnell f
and Miller 1944). Haecker (1948) noted these bluebirds
feeding from a wire, usually 8 to 15 feet above ground.
Courtship and mating sites - Power (1966), "The male chased
his mate and nearly caught her in flight. . .both perched
next to one another on a wire fence. . .while on an elevated
perch, males simply flew up to their mates and mounted
them."
Nest sites - Grinnell and Miller (1944), "For nest sites
dead trees usually are present, but rock crevices and man-
made structures may be used." Peterson (1961), "In hole
in tree, stub, cliff, bird box." Wheelock (1920), "In old
woodpecker holes or in natural cavities of dead trees."
In Wyoming, Calder (1970) noted a Mountain Bluebird pair
nesting in an old Dipper (Cinclus mexicanus) that was placed
under a bridge.
E. Special habitat requirements
On the California desert (Joshua Tree), Miller and Stebbins
(1964) noted that this species "frequents the desert only
in the coldest months."
*
Sialia cur ruco ides (con't.)
F. Seasonal changes in habitat requirements
Small (1974), "for breeding, subalpine forest of Canadian
and Hudsonian life zones... in winter not uncommon in certain
open plains and grasslands and more arid agricultural lands."
Peterson (1961), "Open terrain with scattered trees; in
winter, also treeless terrain."
V FOOD
A. Food preference
Martin et al. (1961) describe animal food as--beetles,
particularly ground beetles, and weevils are the major items
in the diet, followed by grasshoppers and crickets, ants,
caterpillars, and bugs. Plant food includes grapes and
elderberries. In California, Wheelock (1920) noted "Crick-
ets, grasshoppers, beetles, butterflies, and worms are their
menu, with a few berries."
B. Foraging areas
"The insects for which these bluebirds forage may be taken
either on the ground or in the air" (Grinnell and Miller
1944). Grinnell and Storer (1924) noted this species for-
aging on grasslands and meadows in Yosemite. In Arizona,
Phillips et al. (1964) found this bluebird foraging in open
country, farmlands, grasslands, and open berry-bearing
woods and brush.
C. Foraging strategies
Grinnell and Miller (1944), "Open tracts of ground and
snow banks are searched over from the wing by cruising out
from distant resting places. High tolerance of wind and
light exposure is shown." Miller and Stebbins (1964) found
that on California deserts (winter), this bluebird's insect
food is taken chiefly from the open ground. Wheelock (1920)
"they have all the habits of flycatchers. .. flying out after
insects, or skimming the air like swallows, and hovering
like hummingbirds." Power (1966), "Mountain Bluebirds
have three distinct types of foraging behavior, used in
the following order of frequency: Perch- feeding, hovering,
and f lycatching."
D. Feeding phenology
Martin et al. (1961) notes the taking of grapes and elder-
berries by bluebirds, especially during summer, fall and
winter.
Sialia cur ruco ides (con't.)
E. Energy requirements
While wintering on California deserts, Miller and Stebbins
(1964) felt that the insect food of these bluebirds pro-
vided adequate moisture.
VI REPRODUCTION
A. Age at first breeding
Power (1966) reported that a young banded in 1962 returned
to nest in 1963 in a Montana study (no sex given) .
B. Territorial behavior
Power (1966) described this species territory as "a large
breeding area wherein courtship, copulation, nesting, and
food- seeking occur. . .Nesting territories were defended by
both sexes.' Details of the mechanisms of territorial
defense, including advertising song and fighting behavior,
are duscussed.
C. Courtship and mating behavior
Power (1966) noted that "Pair formation occurred quickly,
after females arrived and joined territorial males. . .Early
coition attempts by males were repulsed. In precopulatory
displays, females on an elevated perch held their bodies
horizontal with heads raised, wings slightly lowered, and
tails raised."
D. Nesting phenology
In California, Wheelock (1920) reported the breeding season
as May to July. Power (1966) found that 50% of all pairs
that successfully raised first broods attempted second
broods (Montana). In southwestern California, this species
nests "mostly in May" (Willett 1933). Bent (1964) gives
California egg dates as "34 records, April 5 to July 17;
17 records, June 9 to June 18, indicating the height of
the season."
E. Length of incubation period
Wheelock (1920) reported a 14 day period. In Montana,
Power (1966) listed incubation as lasting 13 days. Haecker
(1948) gave a 13 or 14 day period (Wyoming).
Sialia cu r rue o ides ( con ' t . )
F. Length of nestling period
™ Power (1966) found that "Young normally fledged between
22 and 23 days of age. . .Fledglings began feeding themselves
at about 33-34 days of age. . .Fledglings became completely
food independent at 22-28 days after leaving the nest
(44-51 days of age)."
G. Growth rates
Wheelock (1920) found that "On the second day down begins
to appear.. on the fourth or fifth day the eyes show signs
of opening; on the sixth day they open, and the down is
well spread... The young bluebirds double their weight every
24 hours for the first weeks."
H. Post-breeding behavior
Small (1974) states that after breeding, these bluebirds
frequently range upwards into Arctic Alpine Life Zone in
California. Grinnell and Storer (1924) noted the formation
of "small scattering companies" during fall and winter in
California mountains. Power (1966) noted that "By late
August flocks were composed of birds "of all ages and
sexes."
II POPULATION PARAMETERS
A. Clutch size
Peterson (1961), "Eggs (4-6; 8) pale blue." Bent (1964)
gives a range of 4 to 8 eggs per clutch, with sets of 5
and 6 the commonest.
B. Fledging success
Power (1966) found hatching success was 76.67o, and nest
success (those fledging at least one young) was 68.7% in
a Montana study.
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
Wauer (1962) noted that in Death Valley, wintering Mountain
Bluebirds are "sporadic in occurrence; they are common some
winters and absent others."
Sialia currucoides ( con ' t . )
F. Habitat density figures
In a Sierra Nevada conifer forest, Bock and Lynch (1970)
found 15.2 breeding pairs per 100 acres of Mountain Blue-
birds. In Wyoming, Finzel (1964) noted 6-7 bluebirds per
40 acres. In a Wyoming aspen forest, Salt (1957) found
about 30 Mountain Bluebirds per 100 acres during summer.
Ill INTERSPECIFIC INTERACTIONS
A. Predation
Marti and Braun (1975) found that Mountain Bluebirds made
up 5.6% of a nesting Prairie Falcons diet on the tundra of
Colorado (above 11,000 feet). In north-central Colorado,
Marti (1974) noted this bluebird was taken only once in
over 4,000 kills by a Barn Owl. Power (1966) noted that
"The only probable predators observed were a Marsh Hawk,
a Sparrow Hawk, and a group of Common Crows" (Montana) .
In British Columbia, Munro (1940) found Sharp-skinned
Hawks taking this bluebird for food.
B. Competition
Power (1966), in a Montana study, found "nest-site competitors
were Tree Swallows, House Wrens, Mountain Chickadees, Red-
shafted Flickers, and two rodents." Munro (1943) noted the
unsuccessful attempt by a pair of Mountain Bluebirds to
take a nest hole from Hairy Woodpeckers.
C. Parasitism
Friedmann (1963) and Friedmann et al. (1977) noted that
cowbird parasitism of Mountain Bluebirds is extremely rare.
IX STATUS
A. Past population trends
Grinnell and Miller (1944), "Common summer resident in the
mountains; but rated as very common or abundant in north-
east section."
B. Present population status
Johnson (1974) reported an apparent increase in the Dreed-
ing population of this bluebird since a 1940 study in the
Grapevine Mountains, Death Valley National Monument, Nevada.
Arbib (1976) concluded that the Mountain Bluebird is de-
creasing in the mountain regions of the western United
States. '
1
Sialia currucoides (con't.)
C. Population limiting factors
In Montana, Power (1966) concluded that "highly special-
ized nesting requirements have produced a relatively un-
adaptable species, whose population has declined as a result
of environmental changes of recent decades." Haecker (1948)
felt that lack of nesting cavities was the main deterrent
to range expansion of this species. In northern California,
Grinnell et al. (1930) noted that the presence of this
species was largely determined by the availability of suit-
able nest holes.
D. Environmental quality: adverse impacts
E. Potential for endangered status
10
Sialia currucoides ( con ' t . )
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore MD. 691 pp.
Arbib, R. 1976. The blue list for 1977. Am. Birds 30:1031-
1039.
Bent, A. C. 1964. Life histories of North American thrushes,
kinglets, and their allies. U.S. Nat. Mus. Bull. 196.
Bock, C. E. and J. F. Lynch. 1970. Breeding bird populations
of burned and unburned conifer forest in the Sierra Nevada.
Condor 72:182-189.
Calder, W. M. 1970. Use of Dipper nest by Mountain Bluebird,
Condor 72:498.
Carter, F. 1937. Bird life at Twentynine Palms. Condor 39:
210-219.
Finzel, J. E. 1964. Avian populations of four herbaceous
communities in southeastern Wyoming. Condor 66:496-510.
Friedmann, H. 1963. Host relations of the parasitic cowbirds.
U.S. Nat. Mus. Bull. 233. 276 pp.
Friedmann, H. , L. F. Kiff and S. I. Rothstein. 1977. A further
contribution to knowledge of the host relations of the para-
sitic cowbirds. Smithsonian Contrib. Zool. No. 235. 75 pp.
Gilman, M. F. 1935. Notes on birds in Death Valley. Condor
37:238-242.
Grinnell, J. 1904. Midwinter birds at Palm Springs, California.
Condor 6:40-45.
Grinnell, J., J. Dixon and J. M. Linsdale. 1930. Vertebrate
natural history of a section of northern California through
the Lassen Peak region. Univ. California Publ. Zool. 35:
1-594.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27. 608
pp.
Grinnell, J. and T. I. Storer. 1924. Animal life in the
Yosemite. Univ. California Press, Berkeley. 752 pp.
Haecker, F. W. 1948. A nesting study of the Mountain Bluebird
in Wyoming. Condor 50:216-219.
»
11
Sialia currucoides (con't.)
Johnson, N. K. 1974. Montane avifaunas of southern Nevada:
Historical change in species composition. Condor 76:334-
337.
Lamb, C. 1912. Birds of a Mohave Desert oasis. Condor 14:
32-40.
Lane, J. 1968. A hybrid Eastern Bluebird X Mountain Bluebird.
Auk 85:684.
Mailliard, J. and J. Grinnell. 1905. Midwinter birds on the
Mojave Desert. Condor 7:71-77; 101-102.
Mansfield, G. S. 1946. Wintering Mountain Bluebirds on the
Santa Barbara coast. Condor 48:285.
Marti, C. D. 1974. Feeding ecology of four sympatric owls.
Condor 76:45-61.
Marti, C. D. and C. E. Braun. 1975. Use of tundra habitats
by Prairie Falcons in Colorado. Condor 77:213-214.
Martin, A. C, H. S. Zim and A. L. Nelson. 1961. American
wildlife and plants. McGraw-Hill Book Co., New York.
Miller, A. H. and R. C. Stebbins. 1964. The lives of desert
animals in Joshua Tree National Monument. Univ. California
Press, Berkeley. 452 pp.
Munrb, J. A. 1940. Food of the Sharp- skinned Hawk. Condor
42:168-169.
Munro, J. A. 1943. Competition between Mountain Bluebirds
and Hairy Woodpeckers. Condor 45:74.
Murie, 0. J. 1934. Unusual Mountain Bluebird nests. Condor
36:164-165.
Peters, J. L. 1964. Checklist of birds of the world. Vol.
10 (E. Mayr and R. A. Paynter, Jr., eds.). Mus. Comp.
Zool., Cambridge, Mass. 502 pp.
Peterson, R. T. 1961. A field guide to western birds. Houghton
Mifflin Co., Boston. 309 pp.
Phillips, A., J. Marshall and G. Monson. 1964. The birds of
Arizona. Univ. Arizona Press, Tucson. 212 pp.
Power, H. W. 1966. Biology of the Mountain Bluebird in Montana.
Condor 68:351-371.
Power, H. W. 1974. The Mountain Bluebird: sex and the evolu-
tion of foraging behavior. Ph.D. thesis, Univ. Michigan,
Ann Arbor.
«
12
Sialia currucoides ( con ' t . )
Price, W. W. 1899. Some winter birds of the lower Colorado
Valley. Condor 1:89-93.
Ridgway, R. 1907. The birds of North and Middle America.
Part 4. Bull. U.S. Nat. Mus. No. 50.
Salt, G. W. 1957. An analysis of avifaunas in the Teton
Mountains and Jackson Hole, Wyoming. Condor 59:373-393.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Stoner, E. A. 1939. Mountain Bluebirds hovering. Condor
41:172.
Van Rossem, A. 1911. Winter birds of the Salton Sea region.
Condor 13:129-137.
Wauer, R. H. 1962. A survey of the birds of Death Valley.
Condor 64:220-233.
Wauer, R. H. 1964. Ecological distribution of the birds of
the Panamint Mountains, California. Condor 66:287-301.
Weydemeyer, W. 1934. The song of the Mountain Bluebird.
Condor 36:164.
Wheelock, I. G. 1920. Birds of California. Fifth Edition. ^fc
A. C. McClurg & Co., Chicago. 478 pp. ^^
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna No. 21. 204 pp.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. No. 6. 39 pp.
J
MOUNTAIN CHICKADEE
■ Parus gambeli
I TAXONOMY
A. Type description
AOU (1957) Parus gambeli baileyae Grinnell, Condor, 10
no. 1, Feb. 1, 1908, p. 29. (Mount Wilson, 5500 feet alti-
tude, Sierra San Gabriel, Los Angeles County, California.)
Penthestes gambeli inyoensis Grinnell, Univ. California
Publ. Zool. , 17, no. 17, May 4, 1918, p. 509. (Panamint
Mountains (northern part), 3 miles east of Jackass Spring,
6200 feet altitude, Inyo County, California.)
B. Current systematic treatments
Behle (1956), recognizes seven subspecies of Parus gambeli
(gambeli , grinnelli , abbreviatus , baileyae, atratus ,
inyoensis , wasatchensis ) . Detailed discussion of racial
characters and comparisons; geographic distribution; local-
ities, and geographic variation and intergradation.
Snow (1967) recognizes 43 species in the genus Parus ; five
subspecies of gambeli. Passeriformes : Paridae.
W Ridgway (1904) discussion of morphological characteristics
and geographic distribution in relation to systematic treat-
ment. *
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), P. g_. inyoensis : Penthestes
gambeli ; Penthestes gambeli baileyae ; P. g_. baileyae : Parus
montanus ; Penthestes gambeli baileyae ; Penthestes gambeli
gambeli.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), P. g. inyoensis : Inyo Mountain
Chickadee; Bailey Mountain Chickadee. P. g_. baileyae : Rocky
Mountain Chickadee; Mountain Titmouse; Bailey Chickadee;
Bailey Mountain Chickadee.
II DESCRIPTION
A. External morphology of adults
Ridgway (1904), detailed description of plumage, soft parts,
with measurements, adults spring and summer versus autumn
and winter. Udvardy (1977), "White eye-stripe, black cap
and bib ; pale gray flanks . "
»
Par us gambeli (con't.)
B. External morphology of subadult age classes
Ridgway (1904), "Young. --Similar to adults but the back
of the head and neck duller, white superciliary streak much
less distinct (pale gray rather than white) and edgings
of greater wing-coverts and tertials faintly tinged with
pale brownish buff."
C. Distinguishing characteristics
Interspecific - Peterson (1961), "Similar to Black-capped
Chickadee, but black of cap interrupted by white line over
each eye. Sides lack buff."
Intraspecific - Behle (1956), "The race inyoensis can be
distinguished from baileyae by its much paler, Euffy, less
plumbeous appearance, narrower bill, and longer tail."
LI GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), "Resident in the Rocky Mountains, the Sierra
Nevada, and the inner coast ranges from northwestern British
Columbia and southwestern Alberta to northern Baja California,
central and southeastern Arizona, central and southeastern
New Mexcio, and southwestern Texas.
B. California distribution of the species
AOU (1957), Parus gambeli baileyae: "Resident in the moun-
tains of southern California (San Lucia Mountains, Mount
Pinos, and the San Bernardino, San Jacinto, and Laguna
Mountains)."
Parus gambeli inyoensis: "Resident in the Great Basin from
southcentral Idaho. . . through central and eastern Nevada. . .
and western and central southern Utah. .. south to eastern
California (White, Inyo, and Panamint Mountains, Clark
Mountains), and southern Nevada." Grinnell and Miller
(1944), P. £. inyoensis : "Higher mountain masses lying east
and soutHeast of Sierra Nevada. . . southern Great Basin ranges
...from vicinity of Mono Craters and eastward to include
White Mountains, in Mono County, south along Inyo Mountains
to and including Grapevine, Panamint, and Argus mountains,
in Inyo County, and Clark Mountain, eastern San Bernardino
County."
P. g. baileyae: "Higher Mountains of southern California. . .
southeast from high parts of Santa Lucia Mountains, Monterey
County, interruptedly, to Tejon Mountains, Kern County,
and through mountainous parts of intervening counties as far
as Cuyamaca and Laguna mountains, in San Diego County."
4
m
m
Par us gambeli (con't.)
C. California desert distribution
Dawson (1923) P. g. baileyae: Mt. Wilson, Los Angeles County;
San Bernardino Mountains.
P. £. inyoensis : "from the vicinity of Mono Craters in the
White Mountains, in Mono County, south to the Panamint
Mountains, in Inyo County."
Behle (1956) P. g. baileyae: "In winter chickadees of this
race are known to occur m the lower valleys at the bases
of the mountains , having been recorded from Pasadena and
in the desert along the Mohave River at Victorville. "
Jaeger (1947), observation of individual foraging creosote
bush in Lucerne. Miller (1951) P. g. inyoensis: Inyo Moun-
tains. P. £. baileyae: San Bernardino, San Jacinto, San
Diegan Mountains.
D. Seasonal variations in distribution
Small (1974), "small numbers descend to lowlands during
fall and winter." Dixon and Gilbert (1964), "adult(s)...
are sedentary on their breeding grounds, and that in winter
months they form stable social groups in which the sexes
are approximately equal. . .Alt itudinal movements are performed
largely if not solely by first-year birds. Udvardy (1977),
"frequently descends to the lowlands in winter. In November
an occasional flock can be found near sea level in desert
oases containing conifers such as Palm Springs, California,
while other flocks, will still be at '8500 feet in the
subalpine forest of adjacent Mount San Jacinto."
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), P. g. inyoensis: "Coniferous
trees, from pinons, even where fairly open, up to stunted
limber pines at timber line (on White Mountains); also
tracts of mountain mahogany."
P. _g. baileyae: "Coniferous trees, especially as growing
in open stands. These may be mixed with such deciduous
trees as black oak; used also for foraging and even nesting,
but coniferous trees must also be within daily cruising
radius." Small (1974), "montane forest and lower portions
of the subalpine forest in the Transition and Canadian Life
Zones." Miller (1951), Transition, Canadian, and Hudsonian
Life Zones. Dixon (1961), discussion of distribution and
niche relationships of Parus.
♦
#
Parus gambeli (con't. )
B. Altitudinal range
Gnnnell anc Miller (1944), P. g_. inyoensis : "6500 feet up ^T
to 11,500 feet on White Mountains. Descends to at least
5 60 0 feet in autumn as near Benton, Mono County."
P. g. baileyae : "of known nesting, 3000 feet in Santa Lucia
Mountains up to 10,600 feet on San Bernardino Peak, San
Bernardino County."
C. Home range size
Laudenslayer and Balda (1976), mean territory size of 1.5 ha.
D. Territory requirements
Perch sites -
Courtship and mating sites - Dixon, Stefanki and Folks
(19 70) "terminal solicitation and coition occurred in leaf-
less aspens interspersed among the conifers."
Nest sites - Barlow (1901) "Rotten stubs ... particularly
where the core of the tree has rotted away, leaving a cavity
. . .A majority were in pine or spruce stubs with the entrance
at the top." Also, deserted woodpecker holes.
•
E. Special habitat requirements
Grinnell and Miller (1944), "coniferous trees must also be
within daily cruising radius. For nesting, the pines or
other trees must be, at least in part, dead or decaying...
must afford suitable-sized cavities, woodpecker-excavated
or natural. .. low rotting stumps often suffice."
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Dawson (192 3) "moths' eggs, spiders, wood-boring grubs."
B. Foraging areas
Bock (1969) "predominantly in ponderosa pine ... largely on
the needles and smaller twigs." Bent (1946) reports that
nothing specific has been published on the food of any of
the races of the Mountain Chickadee. "But its feeding habits
are similar to those of other chickadees; it has- repeatedly
been observed examining the twigs, foliage, and crevices in
the bark of trees, where it doubtless finds a variety of
insect food. Laudenslayer and Balda (1976) "foraged in ..
Parus gambeli (con't.)
pinyon pines 45.5% of the time compared to 9.0% usage of the
ponderosa pine ... latter figure is surprisingly low for species
A that normally reach their highest densities in the ponderosa
W pine forest." (Arizona).
C. Foraging strategies
Laudenslayer and Balda (19 76) "used the hanging posture in
addition to standing."
D. Feeding phenology
Dixon (1965) "are exceedingly active birds and seldom remain
in one site for more than a few minutes, even though food
may be abundant there..."
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
C. Courtship and mating behavior
Dixon, Stefanski, and Folks (1970), discussion of precopula-
fc tory behavior, including spectrographs of vocalizations.
J Courtship feeding was not observed." The male solicitation
calls... may be adaptive in attracting the attention of the
mate in dense foliage of conifers."
D. Nesting phenology
Barlow (1901) "begins nest-building early, being but little
influenced by the elements." Weydemeyer (197 5) reports
earliest date for young in nest as 2 8 May (19 38); young
left nest, 17 June (19 7 3) in Lincoln County, Montana.
E. Length of incubation period
Bent (19 46) reports no information on the period of incu-
bation
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
#
Minock (19 71) , examination of dominance hierarchy in winter-
ing flocks. Found that at intraflock level site-related
dominance does not seem to be operating although it is
important between flocks .
Par us gambeli (con't.)
II POPULATION PARAMETERS
A. Clutch size
Dawson (1923), "four white eggs." Barlow (1901), reports
from seven to nine young in nests, eight eggs in another.
B. Fledging success
C. Mortality rates per age class
D. Longevity
Dixon (1975), reports 10 year old male feeding nestling
(identified by bands), Cache County, Utah. Two additional
males of ages 7 years, 11 months; 7 years, 9 months. One
female recorded at age 5 years, 7 months.
E. Seasonal abundance
Winternitz (1976), "The most numerous species [Crow Gulch,
Pikes Peak, ColoradoJ were the Mountain Chickadee and...
Junco caniceps. These two represented less than 10% of the
species present in any one year but contributed about 25%
of the breeding pairs."
F. Habitat density figures
Miller (1940), reports three pairs upon 40 acres of Transi-
tion Zone timber. Franzreb (1975) reported 71.5 breeding
pairs per 100 hectares, Thomas Creek, White Mountains, Arizona,
summer 1973. Franzreb (1976), discussion of method of pre-
dicting avian densities. Calculates 105.6 breeding birds
per 100 hectare and 111.8 breeding birds per hectare using
two different methods (study site in White Mountains, Arizona).
II INTERSPECIFIC INTERACTIONS
A. Predation
B. Competition
Minock (1972), detailed description of observations of
dominance interactions between Black-capped and Mountain
Chickadees at winter feeding stations. "Black-capped
Chickadees usually were dominant over Mountain Chickadees.
However, since Mountain Chickadees won a substantial number
of contests, an analysis of several factors bearing on the
outcome of encounters is made. The ones having the greatest
effect are sex of the participants, individual differences
in birds and site of encounters in relation to Black-cap
<
Parus gambeli (con't.)
winter ranges." Franzreb (1976), observation of unsuccess-
Jk ful attempt by a pair of violet-green Swallows to displace
W a pair of Mountain Chickadees from nest (with nestlings)
in an Aspen tree. The Swallows were able to drive the
owners away and enter the nest cavity for a short while,
but the chickadees were able to regain possession.
C. Parasitism
IX STATUS
A. Past population trends
Grinnell and Miller (1944), P. g. inyoensis: "Resident.
Locally common."
P. £. baileyae; "Resident. Usually common, sometimes abundant.
There is a slight, irregular, down-mountain spread of in-
dividuals in fall and winter; the low country is occasionally
reached."
B. Present population status
Small (1974) "common resident."
C. Population limiting factors
I
W Winternitz (1976), "because woodpeckers are responsible for
the holes in which non-drilling species nest, the nesting
activities of Downy and Hairy Woodpeckers, Williamson's
Sapsucker and Common Flickers are potentially limiting to
the Mountain Chickadee."
D. Environmental quality: adverse impacts
E. Potential for endangered status
*
Parus gambeli (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Barlow, C. 1901. Some characteristics of the Mountain
Chickadee. Condor 3:111-114.
Behle, W. H. 1956. A systematic review of the Mountain
Chickadee. Condor 58:51-70.
Bent, A. C. 1946. Life histories of North American jays,
crows and titmice. Part 2. U.S. Nat. Mus. Bull. 191:
361-367.
Bock, C. E. 1969. Intra- vs. interspecific aggression in
Pygmy Nuthatch flocks. Ecology 59(5) : 903-905.
Dixon, K. L. 1961. IN Vertebrate Speciation Blair, W. F.
(Ed.) pp. 179-216. U. of Texas, Austin, Texas.
Dixon, K. L. 1975. Mountain Chickadee survives a decade.
Western Birds 6:162.
Dixon, K. L. and J. D. Gilbert. 1964. Altitudinal migration
in the Mountain Chickadee. Condor 66:61-64.
Dixon, K. L. , R. A. Stefanski and F. N. Folks. 1970. Acoustic
signals in the mating of Mountain and Black- capped Chicka-
dees. Auk 87:322-328.
Franzreb, K. E. 1975. Avian densities in a mixed-coniferous
forest, Thomas Creek, White Mountains, Arizona. Western
Birds 6:101-105.
Franzreb, K. E. 1976. A comparison of variable strip transect
and spot-map methods for censusing avian populations in a
mixed-coniferous forest. Condor 78:360-363.
Franzreb, K. E. 1976. Nest site competition between Mountain
Chickadees and Violet-green Swallows. Auk 93:836-837.
Grinnell, J. 1908. The biota of the San Bernardino Mountains.
Univ. California Publ. Zool. 5:1-170.
Grinnell, J. and A. H. Miller. 1944. The distribution of birds
of California. Pacific Coast Avifauna No. 27. 608 pp.
Jaeger, E. C. 1947. Use of the creosote bush by birds of the
southern California deserts. Condor 49:126-127.
<
Parus gambeii (con't. )
Laudenslayer , W. F. , Jr., and R. P. Balda. 1976. Breeding bird
use of a pinyon- juniper-ponderosa pine ecotone. Auk 93:571-586
Miller, A. H. 1940. A transition island in the Mohave Desert.
Condor 42:161-163.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. 50:531-624.
Minock, M. E. 19 71. Social relationships among Mountain
Chickadees (Parus gambeii). Condor 73:118-120.
Minock, M. E. 1972. Interspecific aggression between Black-
capped and Mountain Chickadees at winter feeding stations.
Condor 74:454-461.
Peters, J. L. 1960. Checklist of birds of the world. Vol. 9.
(R. Paynter, Jr., and C. Vaurie, eds . ) Mus . Comp. Zool.,
Cambridge, Mass. 50 6 pp.
Peterson, R. T. 19 61. Field guide to western birds. 2nd
Edition. Houghton Mifflin Co., Boston. 366 pp.
Ridgway, R. 1904. The birds of North and Middle America.
Part 3. Bull. U.S. Nat. Mus. No. 50.
Small, A. 1974. The birds of California. Macmillan Co., New
York.
Weydemeyer, W. 1975. Half-century record of the breeding
birds of the fortine area, Montana: nesting data and
population status. Condor 77:281-287.
Winternitz , B. L. 19 76. Temporal change and habitat preference
of some montane breeding birds. Condor 78:383-39 3.
Udvardy, M. D. F. 1977. Audubon Society field guide to North
American birds - western region. Knopf Co., New York.
<
•
•
•
NORTHERN BROAD-TAILED HUMMINGBIRD
Selasphorus platycercus
S. p_. platycercus
I TAXONOMY
A. Type description
AOU (1957), Trochilus platycercus Swainson, Phil. Mag.,
n.s., 1, no. 6, June 1827, p. 441. (No locality given =
Mexico) .
B. Current systematic treatments
Peters (1945) recognizes eight species in genus Selasphorus ;
two subspecies of S. platycercus (platycercus, guatemaiae; .
Apodiformes: TrochTlidae.
C. Synonomies of scientific nomenclature
AOU (1957), Trochilus platycercus Swainson.
D. Synonomies of vernacular nomenclature
II DESCRIPTION
A. External morphology of adults
Ridgway (1911), detailed description of adults, including
plumage, soft parts and measurements. Peterson (1961)
'Male: Black-green; throat bright rose-red. Female: . . .
sides tinged with buffy; touch of rufous at sides of tail
(near base when spread)." Dawson (1923), describes gorget
of male as aster purple to amaranth purple. Upper parts
shining green with brassy reflections; tail chiefly black,
with violet reflections. Adult female similar but without
purple gorget and lacking the shining green of breasts and
sides. Also, female averages slightly larger.
B. External morphology of subadult age classes
Ridgway (1911), "Young male--similar to adult female but
feathers of upper parts (especially rump and upper tail-
coverts) indistinctly margined terminally with pale brownish
buff or cinnamon, and lateral rectrices with much less of
cinnamomeous on basal portion. Young female-- similar to
young male but rectrices as in adult female."
C. Distinguishing characteristics
Interspecific - Peterson (1961) Male recognized by shrill
trilling of wings as it flies. Lacks rufous coloration of
Selasphorus platycercus ( con ' t . ) *-
male Rufous and Allen's; lacks red crown of male Anna's;
lacks orange-red throat of Ruby- throated. Female larger
than female Black- chin.
Intraspecific -
III GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) "From east central California, northern Nevada,
northern Wyoming, eastern Colorado, New Mexico, and south-
western Texas to southern Mexico and the highlands of Guate-
mala." jS. p_. platycercus: "Breeds from the mountains of
east- central California (Inyo region) , northern Nevada,
northern Utah, and northern Wyoming (Yellowstone National
Park, Midwest) south to southeastern California (Clark
Mountain), northeastern Sonora (Sierra de Oposura). Guana-
juato, Mexico, Districto Federal, and southwestern Texas
( Chi so s Mountains ) . "
B. California distribution of the species
Small (1974) "this Rocky Mountain and Great Basin humming-
bird is normally found only in the White, Panamint, Clark Mk
and New York Mountains along the eastern border of the ^^
state." Males sighted in Inyo County and in the San Bernar-
dino Mountains, both in May, indicate they may breed else-
where in California. Johnson and Garrett (1974), reports
sightings in San Bernardino Mountains. "Although occurrence
...could be strictly casual, the species may be preparing
to colonize."
C. California desert distribution
Dawson (1923), "Summer resident in the timbered desert
ranges of eastern California — at least the White Mountains
and the Inyo range, probably the Panamints, Argus, Amargosa,
etc." Miller (1951) Inyo Mountains. Grinnell and Miller
(1944), "White and Inyo Mountains in Mono and Inyo Counties;
the Grapevine Mountains, Inyo County; and Clark Mountains,
San Bernardino County."
D. Seasonal variations in distribution
AOU (1957), "Winters from central Mexico southward. .. re-
corded south to Oaxaca."
•
•
Selasphorus platycercus (con't.)
IV HABITAT
A. Biotopic affinities
Small (1974), "pinon- juniper woodland." Miller (1940),
"especially numerous in the tingles of Garrya f lavescens
from 6000 ft. upward on both north and south slopes of
the mountain." Bent (1940) "lodge-pole pine forest...
close to mountain streams." Miller (1951) Upper Sonoran
and Transition zones. Grinnell and Miller (1944), "Upper
Sonoran belt of pinon, juniper, and mountain mohogany,
those trees of usual open stand, with xerophilous shrubbery
interspersed. Especially favored is the vicinity of
thickets, as of willow Garrya, along wet or dry stream
courses."
B. Altitudinal range
Hall (193 ), one collected 7800 ft. in Snake Mountains,
White Pine Co., Nevada. Wauer (1964), observed at 6000 ft.
Panamint Mtns.
C. Home range size
D. Territory requirements
Perch sites - Woodbury and Sugden (1938), "on twigs on the
sides of either trees or bushes (never on top) .. .favorite
perches were located on the inner sides of trees around the
border of the area (of territory), or on bushes from which
he could see the surrounding trees."
Courtship and mating sites - Miller (1946) "Where this
plant ( Garrya f lavescens) formed thickets over digwater
courses, males were stationed and diving over females."
Nest sites - Dawson (1923), "A cup of felted plant-downs,
often white, not otherwise lined, but covered externally
with lichens, dead leaves, or bark- shreds, held in place
by cobwebs; placed 3 to 20 feet high on twigs, horizontal
branches, or variously, in bushes or trees, usually near
water. "
E. Special habitat requirements
Lyon (1973), "hummingbird territorial systems are often
organized around food resources, usually nectar."
F. Seasonal changes in habitat requirements
Bendire (1895), "By the time the young are large enough to
leave the nest the majority of the flowers have ceased
Selasphoms platycercus (con't.)
blooming, and as the country begins to dry up... retire to
higher altitudes in the mountain parks where everything
is now as green and bright looking as it was in the lower
valleys two or three months earlier."
V FOOD
A. Food preferences
Waser (1976), reported that nectar of Delphinium nelsoni
(Green), D. barbeyi Huth. , Ipomupsis aggregata (V. grant)
and Castilleja mmiata (Dougl. ) Cottam ( 1941) "seen feeding
on oozing maple sap from holes that had been recently drilled
by a Red-naped Sapsucker." Bent (1940) "small spiders and
minute insects of the orders Diptera, Hymenoptera, Hemiptera,
Co leopt era. . .which it finds in the flowers."
B. Foraging areas
C. Foraging strategies
Linsdale (1938) "feeding upon flying insects caught in the
air... after a poise the bird would dart 3 feet after an insect,
then poise and go after another. This was repeated half
a dozen times, the bird being about 10 feet above the
ground."
D. Feeding Phenology
Bent (1940) "The young are fed at first on regurgitated,
semidigested food, but as they grow older they are given
an increasing amount of minute insects."
E. Energy requirements
Calder and Booser (1973) "high ratios of surface (heat dis-
sipating) to volume (heat producing) , intense metabolism,
and slight insulation. .. energy reserves of a hummingbird
must be sufficient to meet the costs of nocturnal maintenance
and the resumption of foraging at daybreak. A limited
supply can be conserved by entry into hypothermic torpor,
wherein the normal 38° to 43 °C range in body temperature
is abandoned and heat production is reduced during the
nocturnal fast." Reports of incident of hypothermic torpor
by incubating female at night. Discussed ecological signi-
ficance of this strategy.
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
f
Selasphorus platycercus (con't.)
C. Courtship and mating behavior
Woodbury and Sugden (1938), "male. . .dancing in the air with
her (female), occasionally touching bills, but more often
performing his characteristic dives, in which he would
spiral up about as high as the tree tops and then dive rapidly
toward the ground making a sweeping curve at the bottom
and come up again on rapidly beating wings. The descent
was generally marked by a peculiar rattling sound which
gave way at the bottom to a decided duck just as the sweep
reversed and he started to rise." Knox (1944), "The female
would sit quietly on a branch somewhere, and a male would
suddenly zoom up past her, so close as nearly to knock
her from her perch, and straight on upwards until he was a
speck in the sky..." "Occasionally. . .he would do a series
of figure-eights and double loops.
D. Nesting phenology
Dawson (1923), May, June, July, two broods. Waser (1976),
work in Gothic, Colorado, showed that 1) the start of hum-
mingbird reproduction corresponds in time and space with
flowering of the earliest nectar source, 2) peak brooding
activity at these nests corresponds with peak density of
♦other main food sources, 3) total duration of summertime
flowering of the main food plants is implicated as a force
that compresses the initiation of nesting toward the earliest
possible date.
E. Length of incubation period
Bent (1940) "about 14 days"
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
Bendire (1895) "By the time the young are large enough to
leave the nest. .. retire to higher altitudes in the mountain
parks. .. raise their second broods under nearly similar
conditions as the first."
VII POPULATION PARAMETERS
A. Clutch size
Dawson (1923), two eggs; two broods.
A B. Fledging success
Waser (1977) "observed mean productivity of 1.15 chicks per
nest in 52 nests in 1971, 1972, 1973."
Selasphorus platycercus (con't.)
C. Mortality rates per age class
D. Longevity
Waser (1977), based on banding records of local population
at Rocky Mountain Biological Laboratory, estimate mean
minimum life span equal to 30 months.
E. Seasonal abundance
F. Habitat density figures
Miller (1940) "especially numerous in the tangles of Garrya
f lave-scens ... as many as five males were counted in one
patch of brush 200 yards long." Franzreb (1975), reports
14.3 average breeding birds per 100 hectares, Thomas Creek,
White Mountains, Arizona, summer 1973.
II INTERSPECIFIC INTERACTIONS
A. Predation
B. Competition
Lyon (1973) "Displays and overt aggression were usually
directed towards conspecifics, but bees feeding on Iris,
especially Bombus and Xylocopa, were frequently attacked
and often successfully ejected from the territory. Feeding
butterflies often appeared to be deliberately supplanted
but were never pursued." Dunford and Dunford (1972), des-
cribes territorial encounter _S. rufus at cluster of
Penstemon. Calder (1972), observed S. platycercus removing
materials from nest of Contopus sordTdulus ; Vireo gilvus
removing materials from nest" of _S. platycercus .
C. Parasitism
IX STATUS
A. Past population trends
Grinnell and Miller (1944), "Summer resident. Sparse."
B. Present population status
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
Selasphonis platycercus (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bendire, C. M. 1895. Life histories of North American birds.
U.S. Nat. Mus. Spec. Bull. No. 3.
Bent, A. C. 1940. Life histories of North American cuckoos,
goatsuckers, hummingbirds and their allies. U.S. Nat. Mus.
Bull. No. 176.
Calder, W. A. 1972. Piracy of nesting materials from and by
the Broad- tailed Hummingbird. Condor 74:485.
Calder, W. A. and J. Booser. 1973. Hypothermia of Broad-
tailed Hummingbirds during incubation in nature with
ecological correlations. Science 180:751-753.
Cottam, C. 1941. Incubation feeding of Calliope Hummingbird.
Auk 58:59-60.
Dawson, W. L. 1923. The birds of California. Vol. 2. South
I Moulton Co., San Francisco.
Dunford, C. and E. Dunford. 1972. Interspecific aggression
of resident Broad- tailed and migrant Rufous Hummingbirds.
Condor 74:479.
Franzreb, K. E. 1975. Avian densities in a mixed-coniferous
forest, Thomas Creek, White Mountains, Arizona. Western
Birds 6:101-105.
Grinnell, J. and A. H. Miller. 1944. The distribution of
birds of California. Pacific Coast Avifauna No. 27.
608 pp.
Hall, R. E. 1938. Broad-tailed Hummingbird attracted to
food of the Red-naped Sapsucker. Condor 40:264.
Johnson, N. K. and K. L. Garrett. 1974. Interior bird species
expand breeding ranges into southern California. Western
Birds 5:45-56.
Knox, D. A. 1944. Summer birds of the Gothic area, Gunnison
County, Colorado. Auk 61:19-30.
Linsdale, J. M. 1938. Environmental responses of vertebrates
in the Great Basin. Amer. Midi. Nat. 19:1-206.
8
Selasphorus platycercus (con't.)
Lyon, D. L. 1973. Territorial and feeding activity of Broad-
tailed Hummingbirds (Selasphorus platycercus) in Iris
missouriensis. Condor 75:346-349.
Miller, A. H. 1940. A transition island in the Mohave Desert.
Condor 42:161-163.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. 50:531-
624.
Peters, J. L. 1945. Checklist of birds of the world. Vol. 5.
Mus. Comp. Zool., Cambridge, Massachusetts. 306 pp.
Peterson, R. T. 1961. A field guide to western birds. Hough-
ton Mifflin Co., Boston. 309 pp.
Ridgway, R. 1911. The birds of North and Middle America.
Part 5. Bull. U.S. Nat. Mus. No. 50.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Waser, N. M. 1976. Food supply and nest timing of Broad- ^^
tailed Hummingbirds in the Rocky Mountains. Condor 78: 41
133-134.
Waser, N. M. and D. W. Inouye. 1977. Implication of recaptures
of Broad- tailed Hummingbirds banded in Colorado. Auk 94:
393-395.
Wauer, R. H. 1964. Ecological distribution of the birds of
the Panamint Mountains, California. Condor 66:287-301.
Woodbury, A. M. and J. W. Sugden. 1938. An hour in the life
of a Broad-tailed Hummingbird. Condor 40:160-162.
NORTHERN GRAY- HEADED JUNCO
Junco c. caniceps
t
I TAXONOMY
A. Type description
Junco caniceps caniceps - AOU (1957) Struthus caniceps
Woodhouse, Proc. Acad. Nat. Sci. Philadelphia, Nov. -Dec.
1852 (Feb. 7, 1853), p. 202. (San Francisco Mountain, New
Mexico (=Arizona) . )
B. Current systematic treatments
AOU (1957) considers the Gray-headed Junco a member of the
avian Order Passeriformes, Family Fringillidae (grosbeaks,
finches, sparrows, and buntings), Subfamily Emberizinae.
Hellmayr (1938) makes note of the close relationships between
J. phaeonotus (=caniceps) and J. oreganus (=hyemalis).
He lists the race caniceps as a race of the species J.
oreganus. Paynter and Storer (1970) also consider caniceps
to be a race of J. hyemalis, although they state that "there
remains much to 'Be understood "in this complex. Johnson
(1965) noted interbreeding of J. oreganus thurberi and J. c.
caniceps in southern Nevada; tKis hybrid has been describee!
as a race (J. o. mutabilis) . Miller (1939) gives a detailed
discussion of Hybridization in J. caniceps.
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), Junco phaeonotus. Miller (1941)
lists Struthus caniceps ; Junco annectens ; J. cinereus caniceps;
J. hiemalis caniceps; J. oreganus caniceps.
D. Synonomies of vernacular nomenclature
Ligon (1961), Red-backed Junco; Mexican Junco.
II DESCRIPTION
A. External morhpology of adults
Miller and Stebbins (1964), "A sparrow with the white lateral
tail feathers of the junco group. Head and flanks light,
uniform gray, the flantcs somewhat paler. Back gray, except
for well defined rust-red patch in center; belly white;
orbital area blackish." Ridgway (1901) adds that the bill
is "pinkish in life, iris brown; tarsi pale yellowish brown,
toes darker." Miller (1941) gives a detailed description
of most races within the Genus Junco , including caniceps.
Junco caniceps (con't.)
B. External morphology of subadult age classes
Young in first winter are essentially like adults, but
the gray of chest and other parts decidedly paler; reddish
brown of back duller (Ridgway 1901).
C. Distinguishing characteristics
Interspecific - Bent (1968), "Juncos usually are distin-
guished from other small birds occurring in their range by
...white outer tail feathers and the characteristic "tic"
notes... in flight." Peterson (1961), "similar species:
(l) Oregon Junco has rusty or pink-buff sides, rusty wings;
male has blackish hood. (2) Mexican Junco has yellow eye.
(3) Hybrids occur (Gray-headed X Oregon)."
Intraspecific - Ridgway (1901) described adult caniceps as
"sexes alike"; adult male, length 152.4 mm; wing 84.58;
tail 72.14; and adult female, length 114.78 mm; wing 78.74;
tail 66.55." Ligon (1961), "6-6.5 inches long. Color
pattern of sexes alike."
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) gives the overall range of the Gray-headed Junco
as "North- central Nevada, northern Utah, and southern Wyoming
south to central Arizona, southern New Mexico, and western
Texas. Winters in breeding range and south to southern
California, northern Sinaloa, and northern Durango."
The range of Junco c. caniceps was described by the AOU
(1957) as "Breeds in mountains from southern Idaho, Nevada,
Utah, and southern Wyoming south through central and east
central Nevada, the White Mountains of California, Utah,
and western and central Colorado to northern Arizona and
northern New Mexico."
B. California distribution of the species
Grinnell and Miller (1944) describe range as "In summer,
two mountain areas on southern Nevada border: Clark Moun-
tain, eastern San Bernardino County. .. (and) Grapevine
Mountains, Inyo County. In winter, coastal district from
Los Angeles County to San Diego County." Small (1974)
also gives Clark and Grapevine Mountains as California
breeding areas; calls this junco a "vary rare winter visitor
elsewhere." Cardiff (1949) noted the rare occurrence of a
Gray-headed Junco on the west slope of the San Gabriel
Mountains (6 November 1948). Dickey (1922) felt that Gray-
heads are normally present in the San Bernardino Mountains
during winter. Kaeding (1899) discusses the occurrence of
Junco in California; only one record of caniceps was listed
at that time.
Junco caniceps (con't.)
C. California desert distribution
Miller and Stebbins (1964) called this junco a "rare winter
visitant" in Joshua Tree National Monument. Recorded from
Upper Covington Flat (4 Nov.) and Pinyon Wells (15, 16 Oct.)
In the Providence Mountains, Johnson et al. (1948) reported
that a "small area on the northwest side of Clark Mountain
appeared to be the only suitable breeding place for juncos
of any kind." Van Rossem (1936) collected an immature cani-
ceps in the Charleston Mountains near Death Valley, Calif-
ornia, in October. Wauer (1964) found an apparent hybrid
Gray-headed X Oregon junco nesting at 10,500 feet in the
Panamint Mountains. Miller and Russell (1956) took non-
hybrid J. c. caniceps during breeding season in the White
Mountains." They noted, however, that introgression between
J. caniceps and J. oreganis thurberi is taking place in this
location. Monson (1949) collected an immature male Gray-
head near Topock on the lower Colorado, "the first record
for the Colorado Valley" (15 October 1946). Miller (1945)
found J. c. caniceps breeding on Clark, Potosi and Charles-
ton Mountains.
D. Seasonal variations in distribution
AOU (1957) states that Junco c. caniceps "Winters in lower
mountains and plains of breeding area, north to northern
Utah, northern Colorado; and from western Nebraska and
eastern Colorado south to northern Sonora, northern Sinaloa,
northern Durango, and western Texas; rarely to southern
California (Pasadena, San Diego R. , Potholes)."
Miller and Stebbins (1964), "This. .. junco occasionally
migrates southwest into southern California, although
chiefly it is found east of the lower Colorado River Valley
in winter." Although the study was based on Oregon Juncos,
Wolf son (1942) gives a detailed study of migration in juncos
IV HABITAT
A. Biotopic affinities
In California, Small (1974) gives California habitat as
"pinon- juniper woodland, montane forests of white fir."
Miller (l941) noted that "Associations in which it breeds
includes coniferous forest types dominated either by spruce
(Picea) , Pseudotsuga, Pinus contorta, P. ponderosa, P.
flexilis, or fir (AEies). It also breeds m pure stands
of aspen and of mountain mahogany." In Colorado, Winternitz
(1976) noted these juncos in aspen-willow (287Q of observa-
tions), ponderosa pine (24%), and Douglas fir (21.3%) during
breeding season.
Junco caniceps (con't.)
B. Altitudinal range
Bent (1968) noted breeding in various western states from
about 6,000 to 10,000 feet. In New Mexico, caniceps nests
from 6,500 to 9,500 feet (Ligon 1961). In Colorado,
Johnston (1943) found gray-heads nesting from 8,000 feet
to timberline.
C. Home range size
In Colorado, Rockwell (1910) found several nests of caniceps
which were usually placed about 100 yards apart.
D. Territory requirements
Perch sites -
Courtship and mating sites - Bent (1968) reported that during
courtship "The male always chose the top of a tall pine as
a singing post."
Nest sites - "The Gray-headed Junco is with rare exceptions
a ground nester" (Bent 1968*). In Colorado, Johnston (1943)
found nests "on the ground and well- concealed, but in a
variety of cover."
E. Special habitat requirements
Bent (1968) recounts that "The spotted distribution of this
junco must be emphasized. It inhabits... a series of mountain-
top islands above 7,000 feet." In Idaho, Burleigh (1972)
noted that caniceps "has rather exacting requirements. .. it
occurs. . .only on the higher ridges (between 6,000 and 7,000
feet) characterized by stretches of stunted junipers and
extensive thickets of mountain mahogany."
F. Seasonal changes in habitat requirements
Grinnell and Miller (1944) found that this race drops down
from the mountains and is in association with other juncos
in such places as open oak woodlands.
V FOOD
A. Food preferences
Bent (1968) noted that these juncos feed on ail available
plant seeds, grasses, herbs, and shrubs; insects are also
taken while feeding on the ground.
•
Junco caniceps (con't.)
B. Foraging areas
Bent (1968), "Juncos are mainly terrestrial and obtain
practically all of their food on or very near the ground."
C. Foraging strategies
"Juncos, like many other members of the sparrow family,
are primarily ground- feeding seed eaters" (Martin et al.
1951).
D. Feeding phenology
Martin et al. (1951) reported that juncos "are partial to
seeds of common weeds. In summer, insects constitute about
half or more of their diet."
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Bent (1968) noted that "observations of territorial conflict
between Gray-headed Juncos are few."
C. Courtship and mating behavior
Bent (1968) noted that "the mating behavior of the Gray-
headed Junco probably differs little, if at all, from that
of the better known Oregon and Slate-colored juncos...
Considerable activity, consisting chiefly of pursuit and
nest-building, was observed." In New Mexico, Tatschl (1967)
reported singing males between 19 March and 27 July.
D. Nesting phenology
Bent (1968) gives Colorado egg dated as: 45 records, 8 May
to 18 July; 24 records, 16 June to 4 July. In northern
Arizona, Hargrove (1936) recorded 3 broods raised in one
season (one brood hatched in early June, another in late
July, and the last in late August) .
E. Length of incubation period
Bent (1968) lists a 11 or 12 day incubation period. Miller
(1938) gave an incubation period of 12 days for a set of
eggs from a Gray-head X Oregon junco mating in captivity.
Junco caniceps (con't.)
F. Length of nestling period
Bent (1968) recounted that the young spend 10-13 days in
the nest after hatching.
G. Growth rates
The development of young was summarized by Phillips (in
Bent 1968): at 3 days, the 4 young weighed 27.5 grams (still
nearly naked, eyes not open); at 5 days, weight 44.5 grams;
at 6 days, eyes opening, weight 48.0 grams; at 7 days, eyes
open, feathers of belly tracts becoming prominent, weight
60.5 grams; at 10 days, weight 70 grams, young began to
fledge.
H. Post-breeding behavior
"After completing their breeding activities the northern
caniceps form small groups, presumably of adults and the
young of the season, and start a southward movement" (Bent
1968).
VII POPULATION PARAMETERS
A. Clutch size
Bert (1968), "The Gray-headed Junco lays from 3 to 5 slightly
glossy eggs." Ligon (1961), "Eggs: 4; greenish white,
marked with lilac and reddish brown around larger end."
B. Fledging success
C. Mortality rates per age class
D. Longevity
E. Seasonal abnndance
In Wyoming, Finzel (1964) noted an increase of Gray-headed
Juncos from 1.0 individuals per 40 acres in breeding season
to 3.0 individuals per 40 acres immediately following breed-
ing.
F. Habitat density figures
In a Colorado study, Winternitz (1976) found an average of
12.0 pair of caniceps breeding per 40 ha (montane study area).
In a Colorado Douglas fir-ponderosa pine study, Snyder
(1950) found 36 breeding pairs of Gray-heads per 40 ha;
this species was twice as common as the next most numerous
species. The breeding density dropped to 5 pairs per 40
ha in lodgepole pine, however. At 9,700 feet in Colorado,
McHugh (1948) recorded 3-4 breeding pairs on a 22 acre study
r
*
Junco caniceps (con't.)
plot. On Clark Mountain (San Bernardino County, California),
Miller (1940) found 2 pairs breeding in the 40 acres of
Transition Zone timber on the mountain.
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Bent (1968) stated that the Gray-headed Junco falls prey
to those predators common to other small birds. Screech
and Pygmy owls, Sharp-skinned Hawks, and Northern Shrikes
take j uncos.
B. Competition
In Colorado, Hering (1948) noted that "two breeding pairs
remained near each other throughout the season. The males
of the... two pairs sang rather often, but both families fed
...without any apparent conflict."
C. Parasitism
Neither Friedmann (1963) nor Friedmann et al. (1977) list
caniceps as a victim of cowbird parasitism. However, J.
hy emails is listed as a cowbird victim.
I
IX STATUS
A. Past population trends
Grinnell and Miller (1944) described this race in California
as a "rare summer resident. . .along eastern border. Occasional
winter visitant to coastal southern section."
B. Present population status
C. Population limiting factors
Concerning J. c. caniceps, Miller (1939) felt that "Its
breeding range is limited almost completely by unfavorable
desert or plains regions."
D. Environmental quality: adverse impacts
E. Potential for endangered status
Junco caniceps (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Ed. American Ornithologists'
Union, Baltimore, MD. 691 pp.
Bent, A. C. 1968. Life histories of North American cardinals,
grosbeaks, buntings, towhees, finches, sparrows, and allies.
Part 2. U.S. Nat. Mus. Bull. 237.
Burleigh, T. D. 1972. Birds of Idaho. Caxton Printers, Ltd.,
Caldwell, Idaho. 467 pp.
Cardiff, E. E. 1949. Sixth record of Gray-headed Junco on
Pacific slope of southern California. Condor 51:231.
Dickey, D. R. 1922. A third record of the Gray-headed Junco
in California. Condor 24:137-138.
Finzel, J. E. 1964. Avian populations of four herbaceous
communities in southeastern Wyoming. Condor 66:496-510.
*
Friedmann, H. 1963. Host relations of the parasitic cowbirds.
U.S. Nat. Mus. Bull. 233:1-276.
Friedmann, H. , L. F. Kiff and S. I. Rothstein. 1977. A
further contribution to knowledge of the host relations
of the parasitic cowbirds. Smithsonian Contrib. Zool.
235. 75 pp.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27. 608
pp.
Hargrave, L. L. 1936. Three broods of Red-backed Junco in
one season. Condor 38:57-59.
Hellmayr, C. E. 1938. Catalogue of birds of the Americas.
Vol. 13, Part 11. Field Mus. Nat. Hist. Zool. Ser. 430.
662 pp.
Hering, L. 1948. Nesting birds of the Black Forest, Colorado.
Condor 50:49-56.
Johnson, D. H. , M. D. Bryant and A. H. Miller. 1948. Verte-
brate animals of the Providence Mountains areas of Calif-
ornia. Univ. California Publ. Zool. 48:221-376.
Johnson, N. K. 1965. The breeding avifaunas of the Sheep and
Spring ranges in southern Nevada. Condor 67:93-124.
f
Junco caniceps (con't.)
Johnston, V. R. 1943. An ecological study of nesting birds
in the vicinity of Boulder, Colorado. Condor 45:61-68.
Kaeding, H. B. 1899. The genus Junco in California. Condor
1:79-81.
Ligon, J. S. 1961. New Mexico birds. Univ. New Mexico Press,
Albuquerque. 360 pp.
Martin, A. C, H. S. Zim and A. L. Nelson. 1951. American
wildlife and plants. McGraw-Hill Book Co., Inc. N.Y.
500 pp.
McHugh, T. C. 1948. A nesting census from the subalpine belt
of Colorado. Condor 50:227-228.
Miller, A. H. 1938. Hybridization of juncos in captivity.
Condor 40:92-93.
Miller, A. H. 1939. Analysis of some hybrid populations of
juncos. Condor 41:211-214.
Miller, A. H. 1940. A transition island in the Mohave Desert.
Condor 42:161-163.
Miller, A. H. 1941. Speciation in the avian Genus Junco .
Univ. California Publ. Zool. 44:173-434.
Miller, A. H. 1945. Birds of the yellow pine association
of Potosi Mountain, southern Nevada. Condor 47:130-131.
Miller, A. H. and W. C. Russell. 1956. Distributional data on
the birds of the White Mountains of California and Nevada.
Condor 58:75-77.
Miller, A. H. and R. C. Stebbins. 1964. The lives of desert
animals in Joshua Tree National Monument. Univ. California
Press, Berkeley. 452 pp.
Monson, G. 1949. Recent notes from the lower Colorado River
valley of Arizona and California. Condor 51:262-265.
Paynter, R. A., Jr. and R. W. Storer. 1970. Checklist of birds
of the world. Vol. 13. Mus. Comp. Zool. , Cambridge, Mass.
443 pp.
Peterson, R. T. 1961. A field guide to western birds. Second
Ed. Houghton Mifflin Co., Boston. 366 pp.
Ridgway, R. 1901. The birds of North and Middle America.
Part 1. U.S. Nat. Mus. Bull. 50. 715 pp.
10
Junco caniceps (con't.)
Rockwell, R. B. 1910. Nesting of the Gray-headed Junco.
Condor 12:164-165.
Small, A. 1974. The birds of California. Winchester Press,
N.Y. 310 pp.
Snyder, D. P. 1950. Bird communities in the coniferous forest
biome. Condor 52:17-27.
Tatschl, J. L. 1967. Breeding birds of the Sandia Mountains
and their ecological distributions. Condor 69:479-490.
Van Rossem, A. J. 1936. Birds of the Charleston Mountains,
Nevada. Pacific Coast Avifauna No. 24. 65 pp.
Wauer, R. H. 1964. Ecological distribution of the birds of
the Panamint Mountains, California. Condor 66:287-301.
Wintermitz, B. L. 1976. Temporal chance and habitat preference
of some montane breeding birds. Condor 78:383-393.
Wolf son, A. 1942. Regulation of spring migration in juncos.
Condor 44:237-263.
<
♦
NORTHERN ORIOLE
Icterus galbula
I TAXONOMY
A. Type description
AOU (1957) Icterus galbula bullockii (Swainson): Xanthornus
bullockii Swainson, Phi i. Mag., n.s., 1. no. 6, June 182/,
p. 436. ("Table land = Real del Monte, Hidalgo, Mexico.)
Icterus galbula parvus : Icterus bullockii parvus van Rossem,
Occ. Fap. Mus. Zool. Louisiana State Univ. , no. 21., Oct.
25, 1945, p. 237. (Jacumba, San Diego County, California.)
B. Current systematic treatments
AOU (1957) places .1. galbula in the Order Passeriformes,
Family Icteridae, with three subspecies. Dawson (1923)
refers only to I. bullockii in California. Bent (1958)
list I. b. bullockii and I. b. parvus. Robbins et al.
(19667 lTst I. galbula as the eastern and central species
and I. bullockii as the western species. Mayr and Short
(197TJ), I. galbula: "This species is comprised of three
morphologically distinct groups, the galbula, bullockii,
and abeillei (Mexico). These interbreed to form hybrid
zones in the Great Plains (galbula, bullockii) and in Durango
Mexico (bullockii, abeillei)^ All are considered conspecific."
C. Synonomies of scientific nomenclature
AOU (1957), I. galbula bullockii - Icterus bullockii,
Xanthornus bullockii; I. g. parvus - I. bullockii parvus.
Grinnell and Miller (1^"44), I. g. bulTocFii - Hyphantes
bullockii, Xanthornis bullockii, Yphantes bullockii, I. b.
bullockii.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944) - Bullock's Oriole, Western
Oriole. Bent (1958) - Baltimore Oriole.
II DESCRIPTION
A. External morphology of adults
Baird et al. (1905): "Icterus. Head all round deep black,
sharply defined against the yellow of the nape; wings black,
with or without white markings. Body generally, including
lesser wing-coverts, deep greenish-yellow. I. bullockii.
Head mainly black, with an orange or yellow superciliary
| stripe, and a broader one beneath the eye, cutting off the
f black of the throat with a narrow stripe; tail orange or
yellow, the feathers with black at ends; greater coverts
Icterus gal bul a (con't.)
with outer webs wholly white, and middle coverts entirely-
white, producing a large conspicuous longitudinal patch on
the wing; tertials and secondaries broadly edged with white,
primaries more narrowly striped with the same. Rump grayish
orange; sides and flanks deep orange; forehead and auriculars
orange; a broad supraloral stripe of the same. Xanthic tints
deep orange, with a reddish tinge on the breast. Tail very
slightly graduated.
Dawson (1923): "Adult male - Black, white and orange; bill,
lore a line through the eye, and throat (narrowly) jet black;
pileum, back, scapulars, lesser wing-coverts, primary coverts
and tertials, chiefly black, or with a little yellowish
skirting; remiges black edged with white; middle and greater
coverts, continuous with edging of tertials and secondaries,
white forming a large patch; tail chiefly cadmium-yellow
but central pair of retrices black on exposed area, and
remaining pairs tipped with blackish; remaining plumage,
including supraloral areas continuous with superciliaries,
orange, most intense on sides of throat and chest, shading
on lower breast to cadmium-yellow posteriorly; rump washed
with olivaceous. In younger adults the orange is less
intense, and the tail is more extensively black. Bill black
above and bluish below; feet and legs dusky-horn color.
Adult female - above drab-gray, clearest on rump and upper
tail coverts; washed with yellow on head; wings fuscous with
whitish edging; pattern of white in coverts of male retained,
but much reduced in area; tail nearly uniform dusky-orange;
sides of throat and chest wax-yellow chin and throat and
remaining underparts sordid white or pale creamy-buff; the
under tail coverts usually tinged with yellow.
Sibley and Short (1964) give extensive color descriptions
and measurements for Baltimore and Bullock's Orioles.
Corbin and Sibley (1977) describe the hybridization of
Bullock's and Baltimore Orioles.
B. External morphology of subadult age classes
Baird et al. (1905): "Young male with black replaced by
greenish-yellow, that on the throat persistent; female with-
out this. Dawson (1923): "Immature - like adult female;
yellow of head and throat stronger." Bent (1958) says young
obtain adult winter plumage in July after their first year,
but the feathers of the back are narrowly edged with dull
orange which is not present in older birds.
t
Icterus galbula (con't.)
G. Distinguishing characteristics
Intraspecific - Bent (1958) describes I. g. parvus as being
smaller than I, g. bullockii. Peterson (T961) describes
the differences between Baltimore and Bullock's Orioles.
Mistra and Short (1974) report on the hybridization of 1^.
f. bullockii and I. g. galbula in the Great Plains,
idgway (1915) provides a key to the Icterids. Rising
(1973) discusses morphological variation of Baltimore and
Bullock's Orioles.
Interspecific - Dawson (1923): "Top of head black and under-
sides of tail yellow as contrasted with the Arizona Hooded
Oriole. Note slender, blackish bill of female, as contrasted
with heavy, light-colored bill of Western Tanager." Willett
(1951): "Bill shorter and less curved than (Hooded). Male
with black back, top of head, and throat patch, a large white
wing-patch, and bright orange underparts.
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), 1^ £. bullockii: "Breeds from southern British
k Columbia, east of the coastal ranges, northwestern Montana,
V southern Alberta, southwestern Saskatchewan, northeastern
Montana, southwestern North Dakota, western South Dakota,
western Nebraska, western Kansas, western Oklahoma, and
central Texas south to central and southern interior Calif-
ornia, southern Nevada, southwestern Utah, central and cen-
tral-southern Arizona, northeastern Sonora, probably northern
Chihuahua, central Coahuila, and southern Texas."
I. g. parvus : "Breeds from central western and southern
California, extreme southern Nevada, and western Arizona,
south to northern Baja California and northwestern Sonora."
B. California distribution of the species
Dawson (1923): "Abundant summer resident in many parts of the
state - from the Nevada line to the seacoast, and from the
Oregon line to the Mexican boundary. Of least abundance in
the northwest coastal belt and on the Santa Barbara Islands.
Centers of abundance are the interior valleys north of
Tehachapi." Grinnell and Miller (1944), I. bullockii: "As
breeding, all sections of the state except the islands, in
coastal fog belt north of Sonoma County and areas of con-
tinuous Montane forest." Small (1974): "Ranges in California
for breeding - length of state except humid coastal coni-
ferous forest, mountain forests."
•
Icterus galbula (con't.)
C. California desert distribution
Grinnell and Miller (1944) give records from Inyo, Kern,
San Diego, San Bernardino Counties. Willett (1951) lists
3 orioles as resident in the southern California desert:
California Hooded (I. cucullatus calif ornicus) , Bullock s
(I_. bullockii) and "Scott's {I. parisorum) . Wauer (1964)
reports Bullock ' s and Hooded Orioles breeding in the upper
canyons of the Panamint Mountains.
D. Seasonal variations in distribution
AOU (1957), I. g. bullockii: "Winters from southern Sinaloa,
Mexico, and FueDla south, west of the continental divide,
to northwestern Costa Rica; casually north to central Calif-
ornia, southern Texas and southern Louisiana."
1. g. parvus : "Winter range largely unknown, possibly
winters sparingly in southern California and Arizona; pro-
bably in central -we stern Mexico south to Guerrero."
Bent (1958) gives a report from Alexander Skutch saying that
I. bullockii arrives on its wintering grounds in Central
America during the second week in September, and departs
in April. I. g. bullockii winter range is given as above.
Phillips et al. (1964) : "On migration prefers the same-broad
leaved trees in open country, especially in the Lower Sonoran
Zone."
IV HABITAT
A. Biotopic affinities
Dawson (1923): "Of very general zonal and faunal preferences:
breeds from Lower Sonoran up through Transition, and from
riparian association on the deserts to the San Francisco Bay
region. Grinnell and Miller (1944): "Riparian oak woodland,
especially where trees are large and well spaced." Phillips
et al. (1964): "Breeds commonly in cottonwood-willow associa-
tion of the Sonoran Zones." Walcheck (1970) reported orioles
nesting in cottonwood forest in Montana, and not in sage-
brush shrubland, sagebrush grassland or pine- juniper wood-
land. Gullion et al. (1959) note the occurrence of I,
bullocki in the desert valleys and in the cottonwoods about
springs in the desert ranges in Nevada. Wauer (1964) reports
Bullock's and Hooded Orioles in the upper and lower canyons
of the Panamint Mountains; in trees in the sidewashes and
in the area just below the pinon- juniper woodland which is
well watered compared to many other localities in these
mountains .
•
•
Icterus galbula (con't.)
B. Altitudinal range
Dawson (1923) says they occur from Lower Sonoran up through
Transition. Wauer (1964) found Bullock's Orioles breeding
1,000 to 4,000 feet in the Panamint Mountains.
C. Home range size
D. Territory requirements
Perch sites
Courtship and mating sites
Nest sites - Dawson (1923): "...deciduous trees, usually
at moderate heights." Bent (1958) describes the usual nest-
ing site as near the top of some fair sized tree, as a
maple, white elm, apple, mesquite, birch. Grinnell and
Miller (1944): "Sycamores, cottonwoods, willows, and deciduous
oaks seem to be especially favored, but live oaks, orchard
trees and occasionally conifers are used." Nests are placed
6 or more feet up, often in the middle area of trees.
Schaefer (1976) found the placement and structure of nests
to vary geographically, mainly because of differences in
vegetation.
E. Special habitat requirements
Grinnell and Miller (1944) state that they seem to need a
nearby water source. Gabrielson and Jewett (1940): "It is
primarily a bird of river bottoms and farming districts.
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Bent (1958) reports caterpillars forming over 1/3 of the
food supply. They also eat web worms, moth larvae, beetles,
ants, wasps, spiders, snails, June berries, mulberries,
blackberries, some seeds. Some problem has been noted with
their pea-eating habit.
B. Foraging areas
Bent (1958) describes them feeding trees and sometimes on
the wing as they chase an insect. Grinnell and Miller (1944)
says they use adjacent open fields next to nesting trees,
grass or brush covered, in addition to foraging in the crown
of trees.
6
Icterus galbula (con't.)
C. Foraging strategies
D. Feeding phenology-
Bent (1958) says during the winter they are found feeding
in Central America on a considerable variety of animal and
vegetable food.
E. Energy requirements
Bent (1958) writes an account of young being fed by regurgi-
tation about every 20 minutes.
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Bent (1958): "...he defends his territory with great vigor
and daring." The males arrive on their breeding grounds
in full song and sing all day until incubation is underway
when they subside.
C. Courtship and mating behavior
Bent (1958) describes the male sitting on a limb next to a
female and bowing, spreading his tail and raising his wings
while uttering "supplicating and seductive" notes. The
female whistles 2 or 3 notes like the males during the nesting
season.
D. Nesting phenology
Bent (1958): "...arrives in southern New England. . .about 10
May." Gabrielson and Jewett (1940): "Eggs are laid primarily
from 16 May to 15 June," in Oregon. Gullion et al. (1959)
report I. bullockii to arrive in Nevada as early as 16 April
and leave in the beginning of September.
E. Length of incubation period
F. Length of nestling period
Bent (1958) - 11 to 14 days.
G. Growth rates
H. Post-breeding behavior
Bent (1958) comments that I. bullockii becomes quite quiet
in August so even when they are still present it is hard to
•
Icterus galbula (con't.)
find them. "Apparently old males do not remain with their
families very long after the breeding season.
VII POPULATION PARAMETERS
A. Clutch size
Dawson (1923) - usually 5. Bent (1958) - 4 to 6.
B. Fledging success
C. Mortality rates per age class
Bent (1958) says that young are comparatively safe for the
first 2 weeks of life when they remain concealed in their
hanging basket nest.
D. Longevity
Kennard (1975) found the oldest 1^ galbula to be 7 years
in a study of band returns.
E. Seasonal abundance
A F. Habitat density figures
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Bent (1958) list predators as: crows, Screech Owl, squirrels.
Ashman (1977) noted a Northern Oriole eating a hummingbird
on South Farallon Island. He did not know if the Oriole
killed the hummingbird.
B. Competition
Bent (1958) reports I. bullockii nesting in the same tree
with a wood peewee, an orchard oriole, kingbirds and other
I. bullockii. It will battle with other species in actual
physical combat. Whitmore (1977) in a study of habitat
partitioning in a community of passerine birds and found
Bullock's Oriole associated with Yellow and Audubon's Warblers,
and Black-headed Grosbeaks in the high canopy.
C. Parasitism
Friedmann et al . (1977): "Experiments involving the addition
of foreign eggs to nests that contained 2 or more oriole
eggs demonstrated that this oriole is a rejecter species,
though sometimes they do raise a cowbird.
»
Icterus galbula (con't.)
IX STATUS
A. Past population trends
Bent (1958) gives an account of the spread of I. bullockii,
allowed by the cutting of forests by settlers and subsequent
growth of bushes. Anderson (1971) discusses the increase
in number and range of I. £. galbula and I. £. bullockii
caused by man's changes to the prairie in South Dakota.
B. Present population status
Weber (1976) comments on the increasingly common occurrence
of I. g. galbula in northeastern British Columbia. I. £.
bulTockii has always been fairly common there.
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
m
«
Icterus gal bul a (con't.)
XI LITERATURE CITED
American Ornithologists Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Anderson, B. W. 1971. Man's influence on hybridization in
two avian species in South Dakota. Condor 73:342-347.
Ashman, P. 1977. Northern (Bullock's) Oriole eats hummingbird.
Western Birds 8:105.
Austin, G. T. 1970. Breeding birds of desert riparian habitat
in southern Nevada. Condor 72:431-436.
Baird, S. F. , T. M. Brewer and R. Ridgway. 1905. A history of
North American birds. Vol. 2. Little, Brown, and Co.,
Boston.
Bent, A. C. 1958. Life histories of North American blackbirds,
orioles, tanagers and allies. U.S. Natl. Mus. No. 211.
Corbin, K. W. and C. G. Sibley. 1977. Rapid evolution in
orioles of the genus Icterus. Condor 79:335-342.
Dawson, W. L. 1923. The birds of California. Vol. 1. South
Moulton, Co., Los Angeles.
Friedmann, H. , L. F. Kiff and S. I. Rothstein. 1977. A further
contribution to knowledge of the host relations of the para-
sitic cowbirds. Smithsonian Contrib. Zool. No. 235. 75 pp.
Gabrielson, I. N. and S. G. Jewett. 1940. Birds of Oregon.
Oregon State college, Corvallis. 650 pp.
Grinnell, J. and A. H. Miller. 1944. The distribution of
the birds of California. Pacific coast avifauna. No. 27.
608 pp.
Gullion, G. W. , W. M. Pulich and F. G. Evenden. 1959. Notes
on the occurrence of birds in southern Nevada. Condor
61:278-297.
Mayr, E. and L. L. Short. 1970. Species taxa of North American
birds. Publ. Nuttal Ornithological Club, No. 9.
Mistra, R. K. and L. L. Short. 1974. A biometric analysis of
oriole hybridization. Condor 76:137-146.
Oberholser, H. C. 1974. The bird life of Texas. Vol. 2.
Univ. of Texas Press, Austin.
10
Icterus galbula (con't.)
Peterson, R. T. 1961. A field guide to western birds. Second
Edition. Houghton Mifflin, Co., Boston. 366 pp.
Phillips, A., J. Marshall and G. Monson. 1964. The birds of
Arizona. Univ. of Arizona Press, Tucson. 212 pp.
Ridgway, R. 1915. A manual of North American birds. Fourth
Edition. J. B. Lippencott Co., Philadelphia. 653 pp.
Rising, J. D. 1973. Morphological variation and status of the
orioles, Icterus galbula, I. bullockii and I, abeillei,
in northern Great Plains and in Durango, Mexico. Can. J.
Zool. 51:1267-1273.
Robbins, C. S., B. Bruun and H. S. Zim. 1966. Birds of North
America. Western Publ. Co., Wisconsin. 340 pp.
Schaefer, V. H. 1976. Geographic variation in the placement
and structure of oriole nests. Condor 78:443-448.
Sibley, C. G. and L. L. Short. 1964. Hybridization in the
orioles of the Great Plains. Condor 66:130-150.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Walcheck, K. C. 1970. Nesting bird ecology of four plant com-
munities in the Missouri River Breaks, Montana. Wil. Bull.
82:370-382.
Wauer, R. H. 1964. Ecological distribution of the birds of the
Panamint Mountains, California. Condor 66:287-301.
Weber, W. C. 1976. Mourning Warbler and Northern Oriole in
northeastern British Columbia. Murrelet 57:68-69.
Whitmore, R. C. 1977. Habitat partitioning in a community of
passerine birds. Wil. Bull. 89:233-265.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Museum Zool. Series 6:1-39.
!
PINON JAY
Gymnorhinus cyanocephalus
I. TAXONOMY
A. Type description
Gymnorhinus cyanocephalus - AOU (1957) Weid, Reise Nord-
Amer. , vol. T, 1841, p. 22. (am Maria-River = between the
Marias and Yellowstone rivers, Montana.).
B. Current systematic treatments
Hellmayr (1934) describes the Pinon Jay as a monotypic
species, with a general range of "...from central Washing-
ton, Idaho, and central Montana south to northern lower
California." Mayr and Greenway (1962) also consider this
species monotypic.
AOU (1957) considers the Pinon Jay a monotypic member of
the avian order Passeriformes, family Corvidae, subfamily
Corvinae.
Mayr and Short (1970) state that the relationships of this
species remain obscure; no further comment given.
Austin and Rea (1976) do not advocate recognition of races
in the Pinon Jay. Ligon (1974) summarizes the taxonomic
relationships of Gymnorhinus in a detailed manner; states
that this species should be considered a "specialized and
perhaps early offshoot of... New World jays. ' Miller and
Stebbins (1964) feel that the Pinon Jay in Joshua Tree
National Monument should be considered a distinct race,
Gymnorhinus cyomocephalus ro stratus.
C. Synonomies of scientific nomenclature
Hellmayr (1934), Cyanocephalus cyanocephalus ; C. wiedi;
Cyanocorax wiedi. Gnnnell and Miller (1944; , Gymnokitta
cyanocephala ; Gymnorhinus cyanocephalus ro stratus.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), Maximilian Jay. Ligon (1961),
Blue Crow. Goodwin (1976) adds Pinon Crow to the previous
names. Dawson (1923) includes Pine Jay in his list of
synonomies. Also called the nutcracker by Wheelock (1904),
II DESCRIPTION
A. External morphology of adults
Ridgway (1904) gives detailed account of all plumages;
"adult male... dull grayish blue, paler on posterior under
Gymnorhinus cyanocephalus (con't.)
parts. . .adult female similar." In appearance and actions
like a small dull blue crow. ..with a long sharp bill (Peter-
son 1961). Phillips et al. (1964), "the Pinon Jay looks
like a small blue crow, and like it, walks rather than
hops." Ligon (1961), 10-11.5 inches long. Ligon and
White (1974) give detailed account of plumage and size
characteristics; the crown in adults is deep blue... color
change due to wear occurs.
B. External morphology of subadult age classes
Ridgway (1904) noted young were duller than the adult
female, without any blue except on wings and tail... plain
gray. Bailey (1928) gives similar description. Goodwin
(1976), "first year plumage. . .grey, the adult blue plumage
not be attained till the second summer molt." Juvenile
body feathers are gray with no hint of blue... the whitish
throat patch of first-year and adult birds is lacking;
mouth color is white (Ligon and White 1974).
C. Distinguishing characteristics
Interspecific - "Easily told from Scrub Jay by its short
tail, uniform blue coloration, and crowlike flight; from
Steller's Jay by lack of crest (Peterson 1961). Robbins
et al. (1966): told from other jays by its uniform steel-
blue color, short tail, and long beak. '
Intraspecific - Ridgway (1904) states that although sexes
are similar in coloration, the female is smaller and duller
than the male; young are similar to adult female, but still
duller. Male: wing 154 mm, length 272.5 mm, tail 114 mm
and female: wing 144.5 mm, length 254.5 mm, tail 104 mm.
Color pattern of sexes alike (Ligon 1961). Dawson (1923),
"adult female like male... with increase of gray." Adult
male Pinon Jays are significantly larger than adult females,
according to results of a detailed study by Ligon and White
(1974).
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) gives distribution of G. cyanocephalus as,
"Resident from central Oregon, east-central Montana, and
western South Dakota, south through eastern California
to northern Baja California, central Nevada, central and
central eastern Arizona, central New Mexico, and western
Oklahoma
Ridgway (1904) gives range as, "Pinyon and juniper wood-
lands of western United States; north to southern British *
•
Gymnorhinus cyanocephalus (con't.)
Columbia, Idaho, ect. , south to northern lower California,
Arizona, New Mexico, and western Texas; east to eastern
side of Rocky Mtns." Peterson (1961): "Resident from Oregon,
Idaho, Montana. .. through eastern California (east of Sierra)
to northern Baja California, Nevada, Arizona, New Mexico,
Oklahoma. "
B. California distribution of the species
Grinnell and Miller (1944), "... resident. . .parts of elevated
Great Basin area, west to east base of Cascade- Sierra Nevada
...south along this system to vicinity of Walker Pass, Kern
Co. ; also south along all higher desert ranges as far as
Providence Mtns., San Bernardino Co." Small (1974) called
California distribution "complex"; Basin and Range Region
south to Walker Pass; south along higher desert ranges to
Providence Mtns. ; north side of San Gabriel and San Bernardino
Mtns.; Mt. San Jacinto area, near Lake Hemet, Riverside
Co. Dawson (1923), "common resident locally of arid upper
Sonoran and Transition, chiefly along the eastern base of
the Sierra Nevada." In southern California, this jay is
a resident, locally, of upper Sonoran and Transition Zones,
mostly on the desert side of mountain ranges, south to Baja
California (Willett 1933) Wheelock (1904) describes the
California breeding range as, "in the pinyon belts of the
desert ranges, southeast of the Sierra Nevada. .. locally
the whole length of the Sierra Nevada... to the San Bernardino
Mountains." Jordan (1956) reported that the occurrence of
this species on the western slope of the central Sierra
Nevada was a rare sighting in the fall. Wall (1915) stated
that Pinon Jays seldom occur in the San Bernardino Valley;
a sighting in October (1914) was the first in 25 years.
C. California desert distribution
Desert locations given by Grinnell and Miller (1944) include -
White, Inyo, Grapevine, Panamint, Argus and Co so Mountains
in Mono and Inyo Counties; San Bernardino and San Jacinto
Mountains. Dawson (1923) noted this species on the desert
mountain ranges of the Inyo district. Johnson et al. (1948)
found Pinon Jays to be widespread near the New York and the
Providence Mountains in both summer and winter; frequented
pinyon and juniper woodlands. Grinnell and Swarth (1913)
noted large flocks near Kenworthy and Hemet Lake between
June and August. Willett (1933), in describing the southern
California distribution — "noted in San Bernardino Mtns. ;
found abundant in Hemet Valley, San Jacinto Mtns. (summer);
also noted in Pasadena; nests on the deserts slopes of the
San Jacinto range." Noted in the desert ranges of the
Inyo district by Grinnell (1915). Willett (1951) only noted
the bird as a straggler out onto the desert in winter (from
nearby desert ranges). Wauer (1964) found Pinon Jays nest-
ing in the pinyon- juniper woodlands of the Panamint Mountains,
Gymnorhinus cyanocephalus (con't.)
Death Valley. Gullion et al. (1959) noted the erratic
occurrence of Pinon Jays on southern Nevada deserts (Joshua
tree, oak chaparral) during all seasons. Several birds
found wintering near ponds in Death Valley by Gilman (1936).
D. Seasonal variations in distribution
Robbins et al. (1966) --"in winter, it wanders erratically
to farmlands." Wanderings. .. seem to be influenced by lack
of a dependable source of food. .. rather than by set, seasonal
migratory movements (Ligon 1961)." Johnson et al. (1948)
noted movement down into Joshua trees during winter in the
Providence Mtns. In Nevada, this jay is a common fall and
winter visitor to the pinyon- juniper belt, and in the fall
is noted in the pines up to 8,700 ft. by Rossem (1936).
"But the species is disposed to undertake wanderings, when
flocks appear sporadically in remote places irrespective
of season' (Grinnell 1915). Called an "irregular visitant"
in Los Angeles Co., mostly in the higher mountains — will
descend into the foothills in fall and winter (Grinnell
1898). Bent (1946) states that the species is not really
migratory, but undertakes seasonal wanderings depending
upon local conditions. Miller (1915) describes the winter
movements of this species as erratic; noted a flock in Los
Angeles from December to March, 1914-15.
IV HABITAT
A. Biotopic affinities
Peterson (1961) describes habitat as, "pinyon pines, juni-
pers; ranges into sage." Grinnell and Miller (1944),
essentially characterized by presence of pinyon and juni-
per." Small (1974), "pinyon- juniper woodland; lower por-
tions of montane forest in Transition Life Zone." Phillips
et al. (1964) describes this jay as characteristic of pinyon
and juniper woodlands, though they often wander into the
pine belt. Goodwin (1976) states that the species inhabits
the foothills and lower mountain ranges where pinyon and
juniper are the dominant vegetation. Grinnell and Swarth
(1913) found jays foraging in sagebrush during June in Hemet
Valley. In Joshua Tree National Monument, Miller and Stebbins
(1964) found Pinon Jays confined to the pinyon- juniper belt
of the upper levels of the western section. They did not
see them in lower desert vegetation.
B. Altitudinal range
Grinnell and Miller (1944) note breeding range from 4,500
ft. (San Jacinto Mtns.) up to 7,500 ft. (Inyo Mtns.). Ligon
(1961) gives 5,500 to 7,400 ft. range in New Mexico. Dawson
(1923) gives an upper range of 9,000 feet in California.
4l
Gymnorhinus cyanocephalus (con't.)
Pinon Jays noted between 5,000 and 8,200 ft. in Nevada
(Lindsdale 1936). Ligon (1971) reported this species nesting
in mature pinyon pines at 7,200 ft. in New Mexico. Found
breeding in a Joshua Tree and juniper woodland at 4,800 ft.
at Joshua Tree National Monument by Miller and Stebbins
(1964). Noted breeding between 5,500 and 6,500 ft. in the
Panamint Mountains, Death Valley (Wauer 1964).
C. Home range size
Balda et al. (1972) studied a flock of about 250 Pinon Jays
on a home range of 8 square miles near Flagstaff, A izona.
D. Territory requirements
Perch sites - Roost sites in Arizona ranged from 3-16 m
above ground with a mean height of 7.4 m; all roosts were
in ponderosa pine (Balda et al. 1977).
Courtship and mating sites - Balda and Bateman (1972) des-
cribes courtship and mating sites in detail. The first
stages of courtship take place on the ground, but as the
nesting season approached, trees were used more often.
Pairs select a branch or crotch of a tree on the breeding
ground where courtship reaches its height of activity.
Nest sites - "A bowl of twigs in pinyon, juniper, scrub
oak; in colony (Peterson 1961). Bailey (l928), "nests
in colonies, in pinyon pines, junipers, or oaks, generally
5 to 12 feet from ground." Ligon (1961) reported nests,
one per tree, in 10 to 15 feet oaks. Dawson (1923), "placed
at moderate height in pinyon or juniper." A nest in the
Joshua Tree National Monument was 7 ft. up in a juniper
(Miller and Stebbins 1964). Bent (1946) reports nests in
juniper from 3 to 18 ft. high, with nests in ponderosa
pine up to 85 ft. (Oregon). Johnson (1902) gives nest
sites as pinyon pine, scrub pine, juniper, and mountain
mahogany. Balda and Bateman (1972) found nests that ranged
from 5.5 to 78 ft. high in a ponderosa pine forest in Arizona.
V FOOD
A. Food preferences
Grinnell and Miller (1944) call this species omnivorous,
supplimenting their pinyon seed diet with insects. Bailey
(1928), "principally pinyon nuts in their season, but also
yellow pine and black pine nuts, cedar and juniper berries,
small seeds, various wild berries, and insects. ' Dawson
(1923) gives favorite food as pinyon nuts; berries also
taken. Food given to nestlings in New Mexico included
numerous insect larvae and nymphs, several adult beetles,
Gymnorhinus cyanocephalus (con't.)
a lizard, but few pine seeds (Ligon 1971). Animal food
includes beetles, grasshoppers, caterpillars, and ants;
pine seeds, especially pinyon pine, wheat, cedar, and corn
constitute the main plant foods taken (Martin et al. 1951).
Bateman and Balda (1973) give a detailed account of food
habits (Arizona) ; terrestrial insects formed the major part
of the diet during the breeding season.
B. Foraging areas
Robbins et al. (1966): "is often seen on ground around
sagebrush." Johnson et al. (1948) noted a flock of jay
foraging on the ground through junipers and pinyons on a
sagebrush flat in the Providence Mtns. When settled into
an area to feed, a flock of about 250 birds occupied an
area of about 2 acres during the morning and evening, and
up to 6 acres during the afternoon when feeding was not so
intense; the flock spent about 80% of its time in pine forest
and 10% in open meadow and woodland (Balda and Bateman
1971). Bateman and Balda (1973) noted that most food for
nestlings was gathered by adult males, who foraged together
in small flocks (6-8 birds) in open parts of the ponderosa
pine forest in northern Arizona.
C. Foraging strategies
Bailey (1928), "in feeding. .. their method of spreading out
and working zigzag over the ground in search of insects...
large flocks. .. engage in catching insects on the wing."
Were also noted both picking seeds from the ground and
extracting them from cones. Wheelock (1904) noted the taking
of insects "on the wing." When feeding in forest and wood-
land, about 40% of the flock foraged on the ground by prob-
ing for insects and/or pine seeds. Pinon Jays often cache
seeds; at 21 cache-sites the number of seeds varied from
6 to 31 (Balda and Bateman 1971). Foraging flocks, "moved
along in a rolling fashion, the members at the rear flying
over and past those ahead of them on the ground" (Miller
and Stebbins 1964).
D. Feeding Phenology
Dawson (1923), "in summer they feed largely on insects of
all kinds, especially grasshoppers." The only plant food
taken in great amounts during spring are pinyon pine seeds;
other grains are also taken in winter when insects cannot
be found (Martin et al. 1951). Balda and Bateman (1972)
found that Pinon Jays harvest and cache seeds of both pon-
derosa and pinyon pines in the fall and early winter.
Gymnorhinus cyanocephalos (con't.)
E. Energy requirements
Balda and Bateman (1976) recount the eating of nestlings
by adult Pinon Jays; they felt that such actions were a
result of a severe energy drain on the adults due to cold
(-17°C to 1°C) temperatures and a heavy snow cover. Ligon
(1974) states that nestling Pinon Jays cannot survive on
a diet composed exclusively of pinyon seeds. Pinon Jays
often eat snow, which at times is their only source of
free water, according to Balda and Bateman (1971). They
also stated that this jay relies heavily on pinyon seeds
for reproductive energy. Balda et al. (1977) found that
roost sites were selected, in part, for thermal economy;
birds roosted within a trees foliage in a south (sun)
facing direction.
VI REPRODUCTION
A. Age at first breeding
Goodwin (1976), "first-year birds do not usually breed."
B. Territorial behavior
•
"Often in large noisy flocks; gregarious" (Peterson 1961).
Ligon (1961), "the birds' social instinct is clearly re-
flected in colony nesting;" two colonies of 50 nests each
and one of 13 nests reported. During breeding, the adult
male performs most territorial defense; the female does
not leave the nest to attack predators (Balda and Bateman
1974).
C. Courtship and mating behavior
"The male usually initiates nest site selection, enticing
his mate to the site by carrying sticks to it and feeding
her. . .both sexes bring nest lining material to the site
for 3 to 5 days before serious building starts (Goodwin
1976)." Feeding of potential mates is low in October but
shows a marked increase in November and December; courtship
occurred most often from mid-morning to mid-afternoon (Balda
and Bateman 1971). Balda and Bateman (1972) give a detailed
account of courtship behavior, which include silent food
transfer, courtship begging, silent sitting, stick mani-
pulation, and display flights.
D. Nesting phenology
Bailey (1928) gives nesting season as from February to June.
Reed (1904) noted nesting during April or May. Ligon (1961)
reports fresh eggs from February to October. Dawson (1923)
--season, April to May 10; one brood. "Probably nests mostly
Gymnorhinus cyanocephalus (con't.)
in late March and early April in southern California"
(Willett 1933). Wheelock (1904) gives California breed-
ing season as March 15 to May 15. Pairs not successful
in their first nesting attempt form a second nesting colony
...pairs failing in the second nesting attempt may try a
third time (Balda and Bateman 1971). By late December
some male jays are in breeding condition; if conditions
are suitable, the birds may breed in early February, al-
though breeding may be delayed several months if food is
scarce (Ligon 1971; . Bent (1946) gives California egg
dates as April 9 to 21.
E. Length of incubation period
Goodwin (1976) gives 16 day incubation, which is performed
only by the female. Wheelock (1904) gives a 16 day incu-
bation period. Ligon (1971) reported a 17 day incubation
period in New Mexico. Bent (1946) listed the period as
16 to 18 days. Bateman and Balda (1973) found a 17 day
period in northern Arizona.
F. Length of nestling period
"The young fledge at about 3 weeks (Goodwin 1976)." Wheelock
(1904) states that the young fledge in about 22 days.
Nestling period of about 20 days in New Mexico at 7,200
ft. (Ligon 1971). In northern Arizona, Bateman and Balda
(1973) found Pinon Jay young fledging at 21-22 days of age.
G. Growth rates
Bateman and Balda (1973) give a detailed description of
growth rates- -"At 10 days of age young Pinon Jays averaged
9.2 times as heavy as on the day of hatching (6.26 g versus
78.00 g) . During the latter half of the nestling period
(days 11-21) increase in weight was greatly reduced while
plumage growth was pronounced.
H. Post-breeding behavior
Young unite with other families in large flocks after fledg-
ing, and forage from place to place with the roving habits
of their species (Wheelock 1904). Upon leaving the nest,
young and parents form tightly knit feeding aggregates that
remain near the nests for 8-12 days; by late April, these
feeding groups increased in size and consisted of 25-50
young and adults (Balda and Bateman 1971). Richards (1924)
noted the wintering behavior of a large flock in northern
California which, divided into three or four flocks, which
were much in evidence. .. (until) the first of April, when
the birds began to leave." At 4 weeks of age, Bateman and
Balda (1973) found that young jays were still fed by their
parents. After 8 weeks of age young were able to fly well
and feed themselves; they joined their parents flock.
#
•
•
Gymnorhinus cyanocephalus (con't.)
II POPULATION PARAMETERS
A. Clutch size
Peterson (1961) - Eggs (3-4; 5). speckled. Bailey (1928)
- eggs usually 4-5. Read (1904) gave clutch of 3-5 eggs.
Ligon (1961), "eggs usually 4, rarely 5." Dawson (1923)
lists usual clutch as 4 or 5. Bent (1946) gives the highest
clutch as 6 eggs. Balda and Bateman (1972) gave an average
clutch as nearly 4 eggs.
B. Fledging success
In New Mexico, Ligon (1971) reported only 4 of 13 nests
successful; these 4 nests produced a maximum of 13 young.
He felt that such low nest success may be usual for the
species. Balda and Bateman (1972) found that nest success
was dependent upon placement within the colony. Nests
near the center of the colony lost fewer eggs than those
towards the edge. Overall nest success was highly variable,
and ranged between 17 and 50%.
C. Mortality rates per age class
Ligon (1961) reports a large number of nestlings dead in
the nest after cold rains. Balda and Bateman (1972) found
that early nesting attempts often failed (80% nest destruc-
tion in one year) due to severe weather conditions. Pre-
dators took 41-68% of all nests in their study.
D. Longevity
Pinon Jays may have a life expectancy of 6 years or more,
based on band returns (Whitney 1963) .
E. Seasonal abundance
Pinon Jays are seen most often in flocks, even in the nest-
ing season. Flocks are much larger in winter than in summer
(Linsdale 1936). Jensen (1926), "...it is not unusual,
during fall and winter, to see flocks of hundreds..."
F. Habitat density figures
Johnson et al. (1948) noted flocks of up to 400 jays during
summer and winter in the Providence Mtns. Grinnell (1908)
found flocks of about 100 birds on the arid slopes of the
San Bernardino Mtns. A colony of at least 100 nests was
found in a pinyon- juniper woodland in Nevada (Lindsdale
1936). A flock of 75 birds in March near San Onofre, San
Diego Co., is a rare spring record for this area (Willett
1933). Balda and Bateman (1971) located 6 Pinon Jay flocks
10
Gymnorhinus cyanocephalus (con't.)
within a 15-mile radius of Flagstaff, Arizona, an area
dominated by ponderosa pine, pinyon pine, and juniper.
A flock of about 50 birds spread their nests about within
a few hundred yards of each other in a Joshua Tree-juniper
woodland (Joshua Tree Nat. Monument) (Miller and Stebbins
1964). They noted groups of 125 to 175 birds in October,
with groups of 50 to 100 seen in late summer and fall.
Gabrielson (1949) saw an unusually large flock of "several
thousand birds" during the winter in Nevada. Jensen (1923)
studied a colony in northern New Mexico which contained 17
nests covering about 10 acres. Balda and Bateman (1972)
found that a flock of 250 jays in Arizona used an area
covering 240 acres for nesting, although their total home
range covered 8 square miles. In each year of their study
the colony averaged one nest per 2.3 acres.
IIII INTERSPECIFIC INTERACTIONS
A. Predation
Potential predators of all age classes, including eggs and
young, in New Mexico listed as Bobcat, Cooper's Hawk, Barn
Owl, Great Horned Owl, and Scrub Jay (Ligon 1971). Bent
(1946) recounts the taking of nestlings by a pair of North-
ern Shrikes. Bond (1940) reported finding Pinon Jay feathers
in a Nevada Goshawk nest. Enderson and Craig (1974; noted
Peregrine Falcon attacks upon Pinon Jays in the Rocky
Mountains. Balda et al. (1972) describe the anti-predator
behavior of Pinon Jays, which was directed against Sharp-
skinned, Cooper's Red-tailed, and Rough-legged hawks, and
Great Horned Owls in Arizona.
B. Competition
Pinon Jays and Starlings found together in Colorado by
Beidleman and Enderson (1964); no further comment given.
C. Parasitism
Friedmann (1963) does not list the Pinon Jay as a victim
of cowbird parasitism.
IX STATUS
A. Past population trends
Called a "common" resident by Grinnell (1915).
B. Present population status
Grinnell and Miller (1944), "resident within state. . irregular,
local shif tings of population. Because they are gregarious. . .
11
Gymnorhirius cyanocephalus (con't.)
usually considered common or even abundant." Small (1974),
"resident, but populations move. . .depending upon local food
conditions and weather." Called a "locally common, permanent
resident," in Joshua Tree National Monument (Miller and
Stebbins 1964).
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
12
Gymnorhinus cyanocephalus (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Austin, G. T. and A. M. Rea. 1976. Recent southern Nevada
bird records. Condor 78:405-408.
Bailey, F. M. 1928. Birds of New Mexico. New Mexico Dept.
Game and Fish. 807 pp.
Balda, R. P. and G. C. Bateman. 1971. Flocking and annual
cycle of the Pinon Jay, Gymnorhinus cyanocephalus . Condor
73:287-302.
Balda, R. P. and G. C. Bateman. 1972. The breeding biology of
the Pinon Jay. Living Bird 11:5-42.
Balda, R. P. and G. C. Bateman. 1973. Unusual mobbing behavior
by incubating Pinon Jays. Condor 75:251-252.
Balda, R. P. and G. C. Bateman. 1976. Cannibalism in the
Pinon Jay. Condor 78:562-564.
Balda, R. P., G. C. Bateman and G. F. Foster. 1972. Flocking
associates of the Pinon Jay. Wilson Bull. 84:60-76.
Balda, R. P., M. L. Morrison, T. R. Bement. 1977. Roosting
behavior of the Pinon Jay in autumn and winter. Auk 94:
494-504.
Bateman, G. C. and R. P. Balda. 1973. Growth, development
and food habits of young Pinon Jays. Auk 90:39-61.
Beidleman, R. G. and J. H. Enderson. 1964. Star ling -Pinon
Jay associations in southern Colorado. Condor 66:437.
Bent, A. C. 1946. Life histories of North American jays,
crows and titmice. Part 2. U.S. Nat. Mus. Bull. 191:
215-495.
Bond, R. M. 1940. A Goshawk nest in the Upper Sonoran life-
zone. Condor 42:100-103.
Braly, J. C. 1931. Nesting of the Pinon Jay in Oregon. Condor
33:29.
Cannon, F. D. 1973. Nesting energetics of the Pinon Jay.
Unpubl. M.S. thesis, Northern Arizona Univ., Flagstaff.
4
^
13
Gymnorhinus cyanocephalus (con't.)
Dawson, W. L. 1923. The birds of California. Vol. 1. South
Moulton Co., San Francisco.
Enderson, J. H. and J. Craig. 1974. Status of the Peregrine
Falcon in the Rocky Mountains in 1973. Auk 91:727-736.
Friedmann, H. 1963. Host relations of the parasitic cowbirds.
U.S. Nat. Mus. Bull. 233. 276 pp.
Gabrielson, I. N. 1949. Bird notes from Nevada. Condor 51:
179-187.
Gilman, M. F. 1936. Additional bird records from Death Valley.
Condor 38:40-41.
Goodwin, D. 1976. Crows of the world. Cornell Univ. Press,
Ithaca, New York. 354 pp.
Grinnell, J. 1898. Birds of the Pacific slope of Los Angeles
County. Pasadena Academy Sci. No. 11:1-52.
Grinnell, J. 1908. The biota of the San Bernardino Mountains.
Univ. California Publ. Zool. 5:1-170.
Grinnell, J. 1915. A distributional list of the birds of
California. Pacific Coast Avifauna No. 11. 217 pp.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27. 608
pp.
Grinnell, J. and H. S. Swarth. 1913. An account of the birds
and mammals of the San Jacinto area of southern California.
Univ. California Publ. Zool. 10:197-406.
Gullion, G. W. , W. M. Pulich and F. G. Evenden. 1959. Notes
on the occurrence of birds in southern Nevada. Condor 61:
278-297.
Hellmayr, C. E. 1934. Catalogue of birds of the Americas.
Part 7. Field Mus. Nat. Hist. Zool. Ser. Publ. 330, Vol.
13.
Henderson, J. 1920. Migrations of the Pinyon Jay in Colorado.
Condor 22:36.
Jensen, J. K. 1923. Notes on the nesting birds of northern
Santa Fe County, New Mexico. Auk 40:452-469.
Jensen, J. K. 1926. The Pirion Jay. Oologists1 Record 6:41-
43.
14
Gymnorhinus cyanocephalus (con't.)
Johnson, H. C. 1902. The Pinyon Jay. Condor 4:14.
Johnson, D. H. , M. D. Bryant and A. H. Miller. 1948. Verte-
brate animals of the Providence Mountains area of California.
Univ. California Publ. Zool. 48:221-376.
Jordon, P. A. 1956. Pinon Jays west of thp Sierra Nevadan
divide in California. Condor 58:238.
Ligon, J. S. 1961. New Mexico birds. Univ. New Mexico Press,
Albuquerque. 360 pp.
Ligon, J. D. 1971. Late summer- autumnal breeding of the Pinon
Jay in New Mexico. Condor 73:147-153.
Ligon, J. D. 1974. Comments on the systematic relationships
of the Pirion Jay (Gymnorhinus cyanocephalus) . Condor 76:
468-470.
Ligon, J. D. and J. L. White. 1974. Molt and its timing in
the Pinon Jay. Condor 76:274-287.
Linsdale, J. M. 1936. The birds of Nevada. Pacific Coast
Avifauna No. 23. 145 pp.
Martin, A. C. , H. S. Zim and A. L. Nelson. 1951. American
wildlife and plants. McGraw-Hill Book Co., New York.
500 pp.
Mayr, E. and J. C. Greenway, Jr. Editors. 1962. Checklist
of birds of the world. Vol. 15. Mus. Comp. Zool., Cam-
bridge, Mass. 315 pp.
Mayr, E. and L. L. Short. 1970. Species taxa of North American
birds. Publ. Nuttall Ornithol. Club 9:1-127.
Miller, L. H. 1915. Pinyon Jays in Los Angeles. Condor 17:
166.
Miller, A. H. and R. C. Stebbins. 1964. The lives of desert
animals in Joshua Tree National Monument. Univ. Calif-
ornia Press, Berkeley. 452 pp.
Peterson, R. T. 1961. A field guide to western birds. 2nd
Edition. Houghton Mifflin Co., Boston. 366 pp.
Phillips, A., J. Marshall, and G. Monson. 1964. The birds of
Arizona. Univ. Arizona Press, Tucson. 212 pp.
Reed, C. A. 1904. North American birds eggs. Doubleday, Page
& Co., New York. 356 pp.
(f
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15
Gymnorhinus cyanocephalus (con't.)
Richards, E. B. 1924. A list of the land birds of the Grass
Valley District, California. Condor 26:98-104.
Ridgway, R. 1904. The birds of North and Middle America.
Part 3. Bull. U.S. Nat. Mus. No. 50.
Robbins, C. S., B. Bruun and H. S. Zim. 1966. Birds of North
America. Western Publ. Co., Wisconsin. 340 pp.
Selander, R. K. 1956. Additional record of the Pinon Jay in
Mexico. Condor 58:239.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Van Rossem, A. J. 1936. Birds of the Charleston Mountains,
Nevada. Pacific Coast Avifauna No. 24. 65 pp.
Wall, E. 1915. Notes from San Bernardino, California. Condor
17:59.
Wauer, R. H. 1964. Ecological distribution of the birds of
the Panamint Mountains, California. Condor 66:287-301.
Westcott, P. W. 1964. Invasion of Clark Nutcrackers and Pinon
Jays into southeastern Arizona. Condor 66:441.
Wheelock, I. G. 1904. Birds of California. A. C. McClurg
and Co., Chicago. 578 pp.
Whitney, M. R. 1963. Results of Pinyon Jay banding in South
Dakota. Bird-Banding 34:219.
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna No. 21. 204 pp.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles Co. Mus. Zool. Ser. 6:1-39.
<p
4
«
PLAIN TITMOUSE
Parus inornatus
TAXONOMY
A. Type description
AOU (1957) Parus inornatus transpositus : Baeolophus inornatus
transpositus . Grinnell, Condor, 30, no. 2, Mar. 15, 1928,
p. 154. (Mount Wilson, Los Angeles County, California.)
P. i. mohavensis : A. H. Miller, Condor 4-8, no. 2, Apr. 2,
1946, p. 76. (Pinyon Wells, 4000 feet, Little San Bernar-
dino Mountains, Riverside County, California.)
P. .i. kernensis : Baeolophus inornatus kernensis Grinnell
and Behle, Condor, 39, no. 5, Sept. 15, 1937, p. 226.
(Rankin Ranch, 3 30 0 feet, Walker Basin, Kern County, Calif-
ornia. )
P. i. zaleptus : Baeolophus inornatus zaleptus Oberholser,
Sci. Publ. Cleveland Mus . Nat. Hist., 4, no. 1, Sept. 19,
19 32, p. 7. (rim of Warner Valley northwest of Jacobs
Ranch, Twenty Mile Creek, 9 miles south of Adel, Oregon.)
P. i_. ridgway : Richmond, Proc. Biol. Soc. Washington, 15,
June 20, 19 02, p. 15 5. New name for Lophophanes inornatus
griseus Ridgway, 1882, preoccupied. (Nevada, Utah, and
Colorado to New Mexico and Arizona = Iron City, Utah.)
P. i. inornatus : Parus inornatus Gambel, Proc. Acad. Nat.
Sci. Philadelphia, 2, no. 10, July-August (Dec. 5) 1845,
p. 265. (Upper California = Monterey.)
B. Current systematic treatments
Snow (1967) recognizes 43 species in the genus Parus ; ten
subspecies of inornatus . Passeriformes = Paridae.
Ridgway (1904), discussion of morphological characteristics
and geographic distribution in relation to systematic treat-
ment.
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), P. i. zaleptus : Parus inornatus
griseus ; Baeolophus inornatus zaleptus ; Baeolophus inornatus
griseus ; P. i. ridgwayi.
P. i. ridgwayi : Baeolophus inornatus griseus .
P. i. kernensis : Lophophanes inornatus ; Baeolophus inornatus
kernensis .
Parus inornatus (con't. )
P. i. transpositus : Lophophanes inornatus ; Baeolophus
inornatus murinus ; P. i. murinus ; B. i. inornatus ; B. i.
transpositus .
P. i. inornatus : Lophophanes inornatus ; Baeolophus inornatus
restrictus ; B. i. inornatus ; B. i. ridgwayi.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (194-4), P. i. zaleptus : Warner Plain
Titmouse; Gray Titmouse; Warner Valley Titmouse.
P. i. ridgwayi : Gray Titmouse; Gray Plain Titmouse.
P. i. kernensis : Kern Plain Titmouse; Gray-tufted Titmouse;
Kern Basin Plain Titmouse.
P. i. transpositus : Plain Chickadee; Plain-crested Titmouse;
Gray-tufted Titmouse; San Diego Titmouse; Plain Titmouse.
P. i. inornatus : Plain Chickadee; Plain-crested Titmouse;
Gray-tufted Titmouse; San Francisco Titmouse; Gray Titmouse;
Plain Tit; Plain Titmouse.
II DESCRIPTION
A. External morphology of adults
Dawson (1923), "Adults (sexes alike) and immature: Crested;
upperparts plain hair-brown with olivaceous reflections on
rump and on wing-edgings, shading on sides into dull gray-
ish white or pale brownish gray, the brownish element
strengthening posteriorly. Bill grayish horn-color with
paler tomia; feet and tarsi bluish gray." Ridgway (1904),
detailed description of plumage and soft parts, with measure-
ments, of Baeolophus inornatus inornatus ; B. i. murinus ,
and B_. i. griseus .
B. External morphology of subadult age classes
Dawson (1923), "Young birds are buffier (than adults),
especially posteriorly."
C. Distinguishing characteristics
Interspecific - Peterson (1961), "young black-crested Tit-
mouse (P. atricristatus ) , which have short gray crests...
are virtually indistinguishable."
Intraspecif ic - Price (19 36), "The sexes... are similar in
appearance and cannot be distinguished in the field... The
male dees not have (a) brood patch and thus the sexes can
be distinguished in the hand (during the breeding season)."
Miller (1946), discussion of variation among subspecies
(murinus, cineraceus , kernensis, mohavensis, transpositus ,
O
<
«
Pams inornatus (con't.)
ridgwayi) . Grinnell and Behle (1937), "Compared as to
coloration with B. i. inornatis, dorsum grayer, less brown-
ish, and flanks and underparts generally slightly less
buffy, clearer whitish; compared with B. i. transpositus,
less olivaceous dorsally, and paler gray "Below; less clearly
gray dorsally, but pale below, than in zaleptus. In size
characters, closest to inornatus; bill decidedly shorter,
less massive, than in zaleptus, and less massive even than
in transpositus."
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), "Southern Oregon, Nevada, southeastern Idaho,
southwestern Wyoming, and southcentral Colorado south to
northern Baja California, central and southeastern Arizona,
southwestern and central New Mexico, and western Texas.
Also resident in extreme southern Baja California."
AOU (1957) P. i^. transpositus: "Resident in southwestern
California "From Santa Barbara County of the Mexican boundary
(Palmdale, Hesperia, Santa Rosa Mountains, Campo)."
P. ^L. mohavensis: "Resident in the Little San Bernardino
Mountains ot southeastern California."
P. i. kernensis: "Resident in California in southern Tulare
and Kern counties (Basin of the Kern River, Walker Basin)
and an adjacent eastern slopes of the Sierra Nevada (Inyo
County) .
P. _i . zaleptus: "Resident from central southern Oregon. . .
northeastern California (Clear Lake, Secret Valley, Manton) ,
and western Nevada (the Peavine and Virginia Mountains,
Carson City) south to central eastern California (Benton;
White, Inyo, and Panamint Mountains).
P. i. ridgwayi: Resident in the mountains from northeastern
Nevada. . .southeastern Idaho. . . southwestern Wyoming. . . south-
central Colorado. . .and western Oklahoma. .. south to south-
eastern California (Clark, New York, and Providence Moun-
tains), central and central southern Utah. . .northeastern
Arizona. . .central New Mexico... and western Texas."
P. i. inornatus : "Resident in central western California
"From Mendocino County and the Sacramento Valley south to
Santa Barbara and Tulare counties."
Parus inornatus (con't.)
B. California distribution of the species
Grinnell and Miller (1944), P. inornatus zaleptus: North-
eastern and eastern and portions of the state, entirely
east of the Cascade-Sierran divides. . .Modoc region from
near Nevada line west at least to Clear Lake and south
from Oregon line at least to Secret Valley, Lassen County
...Inyo region from "head of Owens River" and Benton, Mono
County, south to White, Inyo, Grapevine and Panamint Moun-
tains of Inyo County."
P. i. ridgwayi: "Providence Mountains (in broad sense,
"inclusive of "New York Mountains") and Clark Mountains, in
extreme eastern San Bernardino County."
P. i. kernensis: "Drainage basin of Kern River, within
southeastern rim of San Joaquin Valley, in Kern County and
extreme southern Tulare County, and adjacent eastern slopes
of Sierra Nevada, Inyo County."
P. i_. transpo situs: "Southern California, chiefly west of
the desert divides, southeast from Santa Barbara and Ventura
counties (where intergrading with race inornatus) to Mexican
boundary. "
Grinnell and Miller LcontinuedJ (1944), P. i. inornatus :
"Western California below about the 3000 foot level , From
Mendocino County and head of Sacramento Valley south to
Santa Barbara and Tulare Counties. ... Intergrades southward
with P. i^. kernensis in westward foothills of Sierra Nevada
in Fresno and Tulare Counties; in coast belt with P. i.
transpositus in Santa Barbara and Ventura Counties."
Miller (1946), P. i_. mohavensis: "Little San Bernardino
Mountains, San Bernardino and Riverside Counties. . .Extends
from Morongo Valley eastward to vicinity of Little San
Bernardino Mountain, north of Mecca. Not found on Eagle
Mountain to eastward."
Dawson (1923), P. i. inornatus : "chiefly in the oak asso-
ciation of the Upper Sonoran zone west of the Sierra divide
and north of the Tehachipe, north to Mendocino and Siskiyou
Counties." Wholly within California.
C. California desert distribution
Small (1974), "absent from San Joaquin Valley and eastern
and southeastern desert region." Miller (1946), P. i.
mohavensis: Quail Spring... San Bernardino County; Pinyon
Wells. . .Riverside County.
<T»
<
P
Parus inornatus (con't.)
D. Seasonal variations in distribution
Dixon (1949), "There are in the literature a number of
records of occurrence. . .outside the breeding range of this
species in late fall and winter, usually in marginal habitat
...those individuals which do survive may move back into
adjacent areas suitable for nesting and fill vacancies
which have opened during the winter months."
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944). P. i. zaleptus: "sharply limited
to tracks of pinon and (or) "Juniper of rather old growths,
whether these be on nearly level terrain, as in Modoc County,
or on steep mountain sides, as in Inyo County."
P. i. ridgwayi: "Normal stands of pinon and juniper, typi-
calTy where . . . intermixed . "
P. i. kernensis: "Primarily, open oak woods of mountain
sides, but also often where oaks are mixed with digger
pines or even with pinons."
P. i. transpo situs: "Open woodland where consisting chiefly
of oak"s^ whether on level terrain or on mountain sides."
Grinnell and Miller [.continued] (1944), P. i. inornatus :
"open- type woodland of which oaks of oneHcind or another
are exclusive or dominant constituents. Most frequented
species of oaks are blue oak, live oak and valley oak."
Miller (1951), Upper Sonoran life Zone. Dixon (1961), dis-
cussion of distribution and niche relationships of Parus.
Dawson (1923) "West of the Sierras the range... is nearly
coextensive with that of oak trees. . .occasionally ventures
up into the pines of the Sirrran foothill s--even nests
there. . .excursions into the chaparral." Small (1974),
"oak woodlands, pinon- juniper woodlands." Dixon (1949)
"dry woodlands of small, chiefly evergreen trees character-
istic of the southwest. The coastal races. . .inhabit wood-
land in which oaks predominate, whereas those of the Great
Basin and desert mountain ranges frequent. . .pinons and
junipers." Miller (1946), P, i_. mohavensis: "Resident of
pinon-juniper-scrub oak association. "
B. Altitudinal range
Grinnell and Miller (1944), P. i. zaleptus: "from 4400 feet
near Alturas, Modoc County, to 7500 feet at Waucoba Pass,
Inyo Mountains.
Parus inornatus (con't.) x"~
P. i. ridgwayi: "4500 to 6500 feet."
P. i. kernensis: "2400 up to 6700 feet."
P. i. transpositus: "close to sea level, as at San Onofre,
San Diego County, and 6000 feet, as on San Bernardino and
Santa Rosa Mountains."
Miller (1946), P. i. mohavensis: "3600-4500 feet, San Bern-
ardino County; "500TT-4300 feet, Riverside County."
C. Home range size
Dixon (1949) "twelve territories averaged 6.3 acres in size
...Has a large territory relative to that of other small
passerine species, averaging. . .about 135 meters... in diameter.1
D. Territory requirements
Perch sites - Dixon (1949), "Rarely does a bird take a con-
spicuous exposed perch while making its declaration of terri-
tory, either during autumn or winter boundary disputes
or during spring singing. .. takes place most frequently from
a perch well protected by the canopy of foliage or by twigs
of deciduous trees." Hardy (1945) "in the larger branches
and on the trunk of these fpigmy conifers] same trees."
Courtship and mating sites
Nest sites - Grinnell and Miller (1944), P. i. ridgwayi ;
"Nesting crevices often are provided in tTTe partly decayed ,
split and twisted trunks of junipers, near the ground."
Dawson (1923), "old woodpecker holes... wind crecice, incipient
decay." Price (1936), "readily nesting in bird houses or
nesting boxes."
E. Special habitat requirements
Dixon (1949), "The open spacing of the trees and the general
absence of foliage beneath the canopy enable the birds to
detect the approach of enemies from beneath."
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Dawson (1923) "mixed diet. Insects of many kinds. . .black
olive-scale. . .Vegetable food... 57 per cent. Fruit. .. eaten
chiefly. . .when other forage fails. Weedseeds, leaf-galls,
and poison oak seeds. Chief staple article of diet is the
acorn." Jordan (1925), noted feeding on sunflower seeds.
<
«
9
•
Parus inornatus (con't.)
Davis, Davis, and Davis (1973), discussion of seed size,
seed pattern, and seed color preferences.
B. Foraging areas
Bent(1946) "oak-clad, sunny slopes of the foothills, where
the foliage of the evergreen oaks provides shelter and a
good food supply all the year around."
C. Foraging strategies
Dixon (1949), "devote a large share of their food-gathering
time to bark gleaning."
D. Feeding phenology
E. Energy requirements
Davis, Davis, and Davis (19 73), "The preference for larger
over smaller seeds is undoubtedly advantageous in saving
time and energy by transporting the same amount of food in
fewer trips... the addition of energy needed to carry the
heavier seeds would be almost exactly offset by the increased
amount of food carried in the larger kernel."
VI REPRODUCTION
A. Age at first breeding
Dixon (1949), settle territory by age one year. Price (1936),
"In one case the new mate was known to be a juvenile of the
year before . "
B. Territorial behavior
Dixon (1949), "Detection of titmice intruding on territories
correspondingly is most often by auditory means .. Visual
stimuli. .. used at shorter distances. Action against an
intruder may consist of scolds, calls, or song, often in
combination with wing vibrations ... No patterns (plumage)
to be brought into prominence, and hence physical expressions,
such as puffing out of feathers in aggressive display, are
lacking. A threatening posture ... appears to be an attitude
of potential movement toward the intruder .. .Year-round
defense of a 'retreat' territory." Dixon (1969), analysis
of patterns of singing.
C. Courtship and mating behavior
Dixon (1949), "In the earliest phases of 'courtship,' song
may be followed by an 'approach-threat' directed toward
the female and often accompanied by use of the 'dominance
Parus inomatus (con't.)
note'... The female may take flight rather than shift her
perch. . .There ensues a pursuit. .. the male attempts to over-
take and mate with the female. . .Females were observed giving
...an invitational or begging display... He may respond by
feeding her... The frequency and intensity of this invitational
display. . .apparently is an index to the physiological state
of the female. . .Pair formation occurs in a majority of
cases in young birds soon after family flocks break up in
early summer. This pairing may take place prior to establish-
ment on a territory, or a wandering young bird may mate
with an established, widowed adult."
D. Nesting phenology
Dixon (1949), "Nest site selection appears to be a function
of the female alone, as is construction of the nest. . .Court-
ship feeding occurs from the beginning of nest construction
until the young are hatched. Incubation is by the female."
E. Length of incubation period
Dixon (1949), "approximately 14-16 days."
F. Length of nestling period
Dixon (1949), "The nestlings remain in the cavity for about
three weeks, during which they are fed by both parents.
The family brood remains together for from three to four
weeks."
G. Growth rates
H. Post-breeding behavior
Dixon (1962), "Even though the period of the annual molt
in the population. .. studied does not intrude appreciably
upon the period of fledgling dependency ^fledglings were
about two weeks out of the nestj , it begins earlier in the
calendar date than is the case in most passerines." Dixon
(1949), "After the young leave the nest, they remain with
their parents in a family flock for about a month. Sub-
sequently they leave the area or are driven out by the
adults which continue to occupy the area. . .Winter flocking
does not appear to be the rule. Following the break up of
family groups in late summer, pair formation may occur
among immature birds."
(~>
<
«
Parus inomatus (con't.)
711 POPULATION PARAMETERS
A. Clutch size
Price (1936), average for 62 sets found to be 6.75 eggs;
range 3 to 9. Dixon (1949), "variable."
B. Fledging success
Dixon (1949) "Eight birds of the 24 fledged survived."
This involved seven breeding pairs.
G. Mortality rates per age class
Dixon (1949), Adults: "survival of five of the twelve adults
from the 1947 breeding season is only 41.6 per cent of that
total." Young: "Eight birds of the 24 fledged survived...
death rate of 66 per cent among young birds fledged."
D. Longevity
Dixon (1949) of 22 breeding individuals, one each were 5 and
6 years, three were 4 years, seven were 3 years, six were two
years, and four were one year. "Average life expectancy of
an established adult appears to be about three years."
Price (1936) "The oldest titmouse recorded. . .banded as adult
in 1928 and was recaptured in the same box in 1934 when it
must have been at least seven years old."
E. Seasonal abundance
Hardy (1945) "found in a family group of a half dozen or
so for a short time in the period after the young leave
the nest."
F. Habitat density figures
Dixon (1949) "The breeding population of the study area
[.144 acres] was stabilized at a density of seven pairs."
Gaines (1974), reports from 26 to 66 territorial males per
square kilometers; 26, 43, and 30 per km^ in clumped cotton-
wood and willow woodland; 68 and 66 per km^ in riparian
oak woodland.
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Price (1936), "Jays [ Aphelocoma californicaj are often
seen about the nesting Doxes containing young titmouses
and sometimes perch on the box and peer inside. When young
birds leave the nest the jays often dive at them and kill
them."
10
Parus inomatus (con't.)
B. Competition
Davis, Fisher, and Davis (1963), noted that 3 of 44 attacks
by two territorial pairs of western Flycatchers were dir-
ected at P. inomatus . Dixon (1954), detailed discussion
of interactions between Chestnut-backed Chickadees and Plain
Titmice. "Study of foraging habits suggests only partial
overlap in foraging sites in winter. During the period
when fledglings were being fed, size of food items taken
appeared to differ."
C. Parasitism
IX STATUS
A. Past population trends
Grinnell and Miller (1944), P. i. zaleptus: "Resident.
Distribution much interrupted and population usually sparse."
P. i. ridgwayi : "Resident. Under optimal conditions of
KabTtat, common."
P. i. kernensis; "Resident. Where most favorable habitat
conditions prevail, common."
P. i. transpositus: "Resident. Common, even abundant locally."
B. Present population status
Small (1974), "common resident."
C. Population limiting factors
D. Environmental quality: adverse impacts
Grinnell and Miller (1944), "Retraction of range has taken
place locally, where oaks have been felled to clear for
agriculture; on the other hand, tree-planting, even in sub-
urbs of towns, has brought favoring conditions in previously
unoccupied neighborhoods."
E. Potential for endangered status
«
11
Parus inornatus (con't)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bent, A. C. 1946. Life histories of North American jays,
crows, and titmice. U.S. Nat. Mus. Bull. No. 191.
Davis, J., G. F. Fisler and B. S. Davis. 1963. The breeding
biology of the Western Flycatcher. Condor 65:337-382.
Davis, S., B. S. Davis and J. Davis. 1973. Some factors
affecting foraging behavior of Plain Titmouse. Condor
75:481-482.
Dawson, W. L. 1923. The birds of California. South Moulton
Co., San Francisco.
Dixon, K. L. 1949. Behavior of the Plain Titmouse. Condor
51:110-136.
Dixon, K. L. 1954. Some ecological relations of chickadees
and titmice in central California. Condor 56:113-124.
Dixon, K. L. 1961. IN Vertebrate Speciation Blair, W. F.
(Ed.) pp. 179-216. Univ. Texas Press, Austin.
Dixon, K. L. 1962. Notes on the molt schedule of the Plain
Titmouse. Condor 64:134-139.
Dixon, K. L. 1969. Patterns of singing in a population of
the Plain Titmouse. Condor 71:94-101.
Gaines, D. 1974. A new look at the nesting riparian avifauna
of the Sacramento Valley, California. Western Birds 5(3):
61-79.
Grinnell, J. and W. H. Behle. 1937. A new race of titmouse,
from the Kern Basin of California. Condor 39:225-226.
Grinnell, J. and A. H. Miller. 1944. The distribution of
birds of California. Pacific Coast Avifauna No. 27.
Hardy, R. 1945. Breeding birds of the pigmy conifers in the
Book Cliff region of eastern Utah. Auk 62:523-542.
Jordan, D. S. 1925. California Tufted Titmouse feeds on sun-
flower seeds. Condor 27:241.
Miller, A. H. 1946. Endemic birds of the Little San Bernar-
dino Mountains, California. Condor 48:75-79.
12
Parus inornatus (con't.)
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. Vol.
50, No. 6.
Peters, J. L. 1967. Checklist of the birds of the world.
Vol. 12. (D. Snow, ed. ) Mus. Comp. Zool., Cambridge, Mass-
achusetts.
Peterson, R. T. 1961. Field guide to western birds. Houghton
Mifflin Co. , Boston.
Price, J. B. 1936. The family relations of the Plain Titmouse.
Condor 38:23-28.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Ridgway, R. 1904. The birds of North and Middle America.
Part III. Bull. U.S. Nat. Mus. No. 50.
t*
t
POOR WILL
Phalaenoptilus nuttallii
I TAXONOMY
A. Type description
AOU (1957), P. n. nuttallii: Caprimulgus nuttallii, Audubon,
Bds. Am. octavo ed. , 7, 1844, p. 350, pi. 495.
P. n. hueyi : P. n. hueyi , Dickey, Condor, 30, 1928, p. 152.
TBard, Imperial County, California. )
B. Current systematic treatments
Peters (1940) monospecific genus with four subspecies:
P. n. nuttallii; P. n. calif ornicus; P. n. hueyi ; P. n.
Hicfceyi. CaprimulgiTormes: Caprimulgidae.
C. Synonomies of scientific nomenclature
Peters, J. L. , 1940, Checklist of Birds of the World, Vol.
4, p. 193, Mass.: Harvard U. Press Caprimulgus nuttallii
(Audubon). Grinnell and Miller (1944), P. n. nuttallii:
Ant ro stomas nuttallii ; P. nuttallii nyctophTlus. P_. n.
hueyi: P. nuttallii nitTdus.
D. Synonomies of vernacular nomenclature
Dawson (1923), Nut tail's Poorwill. Grinnell and Miller
(1944), P. n. nuttallii: Nuttall Poor-will; Nuttall Whip-
poor-will; Frosted Poor-will. P. n. hueyi : Frosted Poor-
will; Huey Poor-will.
II DESCRIPTION
A. External morphology of adults
Peterson (1961), "rounded wings (no white bar). Its short
rounded tail has white corners." Ridgway (1914), detailed
description of adults including plumage, soft parts, and
measurements. Dawson (1923), Adult: a central patch of
pure silky white across lower throat; below this, in abrupt
contrast, a band of black. .. the three outer pairs of tail
feathers tipped broadly but decreasingly with white or
buffy whites; remaining plumage. . .black centers of feathers
with buffy intermingled dusky marginings." Selander (1954),
"do not show pronounced color phases."
•
Phalaenop ti lus nuttallii (con't.) / ~jr
B. External morphology of subadult age classes
Ridgway (1914), "Young — not essentially different from adults,
but markings in general less sharply defined, especially on
underparts, and throat patch buff instead of white. Downy
young--Downy covering vinaceous-buf f , paler on underparts,
feathers appearing on upper parts dull buffy white minutely
stippled and vermiculated with grayish and with small spots
and narrow bars of black; those on middle underparts dull
white barred, more or less distinctly, with grayish or
dusky.
C. Distinguishing characteristics
Interspecific - Peterson (1961), "smaller than a nighthawk,
has more rounded wings (no white bar) .„. short rounded tail
with white corners."
Intraspecific - Dawson (1923), "P. n. nuttallii paler than
calif ornicus ; darker than nitidus. " Grinnell (1928), P. n.
hueyi , "nearest in color to the light type of P. n. nuttaTlii
..., but averaging very much lighter. Backs... are a pinkish
tan, almost devoid of the silver frosting. .. the size of the
dark dorsal "owl's eye" marking greatly reduced, in many
cases practically obsolete."
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957): "From southern interior British Columbia, south-
eastern Montana, northwestern South Dakota, Nebraska, and
southwestern Iowa south on the Pacific coast from central
California to southern Baja California and through eastern
Kansas and central Texas to central Mexico (Guanajuato).
Winters from central California, southern Arizona, and
southern Texas southward." P. n. nuttallii: Breeds from
southern interior British CoTumBia (Clinton) , southern
Alberta, southern Montana (Valley, Gallatin, Fergus, and
Prairie counties), northwestern South Dakota (Slim Buttes),
and Nebraska south through eastern Washington, eastern
Oregon, and eastern California (east of the Cascade Moun-
tains and the Sierra Nevada) to the Mohave Desert, central
and southeastern Arizona, Sonora, Coahuila (Saltillo), east
to eastern Kansas (Lawrence), northwestern Oklahoma (Woods
and Cimarron counties), and southern Texas (San Antonio);
casual in Southwestern Iowa (Pottawattamie County)." P. n.
hueyi : "Breeds in valley of lower Colorado River in south-
eastern California, southwestern Arizona, northeastern Baja
California, and extreme northwestern Sonora."
^
Phalaenop ti lus nuttallii (con't.)
B. California distribution of the species
Small (1974), "length of state except humid northwestern
portion and Central Valley." Dawson (1923), "summer resi-
dent of Upper Sonoran and Transition areas east of the
Sierras, from Death Valley northward, and through the
northern counties west at least to Yreka, Siskiyow County."
C. California desert distribution
Jaeger (1949), "Chuckawalla Mountains of the Colorado
Desert, California." Cardiff (1956), reported on two
occasions near Westmoreland. Carter (1937), heard fre-
quently at night during April and May; often seen in Oct-
ober— Twentynine Palms, San Bernardino County. Abbott
(1940), reports nest of P. n. hueyi in May, 1940, at eastern
end of Salton Sea. Bickroro" ( 1929) , reported as resident
in Napa County. Gilman (1935), reported in Death Valley
in November. One dead found in January. Bent (1940) "San
Diego, Escondido, Ojai Valley." Miller (1951) Modec, Inyo,
Shasta Valley, Mojave (P. n. nuttallii) Colorado Desert
(P. n. hueyi) . Grinnell and Miller (1944), P. n. nuttallii:
WHite, Inyo, Grapevine, Funeral, Panamint, and Argas Moun-
tains; Cosa Valley, Death Valley (Inyo County). Mission
gk Valley, San Diego County. Colorado River Valley, Riverside
^f Mountain, Riverside County, to near Picacho, Imperial County.
P. n. hueyi : "Valley of Colorado River, from Needles, San
Bernardino County, at least to Bard, Imperial County. . .
Imperial Valley, as at eastern end of Salton Sean. .. Inter-
grades with P. n. nuttallii occur in Providence Mountains,
area, San Bernardino County."
D. Seasonal variations in distribution
AOU (1950) P. n. nuttallii: "Winters from eastern California
(Death Valley), southern Arizona (Tucson), and southern
Texas (El Paso, Kerrville) south to Sonora (Tiburon Island),
Guanajuato, and Coahuila." Small (1974), "primarily a sum-
mer visitor (California), April to November in the northern
half of the state; some may overwinter by hibernating."
Dawson (1928), "Winters in the southern portion of its
range and irregularly southward over the deserts and in the
valley of the Colorado." Culbertson (1946), discusses
reports of individuals presumably in torpor, including
own sighting in Fresno County in February. "It is well
to note that none of the winter records of the occurrence
of the Poor-will in the Sierran foothills are of birds in
f light. .. flushed in the daytime or found in an inactive
state."
•
'•
Phalaenoptilus nuttallii (con't.)
IV HABITAT
A. Biotopic affinities
Peterson (1961), "Stony arid hills, open pinon- juniper,
sparse brush." Small (1974), "Chaparral, pinon- juniper
woodland, brushy slopes, desert washes and desert floor
with scattered bushes." Orr (1948) "high transition forest
...composed principally of Jeffrey pine (Pinus ponderosa
var. jef freyi) , sugar pine ( Pinus lambertiana) and white
fir (Abies concolor) . ♦ .a rocky knoll strewn with large
granite boulders. . .huckleberry oak (Que reus vaccinifolia)
...clumps of brush, consisting of tobacco brush (Ceanothus
yelutinus) , green manzanita (Arctostaphylos patala) and
bush chinquapin (Castanopsis semipervirensT. Bendire
(1895) "open prairie. . .almost barren and arid regions of
the interior, which are covered only here and there with
stunted patches of sage (Artemisia) and other desert plants.
The climate does not seem to affect it much, as it inhabits
some of the hottest regions of the continent, like Death
Valley, in southern California, as well as the slopes of the
Rocky and Blue Mountains in Oregon, where it reaches alti-
tude of from 6,000 to 8,000 feet." Miller (1951) Upper
and Lower Sonoran and Transition Zones. Grinnell and
Miller (1944), P. n. nuttallii: "rocky or gravelly terrain
grown scatteringly to bushes or trees. Often associated
with sage-brush, antelope-brush, pinon pines, or junipers."
P. n. hueyi : "gravelly or stony desert floor or wash bot-
toms sparsely grown to bushes or small trees."
B. Altitudinal range
Wauer (1964) noted at 3000-6000 ft., Panamint Mtns. Salt
(1953), reports as resident of Boca Springs (6000 ft.),
May through August. Miller (1955) "common along rocky can-
yon walls at 5000 ft. but not noted higher up." Grinnell
and Miller (1944), P. n. nuttallii: *1800 to 8300 feet."
P. n. hueyi : "below T00U feet."
C. Home range size
D. Territory requirements
Perch sites - Wetmore (1932) "rest during the day on the
ground, though after night, when feeding or calling, may
seek higher perches on stones or posts or on low branches."
Courtship and mating sites -
Nest sites - Orr (1948) "pine-needle-matted earth on which
two eggs were deposited." Bent (1940), "The two eggs are
laid on the bare ground, without any semblance of nest 4
building; a slight hollow may be scraped in the bare earth
...on hard gravelly ground... on a flat rock."
%
Phalaenoptilus nuttallii (con't.)
E. Special habitat requirements
F. Seasonal changes in habitat requirements
Jaeger (1949), "the Poor-wills are rock seeking, hibernating
birds in the winter."
V FOOD
A. Food preferences
Brauner (1954) "Birds collected. . .had from 20-61 large
beetles and noctuid moths in their stomachs." Stanford
and Knowlton (1942) "Stomach contained 6 adult Lepidoptera;
1 mirid bug; 2 leafhoppers; 4 Diptera; and 1 click beetle."
Bent (1940; "entirely of insects, mostly the smaller, night
flying species, such as moths, beetles, chinch bugs, and
locusts. '
B. Foraging areas
Grinnell and Miller (1944), "seeks sandy riparian ground
or even mud-bars in the river."
C. Foraging strategies
Bent (1940), "insects are caught on the wing in the capa-
cious mouths. . .many are also picked up on the ground."
D. Feeding Phenology
Brauner (1952) "length of period of activity is apparently
affected by weather conditions and phases of the moon. On
days following or during a rainy period, the numbers of
moths decreased and the period of Poor-will activity was
longer. Under normal weather conditions moths were plenti-
ful and the period of feeding was short."
E. Energy requirements
Jaeger (1948, 1949), describes torpor of presumably same
individual for three successive winters, including body and
ambient temperature measurements. "Known period of profound
hibernation torpidity for the 1947-1948 season was about
85 days." (1949). Brauner (1952), "Prior to the period
of torpidity the food supply available to Poor-wills under
natural conditions is limited. It is at least possible
that the onset of torpidity is associated with reduced
food supply." Report includes body and ambient temperatures
of captive individual. Marshall (1955), reports torpidity
related to amount of food available. Ambient and body
temperatures, respiration rates, and acitivity cycles under
captive conditions. Bartholomew, Howell, and Cade (1957),
Phalaertoptilus nuttallii (con't.)
calculations of energy reserves, based upon measurements f-J*
of oxygen consumption of captive individual active and in
torpor. Arousal rates slow. "Reduced body temperature
and torpor provide a means of energy conservation and are
associated with. .. survival during long periods of fasting."
Bartholomew and Howell (1959) reports on temperature,
metabolic rates, and behavior for entry- torpor-arousal
cycle in captivity. Howell and Bartholomew (1959), further
studies on torpor in captivity. Bartholomew, Hudson, and
Howell (1962), further studies of physiology related to
temperature regulation and torpidity.
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Mengel, Sharpe, and Woolfenden (1972), "The exact behavioral
functions of wing clapping are uncertain at present. .. sug-
gests that such behavior is involved in territorial defense."
Includes descriptions of wing-clapping.
C. Courtship and mating behavior
D. Nesting phenology ^~. v
Dixon (1934), found 2 eggs (June 6) in nest on steep, well
wooded western slope, 7000 ft. Snow on nearby ground 2
inches deep. Eggs on pebbles on ground.
E. Length of incubation period
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
VII POPULATION PARAMETERS
A. Clutch size
Orr (1948), two eggs
B. Fledging success
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
4
Phalaenoptilus nuttallii (con't.)
F. Habitat density figures
VIII INTERSPECIFIC INTERACTIONS
A. Predation
B. Competition
C. Parasitism
IX STATUS
A. Past population trends
Grinnell and Miller (1944), P. n. nuttallii: "Summer resi-
dent to northward and at higKer altitudes; winter visitant
at low altitudes at south common." P. n. hueyi : "Resident.
Locally, fairly common."
B. Present population status
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
8
Phalaenoptilus nuttallii (con't.)
XI LITERATURE CITED
Abbott, C. G. 1940. Notes from the Salton Sea, California.
Condor 42:265.
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bartholomew, G. A. and T. R. Howell. 1959. Further experi-
ments on torpidity in the Poor-will. Condor 61:180-185.
Bartholomew, G. A., T. R. Howell and T. J. Cade. 1957. Tor-
pidity in the White- throated Swift, Anna Hummingbird, and
Poor-will. Condor 59:145-155.
Bartholomew, G. A., J. W. Hudson and T. R. Howell. 1962. Body
temperatures, oxygen consumption, evaporative water loss,
and heart rate in the Poor-will. Condor 64:117-125.
Bendire, C. M. 1895. Life histories of North American birds.
U.S. Nat. Mus. Spec. Bull. No. 3.
Bent, A. C. 1940. Life histories of North American cuckoos, _
goatsuckers, hummingbirds and their allies. U.S. Nat. Mus. ^^
Bull. No. 176.
Bickford, E. L. 1929. Notes from the Napa Valley. Condor 31:
35-36.
Brauner, J. 1952. Reactions of Poor-wills to light and tem-
perature. Condor 54:152-159.
Cardiff, E. A. 1956. Additional records for the Imperial
Valley and Salton Sea Area of California. Condor 58:447-
448.
Carter, F. 1937. Bird life at Twentynine Palms. Condor 39:
210-219.
Culbertson, A. E. 1946. Occurrences of Poor-wills in the
Sierran foothills in winter. Condor 48:158-159.
Dawson, W. L. 1923. The birds of California. Vol. II. South
Moulton Co., San Francisco.
Dickey, D. R. 1928. A new Poor-will from the Colorado River
Valley. Condor 30:152-153.
Dixon, J. B. 1934. Records of the nesting of certain birds
in eastern California. Condor 36:36. 4
Phalaenoptilus nuttallii (con't.)
Gilman, M. F. 1935. Notes on birds in Death Valley. Condor
37:238-242.
Grinnell, J. and A. H. Miller. 1944. The distribution of
birds of California. Pacific Coast Avifauna No. 27.
Howell, T. R. and G. A. Bartholomew. 1959. Further experiments
on Torpidity in the Poor-will. Condor 61:180-185.
Jaeger, E. C. 1948. Does the Poor-will "hibernate"? Condor
50:45.
Jaeger, E. C. 1949. Further observations on the hibernation
of the Poor-will. Condor 51:105-109.
Marshall, J. T. , Jr. 1955. Hibernation in captive goatsuckers.
Condor 57:129-134.
Mengel, R. M. , R. S. Sharpe and G. E. Woolfenden. 1972. Wing
clapping in territorial and courtship behavior of the
Chuck- wills- widow and Poor-will (Caprimulgidae) . Auk 89:
440-444.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. 50:531-
624.
Miller, A. H. 1955. The avifauna of the Sierra del Carmen
of Coahuila, Mexico. Condor 57:154-178.
Orr, R. T. 1948. Nesting behavior of the Poor-will. Auk 65:
46-54.
Peters, J. L. 1940. Checklist of birds of the world. Vol.
IV. Mus. Comp. Zool. , Cambridge, Massachusetts.
Peterson, R. T. 1961. Field guide to western birds. Houghton
Mifflin Co., Boston.
Ridgway, R. 1914. The birds of North and Middle America.
Part VI. Bull. U.S. Nat. Mus. No. 50.
Salt, G. W. 1953. An ecologic analysis of three California
avifaunas. Condor 55:258-273.
Selander, R. K. 1954. A systematic review of the booming
nighthawks of western North America. Condor 56:57-82.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
10
Phalaenoptilus nuttallii (con't.)
Stanford, J. S. and G. F. Knowlton. 1942. Food of some Utah
birds. Auk 59:580-581.
Wauer, R. H. 1964. Ecological distribution of the birds of
the Panamint Mountains, California. Condor 66:287-301.
Wetmore, A. 1932. Seeking the smallest feathered creatures.
Nat. Geogr. Mag., Vol. 62:65-89.
•
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4
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RED-TAILED HAWK
Buteo jamaicensis
I TAXONOMY
A. Type description
Buteo jamaicensis calurus Cassin. (337b) - AOU (1957)
Buteo calurus Cassin, Proc. Acad. Sci. Philadelphia, 7,
Jan. -Feb. (May 22), 1855, p. 281. (Fort Webster (.Rio
MimbresJ , New Mexico.)
B. Current systematic treatments
AOU (1957) Order Falconiformes, Suborder Cathartae, Super-
family Cathartoidea, Family Cathartidae, subfamily
Buteoninae, Genus Buteo, with 8 species; 7 subspecies of
jamaicensis.
Mayr and Short (1970), "The red-tailed 'buzzards' comprise
a cosmopolitan group of allopatric, closely related species
including B. jamaicensis, B. buteo, B. ventralis, B.
oreophilus, and B. brachyp terus . These are believed to
comprise a super species. Of these buteo and ventralis
have been considered conspecific with jamaicensis and this
may prove to be correct. We follow various authors in
merging the western, melanic harlani as a race of jamaicensis.
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), Buteo borealis ; Buteo harlani ;
B. montanus ; B. calurus ; B. borealis calurus; B. b.
socorroensis ; B. jamaicensis*~boreali"s ; B. j. fuertisi.
Knowlton (19097 refers to B. j . calurus as B. borealis
calurus. Grinnell (1915) same as Grinnell and Miller (1944),
Bent (1937) calls this subspecies B. borealis calurus .
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), Red-tailed Buzzard; Harlan Hawk;
Red- tailed Hawk; California Red- tail; Western Red- tail;
Black Red-tailed Hawk; Western Hen Hawk; Texas Red-tailed
Hawk. May (1935), Hen Hawk, Chicken Hawk, Squealing Hawk,
Buzzard Hawk.
II DESCRIPTION
A. External morphology of adults
Dawson (1923) Above dark brown or sooty brown, color nearly
pure on back and minor wing coverts, elsewhere much varied
by lighter grayish brown, tawny, and outcropping white;
long scapulars and tertials dusky and white, and double-
tawny barred; wing when folded usually, but not always,
Buteo jamaicensis (con't.)
2 inches short of tail; tail rich orange- rufous, crossed
near tip by narrow black band; underparts white and variously
broad-marked or washed, except on throat, with pale cinammon-
rufous most heavily on sides of breast; throat and breast
sparingly marked with blackish shaft streaks; bill plumbeous;
tarsus yellow, very stout; claws black. The adults do have
a melanistic phase in which the entire plumage, except tail
and its coverts, is chocolate brown or blackish, rich deep
rusty usually warming on the breast, and lighter rufous
appearing on the shanks. Many gradations exist between
these two plumages. Peterson (1961) - Large, broad-winged
hawk; rufous underside of the tail can be seen in flight.
From beneath, adults have whitish tails. Underparts are
"zoned" (light breast, broad band of streakings across belly).
There is much variation. Black adults usually show red
tails (unlike other Buteos). Robbins et al. (1966) say the
best field marks are the uniformly colored tail, reddish
above, light pink beneath, and the dark belly band. May
(1935) says the Western Red- tail is especially noted for the
wide variation in its colors. Friedmann (1950) gives sizes
for adults and voung and descriptions of plumage. Snyder
and Wiley (1976) give sizes of all North American hawks
and owls.
B. External morphology of subadult age class
Dawson (1923) - above much as in adult, but showing less
of tawny and more outcropping of white; tail entirely diff-
erent, grayish brown crossed by ten or twelve brace-shaped
or waved bands of dusky; upper tail coverts lighter, dusky
and whitish barred, with a mixture of ochraceous; underparts
white or pale ochraceous buffy, heavily streaked, spotted,
and posteriorly barred with brown except on breast which
is nearly immaculate. Immatures frequently show strong
melanistic tendency, in which case the spotting of the under-
parts invades the breast and increases elsewhere nearly to
the point of confluence. Robbins et al. (1966). "The tail
of the immature is finely streaked." May (1935): "Young
Red- tails usually lack the 'wrist-mark' and the dark tips
of the flight feathers are less marked than in the adult."
C. Distinguishing characteristics
Interspecific - Dawson (1923), stouter proportions and more
regal bearing than B. swainsoni , but not always distinguishable
from that species in the field. Peterson (1961), Red- shouldered
has a banded tail and is more uniformly patterned below,
also is chunkier with wider wings, shorter tail. May (1935)
<-
4
Buteo jamaicensis (con't.)
say young Red-tails are very difficult to tell from young
Red- shoulders in the field, also the flight of Red- shouldered
is more rapid, buoyant and owl-like. The American Rough-leg
and the Ferruginois Rough- leg are slightly larger. Phillips
et al. (1964), "...it does not gather into flocks as does
swainsoni."
Intraspecific - Brown and Amadon (1968), "Adults and young
tend to be more heavily marked below" than other races.
Baird et al. (1905), "Adult. Similar to borealis, but
darker, with more rufous and blackish in the plumage."
The young Red-tails, according to Baird et al. (1955), of
the var. calurus have numerous heavy transverse spots on
the tibia while those of the var. borealis are almost
perfectly white.
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), Breeds from central interior Alaska (Circle,
Tanana River), Yukon, (Forty Mile), west-central Mackenzie
and Saskatchewan south to Baja California, Sonora, and
western New Mexico, ranging east to Colorado, Wyoming, and
Montana and to northeastern Manitoba, south-central Ontario,
central and eastern Quebec, Prince Edward Island, and Cape
Breton Island, Casual in Illinois, southern Ontario,
Mississippi, Pennsylvania, and New Jersey. Grinnell and
Miller (1944), Well-nigh universal: from most arid to rain-
iest belts; from below- sea- level "sinks" to at least 12,000
feet altitude on Sierra Nevada; on deserts and on most is-
lands. Has actually been found nesting under such extreme
conditions as are affordable in the following places: Colo-
rado desert; Mohave desert; Lava Beds National Monument,
Siskiyou County; Lake Tahoe; Humboldt County; Anacapa Island;
Santa Catalina Island; Santa Cruz Island. Breeding metro-
polis, however, seems to lie in Upper Sonoran and Transition
Life-Zones. Dawson (1923), Western North America, except
the coastal district of southeastern Alaska, from central
Yukon and western Mackenzie south to Cape San Lucas and cen-
tral America; east to the western borders of the Great
Plains and casually to Ontario. Gullian et al. (1959)
say that Red- tails are common spring and fall migrants in
Nevada but scarcer in July and in the winter. Bent (1937),
"From the western edge of the Great Plains westward. .. from
southeastern Alaska and central western Mackenzie southward
to Mexico."
•
Buteo jamaicensis ( con ' t . )
B. California distribution of the species
Dawson (1923), "Common resident of the widest distribution.
Breeds from Lower Sonoran deserts to the limits of Upper
Transition." Grinnell (1915), "Common resident almost through-
out the state. Recorded from deserts, islands, lowest
valleys and highest mountains, from most arid to rainiest
belts." Baird et al. (1905), "...stated to be common in
all parts of the state not destitute of trees, and to re-
side permanently wherever found, pairing only during the
breeding season." Small (1974), 'Common resident; small
numbers are transient. .. length of state; breeds in almost
any suitable habitat with cliffs or tall trees for nesting
or roosting." Bent (1937) reports Red- tails occurring on
the Farallons during migration.
C. California desert distribution
Willet (1951) calls calurus a permanent resident of the
southern California desert. Phillips et al. (1964) do not
list California desert distribution but do say that Red-
tails nest in desert areas in Arizona, using saguaros or
low shrubs for nest sites. Wauer (1964) says that the
cliffs at the canyon mouths of the Panamint Mountains and
the side washes provide nesting sites for the Red- tails.
They utilize the high cliffs and ledges. Hensley (1959)
reports Red- tails nesting in the Sonoran Desert.
D. Seasonal variations in distribution
AOU (1957), Winters from southwestern British Columbia to
southern Minnesota and south and southwest across its breed-
ing range to Guatemala and northern Nicaragua; east to
Louisiana. Brown and Amadon (1968), "In the more northern
parts of its range it is quite migratory. . .nevertheless,
many winter in areas that are often snowbound." Bent
(1937) says the Red-tail is migratory in its northern
range, leaving the Yellowstone Park area in the middle
of October and returning again in late March, early April.
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), Terrain affording food ordinarily
in the form of rodents, and nesting sites in trees or cliffs
more or less inaccessible to potential dispoilers. Perhaps
nearest ideal: interspersed woodland and open grassland,
the latter in predominance. Dawson (1923), "Possesses
great adaptability, so that it is able to maintain itself
as well upon the Colorado and Mohave deserts as upon the M
Buteo jamaicensis (con't.)
middle slopes of the Sierras and the jutting cliffs of
the boundless chaparral country. Baird et al. (1905)
published a report from Mr. Dresser who says in Texas they
prefer heavily timbered country. Wauer (1964) says Red-
tails are rarely observed above the pinon woodlands during
the colder winter days. Mader (1978; found Red- tails
nesting in flatlands, grasslands, woodland, mountainous
desert.
B. Altitudinal range
Grinnell and Miller (1944) and Dawson (1923), breeds up
to the limits of the Upper Transition zone and wanders in
to the Boreal. Wauer (1964) report a nest at 2500 feet in
the Panamint Mountains.
C. Home range size
Braun and Amadon (1968), "The nesting range of a pair varies
from about a third to two and a half square miles." Fitch
et al. (1946) reported territories of 80 to 200 acres in
the San Joaquin area of California. Most territories were
oval or circular. Frequently a ridge limited a range ex-
tension.
D. Territory requirements
Perch sites - Brown and Amadon (1968), "Night roosts in
winter are in thick conifers. High perches are favored.
May (1935) says they perch for hours at a time, usually
in a dead tree or on a mountain ledge. Fitch et al. (1946)
found Digger pines to be the most popular perch sites in
the San Joaquin area, favored because of their great heights
and open crowns. Live oaks were generally not suitable
due to the dense outer foliage.
Courtship and mating sites - Brown and Amadon (1968) des-
cribe courtship in the air, as do Grossman and Hamlet (1964),
It appears from these two references that part of the court-
ship takes place at the nest, during an extended construc-
tion period when the birds are very sensitive to dis-
turbance. Fitch et al. (1946) describe a pair soaring and
calling loudly during courtship. The male will often fly
above the female and dangle his legs near her. Flights
usually last from 5 to 10 minutes.
Nest sites - Dawson (1923), crannies or ledges of cliff
or high in trees made of sticks lined with bark strips or
grass. Knowlton (1909); "placed in a tree, usually 50 or
60 feet from the ground. Brown and Amadon (1968), "...are
often placed in commanding positions in trees, but in the
Buteo jamaicensis (con't.)
desert may be in cactus 12 or 15 feet from the ground,
occasionally on rock pinacles, ledges or even a steel
tower." Grossman and Hamlet (1964) state that Red- tails
nest in the highest trees they can find: 35 to 70 feet
from the ground. Phillips et al. (1964), "Common nest
sites are crotches of tall trees or saguaros." Wiley (1975)
found 71.7% of nests in sycamores, 17.0% in oaks, 7.5% in
Eucalyptus, and 3.8% on cliff faces in Orange County,
California. Sycamores were the most common tree.
Seidensticker and Reynolds (1971) found 747o of 55 nests
in cottonwood trees, 4 in Doublas fir, 3 on cliffs, 3 in
dead snaps, 2 in aspen, 1 in Engelmann spruce and 1 in
limber pine. Cottonwoods were the only common tall trees
growing on the river. Fitch et al. (1946) and others report
that old nest sites are reused.
E. Special habitat requirements
Brown and Amadon (1968) say that adequate perches and
nesting trees are vital. Usually they perch on dead snaps,
although in hot weather they may seek shade. Fitch (1946)
believes perch sites to be the most essential feature of
a territory.
F. Seasonal changes in habitat requirements
Brown and Amadon (1968) state that territories are still
defended in winter against other pairs of the same species.
V FOOD
A. Food preferences
Knowlton (1909), "It occasionally makes off with a meal of
young poultry, or a game bird... its food consists princi-
pally of mice and other small rodents. .. reptiles, frogs and
insects, and only rarely of poultry or game birds." Brown
and Amadon (1968), "The Red-tail sometimes kills a snake,
rabbit or ground squirrel." In winter they eat mostly mice
in some areas, also catch lizards and sometimes small birds.
Small and medium-sized rodents and rabbits are the staple
items. The Socorro Island race feeds on land crabs and
birds. In May (1935) there is a report on a study done by
the Bureau of Biological Survey which found in 850 stomach
samples taken in nearly all parts of the United States 86%
mammal remains, 12% poultry or game bird remains, 8% other
birds, 8% reptiles and 15% insects. Fitch et al. (1946)
found of 625 prey items; 23 species, the major area of which
were, 380 ground squirrels, 79 pocket gophers, 62 cottontails,
13 wood rats, 10 kangaroo rats and 8 chipmunks. They do cast
pellets and these generally do not contain bone, which is ^fe
digested, but consist of hair, feathers or scales. They I
describe prey items from various times of the year and local-
ities.
•
•
Buteo jamaicensis (con't.)
B. Foraging areas
Robbins et al. (1966), "...feeds in open country." Baird
et al. (1905), "It is said to generally descend upon its
prey from some fixed position, as a branch of a tree. It
is a cautious bird and rarely ventures near a house for
poultry except when the dwelling is isolated and near its
own haunts."
C. Foraging strategies
Brown and Amadon (1968), "Pairs fly from hunting perch to
hunting perch in their territories, not always together.
When leaving the nigh roost they may have a warm-up flight
of up to one hour before beginning to feed. More strikes
at prey are unsuccessful than successful. In some areas
most prey is sighted from a lookout, often a high one.
The hawk often smashes recklessly through small brush for
its prey. It also hunts on the wing, gliding low over
hillsides and swooping down." Baird et al. (1905) says
Red- tails rarely dart down to catch a prey while flying, and
after catching a prey they fly off with it a ways to eat
it. Snyder and Wiley (1976) discuss sexual differences
in food eaten by North American accipiters. Grier (1971),
"The change to alert posture in a relaxed bird that would
attack was very noticeable. . .changes of tail angle. The
time required for a bird to leave its perch. . .depend largely
on the birds familiarity with the situation." Snyder
(1975) determined that Red-tails choose the larger prey
item when given a choice of two. Fitch et al. (1946)
describe two methods of foraging; waiting on a high perch
and dropping upon a prey with a direct swoop, and quartering
back and forth in low flight to drop on an animal in the
open. The first method is most common.
D. Feeding phenology
Brown and Amadon (1968), "In winter in some areas it lives
almost exclusively on meadow mice (Micro tus) , especially
the young hawks of the year. It also takes medium or fairly
large birds, chiefly caught on the ground. Grossman and
Hamlet (1964) suggest that Red- tails feed more on birds
during the fall migration when many small birds are visible.
May (1935) reports that W. L. Finley (1905) says when the
Columbia River overflowed, a pair of Western Red- tails
fed their young on carp and catfish. May (1935) also has
a report from F. H. Chittenden (1911) that Red- tails eat
potato bugs at times. Snyder and Wiley (1976) discuss
breeding season food habits of North American accipiters
and the relationship between prey populations and timing
of breeding. Hofner (1974), ...it appears that males
Buteo jamaicensis (con't.)
occur as prey of Red- tailed Hawks exclusively during winter
and spring." Fitch et al. (1946) say that prey items are
clearly influenced by the season and what is available.
Hensley (1959) found the most active feeding times to be
8 to 9 a.m. and 5 p.m.
E. Energy requirements
Brown and Amadon (1968), "In captivity in winter a Red-
tail will eat about 135 grams per day." The adults often
bring more food to nestlings than they can eat. Snyder and
Wiley (1976) discuss the division of labor between sexes
in accipiters and the amounts of food required and also
feeding rates at nests with different brood sizes.
VI REPRODUCTION
A. Age at first breeding
Luttich et al. (1971) believe it takes 6 years from hatch-
ing for a Red- tail to produce a young.
B. Territorial behavior
Brown and Amadon (1968), Territories are defended even in
winter. Grossman and Hamlet (1964); After returning to
breeding grounds in late February or early March, they begin
to make sounds and movements around the nesting territory
of last year, becoming more beligerent in boundary disputes
as the days pass.
C. Courtship and mating behavior
Knowlton (1909) notes that Red- tails circle about in the
air chasing each other and high, shrill calls. Brown and
Amadon (1968); "...the pair soar about, screaming frequently,
the male often somewhat behind the female... the female
sometimes rolling over in mock combat and presenting her
talons. The male sometimes performs a series of shallow
dives, and flights may terminate by a series of dives end-
ing at a perch; or he may pull up from a dive to continue
soaring. The flights may occur at any time of year in
fine weather, but are regular only at the onset of breeding.
Mating follows such flights. Presumably courtship feeding
occurs." Conner (1974) reports an unusual addition to the
normal courtship flight of the Red- tail. A pair in Virginia
performed the typical dives and ascents as they swirled in
a thermal and then the male, while above the female, reached
down and grasped her back with its claws. The contact
lasted 2 seconds.
•
•
%
»
Buteo jamaicensis (con't.)
D. Nesting phenology
Dawson (1923), "February 15th-May 1st, according to lati-
tude and altitude; one brood." Brown and Araadon (1968),
"Nests may be built as early as January in regions where
incubation does not begin until March.: Phillips et al.
(1964) say that young hatch around April 9-12 on deserts
in Arizona. Snyder and Wiley (1976) state that a factor
contributing to early reproduction in some raptors preying
on mammals may be the susceptibility of their young to pre-
dation by other raptors. Wiley (1975) gives laying dates
in Orange County as from 5 March to 21 April, hatching
dates from 6 April to 23 May, fledging dates from 16 May
to 1 July. Seidensticker and Reynolds (1971): 1st egg
hatched 29 March, last brood fledged 20 June, whole season
in 1967 was 125 days. Mader (1978) says that Red-tails
began nesting in the Sonoran desert in late December through
February. Laying occurred from 25 February through 2 April.
Fledging centered around the last week in May and 1st week
in June. Luttich et al. (1971) report Red-tails first
appearing in their northern breeding range in early April
and departing by mid-October. The first incubation begins
during the second week in April.
E. Length of incubation period
Brown and Amadon (1968), 28-32 days, usually 30. Grossman
and Hamlet (1964), 34 days. Bent (1937), 28 days.
F. Length of nestling period
Brown and Amadon (1968), about 45 days. Grossman and Ham-
let (1964), about 6 weeks. Wiley (1975), "41 days," in
Orange County, California. In nests that were not disturbed
during the later part of the nesting stage fledging dates
averaged 47 days. Luttich et al. (1974) give a nestling
stage of 44 days. Fitch et al. (1946), 45 or 46 days.
G. Growth rates
Brown and Amadon (1968), "On its second day the chick is
very active when awake, bouncing around, flapping the wings.
At 6 or 7 days it pecks at prey. At 10 days the young
whistles back at its parent screaming above. At 16 days
feathers are appearing, the young become aggressive."
Grossman and Hamlet (1964); At 17 days their wing quills
appear, closely followed by... the tail." Fitch et al.
(1946), "At 16 days the nestlings begin to acquire feathers.
Within a month or more of age the young begin to flap and
stretch their wings..."
10
«
Buteo jamaicensis ( con ' t . )
H. Post-breeding behavior
Brown and Amadon (1968), "After leaving the nest the young
gradually learn to hunt." Grossmann and Hamlet (1964;
state that new- flying hawks are fairly inactive in summer
since they require little food for their bodies to maintain
normal temperatures. In the late summer they spend most
of their days and nights in the cool, shaded forest.
Snyder and Wiley (1976) say that long periods of fledgling
dependence are known for some raptors eating mainly mammals,
including Red- tails. Mader (1978) says that young may be
dependent on their parents for 30 to 70 days after fledging.
VII POPULATION PARAMETERS
A. Clutch size
Dawson (1923), 2 or 3, rarely 4, 5. White or pale bluish
white, lightly stained, spotted, blotched, or smeared with
reddish brown. Brown and Amadon (1968), 1 to 3, even 4,
with some geographical variation. Both sexes incubate,
although the female does most. Mader (1978) gives 2.32
eggs per nest. Luttich et al. (1971) give 2.1 eggs per
nest.
B. Fledging success
Brown and Amadon (1968) report that 38 eggs produced 16
fledglings in California, and in 1 year in Wisconsin, 48
young were produced in 27 nests. Wiley (1975) found overall
nest success in Orange County, California, to be 73.6%
and states that other reports ranged from 50% to 74%.
Seidensticker and Reynolds (1971) found fledging success
to be 1.7 + 0.2 per successful nest. Mader (1978) had 81%
of 42 nests successful. Luttich et al. (1971) reported 1.4
young fledged per hatched clutch.
C. Mortality rates per age class
Brown and Amadon (1968), "Young sometimes fall out of the
nest and die." Snyder and Wiley (1976) state that repro-
ductive losses early in the breeding cycle are generally
uncommon in North American accipiters. In 1971, a year
of bad drought and thus low food supply, many pairs failed
to lay or deserted eggs." Generally losses early in the
nestling season involved the runts of broods." There is
almost no loss of young late in the season. Wiley (1975)
reported 25% of the nests he was observing in Orange
County, California, failed before or during incubation,
75% failed during the nestling period. No young were fledged ^^
from 60.0% of the nests in that area. Land development and JH
farming disturbances were responsible for the high failure
i
11
Buteo jamaicensis (con't.)
rate. Luttich et al. (1971) consider an adult mortality
rate of 207o annually to be normal and believe a 1st year
rate of 51% is normal.
D. Longevity
Kennard (1975) lists the oldest banded Red- tail as 13 years
7 months
E. Seasonal abundance
F. Habitat density figures
Dawson (1923), "...after the American Kestrel, the Western
Red- tail is still the commonest hawk in California," Brown
and Amadon (1968), "In southern Wisconsin, nesting popula-
tions averaged 0.29 pairs per square mile in one year, 0.41
in another, only one- fifth as many as in optimum habitat
in California where breeding ranges maybe as little as..."
2 pairs per square mile. "A 37 square-mile tract in Michigan
had 2 nesting pairs in one year, but had 5 when checked a
year later. In Wyoming there were 12 pairs on. a 12 mile
square tract." Wiley (1975), in Orange County found dis-
tances between adjacent nests to be 150 m to 2.09 km (aver-
age, 0.84 km). Seidensticker and Reynolds (1971) found
internest distances to range from 3.1 miles to 0.2 mile
(average 1.3 miles). Luttich et al. (1971) in Alberta found
a habitat density of one pair per 2.7 square miles. Fitch
et al. (1946) found one pair to a half square mile in the
San Joaquin area.
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Brown and Amadon (1968) give a report of Scrub Jays (Aphelecoma)
annoying incubating adult Red- tails until they desert their
nests, then sucking the eggs dry. Blood Sucking flies
swarm in wet years and kill some downy young. Barney (1959)
reports a Red- tail dive-bombing a new born lamb and killing
it. Fitch et al. (1946) record one instance of a California
Jay robbing a nest.
B. Competition
Schnell (1968), "The winter ranges of the Rough-legged and
Red- tailed Hawk overlap to some extent across much of the
U.S. These species are congeneric, similar in size and
anatomy, and have roughly similar food habits."
%
12
Buteo jamaicensis (con't.)
C. Parasitism
Seidensticker and Reynolds (1971) found blood sucking
dipterous larva on almost all hawk nestlings, but could
attribute no mortality to these larvae. Fitch et al. (1946)
reported 7 nestlings being killed by blood-sucking flies
in the San Joaquin area.
IX STATUS
A. Past population trends
B. Present population status
Grinnell and Miller (1944), "Common and widespread; numbers
holding up, probably close to normal save in lowland area
thickly settled by humans, where marked reduction or even,
locally, elimination has taken place." Knowlton (1909)
remarks that Red-tails are deserving of protection since
they eat the destructive rodents from farmer's fields.
Seidensticker and Reynolds (1971), "Henny and Wight (in
press) reported Red-tailed Hawk populations in the U.S.
maintaining themselves." Luttich et al. (1971) believe
their population in Alberta is not maintaining itself.
C. Population limiting factors
May (1935) says that farmers have killed Red- tailed Hawks
because sometimes the hawks will acquire a taste for chick-
ens after finding and eating a few strays. The good they
do by eating rodents in fields far outweighs the bad.
Phillips et al. (1964), "...many are shot by the ignorant,
who suppose they are all killers of chickens." Fitch et al.
(1946) and others comment on nest desertion caused by in-
vestigators to the extent that this appears to be a real
problem. Fitch et al. (1946) say that food supply for the
young is not a limiting factor.
D. Environmental quality: adverse impacts
Seidensticker and Reynolds (1971) found no build up of
chloronated hydrocarbons in breast muscle of newly hatched
young or fledglings but there was a decrease in eggshell
thickness from pre-DDT levels.
E. Potential for endangered status
i
•
13
Buteo jamaicensis ( con ' t . )
XI LITERATURE CITED
American Ornithologists Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Baird, S. F., T. M. Brewer and R. Ridgway. 1905. A history
of North American Birds. Vol. 3. Little, Brown, and Co.,
Boston.
Barney, Merle D. 1959. Red- tailed Hawk killing a Lamb.
Condor 61:157-158.
Bent, Arthur Cleveland. 1937. Life histories of North Amer-
ican birds of prey. U.S. Nat. Mus. Bui. 167:1-409.
Braun, Leslie and Dean Amadon. 1968. Eagles, Hawks and
Falcons of the world. Vol. 2. McGraw-Hill Book Co.
New York. 945 pp.
Clevenger, G. A. and Aryan I. Roest. 1974. Cannibalism in
Red-tailed Hawk. Auk 91:639..
Canner, Richard N. 1974. A note on aerial courtship of Red-
tailed Hawks. Bird-Banding 45:269.
Craighead, Frank. and John Craighead. 1939. Hawks in the Hand.
Houghton Mifflin Company. Boston. 290 pp.
Dawson, W. L. 1923. The birds of California. Vol. 4. South
Moulton Co., San Francisco.
Fitch, Henry S., Freeman Swenson and Daniel F. Tillotson. 1946.
Behavior and Food Habits of the Red-tailed Hawk. Condor
48:205-237.
Friedmann, H. 1950. The birds of North and Middle America.
Part 11. United States Natl. Mus. Bui. 50.
Grier, James W. 1971. Pre-attack posture of the Red-tailed
Hawk. The Wil. Bui. 83:115-123.
Grinnell, Joseph. 1915. A distributional list of the birds
of California. Pacific Coast Avifauna No. 11.
Grinnell, Joseph and Alden H. Miller. 1944. The distribution
of the birds of California. Pacific Coast Avifauna, No.
27. 608 pp.
Grossman, Mary Louise and John Hamlet. 1964. Birds of prey
of the world. Clarkson N. Potter, Inc. , New York. 496 pp.
14
Buteo jamaicensis ( con ' t . )
Gullion, Gordon W. , Warren M. Pulich and Fred G. Evenden. 1959.
Notes on the occurrence of birds in southern Nevada. Condor
61:278-297.
Hafner, John C. 1974. Seasonal predation on moles by the
Red- tailed Hawk. Condor 76:225.
Hagar, Donald C. 1957. Nesting populations of Red- tailed
Hawks and Horned Owls in central New York state. Wil. Bui.
69:263-272.
Hardy, Ross. 1939. Nesting habits of the Western Red- tailed
Hawk. Condor 41:79-80.
Hensley, M. Max. 1959. Notes on the nesting of selected
species of birds of the Sonoran Desert. Wil, Bui. 71:
86-92.
Hubbard, John P. 1965. The summer birds of the forests of the
Megal Ion Mountains, New Mexico. Condor 67:404-415.
Kennard, John H. 1975. Longevity records of North American
birds. Bird-Banding 46:55-73.
Kilham, Lawrence. 1964. Interspecific relations of crows and
Red- shouldered Hawks in mobbing behavior. Condor 66:247-
248.
Knowlton, Frank H. 1909. Birds of the World. Henry Holt and
Co., New York. 873 pp.
Luttich, Stuart H. , Lloyd B. Keith and J. D. Stephenson. 1971.
Population dynamics of the Red- tailed Hawk (Buteo jamaicensis)
at Rochester, Alberta. Auk 88:75-87.
Mader, William J. 1978. A comparative nesting study of Red-
tailed Hawks and Harris Hawks in southern Arizona. Auk
95:327-337.
May, John Bichard. 1935. The hawks of North America. National
Association of Audubon Societies, New York. 140 pp.
Mayr, Ernst and Lester Short. 1970. Species taxa of North
American birds. Publication of the Nuttall Ornithological
Club, No. 9. Cambridge.
Orians, Gordon and Frank Kuhlman. 1956. Red- tailed Hawk and
Horned Owl Populations in Wisconsin. Condor 58:371-385.
Peterson, R. T. 1961. A field guide to Western birds. 2nd
Edition. Houghton Mifflin Co., Boston, 366 pp.
•
15
Buteo jamai cens is (con't.)
Phillips, Allan, Joe Marshall and Gale Monson. 1964. The birds
of Arizona. Univ. of Arizona Press, Tucson. 212 pp.
Robbins, C. S. , B. Bruun and H. S. Zim. 1966. Birds of North
America. Western Publ. Co., Wisconsin. 340 pp.
Schnell, Gary D. 1968. Differential habitat utilization by
wintering Rough- legged and Red- tailed Hawks. Condor 70:
373-377.
Seidensticker, John C. and Harry V. Reynolds. 1971. The
nesting, reproductive performance, and chlorinated hydro-
carbon residues in the Red- tailed Hawk and Great Horned
Owl in south-central Montana. The Wil. Bui. 83:408-418.
Small, Arnold. 1974. The birds of California. Winchester
Press, New York. 310 pp.
Snyder, Noel F. R. and James W. Wiley. 1976. Sexual size
dimorphism in hawks and owls of North America. Ornitholo-
gical Monog. No. 20. Am. Ornith. Union.
Snyder, Rowl. "1975. Some prey preference factors for a Red-
tailed Hawk. Auk 92:547-552.
Stahlecker, Dale W. and A. William Alldredge. 1976. The
impact of an underground nuclear fracturing experiment
on cliff -nesting raptors. Condor 88:151-154.
Wauer, Roland H. 1964. Ecological distribution of the birds
of the Panamint Mountains, California. Condor 66:287-301.
Wiley, James. 1975a. The nesting and reproductive success of
Red- tailed Hawks and Red- shouldered Hawks in Orange County,
California, 1973. Condor 77:133-139.
Wiley, James W. 1975b. Three adult Red-tailed Hawks tending
a nest. Condor 77:480-482.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. No. 6. 39 pp.
•
RED-WINGED BLACKBIRD
Agelaius phoeniceus
TAXONOMY
A. Type description
Agelaius phoeniceus nevadensis - AOU (1957), A. p. nevadensis
Grinneli, Proc. Biol. Soc. Washington, 27, May IT, 1914, p.
107. (Quinn River Crossing, Humboldt County, Nevada.)
Aeglaius phoeniceus aciculatus ^ AOU (1957), A. p. aciculatus
Mailliard, Condor, 17, no. 1, Jan. 30, 1915, p. 13. (Isabella,
Kern County, California.)
Agelaius phoeniceus sonoriensis - AOU (1957), A. p_. sonoriensis
Ridgway, Man, North Amer. Birds, 1887, p. 370. ( Southern
California and Arizona to Mexico = Old Camp Grant, lower San
Pedro River, Arizona.)
B. Current systematic treatments
AOU (1957) considers A. phoenicens a member of the Order
Passeriformes and recognizes 14 subspecies. It is in the
Family Icteridae.
Mayr and Short (1970) say that a study is needed on the
continent wide variation of this species. Phillips et al.
(1964) publish a new spelling for sonoriensis which they
say is correct; sonorensis.
C. Synonomies of scientific nomenclature
A. p_. nevadensis - Grinneli (1944), A. gubernator, part;
A. p. neutralis, A. p. calif ornicus, A. p. aciculatus, A.
£. fortis, A. p. mailliardorumr"
A. p_. sonorensis - Grinneli (1944), A. gubernator, A. p_.
Tongriostris, A. £. neutralis, A. £. thermophilus.
D. Synonomies of vernacular nomenclature
A. p. nevadensis - Grinneli (1944), Crimson- shouldered
Blackbird, Bicolored Blackbird, San Diego Redwing, California
Bi-colored Blackbird, Nevada Redwing, Kern Red-winged Black-
bird, Great Basin Red-winged Blackbird, Thickbilled Red-winged
Blackbird.
A. £. aciculatus - Grinneli (1944), Kern Red-winged Blackbird.
A. £. sonoriensis - Grinneli (1944), Red- shouldered Blackbird,
Red-winged Blackbird, Sonoran Redwing, San Diego Redwing.
Agelaius phoeniceus (con't.)
II DESCRIPTION
A. External morphology of adults
A. p_. sonoriensis - Dawson (1923), Plumage glossy black,
Tesser wing coverts red; middle of coverts ochraceous orange
(male in spring). Female: general plumage streaked dusky
and white; above bordered with dusky and grayish and dull
ochraceous; below heavily streaked or striped dusky and white,
clearing on chin and upper throat. There may be faint
bluish or greenish reflections in the back of the male.
Bill and feet are black. The middle coverts of the male
which are largely hidden are ochraceous buff to ochraceous
tawny, often shading on tips to whitish.
A. p_. nevadensis - Dawson (1923), in shape of bill and
general characters closely similar to sonoriensis; male
scarcely distinguishable, but female conspicuously darker
colored on account of the great relative breadth of the black
streaking both above and below.
A. £. aciculatus - Dawson (1923), similar to A. p_. neutralis,
But of larger size, feet averaging somewhat larger, but
chiefly characterized by a longer and more slender bill
than any other form of this genus in the United States.
Ridgway (1915) provides a key to the subspecies of Red-wings.
B. External morphology of subadult age classes
Dawson (1923) only gives a description for the immature
age classes for A. £. neutralis. Immature male: like adult
male in autumn, But with strong increase of marginal edgings
of ochraceous; markings heavier above, lighter below, but
only throat, crissum, and tail immaculate; the lesser wing
coverts orange or tawny with skirtings of black; middle
coverts entirely black, tipped with buffy white. Increasing
age is marked by increasing redness of the lesser wing
coverts, so that only the older males achieve spectrum red-
ness. Immature female: like adult female and not certainly
di s tingui shabl e .
C. Distinguishing characteristics
Interspecific - Robbins et al. (1966), The red- shouldered
male can be confused only with the western Tricolored Black-
bird.
<
i
k Agelaius phoeniceus (con't.)
Intraspecific - A. p. sonoriensis - Dawson (1923), similar
to A. p_. neutralTs but male slightly larger and with a more
slender bill. The adult female lighter with streaks more
strongly contrasted above, those of lower parts rather
narrower and not so dark, the upper parts more extensively
dusky. Bent (1928), of the slender-billed nevadensis-
caurinus chain. Bill longer and more slender than nevadensis.
Female is lightest of California races.
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) - A. phoeniceus : Northwestern British Columbia,
southeastern Yukon, central Mackenzie, northern Saskatchewan,
north-central Manitoba, northern Ontario, southern Quebec,
Prince Edward Island, and central Nova Scotia south to southern
Baja California, Costa Rica, western Cuba, the Isle of Pines,
and the northern Bahamas.
A. £. nevadensis - AOU (1957), Breeds from central southern
and southeastern British Columbia (Kamloops Newgate) south
through central Washington (Conconully, North Dalles), northern
Idaho (Coeur d'Alene, Lewiston), eastern Oregon (Gateway,
f Prospect), and central northern and eastern California
(Seiad Valley, Yosemite, Little Lake) to southeastern Calif-
ornia (Victorville, Death Valley) and southern Nevada (Ash
Meadows) .
A. p_. aciculatus - AOU (1957), Breeds in the mountain valleys
of east-central Kern County, south-central California (Bod-
fish, Isabella, Weldon, Onyx).
A. d_. sonoriensis - AOU (1957), Resident from southeastern
California (Indio), southern Nevada (opposite Fort Mohave,
Arizona), central western, central, and southeastern Arizona
(Fort Mohave, Wikieup, Safford) south to northeastern Baja
California (Colorado Delta) and northern Sonora.
B. California distribution of the species
A. p_. nevadensis - Grinnell (1944), Breeds from Modoc Plateau,
west to Shasta Valley and upper Klamath River drainage and
in western edge of Great Basin south through Mono and Inyo
Counties to Owens Valley; also disconnectedly on the Mohave
Desert to the Mohave River, San Bernardino County. Occurs
along some stream courses in the Sierra Nevada and Cascade
Mountains; on the Pacific slopes of these mountains at middle
levels. Grinnell (1915), common resident in suitable parts
of Modoc and Inyo areas. Dawson (1923), The plateau region
of northeastern California and the eastern slopes of the
Sierras south to Lane Pine.
Agelaius phoeniceus (con't.)
A. p_. aciculatus - Grinnell (1944), In nesting season,
restricted area in the mountain valleys of east-central
Kern County. Life-zone, Upper Sonoran. Dawson (1923),
east-central Kern County.
A. £. sonoriensis - Grinnell (1944), Colorado River Valley
"From Nevada line to Mexican border and irrigated parts of
Imperial and Coachella Valleys north and west to vicinity
of Indio, Riverside County. Dawson (1923), Resident in the
Imperial Valley, on the Colorado Desert west to Mecca, and
in the valley of the Colorado River north to Needles.
Bent (1958), southeastern California.
C. California desert distribution
A. p_. nevadensis - Grinnell (1944), through Inyo area to
Owens Valley; also disconnectedly on the Mohave Desert, to
the Mohave River, San Bernardino County. Has been reported
in Inyo, Mono, Los Angeles, San Bernardino, Kern and River-
side Counties. Willett (1951), resident of damp localities
on Mohave Desert, south of Mohave River.
A. £. aciculatus - Grinnell (1944), restricted area in the
mountain valleys of Kern County. A single specimen of
doubtful identity was taken in Riverside County. Willett ^g
(1951) doesn't list this subspecies as a resident of southern ^
California deserts. Bent (1958), east-central Kern County,
California, in the Walker Basin.
A. p_. sonoriensis - Grinnell (1944), in irrigated parts of
Tmperial and Coachella Valleys, north and west to the vicinity
of Riverside County. Northwestern record station, 7 miles
west of Indio, Riverside County. Stragglers reported from
San Bernardino and San Diego Counties. Willett (1951),
Resident Colorado River, Imperial, and Coachella Valleys.
D. Seasonal variations in distributions
A. p. nevadensis - Grinnell (1944), Move southward and west-
ward from breeding range. Fairly common in winter, west of
the Sierra Nevada. Found in winter in coast districts of
San Francisco Bay southward.
A. £. aciculatus - Grinnell (1944), moves away from nesting
grounds m winter.
A. p. sonoriensis - Grinnell (1944), There is much local
shifting of populations in winter and some wandering to
points outside the breeding range takes place.
Meanley (1965) reports that several geographic races may
roost together after the breeding season.
•
Agelaius phoeniceus (con't.)
IV HABITAT
A. Biotopic affinities
A._p_. nevadensis - GrinneLl (1944), Life-zones in summer,
Tower Sonoran, Upper Sonoran, Transition. In summer found
around fresh-water marshes and margins of ponds, lakes and
slow moving streams grown with dense sedges, cattails, wil-
lows.
A. p. aciculatus - Grinnell (1944), Marshy meadows and lagoons
wnich support growth of cattails and sedges.
A. £. sonoriensis - Grinnell (1944), Life-zone, Lower Sonoran.
For nesting, willow thickets, patches of tules and cattails,
crowns of tall cottonwoods and the non-native tamarisk
trees in the vicinity of water.
B. Altitudinal range
C. Home range size
Orians (1973) found territories varying in size from 1,022
square m to 4,343 sq. m, with a mean of 2,361 square m.
D. Territory requirements
Perch sites - Meanley (1965) discusses Redwing roosts, say-
ing they form roosts during every month of the year. After
the breeding season they congregate mainly in wetland habi-
tat. A source of water is important at a roost site.
Redwings use dry sites as well as wetlands for roosting
though; deciduous thickets, coniferous stands, canebrakes.
Courtship and mating sites - Bent (1958) considers Redwings
polygamous, as do Goddard and Board (1967) and others.
Nest sites - Bent (1958), "...nests being placed low down
in tufts of grass, in marsh vegetation, in various shrubs
near water, or as high as 5 to 10 feet from the ground in
willows." He also reports them in tules. Peterson (1961)
Breeds in marshes, swamps, hayfields. Nests are built in
tules, reeds, deep grass, bush. Holcomb (1966) in a study
of Redwings in Toledo, Ohio, found them using a great variety
of nest sites. 53% were in goldenrod, but others were found
in dogwood, blackberry, elm, oak, willow and grapevine.
Stowers et al . (1968) report that predominant sites in
Florida are small shrubs or grasses in marshy areas or up-
land fields. Peek et al . (1972) found that females show a
strong attachment to nest site. Brown and Goertz (1978)
I found nests in northern Louisiana in 30 species of plants.
Agelaius phoeniceus (con't.) g~
Major plants used for nest support were buttonbush, willow,
rush, bulrush, cattail, common alder, sweetgum, dock and
grasses. Ratios of plant use changed from one habitat
to another, as did plant occurrence. Holcomb and Twiest
(1968) discuss nest site selection in upland nesting Red-
wings in Ohio.
E. Special habitat requirements
Phillips et al. (1964) say that Redwings are adaptable and
where there are no cattails, will nest in willows, mesquite,
or elderberry. Francis (1971) reports higher nest success
in relatively sturdy shrubs than in herbs and grasses, but
species and growth stage have relatively little effect.
Height did not seem to be significant in his study. Coccamise
(1977) found no relation between nest success and species
of shrub used for nesting. Robertson (1972) believes that
the commencement of nesting is partially dependent on when
vegetation in a particular area becomes suitable. Holcomb
and Twiest (1968) found Redwings to adapt to nesting in a
variety of habitats.
F. Seasonal changes in habitat requirements
Meanley (1965) reports that fall roosts are of several m
types: (a) those used for short stops by in transit birds; ^^
(b) late summer roosts that continue to be used throughout
the fall and sometimes into winter; (c) roosts formed in
the fall and used until early spring.
V FOOD
A. Food preferences
Bent (1958) reports they eat alfalfa weevils, pea aphids
(Macro siphum pisi) , and peach aphids (Myzus persicae) .
Goddard (1969) in a study done in Oklahoma found that 93%
of Redwings examined in the fall and winter had eaten grain
sorghum, 75% had eaten ragweed, 36% insects, 36% Johnson
grass, and lower percentages of about 12 other species.
Beasley and Carothers (1974) reported Redwings eating young
leopard frogs and pursuing mice but not being able to catch
them. Orians (1973) found Redwings eating primarily noctuid
larvae in Costa Rica in July. Meanley (1961) found dotted
smartweed to make up 38% of the total volume in Redwing
stomach sample taken after the breeding season in a fresh
water marsh, wild rice 24%. corn 12%, and Walter's Millet
11%. Dolbeer et al. (1978): "Corn (38%) and weed seeds
(36%) were the dominant foods for redwings."
i
t
Agelaius phoeniceus (con't.)
B. Foraging areas
Orians (1973) studied Redwings in Costa Rica that foraged
in local marshes and fields. Cattails had few insects and
were rarely used as foraging areas. Meanley (1961) did a
study on food of Redwings feeding in a fresh water marsh.
Dolbeer et al. (1978) found daily foraging areas to vary
primarily in response to weather. Redwings were commonly
recorded in soybean fields and corn fields.
C. Foraging strategies
Beasley and Carothers (1974) call Redwings opportunistic
generalists able to use several food sources and forage by
various means.
D. Feeding phenology
Orians (1973) reported nestling blackbirds being fed 89.9%
spiders, orthopterans, and lepidopteran larvae. Seasonal
differences in food fed to young were insignificant. Meanley
(1961) noted Red-wings moving into a marsh to feed as the
wild rice developed, at the end of the breeding season.
During the breeding season they fed more on corn. Dolbeer
et al. (1978) recorded increased use of feedlots for feeding
as winter progressed.
E. Energy requirements
Brenner (1966) found mean existence energy requirements to
be 24.8 kcal/bird-day. "The existence energy requirements
increased from a mean of 25.8 kcal/bird-day at 15 hours of
light and 21 C to a mean of 45.5 kcal/bird-day at 9 hours
of light and 11 C. The gross energy intake and excrement
energy loss also increased as the photo-period and temper-
ature decreased. The variation in photoperiod and temper-
ature did not influence significantly the efficiency of
metabolism by the birds." Orians (1973) reported nestlings
being fed at the rate of 1.7 items/nestling/hour in 1966,
and 2.2 items/nestling/hour in 1967, in a tropical marsh.
Dunson (1965) discusses physiological aspects of the onset
of molt. Meanley and Bond (1970; found Redwings in Maryland
to undergo their most critical molt period during the time
of greatest food availability after breeding. Brenner (1967)
discusses fat deposits in Redwings at various times of the
year. He found average temperature to affect the breeding
cycle, and higher fat deposits present at the beginning
of breeding.
Agelaius phoeniceus (con't.)
VI REPRODUCTION
A. Age at first breeding
Holcomb (1974a) found brood patches on first year females.
Meanley and Bond (1970) believe that first year males usually
do not breed and first year females usually do.
B. Territorial behavior
Peek (1971) says that trespass by conspecific males upon
occupied territory reaches a peak in mid-April and then
decreases significantly. Territorial males pay little
attention to immature males. Muted and epaulet-colored
males were unable to maintain territories. Early in the
season intraspecific defense is important to achieve spacing
of breeding populations, later interspecific defense and
protection of female are important. Strosnider (1960)
observed a male defending his territory with "song spread",
"bill tittling," and attack when necessary. Each female
defends a small area around her nest. Nero (1963) describes
Yellow-headed Blackbird territorial behavior and compares
it with Redwing behavior. Robertson (1972) discusses
various aspects of territorial behavior in detail. Nero
and Emlen (1951) found territorial boundaries to be sharply
defined but not paying particular attention to vegetation
or terrain. Males were found to defend their territory
against other males, alien females and fledged young.
Trespassing by males rarely occurred. Females generally
restricted their movements to a fraction of their mate's
territory.
C. Courtship and mating behavior
Goddard and Board (1967) describe courtship as beingning
when a female enters a male's territory. Coccamise (1977)
"...aggressive interactions between females play an important
role in the mating system..." Strosnider (i960) reported
a male mated with three females. Nero (1963) compares
Redwing behavior with Yellow-headed Blackbird behavior.
Orians (1961) mentions that males chase females during
courtship. Blakley (1976) suggests that the staggered
breeding of females among polygynous Redwings may avoid
problems. Younger females are more often polygynous.
D. Nesting phenology
Goddard and Board (1967) found the first nest in their
study area in Oklahoma on 22 April. Redwings are persistent
renesters. Orians (1973) noted 6 young already fledged ^
on 6 July, 1966, in Costa Rica. Nest construction had begun m
t
Agelaius phoeniceus (con't.)
on 12 June. There were still some nests under construction
on 20 June. Brown and Goertz (1978) found active nests
with eggs from 7 April to 2 August in northern Louisiana.
Robertson (1972) reported nest activity to begin 17 April
in marshes and 8 May in uplands. Young (1963) says that
Blackbirds are persistent renesters after failure. Holcomb
and Twiest (1968) report nest building to take 3 days.
Orians (1961) says territorial defense begins in January
in north-central California. In mid-March males begin to
feed in the area and by April they spend the bulk of the
day in their territories. Faukhauser (1964) found all red-
wings at nests with eggs before May 21 that did not raise
a brood successfully renested. Three cases of second
nesting were found. Dolbeer (1976) in a study done in Ohio
found the first eggs laid on 30 April and the last young
fledged on 6 August.
E. Length of incubation period
Holcomb (1974b) - 11 days. Orians (1973) - 11 to 13 days.
Brown and Goertz (1978) - 11 to 13 days.
F. Length of nestling period
k G. Growth rates
Holcomb and Twiest (1970) did a detailed study on growth
of nestlings. Males grew somewhat faster than females.
Sex can generally be determined by weight by day eight.
H. Post-breeding behavior
Orians (1973) reports Redwings in Costa Rica forming large
flocks during the non-breeding season and roosting in dense,
herbaceous vegetation. During the last 2 weeks of September
the adults were in full molt and during this period terri-
torial behavior was reduced to a minimum. During December
territorial behavior increased and there was sexual chasing.
Orians (1961) says Redwings are highly gregarious in the
non-breeding season but that sexes are often segregated.
Dolbeer et al. (1978) in a study in Tennessee found redwings
to use a post-breeding roost from early November to early
March.
VII POPULATION PARAMETERS
A. Clutch size
Bent (1958) - 4 to 5. Peterson (1961) - 3 to 5. Goddard
and Board (1967) 1 to 5. Orians (1973) - 2 to 4, with a
fc mean of 2.96 in 1966 and 2.67 in 1967. Brown and Goertz
W (1978) - 3.82 average, range 3 to 5. Holcomb (1971) dis-
cusses the effect of artificial manipulations on clutch size,
10
Agelaius phoeniceus (con't.)
B. Fledging success
Goddard and Board (1967) found young fledged from 65 of
243 active nests, but they had removed eggs and young from
these nests. They had .87 young fledge per early nest and
.69 per later nest. Orians (1973) recorded fledging success
for 18 nests in a tropical marsh: 13 fledged 3, 3 fledged 2,
and 2 nests fledged 1 each. In 1967 only 20 out of 93
nests fledged any young. Brown and Goertz (1978) reported
2.77 young fledged per nest from 65 successful nests over
an eight-year period. Dolbeer (1976) reported 5.5 young
fledged per territory and 13.3 per hectare annually. Knox
and Stickley (1974) discuss hand rearing of Redwings.
C. Mortality rates per age class
Goddard and Board (1967) say that early nests tend to be
more successful than nests started after 1 June. Many of
the nests initiated after this were renesting. Holcomb
(1966), "Young (1963) found that mortality. .. is greatest in
nestlings. Nestlings begin crowding each other at 8-11 days
of age..." and some are crowded out of the nest. "One factor
influencing age specific mortality in nestlings may be their
ability to grasp and balance. Robertson (1972) found morta-
lity rates in nestlings to be uniform up to day 19, when
they dropped significantly. Starvation was the single
factor most responsible for mortality of nestlings. Young
(1963) discusses causes of egg and nestling mortality. Most
eggs and young were lost to predation. Faukhouser (1967)
did a study of band returns and found approximately 50%
survival per year. Coccamise (1976) found that nestling
mortality increased with age.
D. Longevity
Kennard (1975) found the oldest banded Redwing to be 14
years, 5 months.
E. Seasonal abundance
Meanley (1961) reports thousands of Redwings invading a
tidal marsh immediately after the breeding season. Meanley
(1964): "As the redwings approach the completion of molt
in the latter half of September, they begin to move toward
the wintering grounds," dispersing over a wide area.
F. Habitat density figures
Robertson (1972) believes that habitat density is kept at
low levels due to territoriality. Density was 10 times
higher in marsh than in upland habitat in his study.
Whitmore (1977) discusses habitat partitioning of redwings
and other passerines.
11
t
Agelaius phoeniceus (con't.)
Ill INTERSPECIFIC INTERACTIONS
A. Predation
Orians (1973) reported 47 young taken during 524 potential
nestling days in a tropical marsh. Snakes were seen taking
young but he believes that few are taken by avian predators.
Robertson (1972) did a study comparing nesting success in
upland vs. marsh habitat and found less predation in marshes,
but that predation was the most common cause of nest failure.
Young (1963) found the most common loss of eggs and young
to be predation. Coccamise (1976) gives a detailed discus-
sion of predation. He found predation while the prime cause
of mortality was less in more dispersed nests.
B. Competition
Bent (1958) does not discuss competition but tells of Red-
wings attacking ravens, magpies and even sparrows. Goddard
(1969) reported Redwings eating grain sorghum in large
quantities and damgaing farmer s crops. The Redwings com-
peted with ducks for sorghum. Burtt and Giltz (1977) report
that starlings, grackles, Redwings and Brown-headed Cowbirds
roost together in the non-breeding season.
C. Parasitism
Friedmann et al. (1977) report most records of parasitism
by the cowbird are from the central U.S. and Canada. 2.3%
of the Red-wing clutches in the Western Foundation of Verte-
brate Zool. are parasitized. Brown and Goertz (1978) found
12 of 755 nests parasitized by the Brown-headed Cowbird.
IX STATUS
A. Past population trends
B. Present population status
Goddard and Board (1967) attribute the upward trend in the
number of Red-winged Blackbirds nesting in Oklahoma to the
increased number of farm ponds and flood dams.
C. Population limiting factors
D. Environmental quality: adverse impacts
Graber et al. (1965) discuss the adverse impact on nesting
Redwings in a field sprayed with dieldrin. Dolbeer et al .
(1978) found Redwings to have little impact on agricultural
k crops. Tanner and Tolbert (1975) discuss the effect of
f chlorinated hydrocarbons on Redwing eggshells.
E. Potential for endangered status
12
Agelaius phoeniceus (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Beasley, L. E. and S. W. Carothers. 1974. Unusual feeding
habits in two species of blackbirds. Wil. Bull. 86:478-479.
Bent, A. C. 1958.. Life histories of North American black-
birds, orioles, tanagers and their allies. Smithsonian
Institution. U.S. Nat. Mus. Bui. No. 211. Washington.
Blakely, N. R. 1976. Successive polygyny in upland nesting
Red-winged Blackbirds. Condor 78:129-133.
Brenner, F. J. 1966. Energy and nutrient requirements of the
Red-winged Blackbird. Wil. Bui. 78:111-120.
Brenner, F. J. 1967. Seasonal correlations of reserve energy
of Red-winged Blackbird. Bird-Banding 38:195-211.
Brenner, F. J. and W. F. Malin. 1965. Metabolism and survival
time of the Red-winged Blackbird population. Wil. Bui.
77:282-289.
Brown, B. T. and J. W. Goertz. 1978. Reproduction and nest
site selection by Red-winged blackbirds in north Louisiana.
Wil. Bui. 90:261-270.
Burtt, H. E. and M. L. Giltz. 1977. Seasonal directional
patterns of movements and migrations of Starlings and black-
birds in North America. Bird-Banding 48:259-271.
Coccamise, D. F. 1976. Nesting mortality in the Red-winged
Blackbird. Auk 93:517-534.
Coccamise, D. F. 1977. Breeding success and nest site character-
istics of the Red-winged Blackbird. Wil. Bui. 89:396-403.
Davis, D. E. 1972. Stability of a population of male Red-winged
Blackbirds. Wil. Bui. 84:349-350.
Dawson, W. L. 1923. The birds of California. Vol. 1. South
Moulton Co., San Francisco.
Dolbeer, R. A. 1976. Reproductive rate and temporal spacing
of nesting of Red-winged Blackbirds in upland habitat.
Auk 93:343-355.
13
Agelaius phoeniceus (con't.)
Dolbeer, R. A., P. P. Woronecki, A. R. Stickley and S. B. White.
1978. Agricultural impact of a winter population of black-
birds and starlings. Wil. Bui. 90:31-44.
Dunson, W. A. 1965. Physiological aspects of the onset of
molt in the Red-winged Blackbird. Condor 67:265-269.
Faukhauser, D. P. 1964. Renesting and second nesting of
individually marked Red-winged Blackbirds. Bird-Banding
35:119-121.
Faukhauser, D. P. 1967. Survival rates in Red-winged Black-
birds. Bird-Banding 38:139-142.
Francis, W. J. 1971. An evaluation of reported reproductive
success in Red-winged Blackbirds. Wil. Bui. 83:178-185.
Friedmann, H. , L. F. Kiff and S. I. Rothstein. 1977. A further
contribution to knowledge of the host relations of the para-
sitic cowbirds. Smithsonian Contrib. Zool. No. 235. 75 pp.
Goddard, S. V. 1969. Fall and winter food habits of Red-winged
Blackbirds and Brown-headed Cowbirds in western Oklahoma.
Wil. Bui. 81:336-337.
Goddard, S. V. and V. V. Board. 1967. Reproductive success
of Red-winged Blackbirds in north-central Oklahoma. Wil.
Bui. 79:283-289.
Grabar, R. R. , S. L. Wunderle and W. N. Bruce. 1965. Effects
of a low-level dieldrin application on a Red-winged Black-
bird population. Wil. Bui. 77:168-174.
Grinnell, J. 1915. A distributional list of the birds of
California. Pacific Coast Avifauna. No. 11, 217 pp.
Grinnell, J. 1928. A distributional summation of the ornithology
of lower California. Univ. of Calif., Berkeley.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna. No. 27.
608 pp.
Helms, C. W. 1962. Red-winged Blackbird killing a Sharp- tailed
Sparrow. Wil. Bui. 74:89-90.
Holcomb, L. C. 1966. Red-winged Blackbird nestling development.
Wil. Bull. 78:283-288.
Holcomb, L. C. 1971. Nest building and egg-laying by Red-winged
Blackbirds in response to artificial manipulations. Auk
88:30-34.
14
Agelaius phoeniceus (con't.)
Holcomb, L. C. and G. Twiest. 1968. Ecological factors affect-
ing nest building in Red-winged Blackbirds. Bird-Banding
39:14-22.
Holcomb, L. C. and G. Twiest. 1970. Growth rates and sex
ratios of Red-winged Blackbirds nestlings. Wil. Bui. 82:
294-303.
Holcomb, L. C. 1974a. The question of possible surplus females
in breeding Red-winged Blackbirds. Wil. Bui. 86:177-179.
Holcomb, L. C. 1974b. Incubation constancy in the Red-winged
Blackbird. Wil. Bui. 86:450-460.
Kennard, J. H. 1975. Longevity records of North American
birds. Bird-Banding 46:55-73.
Knox, C. J. and A. R. Stickley. 1974. Breeding Red-winged
Blackbirds in captivity. Auk 91:808-816.
Knowlton, F. H. 1909. Birds of the World. Henry Holt & Co.,
New York. 873 pp.
Mayr, E. and L. Short. 1970. Species taxa of North American
birds. Publication of the Nuttal Ornithological Club, No.
9. Cambridge.
Meanley, B. 1961. Late-summer food of Red-winged Blackbirds
in a fresh tidal-river marsh. Wil. Bui. 73:36-40.
Meanley, B. 1964. Origin, structure, molt, and dispersal of
a late summer Red- winged Blackbird population. Bird-Banding
35:32-38.
Meanley, B. 1965. The roosting behavior of the Red-winged
Blackbird in the southern United States. Wil. Bui. 77:
217-228.
Meanley, B. and G. M. Bond. 1970. Molts and plumages of the
Red-winged Blackbird with particular reference to fall
migration. Bird-Banding 41:22-27.
Nero, R. W. 1963. Comparative behavior of Yellow-headed Black-
bird, Red-winged Blackbird and other Icterids. Wil. Bui.
75:376-413.
Nero, R. W. and J. T. Emlen, Jr. 1951. An experimental study
of territorial behavior in breeding Red-winged Blackbirds.
Condor 53:105-116.
Orians, G. H. 1961. The ecology of blackbird (Agelaius) social ■
systems. Ecol. Monog. 31:285-312. ^
15
Agelaius phoeniceus (con't.)
Orians, G. H. 1973. The Red-winged Blackbird in Tropical
marshes. Condor 75:28-42.
Peek, F. W. 1971. Seasonal change in the breeding behavior
of the male Red-winged Blackbird. Wil. Bui. 83:383-395.
Peek, F. W. , E. Franks and D. Case. 1972. Recognition of
nest, eggs, nest site, and young in female Red-winged
Blackbirds. Wil. Bui. 84:243-249.
Peterson, R. T. 1961. A field guide to western birds. 2nd
Edition. Houghton Mifflin Co., Boston, 366 pp.
Phillips, A., J. Marshall and G. Monson. 1964. The birds of
Arizona. Univ. of Ariz. Press, Tucson. 212 pp.
Rand, A. L. 1961. Some size gradients in North American birds.
Wil. Bui. 73:46-56.
Ridgway, R. 1915. A manual of North American birds. Fourth
Edition. J. B. Lippincott Company, Philadelphia. 653 pp.
Robbins, C. S., B. Bruun and H. S. Zim. 1966. Birds of North
America. Western Publ. Co., Wisconsin. 340 pp.
Robertson, R. J. 1972. Optimal niche space of Red-winged
Blackbird (Agelaius phoeniceus). I. Nesting success in
marsh and upland habitat. Canadian Jour. Zool. 50:247-263.
Rogers, J. G. , Jr. 1978. Some characteristics of conditioned
aversion in Red-winged Blackbirds. Auk 95:362-369.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Stowers, J. F. , D. T. Harke and A. R. Stickley, Jr. 1968.
Vegetation used for nesting by the Red-winged Blackbird
in Florida. Wil. Bui. 80:320-324.
Strosnider, R. 1960. Polygyny and other notes on the Red-
winged Blackbird. Wil. Bui. 72:200.
Tanner, J. T. and W. W. Tolbert. 1975. Optical and gamma
radiation measurements of the effects of chlorinated
hydrocarbons on egg shells of Red-winged Blackbirds. Wil.
Bui. 87:426-427.
Weatherhead, P. J. and R. J. Robertson. 1977. Male behavior
and female recruitment in the Red-winged Blackbird. Wil.
Bui. 89:583-592.
Wetherbee, D. K. 1962. Breeding of Red-winged Blackbird in
captivity. Wil. Bui. 74:90.
16
Agelaius phoeniceus (con*t.)
Whitmore, R. C. 1977 . Habitat partitioning in a community
of passerine birds. Wil. Bui. 89:253-265.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. No. 6. 39 pp.
Young, H. 1963. Age-specific mortality in the eggs and nestlings
of blackbirds. Auk 80:145-155.
<
4
I
•
%
RUBY-CROWNED KINGLET
Regulus calendula
I TAXONOMY
A. Type description
AOU (1957) Regulus calendula cineraceus Grinnell, Condor,
6 , No . 1 , Jan7~T5~j 1904, p. 2*5"! (Strain ' s Camp , Mount
Wilson, Los Angeles County, California.)
B. Current systematic treatments
AOU (1957) considers the Ruby-crowned Kinglet a member of
the Order Passeriformes, Family Sylviidae, Subgenus Corthylio,
with 4 subspecies. Dawson (1922): "There are probably few
problems more fascinating or difficult than the distribution
of the races of Corthylio calendula [R. calendula"] and the
key to a solution lies in a study of "the songs "
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944) - Regulus calendula calendula,
Corthylio calendula cineraceus, Corthylio c. calendula.
Baird (1905), referring to R. calendula - Motacilla calendula.
D. Synonomies of vernacular nomenclature
Dawson (1923) - Ashy Kinglet. Grinnell and Miller (1944)
Ruby-crowned Wren, Ruby-crowned Kinglet, Ashy Kinglet,
Eastern Ruby-crowned Kinglet.
II DESCRIPTION
A. External morphology of adults
Peterson (1961)' "Note the conspicuous broken white eye-ring,
which gives the bird a big-eyed appearance. A tiny birdlet,
olive-gray above, with 2 pale wing-bars; male with a scarlet
crown patch (erected when excited). Occasional males have
yellow crowns."
Dawson (1923): "Similar to Corthylio (Regulus) calendula
calendula, but larger and much less olivaceous; the color
tone of the foreparts ashy or grayish olive, decided olive-
green often not appearing above the middle of the back;
probably also without increase of olivaceous in fall and
winter.
Bairdet al. (1905), describing R. calendula: "Above dark
greenish olive, passing into bright olive-green on the rump
and outer edges of the wings and tail. The underparts are
Regulus calendula (con't.)
grayish-white tinged with pale olive-yellow, especially
behind. A ring around the eye, two bands on the wing
coverts, and the exterior of the inner tertials white. Male.
Crown with a large concealed patch of scarlet feathers,
which are white at the base. Female without red on the
crown."
Ridgway (1915): "Above grayish olive, the head not darker
than back; adult male with crown-patch bright medium-red,
or scarlet-vermillion. Length 3.75-4.60, wing 2.20-2.30,
tail 1.85-1.90, bill from nostril .20-. 22, tarsus .75."
B. External morphology of subadult age classes
Baird et al. (1905) referring to R. calendula: "Young without
red on the crown."
C. Distinguishing characteristics
Interspecific - Peterson (1961): "Any kinglet not having a
conspicuous crown patch is of this species. The stubbier
tail distinguishes it from any of our warblers, as does the
dark bar bordering the rear wing-bar. Similar species:
Golden-crowned kinglet and Hutton's Viero." Robbins et al .
(1966): "Told from the Golden-crown by eye-ring and from
vireos or fall warblers by its smaller size, short tail,
and habit of flicking its wings."
Intraspecific - Dawson (1923): "Similar to R. c. calendula
but larger and much less olivaceous." Jewett et al . (1953)
says grinnelli is similar to cineraceus but smaller and
darker. Godfrey (1966) says cineraceus is grayer and paler
than calendula.
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
A0U (1957), R. calendula cineraceus: "Breeds from south-
central British Columbia (probably the mountains of south-
western Alberta) and western Montana southward in the moun-
tains to southern California (to Mount Pinos, and the San
Gabriel, San Bernardino, San Jacinto, and White Mountains),
central and southern Arizona, east-central Colorado, and
central New Mexico." Oberholser (1974) gives the distribution
in Texas as: "Taken north to Haskell (May 15) east to Travis
and Victoria (May 5), south to Hidalgo, west to Brewster
and Culberson Counties." Gullion (1959) says that R. calendula
is an uncommon winter visitor in Nevada in the brusHy areas,
arriving as early as 26 September and remaining as late as
28 April. Hines (1963) reports Ruby-crowns as a common m
resident of the Alaskan spruce forest. Jewett et al . (1953) Q
Regulus calendula (con't.)
say that Ruby-crowns are a permanent resident of Washington
state, principally east of the Cascade Mountains, wandering
to western Washington during migration. Sutton (1967)
notes that Ruby-crowns do not nest in Oklahoma, but do
migrate through. Gabrielson and Jewett (1940) note than
cineraceus breeds from the Cascade Mountains and Blue
Mountains of Oregon south to southern California.
B. California distribution of the species
Grinnell and Miller (1944), for R. calendula cineraceus: "As
breeding, Siskiyou, Trinity, and~Warner mountains m north
thence south in Cascade Mountains and Sierra Nevada from
Mount Shasta to southern Tulare County; in southern California,
on Mount Pinos, San Gabriel, San Bernardino and San Jacinto
Mountains." Dawson (1923): "Common breeder in the Boreal
Zone from the Warner and Siskiyou Mountains south along the
central Sierras to about Long Meadow in Tulare County (Grin-
nell); also in the San Bernardino and San Jacinto Mountains.
Common in winter at the lower levels, especially southerly
and southeasterly. Stewart et al. (1974; do not mention
R. calendula in this paper on inland and coastal fall migra-
ting passerines in central California.
C. California desert distribution
Grinnell and Miller (1944) give breeding records from these
sites; San Bernardino and San Jacinto Mountains, Mohave and
Colorado deserts east to Colorado River and from Death Valley
south to Mexican line, Kern County, San Bernardino County,
San Diego County. Willett (1951) lists R. c. cineraceus
as a winter resident only, in the southern (California desert.
D. Seasonal variation in distribution
AOU (1957): "Winters from southern British Columbia, Idaho,
Nevada, and southern Utah, south to Baja California and the
highlands of northern Mexico." Grinnell and Miller (1944):
"Winter visitant in western lowlands and on southeastern
deserts from late September to mid-April. In winter wide
tolerance of conditions is shown." Sutton (1967) says
Ruby-crowns are found in Oklahoma during migration, pri-
marily from mid-September to 1 December and from mid-March
to 6 May.
IV HABITAT
A. Biotopic affinities
Peterson (1961): "Conifer forests; in winter other woodlands,
thickets. Grinnell and Miller (1944): "In breeding season
coniferous forests either of moderately dense type or where
Regulus calendula (con't.)
trees are open and broken. Robbins et al. (1966): "Prefers
conifers." Godfrey (1966): "In nesting season, coniferous
forests and woodlands, muskegs, also mixed woods." Sutton
(1967) says that during the Ruby-crown's migration through
Oklahoma they inhabit all kinds of woods, showing no pre-
ference for evergreens.
B. Altitudinal range
Grinnell and Miller (1944): "Extreme altitudes of nesting
range from 1500 feet to 10,000 feet."
C. Home range size
D. Territory requirements
Perch sites
Courtship and mating sites
Nest sites - Grinnell and Miller (1944) say they nest in
concealing needle tufts at middle heights in lodgpole pines,
mountain hemlock and firs. Godfrey (1966): "In coniferous
trees at almost any height but most often well up."
E. Special habitat requirements
F. Seasonal changes in habitat requirements
Godfrey (1966) says that during migration they are found
in all kinds of woodland; also in thickets of tall shrubs
such as alder and willow.
V FOOD
A. Food preferences
Baird et al. (1905) says they eat chiefly insects, but also
eat the stamens of blossoms of trees. Robertson (1959)
had Ruby-crowns feeding at his hummingbird feeder. Hespen-
heide (1962) give a description of Ruby-crowns feeding on
insects caught in the cracks of buildings.
B. Foraging areas
Grinnell and Miller (1944) say they forage in the terminal
foliage.
IP
i
•
Regulus calendula (con't.)
C. Foraging strategies
Baird et al. (1905) report them to be very active in the
pursuit of insects. Jewett et al. (1953) say they spend
most of their waking hours searching the foliage for insects.
They often make flycatcher-like excursions into the air,
snapping their beak and returning to their perch.
D. Feeding Phenology
Baird et al . (1905): "They are chiefly met in the spring
among the tree tops, where the insects they prefer abound...
In the fall of the year... they are more commonly met among
lower branches, and among bushes near the ground."
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
j* C. Courtship and mating behavior
D. Nesting phenology
Dawson (1923) just gives "June" as the season.
E. Length of incubation period
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
VII POPULATION PARAMETERS
A. Clutch size
Peterson (1961) - 6 to 9. Dawson (1923) - 5 to 9 . Godfrey
(1966) - 5 to 11. Sutton (1967) - as many as 11.
B. Fledging success
C. Mortality rates per age class
D. Longevity
Kennard (1975) did not find any banding records indicating
the banded Ruby-crowns live longer than four years.
6
Regulus calendula (con't.)
E. Seasonal abundance
F. Habitat density figures
III INTERSPECIFIC INTERACTIONS
A. Predation
Gabriel son and Jewett (1940) publish an account of a Rocky-
Mountain Jay taking eggs from a Western Ruby-crowned Kinglet
nest in Oregon.
B. Competition
C. Parasitism
Friedmann et al . (1977): "In spite of its diminutive size,
the Ruby-crowned Kinglet must be rated as a regular. . .host
choice of the Brown-headed Cowbird."
IX STATUS
A. Past population trends
B. Present population status
Grinnell (1933): "Common summer visitant to the Canadian
zone from Warner and Siskiyou Mountains along Sierra Nevada
south to Tulare County. Also sparingly in southern Calif-
ornia on San Gabriel Mountains, San Bernardino Mountains
and San Jacinto Mountains."
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
I
Regulus calendula (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Baird, S. F. , T. M. Brewer and R. Ridgway. 1905. A history
of North American birds. Vol. 1. Little, Brown and Co.,
Boston.
Carter, F. 1939. How does the Ruby-crowned Kinglet's Crown
work? Condor 41:79.
Dawson, W. L. 1923. The birds of California. Vol. 2. South
Moulton Co., Los Angeles.
Friedmann, H. , L. F. Kiff and S. I. Rothstein. 1977. A further
contribution to knowledge of the host relations of the para-
sitic cowbirds. Smithsonian Contrib. Zool. No. 235. 75 pp.
Gabrielson, I. N. and S. G. Jewett. 1940. Birds of Oregon.
Oregon State College, Corvallis. 650 pp.
Godfrey, W. E. 1966. The birds of Canada. National Museum of
Canada, Bull. no. 203.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna. No. 27.
608 pp.
Gullion, G. W. , W. M. Pulich and F. G. Evenden. 1959. Notes
on the occurrence of birds in southern Nevada. Condor 61:
278-297.
Hespenheide, H. A. 1962. Adaptive feeding in a Ruby-crowned
Kinglet. Wil. Bull. 74:93-94.
Hines, J. Q. 1963. Birds of Noatak River, Alaska. Condor
65:410-425.
Jewett, S. G., W. P. Taylor, W. T. Shaw and J. W. Aldrich. 1953.
Birds of Washington State. Univ. of Washington Press, Seattle.
765 pp.
Kennard, J. H. 1975. Longevity records of North American birds.
Bird-Banding 46:55-73.
Knowlton, F. H. 1909. Birds of the world. Henry Holt and Co.,
New York. 873 pp.
Leberman, R. C. 1970. Pattern and timing of skull pneumatiza-
tion in the Ruby-crowned Kinglet. Bird-banding 41:121-124.
8
Regulus calendula (con't.)
Oberholser, H. C. 1974. The bird life of Texas. Vol. 2.
Univ. of Texas Press, Austin.
Peterson, R. T. 1961. A field guide to western birds. Houghton
Mifflin Co., Boston. 366 pp.
Ridgway, R. 1915. A manual of North American birds. Fourth
Edition. J. B. Lippincott Company. 653 pp.
Robbins, C. S., B. Bruun and H. S. Zim. 1966. Birds of North
America. Western Publ. Co., Wisconsin. 340 pp.
Robertson, J. McB. 1959. Ruby-crowned Kinglet feeding on
nectar. Condor 61:371.
Stewart, Robert M. , L. Richard Mewaldt and Susan Kaiser. 1974.
Age ratios of coastal and inland fall migrant passerines in
central California. Bird-Banding 45:46-57.
Sutton, G. M. 1967. Oklahoma birds. Univ. of Oklahoma Press,
Norman. 674 pp.
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna. No. 21. 204 pp.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. No. 6. 39 pp.
I
RUFOUS- SIDED TOWHEE
Pipilo erythrophthalmus
I TAXONOMY
A. Type description
AOU (1957), P. e. montanus : Pipilo maculatus montanus
Swarth, Condor, 7, no. 6, Nov. 22, 1905, p. ITT. (Miller
Canyon, Huachuca Mountains, Arizona.)
P. e. curtatus : Pipilo maculatus curtatus Grinnell, Univ.
California Publ. Zool. , 7, no. 8, Aug. 24, 1911, p. 309.
(Big Creek Ranch, alt. 4350 feet, base of Pine Forest
Mountains, Humboldt County, Nevada.)
P. e. megalonyx: Pipilo megalonyx Baird, in Baird, Cassin,
and Lawrence, Rept. Expl~ and Surv. R. R. Pac. , vol. 9,
1858 pp. XLI, 511, 515. (Fort Tejon, California] . )
B. Current systematic treatments
Swarth (1913), for historical importance, a treatment of
the California forms of the species, at that time recog-
nizing (megalonyx, falcif er, falcinellus, curtatus,
clementae) .
Paynter (1970), recognizes seven species in the genus
Pipilo; twenty- four subspecies in the species erythrophthalmus .
Passeriformes: Emberizidae (Emberizinae) .
C. Synonomies of scientific nomenclature
P. e. megalonyx: Dawson (1923) - P. maculatus megalonyx.
Grinnell and Miller (1944), FringTlla arctica; P. arcticus ;
P. macutatus atratus.
P. e. curtatus : Dawson (1923) - P. maculatus curtatus .
Grinnell and Miller (1944), P. m. falcinellus.
P. e. montanus: Dawson (1923) - _P. maculatus montanus .
D. Synonomies of vernacular nomenclature
P. e. megalonyx: Dawson (1923) - Spurred Towhee; San Diego
Spotted Townee. Grinnell and Miller (1944), Arctic Ground
Finch; California Ground Robin; Southern Pipilo; California
Finch; Long- spurred Towhee.
P. e. curtatus : Dawson (1923) - Spurred Towhee; Mountain
Townee; Nevada Spotted Towhee. Grinnell and Miller (1944),
Long-clawed Towhee Bunting; Long- spurred Towhee, Sacramento
Towhee; Nevada Towhee.
Pipilo e ry throphthalmus (con't.)
P. e_;_ montanus : Dawson (1923) - Arizona Spotted Towhee;
Mountain Towhee .
II DESCRIPTION
A. External morphology of adults
Dawson (1923), P. e. megalonyx: "Adult in spring and summer:
Head and neck all around and breast glossy black, the black
of remaining underparts dulling posteriorly, especially
upon rump and remiges; the scapulars heavily marked with
longitudinal spots of white, included or else occupying
entire outer web of feathers. . .Outer pair of rectrices
narrowly margined and broadly tipped with white. . .Underparts
centrally pure white, the sides and flanks tawny. .. Irides
red; bill black; feet and tarsi dark brown. Fall and winter
specimens have feathers of upperparts slightly washed or
tipped with pale tawny, especially upon rump. Female in
spring: Similar to male, but duller, the black veiled with
olivaceous gray, the ground color strongest on throat and
chest and persisting centrally on pileum and notaeum; the
white tips of scapulars, rectrices, etc., more restricted,
the tibia dusky." P. e. curtatus : "Similar to P. m. (e.)
me gal onyx, but black o"F upperparts less pure, grayer; white
markings notably increased and carried clear across the I m
back; tawny of sides, etc., paler and more restricted, apical
white spots of 3rd pair of rectrices more extended; hind
claw notably weaker." P. e. montanus : "Similar to P. m.
(e.) me gal onyx, but paler every way; back and rump witE
admixture of gray; white markings more extended and diffuse;
apical spotting of tail more extended; hind claw weaker."
Ridgway (1901), P. maculatus megalonyx: detailed description
of adult males and females, including plumage, soft parts,
and measurements. Peterson (1961), Male: head and upper
parts black; rows of white spots on back and wings; sides
robin-red; belly white. Flashes large white spots in tail
corners. Female: Similar, but dusky brown where male is
black."
B. External morphology of subadult age classes
Dawson (1923), P. e. megalonyx: "highly streaked appearance,
not unsuggestive oT a female Redwing (Agelaius phoeniceus) :
Upperparts blackish, margined with cinnamon- buf f . . .white
spotting of adult much restricted; underparts mingled blackish,
whitish, and cinnamon-buff .. .Throat, chest, and sides of
breast finely streaked." Peterson (1961), "in summer are
streaked below like large slender sparrows but have the tail
pattern of this towhee." Baumann (1959), detailed descrip-
tion of skin, other soft parts, and extent of down from ^
day 1 to day 8. «
ifc Pipilo erythrophthalmus (con't.)
C. Distinguishing characteristics
Interspecific - Peterson (1961), "smaller and more slender
than Robin. "
Intraspecific - Dawson (1923), "As compared with the easterly
races of maculatus , megalonyx shows clearer black upon the
back and restriction or white spotting." Borror (1975),
analysis of the nature and amount of geographical variation
in the local repetories of the subspecies occurring in the
U.S.
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) P. erythrophthalmus in general: "Southern British
Columbia, central Alberta, central Saskatchewan, southern
Manitoba, northern Minnesota, northern Michigan, southern
Ontario, northern New York, northern Vermont, central New
Hampshire, and southwestern Maine south to southern Baja
California through Mexico to Guatemala, and western Texas,
northern Oklahoma, northern Arkansas, central southern
Louisiana, the eastern Gulf coast, and southern Florida...
Fossil, in the late Pleistocene of California."
P. e. montanus : "Breeds from central eastern California
"(Benton) , southern and central eastern Nevada (Grapevine
Mountains, Lehman Creek), northern Utah (Stansbury Island,
Uinta Mountains), and northwestern and central northern
Colorado (Boulder) south to southeastern California (Provi-
dence Mountains), central western and central southern
Arizona (Harquahala Mountains, Baboquivari Mountains),
northeastern Sonora (San Jose and San Luis Mountains),
northwestern Chihuahua (Sierra Madre, south to lat. 29°N.),
and central southern and northeastern New Mexico (Mesilla
Park, Sierra Grande) .. .Casual in Nebraska (North Platte)
and Kansas (Morton County), and accidental in New Jersey
(Metuchan)."
P. e. curtatus: "Breeds from central southern British
Columbia (Lilloet, Okanagan Landing, Robson) and northern
Idaho (5 miles west of Cocolalla) south, east of the Cascades,
to northeastern California (south to Mono Lake), western and
central Nevada (Tybo), and southeastern Idaho (Craters
of the Moon)." P. e. megalonyx: "Resident in southwestern
California (Monterey and west slope of Walkers Pass south
to Santa Cruz Island, Little San Bernardino Mountains, and
San Diego County) and northwestern Baja California (south
to about lat. 32° N.). Casual on San Miguel Island, Calif-
ornia. "
Pipilo erythrophthalmus ( con ' t . )
B. California distribution of the species
Dawson (1923), P. e. mega 1 onyx: "Resident in the Pacific
Coast district of southern California and northern Lower
California, north along coast to San Luis Obispo County,
east to southern Sierras (northern Kern County) . Also
Santa Cruz Island and... Santa Rosa." P. _e. curtatus : "
"northeastern California. . .breeds in tEe Warner Mountains
of Modoc County." P. e. montanus : "Known only from the
Panamint Mountains Tn Inyo County, where breeding." Grinnell
and Miller (1944), P. e. curtatus : "breeding, northeastern
section from Oregon line south to Mono Lake; limited to
westward by high-zone forests of Cascade- Sierran system."
P. e. montanus : "Mountain ranges of Inyo district from south-
eastern Mono County south to northern San Bernardino County
and from east side of Owens Valley to Nevada line." P. e.
megalonyx: "Coastal districts from Monterey County west
of lower (northern) Salinas Valley south to Mexican boundary;
interiorly, from Kern County, southward, Included are the
Kern River basin northeast to Walker Pass and the interior
coast ranges north to extreme western Fresno County. Occurs
also on Santa Rosa and Santa Cruz islands. Intergradation
with adjoining races to the northward is notably gradual."
C. California desert distribution
Dawson (1923), P. e. montanus : "south of the Great Basin to
the desert ranges of eastern California, ... Panamint Mountains,
Inyo County, where breeding." Small (1974), "absent only
from higher mountain areas and southeastern deserts."
Grinnell and Miller (1944), P. _e. curtatus: reported in
Potholes, Imperial County. P. e. megalonyx: reported at
Pasadena, Los Angeles County; San Bernardino, San Bernar-
dino County; Escondido, San Diego County; Palm Springs,
Riverside County. Cardiff (1956), reported P. m. megalonyx
collected on the New River northwest of Westmoreland.
Willett (1912), reports two fresh eggs of P. e. megalonyx
near Claremont, Los Angeles County. Miller (1951), P« e.
me gal onyx: Kern Basin and San Diego. P. e. curtatus: Modoc
ana Inyo regions. P. e. montanus : Inyo and Mojave regions.
D. Seasonal variations in distribution
AOU (1957), P. erythophthalmus in general: "Winters from
southern British Columbia, Utah, Colorado, Nebraska, Iowa,
the southern Great Lakes area, and Massachusetts southward."
P. e. montanus : "Winters from southern Utah (Beaverdam
Mountains) , central Colorado (Golden), and western Texas
(Palo Duro Canyon) south to northern Sonora (Sierra Carrizal,
Nacozari) , central Chihuahua (Chihuahua), and central Texas
(Del Rio; Kendall County); casually farther southeast in
Pipilo erythrophthalmus (con't.)
Texas (Victoria, Eagle Lake)." P. e. curtatus : "Winters
in part in breeding range and south to southeastern Calif-
ornia (Potholes), northwestern Sonora (Sonoyta), and south-
eastern Arizona (Huachuca and Chiricahua Mountains)."
Peterson (1961), winters mainly from S. B. C. , Utah,
Colorado south." Grinnell and Miller (1944), P. e.
curtatus: "Summer resident in Great Basin region "From late
March to early October; partly migratory, some birds winter-
ing far to southward in State."
IV HABITAT
A. Biotopic affinities
Small (1974), "chaparral and forest undergrowth, riparian
thickets." Peterson (1961), "brush, chaparral, undergrowth,
forest edges, city shrubs." Grinnell and Miller (1944),
P. e. curtatus : "Basic requirements much as in race montanus
. . .^rush cover inhabited includes willow thickets, artemisia
and rabbit brush. In winter, in Colorado River valley,
occurs in thickets of arrowweed and in atriplex bushes.
P. e. montanus: "Large, stiff -branched shrubs, particularly
Tn bottoms of ravines and canyons and along bases of rock
outcrops. . .Purshia, willow thickets and tall artemisia bushes
commonly provide the necessary cover." P. e. megalonyx:
"Principally river bottom thickets and cEaparral. Tangles
of blackberry, wild grape, willow thickets, poison oak,
scrub oak, ceanothus and manzanita are prominent plant
associates, but any brush cover appears to serve if it is
fairly tall and produces abundant leaf litter either by
reason of the plant types involved or because of favorable
topography of the ground beneath." Miller (1951), Upper
and Lower Sonoran and Transition life zones.
B. Altitudinal range
Grinnell and Miller (1944), P. e. curtatus: "from 4000 feet
in Honey Lake Valley, Lassen County up to 8000 feet on
Warner Mountains." P. e. montanus : "4300 feet to 8000 feet;
may wander up to 10,U00 feet in late summer." P. e. megalonyx:
"from near sea level, as at Laguna Beach, up to 70U0 feet
in San Bernardino Mountains ; late summer vagrants range up
to 9000 feet."
C. Home range size
D. Territory requirements
Perch sites - Grinnell and Miller (1944), P. e. montanus:
"pinons, junipers or mountain mahoganies wKicn" afford exposed
elevated song posts essential for the males." Davis (1958)
Pipilo erythrophthalmus (con't.)
"highly variable. . .may sing from the ground while foraging
or from as high as 50 feet up in tall trees. By far the
greatest number of singing perches noted were in trees,
especially in live and valley oaks, but to some extent in
willows and sycamores. . .May sing from exposed perches,
such as bare limbs or the tops of trees or shrubs, but
usually they sing from leafy cover where they are at least
partly concealed."
Courtship and mating sites - Baumann (1959) "After singing
in one place for a while, the birds often flew to a different
location, sang there for a period of time, and then passed
to another site. In this way they regularly covered most
of their territory (courtship and territorial singing by
males)."
Nest sites - Dawson (1923), "Placed on the ground, or, rarely,
very low in bushes, and usually sunk deeply in loose leaf-
waste or trash; composed of grasses, barkstrips, dried
leaves, lined with fine grasses." Davis (1960), "Since
nests were flush with the ground, or nearly so, surrounding
vegetation. . .provided sufficient lateral screening."
Baumann (1959;, "generally. . .on the ground."
E. Special habitat requirements
Grinnell and Miller (1944), "For desert areas, the brush
required is relatively dense and tall... Only in such brush
is deep leaf litter likely to accumulate, protected from
wind scattering, where these towhees can forage."
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Dawson (1923) "insects. .. fallen seeds." Davis (1960) re-
ports adults feeding insect larvae to nestlings. Graskin
(1950), stomach contents included ants.
B. Foraging areas
Grinnell and Miller (1944), "Although foraging is chiefly
on the ground, in summer and fall berries are taken from
bush tops." Woodbury (1933), "If the visible food supply
on the surface is not sufficient for its needs, the towhee
takes to turning over the leaves and scratching among the
trash with its feet." Davis (1957a), "sheltered soil cover
in which the birds may find their food by scratching. . .
Rarely forage in areas which are not screened from above by -
overhanging vegetation, and even more rarely do they search ^
for food in bare or sparsely covered soil."
»
|fc Pipilo erythrophthalmus (con't.)
C. Foraging strategies
Dawson (1923), "scratching for food... by a succession of
backward kicks, executed. . .by both feet at once, and assisted
by a compensatory flash of the wings." Woodbury (1933)
describes bilateral scratching behavior used when foraging.
Davis (1957a), "involve gleaning exposed food items, mainly
weed seeds and insects, from the soil surface or obtaining
food located by scratching in soil cover or in the upper
layers of exposed soil... The nature of foraging, whether
predominantly by scratching or by pecking at the surface,
is determined by the nature of the terrain traversed."
Includes a detailed discussion of comparative foraging with
the Brown Towhee; foraging behavior, osteology and myology
of the hind limbs, methods of locomotion and foraging.
D. Feeding phenology
Davis (1960), "nestlings in early nests are fed mainly larvae,
whereas nestlings in later nests are fed mainly grasshoppers,
the shift coinciding with the relatively greater abundance
of larvae in the spring and the relatively greater abundance
of grasshoppers in the early summer." Davis (1961), "The
short bill and long intestinal tract of birds taken in winter
apparently correlate with the vegetable diet utilized at
that season; the long bill and short intestinal tract of
birds taken in summer apparently correlate with increased
consumption of insect material in the summer period."
Davis (1957a), "ate cof f eeberries (Rhamnus calif ornica)
between August 22 and December 24. . .The preponderance of
September records. .. suggests that cof f eeberries are also
an important source of water during this hot, dry month."
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
Davis (1958), "Throughout the period of spermatogenesis
there is a definite tendency for adults to precede first
year birds in the attainment of (first primary spermatocytes
in synapsis, predominance of primary spermatocytes in synapsis,
first spermatids, breeding)."
B. Territorial behavior
Bauman (1959), "From fall until late winter there seemed
to be no evidence of territorality. . .However, in February,
the males began to sing vigorously in a given area, and to
spend more of their time there. Foreign males were chased
away, but paired or unpaired females were not disturbed. . .
Males maintained their territories from the time pairing
began to the end of the breeding season.
C. Courtship and mating behavior g*^
Davis (1958) detailed discussion of singing behavior with
respect to breeding season. Baumann (1959;, "after pair-
ing takes place, the song of the male becomes less frequent
and insistent than the calls and songs of the unpaired
males. "
D. Nesting phenology
Dawson (1923), "Season: May, June; one or two broods."
Davis (1960), "at Hastings Reservation in coastal Calif-
ornia occurs between about April 20 and June 20... Most
pairs apparently raise one brood. Nests are built solely
by the female."
E. Length of incubation period
Davis (1960), reports about 12 days, Hastings Reservation.
Baumann (1959), reports 13 or 14 days.
F. Length of nestling period
Baumann (1959), "young birds were found to leave the nest
when from nine to eleven days of age" (range for five
broods) .
G. Growth rates
Baumann (1959), detailed description of development of
plumage from day 1 to day 8, including photographs. Austin
(1968), "In common with most passerines, the growth rate
of the young towhees is very rapid. The weight of these
nestlings increased about fourfold during the six days
of observation."
H. Post-breeding behavior
Baumann (1959), "About one month after leaving the nest
the young were independent. The immature birds were un-
disturbed as they frequented common feeding grounds in
the territories of the breeding pairs. . .About two weeks
after appearing at the common feeding grounds, the young
birds commenced to disappear, and most left within a month.
Within two weeks after the appearance of the first set of
immatures, another group appeared in the common feeding
ground." Austin (1968), "after the young leave the nest
the family stays together near the nesting site all summer.
Young of the year in full juvenile plumage are seen reg-
ularly in July. As the singing of the males diminishes
after the nesting season, the birds become relatively in-
conspicuous as they forage quietly in the dense cover of
their preferred habitat.'
%
Pipilo erythrophthalmus (con't.)
711 POPULATION PARAMETERS
A. Clutch size
Dawson (1923), "3 or 4; white or palest bluish, grayish,
or pinkish, finely and heavily and often uniformly
sprinkled or spotted with reddish brown."
B. Fledging success
C. Mortality rates per age class
D. Longevity
Linsdale (1949), banding at Hastings Reservation revealed
6 individuals survived to age five; 4 to age six; 1 to age
seven. Davis (1957b), discussion of uses of color of
primary coverts, shape of rectrices, width of white spot
on 4th rectrix, amount of wear on wings and tail, and color
of iris to age individuals. Summer (1931), reports, from
banding records, two individuals at least seven years of
age. Kennard (1975) lists this species with a record age
of 12 years, 3 months when banded.
E. Seasonal abundance
F. Habitat density figures
Gaines (1974), reports 92 and 94 territorial males/km^ in
1972 and 1973 in clumped cottonwood and willow woodland in
Butte Co.; 38 territorial males/km^ in brushy field and
cottonwood and willow edge, Glenn and Butte counties;
60/km^ in cottonwood and willow woodland, Glenn; 62 and
58/km^ in riparian oak woodland, Sacramento Co., 1971 and
1972.
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Davis (1960), discusses the probability of the Scrub Jay,
the king snake, and the California ground squirrel as
serious predators. Baumann (1959), "The presence of a jay
within their territory would definitely affect the behavior
of the townees." Bond (1939), noted one carcass under a
Prairie Falcon nest.
B. Competition
•
10
Pipilo erythrophthalmus (con't.)
C. Parasitism
Rowley (1930), reports a nest containing 3 eggs of the
towhee and one of the Dwarf Cowbird (Molothrus ater obscurus) ,
the nest still occupied by the towhees. Hanna (192871 re-
ports one Molothrus ater obscurus egg in a nest of P. m.
megalonyx. Rockwell (1908), reported parasitized by M.
a. obscurus in Mesa Co., Colorado.
IX STATUS
A. Past population trends
Grinnell and Miller (1944), P. e. curtatus : "common on
breeding grounds in summer; winter visitants to other areas
occur only in small numbers." P. e. montanus: "Resident,
so far as known; probably descends from higher mountains
in winter. Common." P. e. megalonyx: "Permanent resident.
Common; in some areas rated as abundant' . "
B. Present population status
Small (1974), "primarily resident" (California).
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
C
11
Pipilo erythrophthalmus (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Austin, 0. L. , Jr. 1968. Life histories of North American
cardinals, grosbeaks, buntings, townees, finches, sparrows,
and allies. Part 1. U.S. Natl. Mus. Bull. No. 237.
Baumann, S. A. 1959. The breeding cycle of the Rufous- sided
Towhee, Pipilo erythrophthalmus (Linnaeus), in central
California. Wasmann J. Biol. 17:161-220.
Bond, R. M. 1939. Observations on raptorial birds in the
Lava Beds-Tule Lake region of northern California. Condor
41:54-61.
Borror, D. J. 1975. Songs of the Rufous-sided Towhee. Condor
77:183-195.
Cardiff, E. A. 1956. Additional records for the Imperial
Valley and Sal ton Sea area of California. Condor 58:447-
448.
Davis, J. 1957a. Comparative foraging behavior of the Spotted
and Brown Towhees. Auk 74:129-166.
Davis, J. 1957b. Determination of age in the Spotted Towhee.
Condor 59:195-202.
Davis, J. 1958. Singing behavior and the gonad cycle of the
Rufous- sided Towhee. Condor 60:308-336.
Davis, J. 1960. Nesting behavior of the Rufous- sided Towhee
in coastal California. Condor 62:434-456.
Davis, J. 1961. Some seasonal changes in morphology of the
Rufous- sided Towhee. Condor 63:313-321.
Dawson, W. L. 1923. The birds of California. South Moulton
Co. , San Francisco.
Gaines, D. 1974. A new look at the nesting riparian avifauna
of the Sacramento Valley, California. Western Birds 5:
61-80.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27.
12
Pipilo erythrophthalmus (con't.)
Groskin, H. 1950. Additional observations and comments on
"anting" by birds. Auk 67:201-209.
Hanna, W. C. 1928. Notes on the Dwarf Cowbird in southern
California. Condor 30:161-162.
Kennard, J. H. 1975. Longevity records of North American
birds. Bird-Banding 46:55-73.
Linsdale, J. M. 1949. Survival in birds banded at the Hastings
Reservation. Condor 51:88-96.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool., Vol.
50, no. 6.
Peters, J. L. 1970. Checklist of birds of the world. Vol.
10. (R. A. Paynter, Jr., ed.) Mus. Comp. Zool., Cambridge,
Massachusetts.
Peterson, R. T. 1961. Field guide to western birds. Houghton
Mifflin Co. , Boston.
Ridgway, R. 1901. The birds of North and Middle- America.
Part 1. U.S. Natl. Mus. Bull. No. 50.
Rockwell, R. B. 1908. An annotated list of the birds of Mesa
Co., Colorado. Condor 10:169.
Rowley, J. S. 1930. Observations on the Dwarf Cowbird.
Condor 32:130-131.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Sumner, E. L. 1931. Some banded birds recaptured after five
to seven and one-half years. Condor 33:128.
Swarth, H. S. 1913. A revision of the California forms of
Pipilo maculatus Swainson, with description of a new sub-
species. Condor 15:167-175.
Willett, G. 1912. Birds of the Pacific slope of southern
California. Pacific Coast Avifauna No. 7.
Woodbury, A. M. 1933. The scratching of the Spurred Towhee.
Condor 35:70.
€
SAGE THRASHER
Oreoscoptes montanus
I TAXONOMY
A. Type description
Oreoscoptes montanus - AOU (1957) J. K. Townsend, Journ.
Acad. Nat. Sci. Philadelphia, 7, pt. 2, Nov. 21, 1837, p. 192.
(Plains of the Rocky Mountains = Sandy Creek, lat. 42 N. ,
long. 109. 30' W. , Wyoming.).
B. Current systematic treatments
Hellmayr (1934) describes the Sage Thrasher as a monotypic
species, with a general range described as "Arid sagebrush
plains and foothills of western United States."
AOU (1957) considers the Sage Thrasher a monotypic member
of the order Passeriformes, family Mimidae.
Mayr and Short (1970), "given the variation with Toxo stoma,
Oreoscoptes is doubtfully separable from it."
C. Synonomies of scientific nomenclature
Hellmayr (1934), Orpheus montanos ; Oroscoptes montanus.
Grinnell and Miller (1944), Mimus montanus.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), Mountain Mockingbird. Dawson
(1923) adds "Sage Mocker."
II DESCRIPTION
A. External morphology of adults
Ridgway (1907) gives detailed description of plumages for
all age classes; "above light grayish brown, the feathers...
producing very indistinct streaks.'" Peterson (1961), "gray-
backed with a Robin-like bill, heavily streaked breast, white
spots at tip of tail, pale yellow eye." Phillips et al.
(1964) "the chest spots are dark, and the tail corners are
white. The bill is short... the iris yellow." Ligon (1961),
8-9 inches long. Dawson (1923) described this thrasher as
towhee size; ashy-brown. . .abundant spotting.
Oreoscoptes montanus (con't.)
B. External morphology of subadult age classes f£
Ridgway (1907) noted that young were "...light grayish brown
...back, scapulars, and rump rather broadly streaked...
streaks on under parts less sharply defined than in adults."
Dawson (1923) notes that young birds are browner and more
streaked than adults.
C. Distinguishing characteristics
Interspecific - Peterson (1961), "small size (8-9 inches),
Shorter tail, shorter bill, striped breast distinguish it
from other. . thrashers." Phillips et al. (1964), "this is
our only thrasher with a fairly definite facial pattern."
Grinnell (1904) thought this thrasher could be confused
with Cactus Wrens.
Intraspecific - Ridgway (1907) describes adults as nearly
identical in plumage, with some size differences; male:
wing 98.7 mm, length 197 mm, tail 88.5 mm. Ligon (1961),
"color pattern of sexes alike."
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
C
Distribution of 0. montanus (AOU 1957) given as, "Breeds
from central southern British Columbia, central Idaho, central
southern Montana, and northern and southeastern Wyoming, with
an apparently isolated colony in southwestern Saskatchewan,
south through eastern Washington, eastern Oregon, and eastern
California (Macdoel, Eagle Lake, White Mtns. , Inyo Mtns.)
to central southern California (Buena Vista Lake, Lockwood
Valley, Victorville) , southern Nevada, Utah, central northern
New Mexico, northwestern Texas, and western Oklahoma."
Ridgway (1907) gives general range as the arid plains,
mesas, and foothills of western United States. Peterson
(1961) gives range as, "from British Columbia, Idaho, Montana,
Saskatchewan, south to southern California, Nevada, northern
Arizona, New Mexico, Texas panhandle, Oklahoma."
B. California distribution of the species
Grinnell and Miller (1944), "As breeding, Great Basin plateau
region, east of the Cascade-Sierran axis from the Oregon
line south to northern end of Owens Valley and White Mtns. ,
thence irregularly southward at higher levels in mountains
around northern, western, and southern margins of Mohave
Desert." Small (1974), "breeds in Great Basin Desert south
to northern edges of Mojave Desert and Walker Basin, Kern Co. ;
also... San Joaquin Valley." Dawson (1923)," breeds locally
C
Oreoscoptes montanus (con't.)
in the high upper Sonoran, Sagebrush areas, east of the
Sierra Nevada, south to the Panamint Mtns." Wheelock (1904)
gives California breeding ranges as, "in upper Sonoran zone
southeast of the Sierra Nevada."
C. California desert distribution
Grinnell and Miller (1944) note the winter distribution of
this thrasher in the Mohave and Colorado deserts; desert
records include: Inyo and Panamint Mtns. ; near Walker Pass,
Kern Co.; near Bakersfield and Buena Vista Lake, Kern Co.;
Lockwood Valley, Ventura Co. ; vicinity of Victorville;
Death Valley, Inyo Co.; Hesperia and Twentynine Palms, San
Bernardino Co. Dawson (1923) notes sporadic nesting near
Bakersfield and Walker Pass. Johnson et al. (1948) found
wintering thrashers near Cima in the Providence Mtns. at 4,500
ft. Called an April to May transient near Blythe, Calif.
(Grinnell 1914). Breeds in some high valleys in northeastern
Ventura Co. and along desert slope of San Gabriel and San
Bernardino Mountains, south at least to Victorville; noted
near Perris, Riverside Co. (Willett 1933). Apparently reaches
its highest numbers on the desert in winter, with Willett
(1951) calling it the "most common thrasher" in winter.
Miller and Stebbins (1964) state that although the species
does not breed at Joshua Tree National Monument, there are
regular breeders on the Mojave Desert near Victorville.
Wauer (1964) found Sage Thrashers breeding on open sage
flats and valleys of the Panamint Mtns., Death Valley.
Rowley (1928) and Hanna (1930) found Sage Thrashers nesting
near Victorville, the most southerly desert locations noted.
D. Seasonal variations in distribution
Grinnell and Miller (1944), "present in two seasonal roles:
summer resident in Artemisia tridentata belt of eastern
California; winter visitant (late September-April) to deserts
and coastal slopes of southern California and to San Joaquin
Valley." Small (1974), "summer visitor (on breeding grounds)
and transient and winter visitor (September- April) elsewhere;
winters south to... Mojave and Colorado deserts." Winters on
the southeastern deserts and... in the San Diegan district
(Dawson 1923). In winter in southern California, this bird
occurs on Pacific slope, north to Ventura Co. and south to
Baja California (Willett 1933). "Common winter visitant to
the deserts of southeastern Calif ornia. .. summer visitant to
sagebrush of northeastern California" (Grinnell 1915). The
Sage Thrasher is called a rare straggler into Los Angeles Co.
from the desert by Grinnell (1898); pair seen in March.
Wintering birds usually arrive after mid- September at Joshua
Tree National Monument, with the earliest record being
September 13 (Miller and Stebbins 1964). Bent (1948) states
Oreoscoptes mem t anus (con't.)
that this thrasher is migratory, spending the winter near ca
or beyond the southern border of the United States. He notes
the California winter range to include San Fernando, Twenty-
nine Palms, and Death Valley. The species usually departs
its more northern breeding range in September. Gullion et
al. (1959) calls this species a spring and fall migrant on
southern Nevada deserts; most birds migrate north by mid-
April. Torrey (1909) found a single Sage Thrasher wintering
near San Diego (city park) in 1908. Van Rossem (1911) listed
this species as a regular winter visitor in the Salton Sea
region (noted in March). Howell and Van Rossem (1915)
discovered a single Sage Thrasher wintering (January) in the
Lower Colorado River Valley in 1913. Gilman (1907) describes
the migrations and habits of Sage Thrashers on southern
California deserts.
IV HABITAT
A. Biotopic affinities
Peterson (1961) describes habitat as, "sagebrush brushy
slopes, mesas; in winter, also desert." 'A common short-
tailed desert bird. . .nests in arid country (Robbins et al.
1966)." Grinnell and Miller (1944), "mesas and slopes of
moderate inclination, well covered with Artemisia tridentata.
Much less frequently other shrubs of similar growth pattern,
such as rabbitbrush, provide the necessary cover for nesting
and escape." Small (1974), "for breeding, flat areas vege-
tated primarily with Great Basin Sagebrush." Ligon (1961),
"the Latin designation, montanus , implying that it is a moun-
tain bird, is misleading" since it shuns the higher, heavily
forested areas." In southern California, species is most
plentiful on brushy foothills and mesas, but occasionally
straggling to lowlands (Willett 1933). Grinnell (1904)
found Sage Thrashers in creosote brush near Palm Springs,
California, during winter.
B. Altitudinal range
Grinnell and Miller (1944), "probable breeding, 300 ft...
up to 10,500 ft. on White Mountain." Breeds in New Mexico
between 5,000 and 6,000 ft. (Bailey 1928). Rossem (1936)
found this thrasher on the desert and up to 5,000 ft. in the
Yucca belt. Found nesting (May) at 5.000 ft. in Lockwood
Valley, Ventura Co., by Willett (1933). Bent (1948) notes
this thrasher up to 4,000 or even 6,000 ft. in juniper wood-
lands. Wauer (1964) noted nesting Sage Thrashers between
4,000 and 5,000 ft. in the Panamint Mountains, Death Valley.
Oreoscoptes montanus (con't.)
D. Territory requirements
Perch sites - Bent (1948) lists posts and the tops of bushes
as favorite perch sites. Pearson (1936) describes the favor-
ite perches of Sage Thrashers as sagebrush and thorny cactus.
Courtship and mating sites - Bailey and Niedrach (1965),
"...during spring and early summer... the males perch on the
tips of vegetation. .. singing for the benefit of their mates..."
Nest sites - Nest a twiggy cup in bush (Peterson 1961).
Bailey (1928) - nest, on ground or in low bushes, especially
sagebrush. Dawson (1923), "nest placed... in sage-bush or
greasewood." Nest. . .placed in sagebrush from 10 inches to
3 ft. from the ground (Wheelock 1904). Bent (1948) gives
usual sites as from a few inches to 3ft. above ground,
usually in sage, greasewood, or rabbi tbrush. Hanna (1930)
found nests in cotton thorn (Tetradymia spinosa) near Victor-
ville, Calif., 18 inches from the ground. Gilman (1907)
describes several sagebrush nests within 3 ft. of the ground
near 6,000 ft. in Colorado.
E. Special habitat requirements
Burleigh (1972) states that the Sage Thrasher has very
exacting habitat requirements, being restricted to sage-
brush.
F. Seasonal changes in habitat requirements
Grinnell and Miller (1944), "in winter, brushland associa-
tions of much wider variety are frequented (than summer
range)." Small (1974) noted that Sage Thrashers move into
more open country with sparse arid vegetation during winter.
Carter (1937) found this thrasher in the mesquite between
an oasis and the open desert near Twentynine Palms, San
Bernardino Co. , during winter.
V Food
A. Food preferences
Bailey (1928) noted food items such as berries, seeds, fruit,
beetles, locusts, ants, small wasps, other insects; as high
as 62% grasshoppers. Wheelock (1904) mentions the taking
of worms and insects. Martin et al. (1951) lists: beetles,
grasshoppers and crickets, ants and other Hymenoptera, cater-
pillars and moths, spiders, bugs, and flies; states that
little plant food is taken, although grape, serviceberry,
and blackberry have been found in diet. Bent (1948) gives
detailed summary of food items; grasshoppers, chinch bugs,
leaf hoppers, ants, and a few berry seeds. Knowlton and
Harmston (1942) gave a detailed summary of Sage Thrasher
prey in Utah; grasshoppers were the major prey taken.
Oreoscoptes montanus (con't.)
B. Foraging areas
Grinnell and Miller (1944), "the ground between arid beneath
bushes, and to some degree the bushes themselves, are searched
over in foraging." Wheelock (1904) found most Sage Thrashers
feeding below bushes in California. During winter at Joshua
Tree National Monument, these birds forage in open desert
terrain, although they utilize as retreats the low shrubs
and bushes present there (Miller and Stebbins 1964). Pearson
(1936) noted that Sage Thrashers are seldom seen far from
the ground.
C. Foraging strategies
"He would run to a bush. .if bushes were far apart he would
sometimes fly from one cover to another, halt, and then
forward again" (Gilman 1907). Bent (1948) states that al-
though the majority of feeding takes place on the ground,
this thrasher will feed on grapes and berries in low shrubs.
Pearson (1936), "it is found on the ground, running about
among the clumps of bushes."
D. Feeding Phenology
Feed primarily on berries during the non-breeding season
(Dawson 1923). Little plant material is taken by this
species; serviceberry and grape are favored in the fall
(Martin et al. 1951). Kennedy (1911), "with young independ-
ence, habits change greatly. After July, Sage Thrashers
feed heavily on grapes" (Washington).
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Bent (1948) states that the Sage Thrasher acts somewhat
like the Mockingbird. It frequently raises its tail rapidly,
moving its head from side to side at an intruder.
C. Courtship and mating behavior
"Song, given from conspicuous perch or in flight, resembles
Brown's (Thrasher), but is more melodious and lacks the
pauses between phrases (Robbins et al. 1966)." Ligon (1961),
its song... is somewhat like that of the Mockingbird."
During pairing, the males often fluttered their wings and gave
a warbling song as they flew; they flew in a zigzag fashion
over the sage (Bent 1948).
Qreoscoptes montanus (con't.)
t D. Nesting phenology
Dawson (1923) gives breeding season as May 1 to June 15
with 1 or 2 broods raised; the nesting season is very ir-
regular, however. Wheelock (1904) gives California season
as March to July. Bent (1948) gives California egg dates
as 19 April to 18 July; most nesting begins in mid-April.
E. Length of incubation period
Incubation period of 14 days given by Wheelock (1904).
F. Length of nestling period
Killpack (1970) found an 11 day nestling period in Colorado
Sage Thrashers.
G. Growth rates
General account of development given by Wheelock (1904);
down more perceptible by second day; eyes open by fifth
day. In Colorado, nestlings gained an average of 3.4 (1.5-
4.7) g. per day; their average weight was 87% of adult females
at fledging (Killpack 1970).
j H. Post-breeding behavior
Form large flocks after breeding (Bailey 1928). "At the
close of the (nestling) season. ..the birds. . .resort in
numbers to the hillside springs and brushy draws (Dawson
1923)." In the late summer, family groups band together
(Bailey and Niedrach 1965) .
VII POPULATION PARAMETERS
A. Clutch size
Eggs (4-5; 7) blue, spotted (Peterson 1961). Bailey (1928)
gives clutch as 4 eggs. Reed (1904) gives clutch of 3-4.
Ligon (1961), "eggs 4, greenish blue, spotted." Eggs 4 or
5 (Dawson 1923). Bent (1948) reports the normal clutch as
4 or 5 eggs, with 7 being the record.
B. Fledging success
In Colorado, Killpack (1970) stated that nest success was
variable. Of 19 eggs laid, 11 young hatched and all 11
fledged.
C. Mortality rates per age class
Wheelock (1904) felt that lizards and snakes took a large
number of eggs and nestlings in California.
8
Oreoscoptes montanus (con't.)
D. Longevity
E. Seasonal abundance
Carter (1937) states that wintering Sage Thrashers near
Twentynine Palms, California, vary widely in numbers from
year to year, from "quite numerous" to rare. After breed-
ing, family groups form and the birds become fairly numer-
ous around waterholes (Bailey and Niedrach 1965).
F. Habitat density figures
Hoppes (1978) found 2 territorial males on a 12.26 ha
"Sagebrush flat" study area in Wyoming. On another sage-
brush study area, also in Wyoming, Todd (1974) reported
1 territorial male on an 8.1 ha plot. Jewett (1953) reported
a density of 5 pairs per square mile in Washington.
VII INTERSPECIFIC INTERACTIONS
A. Predation
Killpack (1970) noted the taking of eggs by a coyote in
Colorado.
B. Competition
C. Parasitism
Friedmann (1963) gives a single record of the Sage Thrasher
being parasitised by a cowbird (Utah) .
IX STATUS
A. Past population trends
Called "common" by Grinnell (1915). Bent (1948) notes a
slight northward range expansion during the early 1940' s.
Called a common wintering bird along the lower Colorado
River (Price 1899). Mailliard and Grinnell (1905) described
the thrasher as "unexpectedly rare" on the Mojave Desert
in winter. Hollister (1908) called the species "common
and in full song in April (1905) near Needles, California.
B. Present population status
Grinnell and Miller (1944), "Common, even abundant locally,
on breeding grounds; common in eastern part of winter range."
Miller and Stebbins (1964) listed the birds as "fairly com-
mon" during winter at Joshua Tree National Monument. Called
a "common breeder" in eastern California (McCaskie and De
Benedictis.1967) .
Oreoscoptes montanus (con't.)
C. Population limiting factors
Bent (1948), "...it is limited almost entirely to the semiarid
regions where immense areas are clothed with. .. sage." Pear-
son (1936) states that Sage Thrashers appear to be confined
very largely to the open areas of the far West.
D. Environmental quality: adverse impacts
Jewett (1953) stated that agricultural activities (irriga-
tion and cultivation) usually drives Sage Thrashers out of
an area. However, tracts of sagebrush left adjacent to the
agricultural fields will be utilized for nesting.
E. Potential for endangered status
10
Oreoscoptes montanus ( con ' t . )
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bailey, F. M. 1928. Birds of New Mexico. New Mexico Dept.
Game and Fish. 807 pp.
Bailey, A. M. and R. J. Niedrach. 1965. Birds of Colorado.
Vol. 2. Denver Mus. Nat. Hist., Denver, Colorado.
Bent, A. C. 1948. Life histories of North American nuthatches,
wrens, thrashers, and their allies. U.S. Nat. Mus. Bull.
195:1-475.
Burleigh, T. D. 1972. Birds of Idaho. Caxton Printers, Ltd.,
Caldwell, Idaho. 467 pp.
Carter, F. 1937. Bird life at Twentynine Palms. Condor 39:
210-219.
Dawson, W. L. 1923. The birds of California. Vol. 2. South
Moulton Co. , San Francisco.
Friedmann, H. 1963. Host relations of the parasitic cowbirds.
U.S. Nat. Mus. Bull. 233. 276 pp.
Gilman, M. F. 1907. Migration and nesting of the Sage
Thrasher. Condor 9:42-44.
Grinnell, J. 1898. Birds of the Pacific slope of Los Angeles
County. Pasadena Academy Sci. No. 11:1-52.
Grinnell, J. 1904. Midwinter birds at Palm Springs, Calif-
ornia. Condor 6:40-45.
Grinnell, J. 1914. An account of the mammals and birds of
the lower Colorado Valley. Univ. California Publ. Zool.
12:51-294.
Grinnell, J. 1915. A distributional list of the birds of
California. Pacific Coast Avifauna No. 11. 217 pp.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27. 608
pp.
Gullion, G. W., W. M. Pulich and F. G. Evenden. 1959. Notes
on the occurrence of birds in southern Nevada. Condor 61:
278-297.
:
11
Oreoscoptes montanus (con't.)
Hanna, W. C. 1930. Southerly breeding record of Sage Thrasher
in California. Condor 32:263.
Hellmayr, C. E. 1934. Catalogue of birds of the Americas.
Part 7. Field Mus. Nat. Hist. Zool. Ser. Publ. 330, Vol.
13.
Hollister, N. 1908. Birds of the region about Needles, Cal-
ifornia. Auk 25:455-462.
Hoppes, W. 1978. Forty-first breeding bird census. Am. Birds
32:97.
Howell, A. B. and A. Van Rossem. 1915. Additional observations
on the birds of the Lower Colorado Valley in California.
Condor 17:232-234.
Jewett, S. G., W. P. Taylor, W. T. Shaw and J. W. Aldrich.
1953. Birds of Washington State. Univ. Washington Press,
Seattle. 767 pp.
Johnson, D. H. , M. D. Bryant and A. H. Miller. 1948. Verte-
brate animals of the Providence Mountains area of Calif-
ornia. Univ. California Publ. Zool. 48:221-376.
Ligon, J. S. 1961. New Mexico birds. Univ. New Mexico Press,
Albuquerque. 360 pp.
Kennedy, C. H. 1911. Notes on the fruit-eating habits of
the Sage Thrasher in the Yakima Valley. Auk 28:225-228.
Killpack, M. L. 1970. Notes on Sage Thrasher nestlings in
Colorado. Condor 72:486-488.
Knowlton, G. F. and F. C. Harmston. 1942. Insect food of
the Sage Thrasher. Condor 44:76-77.
Mailliard, J. and J. Grinnell. 1905. Midwinter birds on the
Mohave Desert. Condor 7:71-77, 101-102.
Martin, A. C. , H. S. Zim and A. L. Nelson. 1951. American
wildlife and plants. McGraw-Hill Book Co., New York.
500 pp.
Mayr, E. and L. L. Short. 1970. Species taxa of North American
birds. Publ. Nuttall Ornithol. Club 9:1-127.
McCaskie, G. and P. De Benedictis. 1967. The distribution of
certain Mimidae in California. Condor 69:310-311.
12
Oreoscoptes montanus (con't.)
Miller, A. H. and R. C. Stebbins. 1964. The lives of desert
animals in Joshua Tree National Monument. Univ. California
Press, Berkeley. 452 pp.
Pearson, T. G. 1936. Birds of America. Garden City Publ.
Co., Inc., Garden City. N.Y.
Peterson, R. T. 1961. A field guide to western birds. 2nd
Edition. Houghton Mifflin Co., Boston. 366 pp.
Phillips, A., J. Marshall and G. Monson. 1964. The birds of
Arizona. Univ. Arizona Press, Tucson. 212 pp.
Price, W. W. 1899. Some winter birds of the Lower Colorado
Valley. Condor 1:89-93.
Reed, C. A. 1904. North American birds eggs. Doubleday,
Page & Co., New York. 356 pp.
Ridgway, R. 1907. The birds of North and Middle America.
Part 4. Bull. U.S. Nat. Mus. No. 50.
Robbins, C. S., B. Bruun and H. S. Zim. 1966. Birds of North
America. Western Publ. Co., Wisconsin. 340 pp.
Rowley, J. S. 1928. Sage Thrasher nesting near Victorville,
California. Condor 30:325.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Swarth, H. S. 1900. Sage Thrasher in Los Angeles Co., Cal.
Condor 2:89.
Todd, F. W. 1974. Thirty-eighth breeding bird census. Am.
Birds 28:1044.
Torrey, B. 1909. The Sage Thrasher at San Diego. Condor
11:174.
Van Rossem, A. 1911. Winter birds of the Salton Sea region.
Condor 13:129-137.
Van Rossem, A. 1936. Birds of the Charleston Mountains,
Nevada. Pacific Coast Avifauna No. 24. 65 pp.
Wauer, R. H. 1964. Ecological distribution of the birds of the
Panamint Mountains, California. Condor 66:287-301.
Wheelock, I. G. 1904. Birds of California. A. C. McClurg
and Co., Chicago. 578 pp.
13
Oreoscoptes montanus (con't.)
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna No. 21. 204 pp.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles Co. Mus. Zool. Ser. 6:1-39.
m
m
i
SOLITARY VIREO
Vireo solitarius cassinii
I TAXONOMY
A. Type description
Vireo solitarius cassinii - AOU (1957) Vireo cassinii Xantus,
Proc. Acad. Nat. Sci. Philadelphia, 10, sig. 8, Apr*-May
(after May 25) 1858, p. 117. (Fort Tejon, California.)
B. Current systematic treatments
AOU (1957) considers Vireo solitarius a member of the avian
Order Passeriformes, Family Vireonidae, Subfamily Vireoninae.
Hellmayr (1935) lists 7 races of Vireo solitarius, including
cassinii. Hamilton (1962) presents a detailed study of the
relationships within the genus Vireo. V. solitarius is
most closely related to V. f lavifrons, V. atricapillus, and
V. huttoni.
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), Vireo cassinii, Vireosylvia
solitaria; Lanivireo solitarius; L. cassinii.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), Cassin Vireo; Blue-headed Fly-
catcher; Blue-headed Vireo; Blue-headed Greenlet; Cassin
Greenlet.
II DESCRIPTION
A. External morphology of adults
Miller and Stebbins (1964): "A large (14-16 gram) vireo with
heavy bill. Gray head marked with conspicuous white eye
ring connected with white running to base of bill; two
prominent white wing bars on secondary coverts; back and
flanks greenish." Ridgway (1904) adds that the "mandible
grayish (pale bluish gray in life) with blackish tip; iris
brown; legs and feet dusky." Hamilton (1958) gave a detailed
analysis of geographic variation in the genus Vireo.
B. External morphology of subadult age classes
Ridgway (1904) described young as: "(in first autumn and
winter) --Pileum, hindneck and sides of head and neck varying
from olivaceous hair brown to grayish olive, not very differ-
ent...from color of back; (first plumage) --Wings and tails
as in adults; rest of upper parts brownish gray."
^
Vireo solitarius (con't.)
C. Distinguishing characteristics
Interspecific - Peterson (1961), "Similar species: (1)
Hutton s Vireo has dull throat; eye-ring broken at top.
(2) Bell's Vireo has inconspicuous wing-bars and eye- ring."
Intraspecific - Ridgway (1904), "Adult female—Similar to
adult male but duller in color; length 121.7 mm; wing 72.1;
tail 52.0; Adult male, length 123.2 mm; wing 72.3; tail
52.3."
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) gives the overall distribution of the Solitary
Vireo as "Breeds from central "Bitish Columbia, southwestern
Mackenzie, central Saskatchewan, central Manitoba, northern
Ontario, southern Quebec, Newfoundland, and Nova Scotia
south to southern Baja California, Guatemala, and El
Salvador. Winters from Arizona and South Carolina south
to the Cape district of Baja California, southwestern
Mexico, northern Nicaragua, and Cuba."
The range of Vireo solitarius cassinii is given by the AOU
(1957) as "Breeds from southern British Columbia, northern S^L
Idaho, and northwestern Montana south through central northern
Washington, northeastern Oregon, central Idaho to the moun-
tains and foothills of California (Humboldt County, Warner
Mountains, Campo, Kings Canyon) and southern Nevada (Poyosi
Mountain) . "
Hellmayr (1935) gives range of cassinii as "Transition zone
from British Columbia, southwestern Alberta, Idaho, and
western Montana south through California and western Nevada
to the Sierra San Pedro Martir, Lower California; in winter
south through Arizona to Jalisco, Michoacan, Guanajuato,
Oaxaca, and Chiapas."
B. California distribution of the species
Small (1974), "range in California--for breeding, foothills
and mountains of most of California east of the deserts and
excluding the humid coniferous forest of the northwest coast;
in migration, throughout state." McCaskie (1968) called
solitarius "a regular migrant and summer visitor between
late March and mid-October with stragglers regularly occurring
in November." He further notes that the appearance of birds
in December may mean that the species now winters in Calif-
ornia.
%
Vireo solitarius (con't.)
C. California desert distribution
Miller and Stebbins (1964) called this vireo a "sparse but
regular spring migrant" in Joshua Tree National Monument;
recorded from Lower Covington Flat, Smithwater Canyon,
Twentynine Palms, Eagle Mountain, and Cottonwood Spring,
from March to May. Only one fall record, on 17 September.
Willett (1951) calls this species a migrant across the
deserts of southern California. Johnson et al. (1948)
called cassinii uncommon migrants, with no evidence of
breeding^ in the Providence Mountains in May. Grinnell
(1914) called cassinii a transient during April in the
lower Colorado River valley. Grinnell and Swarth (1913)
noted that this vireo was "Found in fair abundance in. . .
the Transition Zone" of the San Jacinto area of southern
California. Van Rossem (1936) called this vireo "a common
late-August migrant" in the Charleston Mountains, Nevada
(near Death Valley, California) ; he could find no evidence
of breeding, however. Johnson (1974) found that V. _s.
cassinii has been replaced by V. s. plumbeus in some areas
of southern Nevada (Grapevine and Potosi Mountains).
De Benedictis and McCaskie (1967) collected singing male
V. _s. plumbeus in the White Mountains of California during
July; they feel that this race may breed in these mountains.
Cardiff (1963) collected a male plumbeus near Needles. San
Bernardino County, on 26 November 1960. Miller (1945)
found cassinii breeding on Potosi Mountain (South Nevada),
but could not find breeders on Clark Mountain (San Bernardino
County) or in the Charleston Mountains. At Twentynine Palms,
Carter (1937) called cassinii a "casual spring migrant";
was noted between late-March and mid-May.
D. Seasonal variations in distribution
AOU (1957) states that V. s. cassinii "Winters from south-
eastern Arizona and Nuevo Leon south to Michoacan and
Guerrero. Migrates through the Great Basin region through
Colorado, New Mexico, and western Texas."
Grinnell and Miller (1944) found that this species is pre-
sent in two seasonal roles in California: "summer resident,
on nesting grounds, from mid-April through August; migrant
...from the first of April through May, and from late August
through the first half of October, rarely later." In
Joshua Tree, the protracted period of passage through the
desert suggests the presence of populations moving both to
southern and northern parts of the breeding range of the
race (cassinii) (Miller and Stebbins 1964; . Small (1974)
in California, "transient and summer visitor, late March
to October."
Vireo solitarius (con't.)
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944) describe this species California
habitat as "oak and conifer forests that offer open branch-
work at low and middle levels. . .Comparatively dry, warm
forests are favored. .. Principal trees frequented in summer
are yellow pine, Jeffery pine, incense cedar, black oak,
and golden oak; mature willows, cottonwoods and alders also
may be occupied." Small (1974) gives California habitat
as "for breeding, oak woodlands and mixtures of oaks and
conifers; otherwise, lowlands in general where there are
thickets, riparian woodlands..." In the Charleston Moun-
tains of Nevada, Van Rossem (1936) found late-August migrants
through the Upper Sonoran and Transition Zones. Johnson
et al. (1948) found cassinii "in a juniper among rocks on
a steep hillside at 6,300 feet on the southeast side of
Clark Mountain." During a May study in the Providence
Mountains. Hamilton (1962) noted that "The Solitary
Vireo appears to be the only vireo sufficiently wide in
habitat tolerance to utilize coniferous vegetation. .. the
breeding territories are usually in broadleaved or mixed
broadleaf -conifer habitats."
41
B. Altitudinal range %t>-"
In California, nesting from 300 feet (Contra Costa Co.)
to 7,500 feet (Tulare County) (Grinnell and Miller 1944).
Fall migrants were observed from 6,200 to 9,000 feet in
Nevada by Van Rossem (1936). In Kings Canyon National Park,
Dixon (1943) found cassinii up to 6,000 feet.
C. Home range size
In Arizona, Launders layer and Balda (1976) gave the mean
size of a breeding territory as 1.7 ha.
D. Territory requirements
Perch sites -
Courtship and mating sites -
Nest sites - "Nest emplacements usually are in the lower
branches of... trees, not uncommonly in exposed, though shaded,
situations" Grinnell and Miller (1944). Bent (1950), "it
...builds its dainty nest low in bushes or trees." Ligon
(1961), "nest: From 5 to 20 feet above ground." In the San
Bernardino Mountains, Grinnell (1908) found nests in "golden
oaks at lower levels and cottonwoods at higher altitudes...
but nests were also found in the incense cedar, silver fir,
Jeffrey pine, black oak, and alder."
Vireo solitarius (con't.)
E. Special habitat requirements
During nesting, Grinnell and Storer (1924) found that the
distribution of cassinii "closely parallels the range of
golden oak and incense cedar, though the bird does not
restrict itself exclusively to these two trees."
F. Seasonal changes in habitat requirements
Grinnell and Storer (1924) reported that cassinii is found
in blue oaks and chaparral on dry hillsides during spring
migration, while in the fall, they wander up in the Hudsonian
Zone before leaving for wintering grounds. Phillips and
Amadon (1952) found cassinii wintering in mesquite thickets
in Sonora, Mexico.
V FOOD
A. Food preferences
Martin et al. (1951) found that "the food of vireos is
primarily insects. .. caterpillars, moths, bugs, beetles,
wasps, ants, bees, and flies. Spiders are also taken."
Bent (1950) stated that animal matter accounted for 98.0%
of the diet--Hemiptera (51.0%), Lepidoptera (23.0%).
B. Foraging areas
Bent (1950) reported that this vireo "lives mainly in trees
of the forest and obtains most of its food among the twigs
and foliage." Hamilton (1962) described V. solitarius as
an "arboreal forager", utilizing the crown- to- shrub area
of a woodland.
C. Foraging strategies
The Solitary Vireo was described as a "foliage gleaner"
by Bent (1950). Hamilton (1962) noted that Solitary Vireos
normally glean broadleaved foliage for insects.
D. Feeding phenology
Bent (1950) reported that although vegetable matter makes
up less than 5% of the yearly diet of this species, up to
one quarter of the diet may be plant material during winter
(January) .
E. Energy requirements
»
' ^
Vireo solitarius (con't.)
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
The male apparently wanders about the territory while sing-
ing, with no fixed singing post (Bent 1950).
C. Courtship and mating behavior
Bent (1950) recounted that the male "bobs and bows to the
female... and sings repeatedly." In New Mexico, Tatschl
(1967) noted singing males between 28 April and 26 September.
D. Nesting phenology
Bent (1950) gives California egg dates as "100 records,
April 26 to July 9; 52 records, May 20 to June 6, indicating
the height of the season."
E. Length of incubation period
Bent (1950) concluded that the incubation period was at
least 11 days; both sexes incubate. C>
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
VII POPULATION PARAMETERS
A. Clutch size
Bent (1950) reported that cassinii lays 3-5 eggs. Ligon
(1961), "Eggs: 4; white, lightly spotted around larger end
with brown and black,"
B. Fledging success
C. Mortality rates per age class
In southern California, Edwards (1919) noted the frequent
destruction of nests and eggs by rain and windstorms.
D. Longevity
<
Vireo solitarius (con't.)
E. Seasonal abundance
In Oregon, Anderson (1970) located 8 Solitary Vireos per
100 acres between June and February, but only 4 per 100
acres between March and May.
F. Habitat density figures
In white oak stands of Oregon, Anderson (1970) found 4 to
8 Solitary Vireos per 100 acres during all season of the year.
In an oak-juniper-pine woodland of southern Arizona, Balda
(1970) reported 5 breeding pair per 100 acres. Bock and
Lynch (1970) found 0.5 pair of Solitary Vireos breeding per
100 acres in an unburned conifer forest of the Sierra Nevada;
this species was not present in a similar, but burned, plot.
In a ponderosa pine forest in southeastern Arizona, Balda
(1969; recorded a breeding population of 14 pair of Solitary
Vireos per 100 acres. Johnston (1949) found a breeding
density of 10 to 20 pairs per 100 acres in a Douglas fir
dominated area in Idaho. Launderslayer and Balda (1976)
found 9.9 pairs per 100 ha in a Arizona pinyon-juniper-
ponderosa pine ecotone.
jVIII INTERSPECIFIC INTERACTIONS
A. Predation
B. Competition
Hamilton (1962) found that in areas of sympatry, V. solitarius,
V. atricapillus, and V. vicinior reduce competition through
altitudinal segregation.
C. Parasitism
Friedmann (1963) and Friedmann et al. (1977) found that
6.7% of cassinii nests were parasitized by Brown-headed
Cowbirds.
IX STATUS
A. Past population trends
Grinnell and Miller (1944) called cassinii "common" in Calif-
ornia. In Oregon, cassinii was called "second in abundance
among Oregon members of the family" by Gabriel son and
Jewett (1940).
8
Vireo solitarius (con't.)
B. Present population status
In Montana, Weydemeyer (1975) reported that solitarius
"has been dwindling in numbers for the past 15 or 20 years
However, Johnson (1974) noted that in southern Nevada,
"Solitary Vireo. .. either colonized for the first time...
or definitely increased in number in both the Grapevine
Mountains and on Potosi Mountain." Johnson and Garrett
(1974) noted that "the breeding range of V. s. plumb eus
has undergone a major westward expansion ourTng the last
decade"; race is moving into California.
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
<>
«~
Vireo solitarius (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American Birds. Fifth Edition. American Ornithologists'
Union, Baltimore, MD. 691 pp.
Anderson, S. H. 1970. The avifaunal composition of Oregon
white oak stands. Condor 72:417-423.
Balda, R. P. 1969. Foliage use by birds of the oak-juniper
woodland and ponderosa pine forest in southeastern Arizona.
Condor 71:399-412.
Balda, R. P. 1970. Effects of spring leaf-fall on composition
and density of breeding birds in two southern Arizona wood-
lands. Condor 72:325-331.
Bent, A. C. 1950. Life histories of North American wagtails,
shrikes, vireos, and their allies. U. S. Nat. Mus. Bull.
197:1-411.
Bock, C. E. and J. F. Lynch. 1970. Breeding bird population
of burned and unburned conifer forest in the Sierra Nevada.
Condor 72:182-189.
Cardiff, E. A. 1963. Solitary vireo of the race Plumbeus in
California. Condor 65:534.
Carter, F. 1937. Bird life at Twentynine Palms. Condor 39:
210-219.
De Benedictis, P. and R. G. McCaskie. 1967. Cassin's King-
bird and plumbeous Solitary Vireo in the White Mountains
of California. Condor 69:424-425.
Dixon, J. S. 1943. Birds of the Kings Canyon National Park
area of California. Condor 45:205-219.
Edwards, H. A. 1919. Losses suffered by breeding birds in
southern California. Condor 21:65-68.
Friedmann, H. 1963. Host relations of the parasitic cowbirds.
U.S. Nat. Mus. Bull. 233:1-276.
Friedmann, H. , L. F. Kiff and S. I. Rothstein. 1977. A further
contribution to knowledge of the host relations of the
parasitic cowbirds. Smithsonian Contrib. Zool. 235. 75 pp.
Gabrielson, I. N. and S. G. Jewett. 1940. Birds of Oregon.
Oregon St. Univ., Corvallis. 650 pp.
m
10
Vireo solitarius (con't)
Grinnell, J. 1908. The biota of the San Bernardino Mountains.
Univ. California Publ. Zool. 5:1-170.
Grinnell, J. 1914. An account of the mammals and birds of the
lower Colorado Valley. Univ. California Publ. Zool. 12:
51-294.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27. 608
pp.
Grinnell, J. and T. I. Storer. 1924. Animal life in the Yose-
mite. Univ. California Press, Berkeley. 752 pp.
Grinnell, J. and H. S. Swarth. 1913. An account of the birds
and mammals of the San Jacinto area of southern California.
Univ. California Publ. Zool. 10:197-406.
Hamilton, T. H. 1958. Adaptive variation in the genus Vireo.
Wilson Bull. 70:307-346.
Hamilton, T. H. 1962. Species relationships and adaptations
for sympatry in the avian genus Vireo. Condor 64:40-68.
Hellmayr, C. E. 1935. Catalogue of birds of the Americas. ^jfek
Vol. 13, Part 8. Field Mus. Nat. Hist. Zool. Ser. 347.
541 pp.
Johnston, D. W. 1949. Populations and distribution of summer
birds of Latah County, Idaho. Condor 51:140-149.
Johnson, D. H. , M. D. Bryant and A. H. Miller. 1948. Verte-
brate animals of the Providence Mountains area of Calif-
ornia. Univ. California Publ. Zool. 48:221-376.
Johnson, N. K. 1974. Montane avifaunas of southern Nevada:
Historical change in species composition. Condor 76:334-
337.
Johnson, N. K. and K. L. Garrett. 1974. Interior bird species
expand breeding ranges into southern California. Western
Birds 5:45-56.
Laundens layer, W. F., Jr. and R. P. Balda. 1976. Breeding
bird use of a pinyon-juniper-ponderosa pine ecotone. Auk
93:571-586.
Ligon, S. J. 1961. New Mexico birds. Univ. New Mexico Press,
Albuquerque. 360 pp.
Martin, A. C. , H. S. Zim-, and A. L. Nelson. 1951. American
wildlife and plants. McGraw-Hill Book Co., Inc., N.Y.
500 pp.
«-
11
Vireo solitarius ( con ' t . )
McCaskie, R. S. 1968. Noteworthy records of vireos in Calif-
ornia. Condor 70:186.
Miller, A. H. 1945. Birds of the yellow pine association of
Potosi Mountain, southern Nevada. Condor 47:130-131.
Miller, A. H. and R. C. Stebbins. 1964. The lives of desert
animals in Joshua Tree National Monument. Univ. California
Press, Berkeley. 452 pp.
Peterson, R. T. 1961. A field guide to western birds. 2nd
Edition. Houghton Mifflin Co., Boston. 366 pp.
Phillips, A. R. and D. Amadon. 1952. Some birds of north-
western Sonora, Mexico. Condor 54:163-168.
Ridgway, R. 1904. The birds of North and Middle America.
Part 3. U.S. Nat. Mus. Bull. 50. 801. pp.
Small, A. 1974. The birds of California. Winchester Press,
N.Y. 310 pp.
Tatschl, J. L. 1967. Breeding birds of the Sandia Mountains
and their ecological distributions. Condor 69:479-490.
Van Rossem, A. J. 1936. Birds of the Charleston Mountains
Nevada. Pacific Coast Avifauna No. 24. 65 pp.
Weydemeyer, W. 1975. Half-century record of the breeding
birds of the Fortine area, Montana: Nesting data and popu-
lation status. Condor 77:281-287.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. 6. 39 pp.
>£:
o
SONG SPARROW
Melospiza melodia
I TAXONOMY
A. Type description
AOU (1957) Melospiza melodia melodia (Wilson); Fringilla
melodia Wilson, Amer. Orn. , vol. 2, 1810, p. 125, pi. TE,
fig. 4. (Canada to Georgia = Philadelphia, Pennsylvania.)
Melospiza melodia montana Henshaw; Melospiza fasciata montana
Henshaw, Auk, 1, no. 3, July 1884, p. 224. (Fort Bridger,
Utah f}= Wyoming} . )
Melospiza melodia merrilli Brewster; Melospiza fasciata
merrilli Brewster, Auk, 13, no. 1, Jan"! 189b, p~ 4b.
(Fort Sherman, Idaho.)
Melospiza melodia fisherella Oberholser, Proc. Biol. Soc.
Washington, 24, no. 49, Dec. 23, 1911, p. 251. (Honey Lake,
near Millford, California.)
Melospiza melodia cooperi Ridgway; Melospiza fasciata cooperi
Ridgway, Auk, lb, no. 1, Jan. 1899, p. 35. (San Diego,
California. )
Melospiza melodia saltonis Grinnell, Univ. California Publ.
Zool. , 57 no. 3, Apr. T", T909, p. 268. (One mile southeast
of Mecca, "Colorado Desert, California.)
B. Current systematic treatments
AOU (1957) places Melospiza melodia in the Order Passeri-
formes, Family Fringiilidae, and lists 31 races. Linsdale
(1928) suggests that Melospiza and Passerella properly belong
in the same genus, as does Paynter (wI9b4/) , wHile Parkes
(1954) maintains that they should be separate.
C. Synonomies of scientific nomenclature
AOU (1957) lists the synonomies as above. Grinnell and
Miller (1944), M. m. montana - M. m. fall ax, part; M. m.
yirginis; M. m. fisherella, part; M. m. fisherella - Melospiza
fallax,~M. ruTina, M. fasciata, M. cinerea faliax~ M. m.
maiiliarai,~FassereTla melodia Tisherella: M. m. merrilli -
M. fasciata guttata, M. f. ingersolli, M. m. Tngersolli,
H. cinerea merrilli, H. m. morphnal M. m. cooperi -
ZonotrichiaTasciata, M. heermanni , M. m. heermanni , M.
fasciata heermanni, M. f. samueiis, H. T. grammea, MT f .
cooperi7 M. cinerea cooperi, M. mT santaecrucis: M. m.
saltoni's - M. fallax, M. m. fallax, M. cinerea falTax.
•
Melospiza melodia (con't.)
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944) list the following as synonomies
for the Song Sparrow: Rocky Mountain Song Sparrow, Modoc
Song Sparrow, Virgin River Song Sparrow, Mountain Song Spar-
row, Oregon Song Sparrow, Heerman Song Sparrow, Merrill
Song Sparrow, Desert Song Sparrow, Modesto Song Sparrow,
Tehama Song Sparrow, Calif ornian Song Sparrow, Samuel's Song
Sparrow, Santa Barbara Song Sparrow, Arizona Song Sparrow,
Western Song Sparrow, Salton Sink Song Sparrow.
II DESCRIPTION
A. External morphology of adults
Baird et al . (1905) describe the species as a whole as fol-
lows: general tint of upper parts rufous and distinctly
streaked dark-brown, and ashy-gray. The crown is rufous,
with a superciliary and median stripe of dull gray, the former
lighter; nearly white anteriorly, where it sometimes has
a faint shade of yellow, principally in autumn; each feather
of the crown with a narrow streak of black forming about
six narrow lines. Interscapulars black in the center, then
rufous, then pale grayish on the margin, these three colors
on each feather very sharply contrasted. Rump grayer than
upper- tail coverts, both with obsolete dark streaks. There
is a whitish maxillary stripe, bordered above and below
by one of dark rufous-brown, and with another from behind
the eye. The underparts are white; the jugulum and sides
of body streaked with clear dark-brown, sometimes with a
rufous suffusion. On the middle of the breast these marks
are rather aggregated so as to form a spot. No distinct
white on tail or wings. Specimens vary somewhat in having
the streaks across the breast more or less sparse, the spot
more or less distinct. In autumn the colors are more
blended. Peterson (1961): "Note the heavy breast streaks
confluent into a large central spot. Many subspecies vary
in color and size; those of arid sections are paler; those
in humid regions darker. Oberholser (1974) gives measure-
ments for the races. Marshall (1948b) gives detailed
descriptions of adults for the races occurring around the
San Francisco Bay region.
B. External morphology of subadult age classes
Baird et al. (1905) describes young as having upper parts
paler, the streaks more distinct; the lines on the head
scarcely appreciable. The underparts are yellowish; the
streaks narrower and more sharply defined dark brown.
Peterson (1961): "...more finely streaked, often without
central spot."
Melospiza melodia (con't.)
C. Distinguishing characteristics
Intraspecific - Bent (1968): "montana is similar to melodia,
but wing, tail and tarsi averaging longer, bill smaller
and relatively more slender, coloration grayer. Merrilli
is very similar to montana but slightly darker and more
uniform above, with grayish edges to the interscapulars and
scapulars less strongly contrasted with the darker mesial
streaks. Fisherella. . .similar to heermanni but larger;
upper surface paler, less rufuscent"; streaks on lower parts
less blackish. Fisherella differs from montana in its darker
upper parts, more blackish brown streaks of under surface,
heavier bill, and shorter wing. Cooperi . . . similar to
heermanni but slightly smaller and coloration much lighter
and grayer; prevailing color of the back, etc., grayish
olive, the back broadly streaked with black streaks with little
if any, rusty external suffusion. Saltonis. . .resembling
fallax but very much paler throughout , the ground color being
white ventral ly and ashy dorsally, with streaking of pale
hazel; superciliary stripe wholly white; general size much
less than montana. Robbins et al. (1966): "Geographic races
vary from rusty to gray and light to dark." Wolf son (1955)
describes some races on the Pacific coast and their variation.
Marshall (1948a & b) describes race variation in California.
Interspecific - Peterson (1961): "Savannah Sparrow often
shows yellow average, has pinker legs, shorter notched tail.
Fox Sparrow is larger, more- heavily marked." Robbins et al.
(1966) add that it lacks a yellow or buffy color.
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution
AOU (1957) Melospiza melodia, "Aleutian Islands, southern
Alaska, southern Yukon, southern Mackenzie, northern
Saskatchewan, northern Manitoba, northern Ontario, central
Quebec, and Newfoundland south to south-central Baja Calif-
ornia, northern Sonora, Michoacan, and Puebla; and to north-
ern New Mexico, northeastern Kansas, northern Arkansas,
southeastern Tennessee, northern Georgia, and northwestern
South Carolina.
M. m. montana: "Breeds from northeastern Oregon, central
western Idaho, and north- central Montana, south to eastern
Nevada, southwestern Utah, central eastern Arizona, and
northern New Mexico."
•
M. m. merrilli: "Breeds from southern interior British
Columbia and southwestern Alberta south to eastern Wash-
ington, east of the Cascade Range, northern Idaho, and north-
western Montana."
Melospiza melodia (con't.)
M. m. fisherella; "Breeds from northeastern Oregon, east
of the Cascade Range and west of the Blue Mountains, and
extreme southwestern Idaho south to south-central Oregon,
north-central and central eastern California, and western
Nevada."
M. m. cooperi : "Resident in the coastal districts of southern
California from Santa Cruz County southward to northern Baja
California, as far as at lat. 30° N. ; east to streams pene-
trating Mohave and Colorado deserts. f
M. m. saltonis; "Resident in lower Colorado River Valley
Th extreme southern Nevada, southeastern California, western
Arizona, northwestern Baja California, and northwestern
Sonora, extending northwest through Imperial Valley of Calif-
ornia. Casual is desert area of southeastern California, south-
central Arizona, and northwestern Sonora.
Bent (1968), M. m. montana: "Northeastern Oregon and north-
central Montana to southeastern California, northern Sonora,
central Chihuahua, and western Texas."
M. m. merrilli: "Southern interior British Columbia and
southwestern Albert south to southern California, southern
Utah, and northern New Mexico."
M. m. fisheri: "Northeastern Oregon and southwestern Idaho
south to southern California."
M. m. cooperi : "The San Diego Song Sparrow is resident in
the coastal districts of southern California from Santa Cruz
County southward to northern Baja California; east to streams
penetrating Mohave and Colorado Deserts."
M._m. saltonis: "The Desert Song Sparrow is resident in
"the lower Colorado Valley in extreme southern Nevada, south-
eastern California, western Arizona, northwestern Baja
California, and northwestern Sonora, extending northwest
through Imperial Valley, California."
Phillips (1964) list montana, saltoni, uddi, fisherella,
merrilli and ruf ina as occurring in Arizona. Gabrielson
and Jewett (1940) say that fallax merges into fisherella
as you go east in Oregon.
B. California distribution
Grinnell and Miller (1944), M. m. montana: "Known princi-
pally from Death Valley, Inyo County, and Colorado River
Valley south to Fort Yuma, Imperial County; recorded also
from Riverside County."
v-
Melospiza melodia (con't.)
M. m. fisherella; "Summer resident in northern interior and
eastern sections, and on considerable numbers present there
throughout the year. Partial migration in late September
and October accounts for appearance of winter visitants to
southward and westward. As breeding, Great Basin region
from Oregon line southward along eastern flank of Sierras
through Owens Valley, and westward through lower mountains
and valleys, exclusive of coastal belt, from Klamath River
Valley and Shasta Valley south to upper Trinity River System
and in Sacramento drainage to Tehama County."
M. m. merrilli: "Chiefly Sacramento Valley, northern San
Joaquin Valley, and surrounding foothills, but recorded also
from lower and middle elevations in State, generally from
Oregon line south to Mohave Desert and Los Angeles County,
exclusive of northern coastal strip."
M. m. cooperi: "Valleys of coast ranges from southern
Monterey County southward, and Pacific slopes of southern
California south to Mexican boundary; extends eastward
across desert divides into Mohave drainage and to streams
on east side of San Jacinto Mountains of San Diego County."
M. m. saltonis: "Valley of Colorado River from Nevada line
to Mexican boundary and waterways of Imperial Valley north
to vicinity of Sal ton Sea in Imperial and Riverside Counties,
Twice recorded as a vagrant in the Mohave-Inyo region."
Grinnell (1928) discusses the distribution of cooperi,
cor onator ium , saltonis and rivularis in Baja California.
Marshall (,1948a! says there are eleven races breeding in
California, and no two of them occur together during the
breeding season.
C. California desert distribution
Grinnell and Miller (1944) list montana as occurring in
Inyo, Imperial and Riverside Counties. Fisherella occurs
in Owens Valley, Klamath River Valley, upper Trinity River
System. In winter it is found on the western part of the
Mohave desert, rarely to Coachella Valley. These two races
are not sharply contrasted in the western part of the Great
Basin. Merrilli occurs in the Mohave desert, Los Angeles
County, Inyo and San Bernardino Counties. Cooperi extends
into the Mohave River drainage and to streams on east side
of San Jacinto Mountains, and mountains of San Diego County.
Records from San Bernardino, Riverside, San Diego and Los
Angeles Counties. Saltonis is found in the Colorado River
Valley and waterways in Imperial Valley north to vicinity
of Sal ton Sea in Imperial and Riverside Counties. Twice re-
corded as a vagrant in Mohave- Inyo region. Records from
Riverside, San Bernardino, Imperial and Inyo Counties.
Melospiza melodia (con't.)
Willett (1951) only lists saltonis as being a resident of
the California desert. "Resident of watered sections of
Colorado River and Imperial Valleys, north to Sal ton Sea."
D. Seasonal variations in distribution
AOU (1957), M. m. montana : "Winters throughout the breeding
range and south to southeastern California, northern Sonora,
central Chihuahua, and western Texas; east casually to
western Nebraska, western Kansas, and western Oklahoma."
M. m. merrilli : "Winters from southern interior British
Columbia and northwestern Montana west to western Washington
and south to southern California, southern Nevada, southern
Utah and northern New Mexico. Casually to southern Arizona
and northern Sonora."
M. m. fisheri: "Winters throughout breeding range south to
western and southern California; rarely to northern Sonora
and southern Arizona."
M. m. cooperi: Winters throughout breeding range.
M. m. saltonis: Winters throughout breeding range.
Dawson (1923): "California Song Sparrows are sedentary
save in the territory east of the Sierras, where increased
altitudes and lower temperatures enforce evacuation in
winter." Small (1974): "Common resident but birds of
Mountains and Great Basin move to lowlands for winter."
Marshall (1948a) describes the more northern races as
being migratory.
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944) report Song Sparrows breeding
in thickets arrowweed, and willows and reeds at the edges
of ditches and river courses. Life- zones in summer, Lower
Sonoran, Upper Sonoran and Transition. In general they
favor riparian growth and damp places, freshwater marshes
and garden shrubbery. Reported tule beds and cattails.
Saltonis has occasionally been noted in mesquite thickets
at some distance from water.
Baird et al . (1905): "The birds are found in almost any
cultivated locality where the grounds are sufficiently open.
They prefer the edges of open fields, and those of meadows
and low grounds, but are rarely found in woods or in thick
bushes, except near their outer edges.
Melospiza melodia (con't.)
} Bent et al . (1968): "...water-edge vegetation, whether it
be marshes around mountain lakes,.... in stream-side willows,
...or in boggy areas of cultivated fields and meadows...
clumps of dead tule...into sagebrush. . .dense thickets 6 to
10 feet high along open water." Peterson (1961): "Thickets,
brush, marshes, roadsides, gardens, seabeaches." Small
(1974): "Streamside thickets, tangles, weed thickets, thickets
of willows and reeds at edges of watercourses, marshes,
lake borders, brushpiles, gardens, shrubs, edges of marshes."
Phillips, et al. (1964), for song sparrows in Arizona:
"Locally common resident of reed- sedge-brush types along
major permanent rivers... and on permanent brush-lined streams.
Rather common winter resident locally at reedy ponds, brushy
streams, and farmlands with brushy, weedy edges." They refer
to three types of Song Sparrows by biotopic affinity (1)
saltonis, fallax - desert, (2) montana, fisherella, juddi -
mountain, (3) merrilli, rufina - northwest.
Marshall (1948a): "...is a characteristic inhabitant of
vegetation growing in wet places..." Evidentally fisherella
can forage in drier brush than some of the other races.
B. Altitudinal range
k Grinnell and Miller (1944) - From near sea level up to 8,000
feet. Bent et al. (1968) - From near sea level to as high
as 9,000 feet.
C. Home range size
Marshall (1948a) - 2/3 acre per pair roughly. He goes on
to describe reasons for variation in range size which are
generally related to food availability. Nice (1931b) has
similar data. Suthers (1960) gives a range of 0.30 to 0.65
acre for territory size.
D. Territory requirements
Perch sites
Courtship and mating sites
Nest sites - Grinnell and Miller (1944): "Nests are placed
in the vegetation above the mud which marks flood level."
Baird et al. (1905): "They nest naturally on the ground,"
and in bushes above the ground. Bent et al. (1968): "Ground
nests appear to be the commonest and are built in grass,
alfalfa, in hollows under sage and willows, among ferns
under fallen trees.
Melospiza melodia (con't.)
E. Special habitat requirements <-g0
Grinnell and Miller (1944): "The presence of water is essen-
tial, coupled with cover." Phillips et al. (1964) state
that south-central Arizona Song Sparrows have led a pre-
carious existence, depending on water as they do. Marshall
(1948a) gives detailed descriptions of habitat used by Song
Sparrows in California. Two of the most important factors
are moisture and light. Whitmore (1977) discusses habitat
partitioning in some passerines saying that song sparrows
are high shrub density species with little canopy cover and
moderate ground cover.
F. Seasonal changes in habitat requirements
Oberholser (1974) says that Song Sparrows appear restricted
in habitat use during migration, using cattails, tall grass
or weed patches, and bushes growing near streams or lakes.
V FOOD
A. Food preferences
Baird et al. (1905) - insects, caterpillars, larvae, moths.
Bent et al. (1968) give estimated plant food consumption as
60% of total diet. Oberholser (1974) describes Song Sparrows
as eating varied food depending on their location; crustaceans,
mollusks, seeds.
B. Foraging areas
Grinnell and Miller (1944): "The birds forage short distances
out into grassy or weedy places and about root tangles and
piles of wood. ' Bent et al. (1968) report them foraging
along open water often with their feet in the water.
C. Foraging strategies
Oberholser (1974) describes Song Sparrows as being the most
plastic passerine species in reference to feeding behavior.
Marshall (1948a) says that he has never seen them eating
seeds off a plant but apparently they must wait for the
seeds to fall to the ground. Nice (1940) describes anting
in Song Sparrows.
D. Feeding phenology
Oberholser (1974): "Especially in warm months, it gleans
beetles, grasshoppers, crickets, caterpillars, and ants."
E. Energy requirements
Melospiza melodia (con't.)
^"i REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Nice (1934): "Some resident males begin to proclaim their
territories in late January or early February, according
to the weather." Nice (1936c) reports song sparrows in Ohio
to be very "sessile" on territories. The male chooses the
territory. The female returns to her previous nesting site
or as near as possible. Nice (1931a) in a paper on song
sparrows returning to breeding grounds says that males
go directly to their territories.
C. Courtship and mating behavior
Martin (1977) discusses the functional aspects of song in
the Fox and Song Sparrows. Nice (1933c) describes mate
fidelity in song sparrows in Ohio.
D. Nesting phenology
Bent et al. (1968) report the breeding season to begin about
5 February and end about 5 July. Oberholser (1974) says that
^ females commonly raise three broods a year. Nice (1931a)
W gives arrival dates in spring as 8 February to 26 March.
Nice (1931b): "...nesting began in mid-April.
E. Length of incubation period
Nice (1940) - 13 days.
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
Oberholser (1944) reports that Song Sparrows seldom sing
on their southern wintering grounds. Nice (1934) says the
male usually indulges in singing on his territory after the
molt in the fall.
VII POPULATION PARAMETERS
A. Clutch size
Baird et al. (1905) - 4 to 5. Bent et al. (1968) - 3.69
mean. Peterson (1961) - 3 to 5. Gabrielson and Jewett
(1940) - 4 to 5. Nice (1933b) - 1 to 5.
10
Melospiza melodia (con't.)
B. Fledging success
Nice (1933b): "In 1930 the numbers of young fledged per
pair by 15 pairs that survived the season were as follows:
0,2,2,3,3,3,4,4,4,4,5,6,7,7,10; an average of 4.3 per pair.
She calculated 3.2 young raised per successful nest over a
3-year period.
C. Mortality rates per age class
Nice (1933a) gives mortality for eggs and young in 3 years.
Nice (1933c) says that mortality of adult males and females
is very high each year. Nice (1931b): "Mortality during the
14 to 18 days of parental care after the young leave the
nest is hard to keep track of... 3 broods were wiped out...
but at least some of 19 broods were reared to independence."
D. Longevity
Kennard (1975) gives the oldest banded song sparrow as 10
years 4 months.
E. Seasonal abundance
Nice (1933a): "It is possible that the weather in October
may have something to do with some of the birds staying
or leaving."
F. Habitat density figures
Bent et al. (1968): "Population density was approximately
3 individuals per 10 acres." Wolf son (1955) describes an
effective breeding unit as an area of about 400 meters'
radius and about 150 individuals. Nice (1931a) presents
maps of territories for an area in Ohio. Nice (1931b)
had 64 pairs living on 50 acres in Columbus, Ohio.
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Nice (1931b) lists dogs, cats and rats as nest predators.
She also saw a Ring-necked Pheasant empty a nest.
B. Competition
Marshall (1948a) reports that habitat is shared in winter
with White-crowned and Lincoln Sparrows. Gorton (1977)
found song sparrows to be intensely intraspecif ically terri-
torial.
11
Melospiza melodia (con't.)
P C. Parasitism
Friedmann et al. (1977) list these records of parasitism
by the cowbird from sets of eggs at the Western Foundation
of Vert. Zool.: M. m. montana - 2 sets; M. m. cooperi -
16 sets; M. m. saltonis - 5 sets; M. m. fTsherella - 4 sets.
They report the Song Sparrow is a common and good host.
Nice (1933b) notes cowbird parasitism in some song sparrow
nests.
IX STATUS
A. Past population trends
Dawson (1948) describes fossil specimens of M. melodia found
at Rancho La Brea.
B. Present population status
Grinnell and Miller (1944) believe that the development of
irrigation has increased the total population of saltonis
in the last 30 years.
C. Population limiting factors
P Dawson (1923): "A young Song Sparrow is the choice morsel
for everything that preys--cats, skunks, weasels, chipmunks,
foxes, hawks, crows, magpies, jays, snakes."
D. Environmental quality: adverse impacts
E. Potential for endangered status
12
Melospiza melodia (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Baird, S. F. , T. M. Brewer and R. Ridgway. 1905. A history
of North American birds. Vol. 2. Little, Brown, and Co.,
Boston.
Bent, A. C. and collaborators. 1968. Life histories of North
American cardinals, grosbeaks, buntings, towhees, finches,
sparrows, and allies. Part Three. U.S. Natl. Mus. Bull.
No. 237.
Dawson, W. L. 1923. The birds of California. Vol. 1. South
Moulton Co., Los Angeles.
Dawson, W. R. 1948. Records of fringillids from the pleisto-
cene of Rancho La Brea. Condor 50:57-63.
Eberhardt, C. and L. F. Baptista. 1977. Intraspecif ic and
interspecific song mimesis in California song sparrows.
Bird-Banding 48:193-205.
Friedmann, H. , L. F. Kiff and S. I. Rothstein. 1977. A further
contribution to knowledge of the host relations of the para-
sitic cowbirds. Smithsonian Contrib. Zool. No. 235. 75 pp.
Gabrielson, I. N. and S. G. Jewett. 1940. Birds of Oregon.
Oregon State College, Corvallis, 650 pp
Gorton, R. E. , Jr. 1977. Territorial interactions in sympatric
song sparrow and Bewick's wren populations. Auk 94:701-708.
Grinnell, J. 1928. A distributional summation of the ornithology
of lower California. Univ. of California Publ. Zool. 32:
1-300.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna. No. 27.
608 pp.
Harris, M. A. and R. E. Lemon. 1974. Songs of song sparrows:
reactions of males to songs of different localities. Condor
76:33-44.
Hoyt, S. F. 1961. Nest-building movements performed by juvenile
song sparrow. Wil. Bui. 73:386-387.
Kennard, J. H. 1975. Longevity records of North American birds.
Bird-Banding 46:55-73.
13
Melospiza melodia (con't.)
Linsdale, J. M. 1928. The species and subspecies of the
fringillid genus Passerella Swainson. Condor 30:349-351.
Marshall, J. T. , Jr. 1948a. Ecological races of Song Sparrows
in the San Francisco Bay region. Part I. Habitat and
Abundance. Condor 50:193-215.
Marshall, J. T. , Jr. 1948b. Ecological races of Song Sparrows
in the San Francisco Bay region. Part II. Geographic
variation. Condor 50:233-256.
Martin, D. J. 1977. Songs of the Fox Sparrow. I. Structure
of song and its comparison with song in other emberizidae.
Condor 79:209-221.
Nice, M. M. 1930. The technique of studying nesting song
sparrows. Bird-Banding 1:177-181.
Nice, M. M. 1931a. Returns of song sparrows in 1931. Bird-
Banding 2:89-98.
Nice, M. M. 1931b. Survival and reproduction in a song sparrow
population during one season. Wil. Bull. 43:91-102.
Nice, M. M. 1933a. Migratory behavior in song sparrows. Condor
35:219-224.
Nice, M. M. 1933b. Nesting success during three seasons in
a song sparrow population. Bird-Banding 4:119-131.
Nice, M. M. 1933c. Relations between the sexes in song spar-
rows. Wil. Bull. 45:51-59.
Nice, M. M. 1934. Song sparrows and territory. Condor 36:
49-57.
Nice, M. M. 1937. Studies in the life history of the song
sparrow I. A population study of the song sparrow. Trans.
Linn. Soc. , N.Y. 4:1-247.
Nice, M. M. 1939. What determines the time of the song sparrow's
awakening song? Proc. of the IX International Ornithological
Congress, Roven.
Nice, M. M. 1940. Anting by the song sparrow. Auk 57:520-522.
Nice, M. M. 1943. Studies in the life history of the song spar-
row III. The behavior of the song sparrow and other passerines.
Trans. Linn. Soc, N.Y. 6:1-328.
Nice, M. M. 1953. The question of ten-day incubation periods.
Wil. Bull. 65:81-93.
14
Melospiza melodia (con't.)
Oberholser, H. C. 1974. The bird life of Texas. Vol. 2.
Univ. of Texas Press, Austin.
Parkes, K. C. 1954. Notes on some birds of the Adirondack and
Catskill mountains, New York. Ann. Carnegie Mus. 33:149-
178.
Paynter, R. A. 1964. Generic limits of Zonotricha. Condor
66:277-287.
Peterson, R. T. 1961. A field guide to western birds. Second
Edition. Houghton Mifflin, Co., Boston. 366 pp.
Phillips, A., J. Marshall, G. Monson. 1964. The birds of
Arizona. Univ. of Arizona Press, Tucson. 212 pp.
Phillips, A. R. and R. W. Dickerman. 1957. Notes on the song
sparrow of the Mexican plateau. Auk 74:376-382.
Robbins, C. S. , B. Bruun and H. S. Zim. 1966. Birds of North
America. Western Publ. Co., Wisconsin. 340 pp.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Suthers, R. A. 1960. Measurement of some lake- shore territories
of the song sparrow. Wil. Bull. 72:232-237.
Whitmore, R. C. 1977. Habitat partitioning in a community of
passerine birds. Wil. Bull. 89:253-265.
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna. No. 21. 204 pp.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. No. 6. 39 pp
Wolfson, A., Ed. 1955. Recent studies in avian biology. Univ.
of Illinois Press, Urbana. 479 pp.
9
I TURKEY VULTURE
Cathartes aura
I TAXONOMY
A. Type description
AOU (1957), Cathartes aura teter Friedmann, Proc. Biol.
Soc. Washington, 46, Oct. 2TT, H)33, p. 188. (Riverside,
California. J
B. Current systematic treatments
AOU (1957) recognizes 3 subspecies of C. aura; 4 species
in the Genus Cathartes, Family CathartTdae, Super family
Cathartoidea, suborder Cathartae, Order Falconiformes.
Taverner (1926) recognizes one subspecies, C. a. septen-
trionalis, the Northern Turkey Vulture, in the Family
Cathartidae, Suborder Sarcorhamphi, Order Raptores.
Brown and Amadon (1968) don't recognize teter, but put the
western United States subspecies under C. a. aura. Wetmore
(1964) calls teter C. a. meridionalis, comBining the two
as one.
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), Western Turkey Vulture, C. aura;
Rhinogryphus aura; Oenops aura; C. aurea ; C. a. septen-
trionalis. Wetmore (1964) : C. a. meridionalis.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944): Turkey Vulture; Turkey Buzzard;
Red-headed Turkey Vulture; Red-headed Vulture; Northern
Turkey Vulture; May (1935): Carrion Crow, John Crow, Red-
headed Buzzard.
II DESCRIPTION
A. External morphology of adults
Dawson (1923): Head and neck all naked, livid crimson;
above a lustrous black with purple, varied grayish brown
edgings of feathers; plumage changing below to more uniform
sooty brown, lustrous only on the breast; wing-quills and
retrices light to dusky below, with whitish shaft; primaries
deeply emarginate; iris brownish gray; bill dull white; cere
bright red. Dawson (1923) also give measurements. Taverner
(1926) feet resemble those of a chicken rather than a hawk;
claws are blunt and foot is poorly adapted for seizing or
holding prey. Peterson (196!) sexes alike; 2- toned blackish
wings (flight feathers lighter than wing linings) ; nearly
eagle size; soars with wings slightly above Tiorizontal.
Cathartes aura (con't.)
B. External morphology of subadult age classes
Dawson (1923) Similar to adult but dusky on head and neck,
with grayish brown feathers; bill blackish.
C. Distinguishing characteristics
Interspecific - Peterson (1961); diminutive head and slimmer
tail distinguish Turkey Vultures from eagles. Brown and
Amadon (1968); very similar to Yellow-headed Vulture, dis-
tinguished by red, not yellow, head and by darker base of
wing in flight. Zone- tailed Hawk has a similar flight
profile, but its tail has white bars.
Intraspecific - Grossman and Hamlet (1964): Most do not
differ noticeably, but populations in the Amazon rain forest
are darker; green and bronze- glossed plumage occurs in the
Falkland Island race.
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957): Breeds from southern British Columbia, central
Alberta, Saskatchewan, southern Manitoba, western Ontario,
northern Minnesota, and Wisconsin south to southern Baja
California, and in the interior of Mexico to Colima, Jalisco,
Guanajuato, Michoacan, and Districto Federal; east to eastern
Texas. Grinnell and Miller (1944): In summer seen more
or less commonly from Mexican line to Oregon line, and from
seashore to Nevada line and up to altitudes of 10,000 feet
in Sierra Nevada, as on Mount Dana, Tuolumme County. Breeds
chiefly in the upper Sonoran Zone. Dawson (1923): North
America from the southern portions of the western Canadian
Provinces, southwestern Ontario, southern New York, and
New Jersey, south to northern Mexico and southern lower
California. Phillips et al. (1964) describe the Turkey
Vulture as a common summer resident, except in extensive
forested areas, in Arizona. In southern Nevada, Gullion
et al. (1959) describe the Turkey Vulture as "primarily
spring and fall migrants on the desert."
B. California distribution of the species
Grinnell and Miller (1944): "Sample localities. . .Modoc
County; Requa, Del Norte County; Cape Mendocino, Humboldt
County; San Francisco Bay area; Mount Diablo, Contra Costa
County; 15 miles northeast of San Jose in Alameda County;
Yosemite region; Fresno district, Fresno County; Elk Hills,
Kern County; Death Valley, Inyo County; Santa Barbara, Santa
Barbara County; Whittier, Los Angeles County; Buena Park,
Orange County; San Jacinto Mountains; Colorado River Valley."
»
Cathartes aura (con't.)
Dawson (1923): Resident south of the Tehachipe and casually
north to Vaca Valley, Solano County. Elsewhere found commonly
in spring, summer, fall throughout the State (California),
gave in the Boreal Zone. Most abundant in warmer sections,
and breeding almost exclusively in Upper Sonoran zone.
Small (1974), "length of the state. Breeds throughout
the State."
C. California desert distribution
Grinnell and Miller (1944): Yosemite region; Elk Hills,
Kern County; Death Valley, Inyo County. Willet (1951)
refers to calurus as a "migrant, probably resident locally,"
in the southern California desert.
D. Seasonal variations in distribution
Grinnell and Miller (1944): In winter, only west of the
Sierras and at low altitudes; there north to Red Bluff,
Tehama County and Ornbaun Springs, Mendocino County.
Grinnell (1915): remains throughout winter in small number
in the San Diegan district, and north interiorly at least
to Vaca Valley, Solano County. Dawson (1923): winters
easterly in all except the northern portion of its range,
but in the West retiring as far as Nebraska and California.
AOU (1957): Winters from California and Nebraska south to
Ecuador. One winter record for Vancouver Island. Small
(1974), "part of the population is resident and part is
migratory. "
IV HABITAT
A. Biotopic affinities
Dawson (1923) and Grinnell (1915); Upper Sonoran Zone.
Brown and Amadon (1968) refer to C. aura as a bird of open
plains, desert, forest, jungle an3 even high barren desert
plateau. Small (1974) "...over open country of mountains,
grasslands, deserts, savannahs, and agricultural lands."
B. Altitudinal range
Grinnell (1915): Breeds chiefly if not altogether in the
Upper Sonoran Zone. Dawson (1923): agrees with Grinnell
(1915), and adds that the bird is not a high flier.
C. Home range size
•
Cathartes aura (con't.)
D. Territory requirements *&
Perch sites - Griimell and Miller (1944): When roosting,
uses tree with open branch work. Brown and Amadon (1968);
"...rather slow in leaving the roost each morning. During
the middle of the day there are, except in rainy weather,
no vultures near the roost. . .The roost is sometimes shared
with Black Vultures. Neither species nests near the roost,
as a rule." Prather et al. (1976) report a roost in Virginia
containing 13 Black Vultures and 320 Turkey Vultures.
Courtship and mating sites - Brown and Amadon (1968); "Both
birds may roost in the nesting cavity for some time before
the eggs are laid."
Nest sites - Grinnell and Miller (1944): prefers shelter
of rocks or brush on steep hillsides, or cavities in cliff
faces. Dawson (1923): "in hollow trees, stumps, fallen
logs, crannies in cliffs; unlined." Taverner (1926); on
the ground usually in a hollow log, or under an upturned
stump. Brown and Amadon (1968), "eggs are laid in caves,
preferably ones with two entrances; in hollow logs or stumps,
or on the ground in dense inaccessible briar patches or
swamps. Occasionally. . .well above the ground." No real
nest is built.
m
E. Special habitat requirements
Brown <and Amadon (1968); may remain inactive in quiet air,
and for the same reason leaves its perch late in the morn-
ings.
F. Seasonal changes in habitat requirements.
V FOOD
A. Food preferences
Dawson (1923); no live food; gleaners and scavengers; noth-
ing is skipped, a dead frog, a snake. Taverner (1926);
they do not kill what they eat. Brown and Amadon (1968);
eat carrion and offal of all sorts, excrement of sea lions,
and exceptionally rotting fruit and vegetables. "It is
less apt to kill live young animals than is the Black
Vultuie, but sometimes takes young herons and ibises from
their nests and sucks the eggs."
B. Foraging areas
Grinnell and Miller (1944): over or on more or less open
terrain of mountain sides, hills, plains, beaches and deserts.
n
Cathartes aura (con't.)
Dawson (1923); cattle ranges are not particularly favored;
they will resort to seashores. Brown and Amadon (1968)
"...it secures much food from animals killed on highways..."
C. Foraging strategies
Dawson (1923); soars overhead watching the open ground.
Brown and Amadon (1968), "...its ability to find small
bits of food in dense vegetation is fabulous; in this it
is aided by a sense of smell." Rarely flies holding food
in its bill. "Although numbers may soar together over a
potential food source, or descend to eat together, the Turkey
Vulture is probably truly social only when roosting."
Temple (1969) reported watching Turkey Vultures causing
nestling herons to regurgitate, eating that and then re-
turning to its own nest to feed its young. Knowlton (1909);
"When they find a dead animal they will often remain near
it for days, resting by night in the trees nearby..." until
the whole thing is consumed."
D. Feeding phenology
Rea (1973) reports finding Turkey Vultures casting pellets;
a phenomenon not previously reported.
fr E. Energy requirements
Brown and Amadon (1968); "When asleep the body temperature
drops from 38 °C to 34 °C, an adaptation which must be of value
in retaining energy in a bird with a precarious food supply."
Heath (1962) reports temperature rising in a captive to 41 °C.
When trying to insert a temperature probe in the Turkey Vul-
ture. The surrounding room temperature was 15 °C. He hypo-
thesizes that temperatures are raised to this level during
flight.
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
C. Courtship add mating behavior
Brown and Amadon (1968); "A small group have sometimes been
seen to perform a rather ritualized display. Both sexes
participate in the whole nesting cycle." Loftin and Tyson
(1965); "Mating... is often preceded by a gregarious dance
...a number of vultures gather on a cleared area where they
go through a series of hops with wings outstretched..."
Upon examining the vultures tracks on sand where they had
Cathartes aura (con't.)
been hopping Loftin and Tyson (1965) found that the birds
were hopping in a figure-8 pattern.
D. Nesting phenology
Brown and Amadon (1968); return to breeding sites in early
to mid-March. "Nesting begins in March in Florida, but in
May or June farther north." Wheelock (1904); "...nesting
season... in California begins about April 15." The breeding
season is given as April 1 to June 15.
E. Length of incubation period
Brown & Amadon (1968); 38-41 days.
F. Length of nestling period
Brown & Amadon (1968); "...70 to 80 days, or even more."
Bent (1937) reports that Turkey Vultures must stay in the
nest until well over 10 weeks of age.
G. Growth rates
Brown & Amadon (1968); "The young open their eyes from the
first and are more alert and move about more easily than
young hawks. Bent (1937); "When about 37 days old... young
were still covered with down, but the primaries and second-
aries and their coverts were about 4 inches long... tail
feathers. . .about 3 inches long. . .When about 47 days old...
about 2/3 grown. . .about 60 days old... the wings appeared
...fully developed, the back was well feathered, and the
plumage was coming in on the sides of the breast, but the
neck and the remainder of the underparts were still downy."
H. Post-breeding behavior
Brown and Amadon (1968); migrate south 12th October to 13th
November. Phillips et al. (1964) describe migration as
taking place in spectacular flocks.
VII POPULATION PARAMETERS
A. Clutch size
Peterson (1961); "1-3, blotched." Brown and Amadon (1968);
"invariabiy 2 in number."
B. Fledging success
C. Mortality rates per age class
<•
Cathartes aura (con't.)
D. Longevity
Kennard (1975) didn't find any band returns for turkey
Vultures over 5 years old but the oldest Black Vulture
he found was 16 years, 6 months.
E. Seasonal abundance
F. Habitat density figures
Brown and Amadon (1968); "A typical roost might contain
thirty vultures but perhaps some are much larger."
VIII INTERSPECIFIC INTERACTIONS
A. Predation
B. Competition
Grossman and Hamlet (1964) report Turkey Vultures feeding
with California Condors. "...Turkey Vultures have the
weakest carrion-feeding bills, and generally must wait
until others have ripped open a carcass or it has decayed..."
Pennycuick (1973) discussed competition between East African
|t vultures and hyena in regards to the speed of 'slight of
W vultures.
C. Parasitism
IX STATUS
A. Past population trends
Grinnell (1915): Most abundant in San Diegan district and
through the interior valleys. Common in spring and summer
throughout the State (California) save in the highest moun-
tains .
B. Present population status
Grinnell and Miller (1944); Present within the state through-
out the year, but numbers and distribution vary with seasons.
Northerly and at higher altitudes, altogether absent in
winter; even at low altitudes, reduced to small numbers
in winter where common in summer. Thus where definite
migration of a large share of population southward out of
state in October and back again in March. Thought to be
less numerous now than formerly. Taverner (1926); in many
places they are rigorously protected by law for sanitary
reasons*
»
Cathartes aura (con't.)
C. Population limiting factors
Dawson (1923) points out that ranchers put out poisoned
carcasses for coyotes which are eaten by vultures which
then regurgitate. An increase in sanitary science had
made food harder to come by. Bent (1937): Turkey Vultures
are dependent on death coming to animals.
D. Environmental quality: adverse impacts
Braun and Amadon (1968); "There has been much debate as to
whether this species and the Black Vulture carry bacteria
and viruses of anthrax and other diseases of livestock.
It is probable that they seldom come into close enough con-
tact with living stock to constitute a hazard. Neverthe-
less, large numbers of both species have been trapped and
killed, especially in Texas, on the grounds that they carry
disease and may also attack helpless young livestock."
Turkey Vultures are seldom guilty of the latter.
E. Potential for endangered status
«
Cathartes aura (con't.)
Id LITERATURE CITED
Amadon, Dean. 1977. Notes on the taxonomy of vultures.
Condor 79:413-416.
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bent, Arthur Cleveland. 1937. Life histories of North American
birds of prey. U.S. Nat. Mus. Bui. 167:1-409.
Brown, L. and Dean Amadon. 1968. Eagles, Hawks and Falcons
of the World. Vol. 1, McGraw-Hill Book Co., New York.
945 pp.
Chapman, Frank M. 1933. The migration of Turkey Buzzards as
observed on Barro Colorado Island, Canal Zone. Auk 50:
30-34.
Dawson, William Leon. 1923. The birds of California. Vol.
4. South Moulton Company, San Francisco.
Grinnell, Joseph. 1915. A distributional list of the birds
of California. Pacific Coast Avifauna, No. 11. 217 pp.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27.
608 pp.
Grossman, Mary Louise and John Hamlet. 1964. Birds of prey
of the world. Clarkson N. Potter, Inc., New York. 496 pp.
Gullion, Gordon W. , Warren M. Pulich and Fred G. Evenden. 1959.
Notes on the occurrence of birds in southern Nevada. Condor
61:278-297.
Heath, James Edward. 1962. Temperature fluctuation in the
Turkey Vulture. Condor 64:234-235
Heintzelman, Donald S. 1974. Turkey Vultures thermal soaring
into opaque clouds. Auk 91:849.
Kennard, John H. 1975. Longevity records of North American
birds. Bird-Banding 46:55-73.
Knowlton, Frank H. 1909. Birds of the world, a popular account.
Henry Holt and Co., New York. 873 pp.
Loftin, Horace and E. L. Tysar. 1965. Stylized behavior in
. Turkey Vulture courtship dance. Wilson Bull. 77:193.
10
Cathartes aura (con't.)
May, J. B. 1935. The hawks of North America. National Asso-
ciation of Audubon Societies, New York, 140 pp. ^1
McKelvey, Mike. 1965. Unusual bathing habits of the Turkey
Vulture. Condor 67:265.
Miskimen, Mildred. 1957. Absence of syrinx in the Turkey
Vulture (Cathartes aura). Auk 74:104-105.
Pennycuick, C. J. 1973. The soaring flight of vultures.
Scientific American 229:102-109.
Peterson, R. T. 1961. A field guide to Western birds. Second
Edition. Houghton Mifflin Co., Boston, 366 pp.
Phillips, Allan, Joe Marshall and Gale Monson. 1964. The birds
of Arizona. Univ. of Arizona, Tucson. 212 pp.
Prather, Irvine D. , Richard N. Connor and Curtis S. Adkisson.
1976. Unusually large vulture roost in Virginia. Wilson
Bui. 88:667-668.
Rea, Amadeo M. 1973. Turkey Vultures casting pellets. Auk
90:209-210.
Small, Arnold. 1974. The birds of California. Winchester
Press, New York. 310 pp. <
Stager, Kenneth E. 1964. The role of olfaction in food loca- .
tion by the Turkey Vulture (Cathartes aura). Contributions
in Science No. 81. Los Angeles County Museum.
Taverner, P. A. 1926. Birds of western Canada. Bull. Victoria
Memorial Mus. No. 41
Temple, Stanley A. 1969. A case of Turkey Vulture piracy on
Great Blue Herons. Wilson Bui. 81:94.
Wauer, Roland H. 1964. Ecological distribution of the birds
of the Panamint Mountains, California. Condor 66:287-301.
Wetmore, Alexander. 1964. A revision of the American vultures
of the genus Cathartes. Smithsonian miscellaneous collec-
tions, Vol. 146.
Wheelock, I. G. 1904. Birds of California. A. C. McClurg
and Co. , Chicago. 578 pp.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Museum Zool. Publ. No. 6. 39 pp.
Willis, Edwin 0. 1963. Is the zone- tailed hawk a mimic of the
Turkey Vulture? Condor 65:313-317. <
9
*
VIOLET-GREEN SWALLOW
Tachycineta thalassina
T. t. lepida - Northern Violet-green Swallow
TAXONOMY
A. Type description
AOU (1957) T. t. lepida: Tachycineta lepida Mearns, Proc.
Biol. Soc. Washington, 15, March 5, 1902, p. 31. (Campbell's
ranch in the Laguna Mountains (Coast Range) 20 miles north
of Campo, San Diego County, California.)
T. thalassina: Hirundo thalas sinus Swainson, Phil. Mag. ,
N. S., 1, no. 5, May 1827, p. 366. (Realdel Monte = Hidalgo,
Mexico. )
B. Current systematic treatments
Peters (1960), recognizes six species in the genus Tachycineta;
three subspecies in the species T. thalassina (lepida,
brachyptera, thalasina) . PasserTformes: Hi rundini dae .
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), Hirundo thalassina; Petrochelidon
thalassina; Tachycineta lepida
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), Green Swallow
II DESCRIPTION
A. External morphology of adults
Dawson (1923), "Adult male: Upper parts, including pileum,
hind-neck, back, upper portion of rump, scapulars, and
lesser wing coverts, rich, velvety bronze-green, occasionally
tinged with purple. . .wings and tail blackish, glossed with
violet or purple; lores grayish; under parts, continuous
with cheeks and area over and behind eye, and with conspicuous
flank-patch, nearly meeting. . .across rump, pure white; under
wing- coverts pale gray, whitening on edge of wing. Bill
black, feet brownish black; iris brown. Adult female:
Like male but usually much duller; bronze-green of upper
parts reduced to greenish brown, or brown with faint green-
ish reflections. . .cheeks brown with white skirtings.
Ridgway (1904), detailed description of plumage, soft parts,
^^ and measurements, including comments on winter plumage.
Tachycineta thalassina ( con ' t . )
B. External morphology of subadult age classes .
Dawson (1923), "plain mouse-gray above, white or pale
sooty gray below. .. inner secondaries tipped with grayish."
Ridgway (1904), detailed description of young.
C. Distinguishing characteristics
Interspecific - Peterson (1961), "Separated from Tree
Swallow by greener back, white rump patches. White of
face partially encircles eye." Dawson (1923), "Smaller
.. .white- cheeked and white-rumped. . .as distinguished from
the Tree Swallow."
Intraspecifc -
III GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) Tachycineta thalassina: "Western North America
from the Yukon River Valley through southern Alaska, western
and southern British Columbia, southwestern Alberta, Montana,
southwestern South Dakota, and northwestern Nebraska south
to southern Baja California and Sonora in the west, and
through Colorado, New Mexico, and western Texas to central
Mexico in the east." T. t. lepida: "Breeds from Alaska 4
(Yukon River Valley, McCarthy, Yakutat Bay) , southwestern
Yukon (Dawson, Selkirk, White horse), British Columbia,
southwestern Alberta (Deer Park, Donald), central Montana
(Judith Basin, Billings, Big Horn), and southwestern South
Dakota (Rapid City, Pine Ridge) south to northern Baja
California (San Fernando), southern Arizona (Fort Huachuca,
Chiricahua Mountains), and southern New Mexico (Gila Fork
Reservation, Sacramento Mountains) ; recorded in summer in
Sonora, Chihuahua and Coahuila."
B. California distribution of the species
Small (1974), "for breeding, length of state west of south-
eastern deserts." Dawson (1923), "Abundant migrant through-
out the state. Breeds in the mountains and throughout the
state at Transitional levels; also well down into the Upper
Sonoran zone in the coastal valleys, and upon the southern
coastal ranges.
C. California desert distribution
Miller (1951) San Bernardino, San Jacinto, San Diegan Moun-
tains, Sierra San Pedro Martir, Inyo Mountains. Grinnell
and Miller (1944), "occasional records of wintering extend
northwest from vicinity of Salton Sea, in Imperial County
to Monterey County." <
►
►
Tachycineta thalassina (con't.)
D. Seasonal variations in distribution
Small (1934), "transient and summer visitor (California),
February to October, some winter in lowland coastal
regions." AOU (1957), "Winters from central coastal (Salinas
River) and southern California (San Diego, Needles), Sonora,
Chihuahua, and Coahuila south to Guatemala (San Mateo,
Chichicastenango) , Honduras, and El Salvador (Puerto del
Triunfo), casually to Costa Rica (Bebedero) . Dawson (1923),
"Winters sparingly in the Imperial Valley and casually
in the San Diegan district, north to Santa Barbara (Dec.
19-24,1914; Dec. 24, 1919)... most February records and some
in January are of returning migrants."
IV HABITAT
A. Biotopic affinities
Small (1974), "open forest or woodland of deciduous, coni-
ferous, or mixed trees when on breeding grounds; elsewhere,
open country for foraging." Bent (1942) "partial to such
surroundings in the vicinity of streams. .. lakes. .. tide
water." Miller (1951), Upper Sonoran and Transition zones.
Grinnell and Miller (1944) "Vicinity of cliff- faces or pre-
cipitous canyon walls. . .broken or open type of woods, or
margins of heavy forest, on either level, rolling or steep-
sloping terrain... no special preference for the presence
of water. In rock-walled canyons of desert mountains...
shade is. .. sought."
B. Altitudinal range
Wauer (1964), observed 1-4000 ft., Panamint Mtns. Dawson
(1923), "altitudinal breeding range from sea-level to about
10,000 (Granite Basin, eastern Fresno County. .. 1913) ."
Miller (1940) "nesting fairly commonly in cliffs above
Transition areas and on shaded cliffs of canyons on the
south side of Clark Mountain above 6500 ft."
C. Home range size
D. Territory requirements
Perch sites - Edson (1943) "on wires and roofs" Bent (1942),
"often seen perched in long rows on telegraph wires... in the
tops of leafless trees." Grinnell and Miller (1944), "dead-
topped trees... tips of dead branches."
Courtship and mating sites -
Tachycineta thalassina (con't)
Nest sites - Dawson (1923), "of dried grasses, with or
without feathers; placed in cranny of crevice of cliff
(especially in vapor holes of volcanic formations), or in
old woodpecker holes-- latterally and less commonly in bird
boxes, or in cranny of building." Nichols (1938), "Great
numbers. . .nesting on the islands (Mono Lake, Ca. ) , in
cracks between loose rocks which make up the steep volcanic
rubble heaps." Edson (1943) "readily accept a bird house
or a box attached to a building. An apature in a cornice
or a wall... a hole in a tree... a crevice in a stone wall
or rocky cliff."
E. Special habitat requirements
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Edson (1943) "gnats and flies." Bent (1942), of 67 stomachs
examined, Heminoptera constituted 36%, Diptera 29%, Hymenop-
tera 23%. "Six stomachs taken on one day were entirely
filled with ants... the remainder of the Hymenoptera each
were wasps and wild bees." Others of note include moths
and beetles.
B. Foraging areas
C. Foraging strategies
Bent (1942), "lives entirely on insect food taken on the
wing." Grinnell and Miller (1944) "from perches on neighbor-
ing dead topped trees the birds range out in rather long
cruising radius for aerial foraging, low or high according
to wind rate, degree of cloudiness or other factors control-
ling presence of preferred insects or ability of the swallows
to capture them."
D. Feeding Phenology
E. Enery requirements
Lasiewski and Thompson (1966), reports torpor of three
individuals in the wild, Saratoga Springs, Calif., April,
1965.
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
4
Tachycineta thalassina (con't.)
C. Courtship and mating behavior
D. Nesting phenology
Dawson (1923), "May or June, according to altitudes; one
brood. Combellack (1954), "a new egg was found each morning,
June 14 through June 17. .. incubation was undoubtedly done
only by the female." Edson (1943) "Occasionally eggs are
laid before the nest is completed, and the feathers are added
while laying is in progress. An egg a day is laid in most
cases till the clutch of five is complete."
E. Length of incubation period
Combellack (1954), 13-16 days, asynchromans hatching. Edson
(1943), "approximately 15 days... it is not unusual for in-
cubation to be commenced before the clutch is complete."
F. Length of nestling period
Combellack (1954) 23-25 days. Edson (1943) "the brooding
period 23-24 days, sometimes even longer."
G. Growth rates
Edson (1943) measurements of length and weight taken daily
up to age 13 days. Average length = 4 mm/ day. Record of
weights for four seasons for comparison. Discussion of
possible causes for different rates for different seasons.
H. Post-breeding behavior
Edson (1943) "in the latter half of July, they may be seen
flocking with Barn Swallows and others on wires and roofs."
Grinnell and Miller (1944) "in post-breeding gathering and
in migrations, it may associate with other kinds of swallows."
:i POPULATION PARAMETERS
A. Clutch size
Dawson (1923), "4 to 6; pure white."
B. Fledging success
C. Mortality rates per age class
D. Longevity
Tachycineta thalassina (con't.)
E. Seasonal abundance
Grinnell (1908) "many adults and full-grown young were
found congregated about the shore of Bear Lake (San Bernar-
dino Mountains, California) ... on the bare branches of one
dead pine on the north shore of the lake, July 31, hundreds
...were perching, mostly young- of - the-year. "
F. Habitat density figures
Dawson (1923), "favorable circumstances may attract a con-
siderable colony, to a number of a hundred pairs or more."
Grinnell and Miller (1944), "solitary or weakly colonial,
apparently as according with the number of nesting sites
available in any one place."
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Webster (1944) "have, on occasion, seen the amazing feat
of a small Prairie Falcon taking. . .violet-green Swallows."
B. Competition
Franzreb (1976), reports encounter between Mountain Chickadees
feeding nestlings in nest whole and swallow attempting to
overtake nest site. Involved aerial and ground combat with
physical contact, but chickadee able to retain possession of
nest. Edson (1943) reports destruction of nest with eggs
by Passer domesticus. "Then the swallows transferred their
endeavors to the box in which the sparrows had left a
nearly completed nest... they mearly added a lining of feathers,
and then three eggs were promptly laid.
C. Parasitism
Edson (1943) "botflies have victimized the nestlings and
they were relieved of a number of large maggots. No fatal -
aties resulted but it was detrimental to health and growth."
IX STATUS
A. Past population trends
Grinnell and Miller (1944), "Essentially summer resident,
March to September. Common; locally abundant. Also transient
orderly; and a few, probably not every year, present in mid-
winter months, southerly, and coastwise northwest to San
Francisco Bay region."
<•
>
Tachycineta thalassina (con't.)
B. Present population status
C. Population limiting factors
Franzreb (1976) "A hole-nesting species such as the Violet-
green Swallow breeding, later in the season may have diffi-
culty in locating suitable nest cavities as most are already
occupied by other species... If such sites are in short
supply, the number of nest cavities may be an important
factor in limiting population densities.
D. Environmental quality: adverse impacts
E. Potential for endangered status
P
Tachycineta thalassina (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bent, A. C. 1942. Life histories of North American fly-
catchers, larks, swallows, and their allies. U.S. Nat.
Mus. Bull. 179.
Combellack, C. R. B. 1954. A nesting of Violet-green Swallows.
Auk 71:435-442.
Dawson, W. L. 1923. The birds of California. Vol. 1. South
Moulton Co., San Francisco.
Edson, J. M. 1943. A study of the Violet-green Swallows.
Auk 60:396-403.
Franzreb, K. E. 1976. Nest site competition between Mountain
Chickadees and Violet-green Swallows. Auk 93:836-837.
Grinnell, J. 1908. The biota of the San Bernardino Mountains.
Univ. California Publ. Zool. Vol. 5:1-170.
Grinnell, J. and A. H. Miller. 1944. The distribution of birds
of California. Pacific Coast Avifauna No. 27. 608 pp.
Lasiewski, R. C. and H. J. Thompson. 1966. Field observation
of torpidity in the Violet-green Swallow. Condor 68:102-
103.
Miller, A. H. 1940. A transition island in the Mohave Desert.
Condor 42:161-163.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. No. 50:
531-624.
Nichols, W. F. 1938. Some notes from Negit Island, Mono Lake,
California. Condor 40:262.
Peters, J. L. 1960. Checklist of birds of the world. Vol. 9.
Mus. Comp. Zool., Cambridge, Massachusetts, 506 pp.
Peterson, R. T. 1961. A field guide to western birds. Hough-
ton Mifflin Co., Boston. 309 pp.
Ridgway, R. 1904. The birds of North and Middle America.
Part 3. Bull. U.S. Nat. Mus. No. 50.
Tachycineta thalassina (con't.)
Small, A. 1974. The birds of California, Macmillan Co.,
New York.
Wauer, R. H. 1964. Ecological distribution of the birds of
the Panamint Mountains, California. Condor 66:287-301.
Webster, H. , Jr. 1944. A survey of the Prairie Falcon in
Colorado. Auk 61:609-616.
(
r
■
WESTERN BLUEBIRD
Sialia rnexicana
I TAXONOMY
A. Type description
Sialia rnexicana bairdi - AOU (1957) Ridgway, Auk, 11, no.
2, Apr. 1894, pp. 151 and 157. (Camp 110, New Mexico =
Cactus Pass, 20 miles east of Kingman, Mohave County,
Arizona. ) .
Sialia m. occidentalis - AOU (1957) Townsend, Journ. Acad.
Sci. Philadelphia, 7, pt. 2, (Nov. 21) 1837, p. 188. (Col-
umbia River = Fort Vancouver, Washington.).
B. Current systematic treatments
AOU (1957) considers this species a member of the avian
Order Passeriformes, Family Turdidae (Thrushes, Solitaires,
and Bluebirds).
Peters (1964) includes Western Bluebirds in the Family
Musicapidae, Subfamily Turdinae. He recognized six races
of S. rnexicana, including bairdi and occidentalis.
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), Sialia occidentalis; S.
caeruleocollig; S. rnexicana anabelae; Sylvia occiHentalis.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), Mexican Bluebird; California
Bluebird; Anabel Bluebird; Chestnut-backed Bluebird; San
Pedro Bluebird.
II DESCRIPTION
A. External morphology of adults
Ridgway (1907) gives a detailed description of plumages
of several races. He describes the species general appear-
ance as "Above plain rich blue, brighter. . .on the rump,
upper tail-coverts, tail, and outer webs of primaries...
the blue gradually fading on abdomen. .. sides of chest and
breast and anterior portion of sides chestnut. . .bill black;
iris dark brown; legs and feet black." Miller and Stebbins
(1964), "A bluebird marked with rust-brown areas on breast
and back."
Sialia mexicana (con't©)
B. External morphology of subadult age classes
Ridgway (1907) describes young as plain sooty gray with
wing coverts, remiges, and rectrices blue. Wheelock (1920),
"Young: Gray, mottled and streaked with white, darkest on
upper parts."
C. Distinguishing characteristics
Interspecific - Peterson (1961), "Similar species: (1)
See Eastern Bluebird. (2) Male Lazuli Bunting has white
wing-bars. (3) Mountain Bluebird has blue breast."
Intraspecific - Ridgway (1907) states that bairdi is "Similar
to S. m. occidental! s, but adult male with whole back and
scapulars uniform chestnut, producing a large and conspi-
cuous dorsal patch." Measurements of both races are given.
Miller and Stebbins (1964), "Female with blue and brown
areas much duller than in male, the throat often nearly
gray."
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) lists the overall range of the Western Bluebird
(Sialia mexicana) as "From southern British Columbia and
central Montana south through the mountains to northern
Baja California, Michoacan, Puebla, and central Veracruz."
Sialia m. bairdi - AOU (1957), range "Breeds from southern
Nevada, central Utah and Colorado south through the moun-
tains to central western and southeastern Arizona, northern
Chihuahua, and western Texas. Winters throughout breeding
range at lower altitudes; wandering to southeastern Calif-
ornia (Little Lake, Victorville, lower Colorado Valley),
eastern Sonora, and central Texas." Peters (1964), "Southern
Nevada, central Utah, and Colorado south to Arizona, western
Texas, northern Sonora, and northern Chihuahua; wintering
at lower altitudes in same areas and as far as southeast
California." Sialia m. occidental is - AOU (1957), range
"Breeds from southern British Columbia and western and central
southern Montana south in eastern Oregon, northern Idaho,
and northwestern Wyoming, and through the mountains to south-
ern California (San Diego, San Bernardino Mountains, Walker
Pass) and western Nevada. Winters in breeding range at
lower altitudes, rarely north to British Columbia, wandering
to southeastern California (Death Valley, Potholes, Twenty-
nine Palms), and Santa Catalina and San Clemente Islands. '
Peters (1964), "Southern British Columbia, Montana, eastern
Oregon, Idaho, and Wyoming south in the mountains to southern
California and Western Nevada; wintering at lower altitudes;
wandering to southeast California, Santa Catalina and San
Clemente Islands."
Sialia mexicana (con't.)
P B. California distribution of the species
Sialia m. bairdi - Grinnell and Miller (1944), "In summer
known only from Clark Mountain, 7300 feet, northeastern San
Bernardino Co. In winter, Providence Mountains. . .Colorado
River, Needles to Potholes." Sialia m. occidentalis -
Grinnell and Miller (1944), "As breeding" entire length
of State west of eastern margins of Sierran forests, but
including Great Basin plateau south to the vicinity of
Lake Tahoe." Small (1974), range in California of S.
mexicana (Races combined) — "for breedings length of~"state
exclusive of eastern and southeastern deserts; in winter,
almost statewide."
C. California desert distribution
Grinnell and Miller (1944) list Death Valley, Twentynine
Palms, Colorado River Valley, Needles, Little Lake, Victor-
ville, and Oro Grande as areas of winter occurrence. They
conclude that "the winter population in this region now
appears to us to be composed chiefly of bairdi; occasional
individuals apparently represent occidentalis." In Joshua
Tree National Monument, Miller and Stebbins (1964) called
this species a "Common winter resident." They listed sev-
eral sightings, including: Morongo Valley (April); Little
Morongo Canyon (March) ; and Twentynine Palms (November
through late March) . Most birds were occidentalis, although
bairdi can be expected. Although they do not breed, Willett
(1951) described these bluebirds as winter visitants on
southern California deserts. Smyth and Coulombe (1971)
noted this species during winter at Upper Carrizo Spring,
Riverside Co. Wauer (1964) found breeding bluebirds above
9,000 feet in the bristlecone pine association of the Pana-
mint Mountains, Death Valley. Grinnell (1914) found occi-
dentalis to be a common winter visitor along the lower
Colorado River; bairdi not present. Grinnell (1934) noted
occidentalis wintering in Death Valley. Gilman (1935)
also found this race wintering in Death Valley (Furnace
Creek Ranch). Carter (1937) describes wintering flocks of
Western Bluebirds at Twentynine Palms, San Bernardino Co.,
California, from early November to late March. Van Rossem
(1911) noted this species wintering near the Sal ton Sea.
Lamb (1912) found Western Bluebirds between November and
March on the Mohave Desert near Daggett (San Bernardino
Co.). In the lower Colorado Valley during winter, Price
(1899) described these bluebirds as "Common in the river
bottom, feeding largely on the. . .mistletoe." Grinnell
(1901) noted several flocks of occidentalis near Barstow,
San Bernardino Co., in January. Grinnell (1904) found this
species wintering near Palm Springs (Palm Canyon) in "great
numbers." Near Victorville (Mojave River), Mailliard and
Grinnell (1905) described Western Bluebirds during winter
as "Abundant along the river bottom where they were feeding
largely on mistletoe berries."
Sialia mexicana (con't.)
D. Seasonal variations in distribution /gj*
In California, Grinnell and Miller (1944) found that "Migra-
tory movements are irregular as to date and apparently
often are local or altitudinal. In many sections these
bluebirds are permanently resident." Peters (1964) notes
that both bai rdi and occidentalis drop to lower elevations
during the winter, wandering onto southeast California
deserts. Wintering birds in Arizona were found "somewhat
irregularly in farmlands and on the desert wherever mistle-
toe occurs." In southwestern California, Willett (1933)
found this species breeding to over 10,000 feet; is more
widely distributed over lowlands in winter.
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), "In breeding season, the prime
requisite is well spaced, broken timber, providing nest
sites and an abundance of exposed lookout posts. . .mature,
scattered groups of willows and cottonwoods along stream
courses; typically open stands of wild walnut and sycamore,
and of blue, valley and black oaks; yellow and Monterey
pine forests, and even conifers of higher zonal type when
displaying the requisite spacing." In California, Small
(1974) gives habitat as "open forests of deciduous, coni-
ferous, or mixed trees; savannah; edges of riparian wood-
lands." In Joshua Tree, Miller and Stebbins (1964) found
Western Bluebirds wintering in the pinon belt and in the
lower, open desert. Peterson (1961; describes habitat as
"scattered trees, open conifer forests, farms." In a
montane forest of Colorado, Winternitz (1976) found that
Western Bluebirds spent 67% of their time in an aspen-willow
woodland, 13% in ponderosa pine, 13% in Douglas fir, and
TL in spruce-aspen.
B. Altitudinal range
Grinnell and Miller (1944), "Altitudes of summer residence
range from near sea level... up to 10,600 feet in San
Bernardino Mountains." In southern Nevada, Johnson (1965)
found this bluebird breeding between 7,500 and 9,200 feet.
C. Home range size
D. Territory requirements
Perch sites - Grinnell and Miller (1944) stated that exposed
limbs and dead trees are favorite perch sites. Grinnell and
Storer (1924), "It ordinarily seeks a perch which will com-
mand a wide field of view, as on some upper or outer branch."
Sialia mexicana (con't.)
Courtship and mating sites - Bent (1964) noted a pair of
bluebirds mating while perched next to one another.
Nest sites - Peterson (1961) describes nests as "In hole
in tree, stub, bird box." Wheelock (1920), "In old wood-
pecker holes or in cavities of pine trees, usually rather
high."
E. Special habitat requirements
Grinnell and Miller (1944) found that this species requires
areas of well spaced timber along with abundant dead trees
or limbs; the presence of mistletoe (berries) may govern
local occurrence during winter.
F. Seasonal changes in habitat requirements
Speaking of bairdi, Grinnell and Miller (1944) found that
"In summer, open patches of white fir, interspersed with
pirion, on mountain slopes. In winter, yucca, sagebrush
and creosote bush associations." Peterson (1961) found
that during winter, this species moves from conifer forests
out onto semiopen terrain, brush, and deserts. Wheelock
(1920), "He is a resident throughout the foothills and
lower mountains, coming down to the valleys in winter."
V FOOD
A. Food preferences
In Joshua Tree, Miller and Stebbins (1964) noted wintering
birds feeding on insects and mistletoe berries. Martin
et al. (1961) describe animal food as--Grasshoppers con-
stitute the largest and most regular item, followed by
caterpillars, beetles (particularly ground beetles), and ants
Plant food includes- -grape, mistletoe, elderberry, and fig.
In California, Wheelock (1920) found "crickets, moths,
grasshoppers, caterpillars, ants, and weevils form his diet,
varied with fruits.
B. Foraging areas
Grinnell and Miller (1944) found this species feeding in
"open patches of grassy, meadowy, or even rocky ground."
Pitelka (1941) watched Western Bluebirds feeding "on a
south-facing, open, grassy slope" in California.
•
Sialia mexicana ( con ' t . )
C. Foraging strategies
Grinnell and Miller (1944) noted that feeding is "by the
hovering method or from scattered bush tops or weed stalks...
some flycatching of insects is indulged in." Miller and
Stebbins (1964) noted that "these bluebirds forage on in-
sects, dropping down to the desert floor." Wheelock (1920)
noted that 'This bluebird, has the habit of darting down
from a perch for insects, and often hunting through the
grass for them..." Pitelka (1941) noted Western Bluebirds
hovering and soaring for food items.
D. Feeding phenology
Grinnell and Miller (1944), "Although most of the food in
summer is taken from the ground or the grass tops, some
flycatching of insects is indulged in. In winter, mistle-
toe berries commonly are taken..." Martin et al. (1961)
found that animal matter makes up the largest part of this
bluebird's diet. They found that plant material accounts
for 4% of the diet in summer, 21% in fall, 267o in winter,
and 0% in spring. Grinnell and Storer (1924) discuss the
important role that mistletoe berries play in the diet of
wintering bluebirds in California--"In summer the birds
live chiefly upon insects. . .But in the colder months of
the year, when insects are relatively scarce, the bluebirds
...gave their attention to berries."
E. Energy requirements
During winter on the California desert (Joshua Tree) , Miller
and Stebbins (1964) noted bluebirds drinking from tanks and
taking moist food. Smyth and Coulombe (1971) noted the
frequent drinking at springs in the California desert during
winter by Western Bluebirds.
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Bailey and Niedrach (1965) found that in Colorado, Western
Bluebirds seldom show aggressive behavior towards swallows,
chickadees > and nuthatches, even though they often nest in
the same tree as the bluebirds.
C. Courtship and mating behavior
Bent (1964) gives a brief account of courtship behavior,
in which both male and female mounted one another.
e
I
Sialia mexicana (con't.)
D. Nesting phenology
In California, Wheelock (1920) gave the breeding season as
April through June. Bent (1964; gave California egg dates
as "104 records, April 4 to June 20; 58 records, May 2 to
May 31, indicating the height of the season."
E. Length of incubation period
Bent (1964) found that "The period of incubation does not
seem to have been definitely determined. .. similar to... the
Eastern Bluebird (about 12 days)."
F. Length of nestling period
Bent (1964) could not find reference to the nestling period
of Western Bluebirds, but felt that it was similar to that
of Eastern Bluebirds (15-18 days).
G. Growth rates
H. Post-breeding behavior
Grinnell and Storer (1924) noted an upward altitudinal
shift in the fall (Yosemite). Flocks form by September
^ which include both adults and immatures, numbering from
™ 6 to 25 individuals. In northern California, Grinnell
et al. (1930) noted that "Western Bluebirds were observed
in small groups, through the winter and as late in the
spring as the middle of April."
VII POPULATION PARAMETERS
A. Clutch size
Peterson (1961), "Eggs (4-6; 8) pale blue." Bent (1964)
gives a range of 3 to 8 eggs per clutch, with sets of 4,
5, and 6 being the most common.
B. Fledging success
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
In Nevada, Van Rossem (1936) noted that "In fall, bluebirds
became more common, an increase which probably resulted from
an increase of migrants." Bent (1964) recounted that "This
•species is varyingly numerous in lowland areas from late
summer to early spring but is usually abundant in the foot-
hill areas around Pasadena (Los Angeles Co., California) and
in the more open mountain canyons below snow level."
Sialia mexicana (con't.)
F. Habitat density figures
During winter at Joshua Tree on the California desert,
Miller and Stebbins (1964) noted flocks of bluebirds as
large as 25 to 50 individuals. In Colorado, Winternitz
(1976) found an average of 0.6 pairs per 40 ha breeding in
montane forests. In a ponderosa pine forest in Arizona,
Balda (1969) reported a breeding population of 20 pairs
of Western Bluebirds per 100 acreas. Anderson (1970) found
a wintering population of 8 to 20 Western Bluebirds per
100 acres in an Oregon white oak forest. Hering (1948)
listed 7 pairs of this bluebird nesting on a 75 acre study
plot in a Colorado forest. Hosterman and Madding (1978)
give a winter density of 40 Western Bluebirds per sq. km.
(20/100 acres) in paloverde desert scrub of Arizona. Wilson
(1978) found 37 bluebirds per sq. km. (15/100 acres) at
Morongo Valley, San Bernardino Co. , California during winter.
In a Mojavian desert scrub community, Fees (1976) noted 22
bluebirds per sq. km. (9/100 acres) in winter.
Ill INTERSPECIFIC INTERACTIONS
A. Predation
Page and Whitacre (1975) noted the taking of a Western Blue-
bird by a Merlin on the central California coast during
winter. Great Horned Owl predation upon Western Bluebirds {
in California was recorded by Fitch (1947). Mills (1976)
recounts the capture of a Western Bluebird by an American
Kestrel.
B. Competition
Miller and Bock (1972) concluded that interactions between
woodpeckers and bluebirds (Monterey Co. , California) sug-
gested that competition for nest sites was high in hole-
nesters.
C. Parasitism
Friedmann (1963) felt that this bluebird is a very rare
victim of cowbird parasitism.
IX STATUS
A. Past population trends
Grinnell and Miller (1944) called bairdi a "summer resident;
rare by reason of greatly restricted breeding habitat along
southeastern border. .. Common winter visitant"; and occiden-
talis a "Common summer resident over most of the northern
and western sections. .. In winter, widespread in lowlands"
9
Sialia mexicana (con't.)
(California). Willett (1912) called this species "an
abundant breeder in the San Bernardino and San Jacinto
Mountains" (California). Sherpardson (1915) felt Western
Bluebirds were "much more common lately near the city of
Los Angeles than in former years."
B. Present population status
Small (1974) calls Western Bluebirds "common residents"
in California.
C. Population limiting factors
In Colorado, Winternitz (1976) concluded that because blue-
birds must rely on the hole-drilling activities of wood-
peckers for nest sites, the nesting activities (or lack
thereof) of woodpeckers are potentially limiting to Western
Bluebirds. Grinnell (1934) felt that the scarcity of blue-
birds wintering in Death Valley was due to the lack of
mistletoe berries.
D. Environmental quality: adverse impacts
In southern California, Ross (1933) felt that removal of
dead trees and branches have produced a nesting cavity
shortage sufficient enough to force bluebirds to nest on
buildings.
E. Potential for endangered status
3
10
Sialia mexicana (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, MD. 691 pp.
Anderson, S. H. 1970. The avifaunal composition of Oregon
white oak stands. Condor 72:417-423.
Bailey, A. M. and R. J. Niedrach. 1965. Birds of Colorado.
Vol. 2. Denver Mus. Nat. Hist., Denver, Colorado.
Balda, R. P. 1969. Foliage use by birds on the oak- juniper
woodland and ponderosa pine forest in southeastern Arizona.
Condor 71:399-412.
Bent, A. C. 1964. Life histories of North American thrushes,
kinglets, and their allies. U.S. Nat. Mus. Bull. 196.
Carter, F. 1937. Bird life at Twentynine Palms. Condor 39:
210-219.
Fees, D. 1976. 29th winter bird-population study. Am. Birds
30:1064-1065.
Fitch, H. S. 1947. Predation by owls in the Sierran foothills
of California. Condor 49:137-151.
Friedmann, H. 1963. Host relations of the parasitic cowbirds.
U.S. Nat. Mus. Bull. 233. 276 pp.
Gilman, M. F. 1935. Notes on birds in Death Valley. Condor
37:238-242.
Grinnell, J. 1901. Midwinter birds at Barstow. Condor 3:
70-71.
Grinnell, J. 1904. Midwinter birds at Palm Springs, Calif-
ornia. Condor 6:40-45.
Grinnell, J. 1914. An account of the mammals and birds of the
lower Colorado Valley. Univ. California Publ. Zool. 12:
51-294.
Grinnell, J. 1934. Further observations upon the bird life
of Death Valley. Condor 36:67-72.
Grinnell, J., J. Dixon and J. M. Linsdale. 1930. Vertebrate
natural history of a section of northern California through
the Lassen Peak region. Univ. California Publ. Zool. 35:
1-594.
11
Sialia mexicana (con't.)
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna No. 27. 608 pp.
Grinnell, J. and T. I. Storer. 1924. Animal life in the Yose-
mite. Univ. California Press, Berkeley. 752 pp.
Hering, L. 1948. Nesting birds of the Black Forest, Colorado.
Condor 50:49-56.
Hosterman, G. and R. Madding. 1978. Thirtieth winter bird-
population study. Am. Birds 32:37-38.
Johnson, N. K. 1965. The breeding avifaunas of the Sheep and
Spring ranges in southern Nevada. Condor 67:93-124.
Lamb, C. 1912. Birds of a Mohave Desert oasis. Condor 14:
32-40.
Mailliard, J. and J. Grinnell. 1905. Midwinter birds on the
Mohave Desert. Condor 7:71-77; 101-102.
Mansfield, G. S. 1946. Wintering Mountain Bluebirds on the
Santa Barbara coast. Condor 48:285.
Martin, A. C. , H. S. Zim and A. L. Nelson. 1961. American
wildlife and plants. McGraw-Hill Book Co., New York.
Miller, A. H. and C. E. Bock. 1972. Natura-1 history of the
Nuttall Woodpecker at the Hastings Reservation. Condor
74:284-294.
Miller, A. H. and R. C. Stebbins. 1964. The lives of desert
animals in Joshua Tree National Monument. Univ. California
Press, Berkeley 452 pp.
Mills, G. S. 1976. American Kestrel sex ratios and habitat
separation. Auk 93:740-748.
Myers, H. W. 1912. Nesting habits of the Western Bluebird.
Condor 14:221-222.
Page, G. and D. F. Whitacre. 1975. Raptor predation on
wintering shorebirds. Condor 77:73-83.
Peters, J. L. 1964. Checklist of birds of the world. Vol.
10. (E. Mayr and R. A. Paynter, Jr., eds.). Mus. Comp.
Zool., Cambridge, Mass. 502 pp.
Peterson, R. T. 1961. A field guide to western birds.
Houghton Mifflin Co., Boston. 309 pp.
12
Sialia mexicana (c n't.)
Phillips, A., J. Marshall and G. Monson. 1964. The birds
of Arizona. Univ. Arizona Press, Tucson. 212 pp.
Pitelka, F. A. 1941. Foraging behavior in the Western Blue-
bird. Condor 43:198-199.
Price, W. W. 1899. Some winter birds of the lower Colorado
Valley. Condor 1:89-93.
Ridgway, R. 1907. The birds of North and Middle America.
Part 4. Bull. U.S. Nat. Mus. No. 50
Ross, R. C. 1933. Western Bluebird nesting in wall tile.
Condor 35:73-74.
Shepardson, D. I. 1915. Bluebird nesting in low country.
Condor 17:206.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Smyth, M. and H. N. Coulombe. 1971. Notes on the use of desert
springs by birds in California. Condor 73:240-243.
Van Rossem, A. 1911. Winter birds of the Salton Sea region.
Condor 13:129-137.
Van Rossem, A. J. 1936. Birds of the Charleston Mountains,
Nevada. Pacific Coast Avifauna No. 24. 65 pp.
Wauer, R. H. 1962. A survey of the birds of Death Valley.
Condor 64:220-233.
Wauer, R. H. 1964. Ecological distribution of the birds of
the Panamint Mountains, California. Condor 66:287-301.
Wheelock, I. G. 1920. Birds of California. Fifth Editon.
A. C. McClurg & Co., Chicago. 578 pp.
Willett, G. 1912. Birds of the Pacific slope of southern
California. Pacific Coast Avifauna No. 7. 122 pp.
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna No. 21. 204 pp.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. No. 6. 39 pp.
Wilson, D. L. 1978. Thirtieth winter bird-population study.
Am. Birds 32:41.
Winternitz, B. L. 1976. Temporal change and habitat prefer-
ence of some montane breeding birds. Condor 78:383-393. ^'
9
WESTERN FLYCATCHER
Empidonax d. diff icilis
I TAXONOMY
A. Type description
Empidonax d. difficilis - AOU (1957) Baird, in Baird, Cassin,
and Lawrence, Rep. Expl. and Surv. R. R. Pac. , vol. 9,
1858, pp. xxx, 198. (West coast; Ft. Steilacoom, Shoalwater
Bay, Ft. Tejon = Fort Steilcoom, Washington.)
B. Current systematic treatments
AOU (1957) lists the Western Flycatcher as a member of the
avian Order Passeriformes, Suborder Tyranni, Superfamily
Tyrannoidea, and Family Tyrannidae; this species is poly-
typic.
Hellmayr (1927) gives 5 races of Western Flycatcher, includ-
ing E. d. difficilis. Ridgway (1907) states that Western
FlycatcRers were once considered a race of the Yellow-
bellied Flycatchers (E. f laviventris) .
Brodkorb (1949) discusses variations in North American
Western Flycatchers, including measurements and plumages.
C. Synonomies of scientific nomenclature
Hellmayr (1927) gives Empidonax insulicola; E. bairdi
perplexus. Ridgway (190/) adds E. pusillus; E. f laviventris
aif ficiTTs. Grinnell and Miller (1944J incluHed Tyranni 11a
pusilla; E. cineritius. Brodkorb (1949) adds E. d. immodulatus
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944) list Little Pewee Flycatcher;
Yellow-bellied Flycatcher; Western Yellow-bellied Flycatcher;
Baird Flycatcher; San Lucas Flycatcher; Island Flycatcher;
Santa Barbara Flycatcher.
II DESCRIPTION
A. External morphology of adults
Ridgway (1907) gives detailed description of plumages;
above plain brownish olive, tail grayish brown, wings
dusky, two distinct wing bands, a broad orbital ring of
yellowish white, mandible wholly yellowish, iris brown,
legs and feet dusky brown. Peterson (1961), "Upper parts
olive-brown, underparts washed with yellowish, wing-bars
whitish, eye-ring white. . .5.5-6 inches."
Empidonax dif ficilis (con't.)
B. External morphology of subadult age classes
"Young similar to adults, but color of upper parts much
browner. . .and yellow of under parts paler' (Ridgway 1907).
"Young, similar (to adults), but upper parts browner, with
wing-bars rusty buff, the sulphur-yellow of belly replaced
by dull white" (Wheelock 1904).
C. Distinguishing characteristics
Interspecific - Ridgway (1907), "...like E. f laviventris
(yellow-bellied Flycatcher), but much less greenish; tail
longer." Peterson (1961), "Very similar to the other small
flycatchers of this group, but underparts more yellowish."
Intraspecif ic - Ridgway (1907), sexes alike; adult male -
length 127 mm; wing 67.5 mm; tail 57.1 mm and adult female -
length 123 mm; wing 64.4 mm; tail 55 mm. Brodkorb (1949)
also gives detailed description of intraspecific measure-
ments. Johnson (1974) presents an extensive description
of molt and age determination in Western Flycatcher.
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) gives overall range of E. difficilis as "Breeds
from southeastern Alaska, southern British Columbia, west-
central Montana, northern Wyoming, and southwestern South
Dakota south in the mountains to Baja California, Honduras,
and western Texas."
The range of E. d. difficilis (AOU 1957) is given as "Breeds
from southeastern Alaska, coastal and central southern
British Columbia, northern Idaho, and western Montana south
to southwestern California (San Clemente Island, San Jacinto)
and central western Nevada."
Hellmayr (1927), "Western North America, breeding from
eastern base of Rocky Mountains and western Manitoba to
Pacific coast, north to the Alaskan coast, south to Southern
California, New Mexico, and western Texas; wintering in
Mexico south to Cape San Lucas, Tres Marias Islands, and
Oaxaca. "
B. California distribution of the species
Grinnell and Miller (1944) describes the California dis-
tribution of this species as "In general, nearly entire
length and breadth of state. As breeding, more restricted,
almost altogether the area west of the main Sierran axis."
»
9
Empidonax d. dif ficilis (con't.)
Small (1974), "length of state west of Sierra Nevada except
for Warner Mountains." Willett (1933) calls this species
a resident of canyons in foothills and mesa regions and
up to about 6000 feet in the mountains.
C. California desert distribution
Grinnell and Miller (1944) state that Western Flycatchers
range out onto the California deserts during winter, some-
times remaining until early June. Small (1974) called
Western Flycatchers transients through southeastern deserts
of California. Willett (1933) recounts the taking of eggs
by W. C. Hanna near San Bernardino (16 May to 16 June).
Johnson et al. (1948) found migrating Western Flycatchers
during spring (late May-early June) in the Providence
Mountains. Grinnell (1914) describes this species as a
migrant along the lower Colorado River Valley; does not
breed (from Needles southward). Wauer (1962; found several
Western Flycatchers during the spring and fall of 1960 at
Furnace Creek Ranch, Death Valley (listed as uncommon fall
migrants). Carter (1937) reported Western Flycatchers as
rare during April and May at Twentynine Palms; not breeding.
In the Joshua Tree National Monument, Miller and Stebbins
(1964) found Western Flycatchers during spring (2 April to
3 June) and fall (25 August to 15 September) migration.
Willett (1951) found this species migrating across the deserts
of southern California.
D. Seasonal variations in distribution
AOU (1957) lists winter range of E. d. difficilis as "...
from southern Baja California, rarely northern Sonora, south
to southern Sinaloa and southern Oaxaca." Small (1974)
gives seasonal status in California as "transient and summer
visitor, March to October." Willett (1933) notes that
Western Flycatchers are "Found all over lowlands during
migration. Rare in winter" throughout their California
range. Bent (1963), "The winter range... is in Western
Mexico from southern Baja California and southern Sonora
south to southern Guerrero and Oaxaca." He gives date of
spring arrival in California as 12 March, and latest date
of fall departure as 10 October.
IV HABITAT
A. Biotopic affinities
Peterson (1961) describes this species habitat as "moist
woods, mixed or conifer forest, canyons, groves." Grinnell
and Miller (1944) give extensive summary of habitat require-
ments. Characteristically, places that are well shaded by
Empidonax difficilis (con't.)
tall trees or by steep canyon walls are favored. This species ^*
breeding habitat in California was given by Small (1974)
as "humid coniferous forest, well- shaded woodlands or forests
with running water close at hand, deep, shaded canyons."
Johnson et al. (1948) discovered Western Flycatchers in
bushes along wash bottoms and ravines in the Providence
Mountains, California, during spring migration. Grinnell
and Swarth (1913) found this species breeding in small
numbers in the high Upper Sonoran and Transition zones of
the San Jacinto Mountains, California. In Joshua Tree,
Miller and Stebbins (1964) found this species inhabiting
pinon, scrub oaks, cottonwoods and willows during migration.
B. Altitudinal range
Grinnell and Miller (1944) give range as from near sea level
up to 6000 feet in southern California; Willett (1933)
listed a similar range. Johnson et al. (1948) found this
species migrating through the Providence Mountains (Calif-
ornia) in spring between 4800 and 7300 feet. Bailey (1906)
noted Western Flycatchers breeding at 11,000 feet in New
Mexico.
C. Home range size
D. Territory requirements
Perch sites - Grinnell and Miller (1944), "look-out and
singing posts, even though up to 40 feet above the ground,
are still well beneath the leafy canopy and hence shaded."
In southern California, Myers (1911) found that male and
female Western Flycatchers used tree limbs as perch sites.
Verbeek (1975b) reported perch sites were "almost entirely
restricted to the middle and lower interior of trees"; mean
perch height was 5.05 m (range = 0.25-17m).
Courtship and mating sites - Davis et al . (1963) noted that
most pair formation took place within the male's territory.
Nest sites - Grinnell and Miller (1944), "A typical nesting
locality. . .would thus be the bottom of a foothill canyon or
ravine carrying running water at least in spring, with more
or less over-arching canopy..." They stated that nests are
placed in rock crevices, cavities in trees, or near protected
beams or posts under bridges and about buildings. Dawson
(1923), "placed in any convenient cranny, but chiefly in
well-sheltered niches of banks or up-turned tree roots...
near streams." Phillips et al . (1964) state that in the'
absence of natural nest sites, such as crannies of banks
or tree cavities, the eaves of buildings have proved an
acceptable substitute. Davis et al . (1963) give a detailed jfl
I
Empidonax difficilis (con't.)
account of nest sites in Monterey Co., California. "Natural"
situations averaged 10.9 feet above ground (0 to 25 feet);
all nests were in trees (oaks, sycamores, willows) except
one, which was on the shelf of a creek bank. Nests were
placed against the trunk of a tree or in a natural cavity.
Several nests were also found in buildings. In Texas,
Ohlendorf (1974) reported an average tree nest height as
being 21.0 + 3.4 feet; over one-half of the nests were in
the middle third of these trees.
E. Special habitat requirements
Peterson (1961) stated that this species requires water and
shade in order for it to inhabit an area. In southeast
California, the water factor as well as shade limits the
range of this species (occurrence of the birds becomes more
restricted and spotty) (Grinnell and Miller 1944). VanRossem
(1936) felt that the absence of water in much of the mountains
of Nevada restricted this species range in that state. In
the San Bernardino Mountains of California, Western Fly-
catchers are restricted (during breeding) to the lower can-
yons of the Pacific slope.
F. Seasonal changes in habitat requirements
Willett (1933) noted that Western Flycatchers ascend to at
least 8000 feet during late summer in California.
V FOOD
A. Food preferences
Prey items taken by this species in Colorado were--Diptera
(31%), Coleoptera (25%), Lepidoptera (22%), Hymenoptera 17%),
Hemiptera (3%), and Homoptera (1%) (Beaver and Baldwin
1975). Bent (1963) reports that over 99% of the diet is
animal matter. Over 38% of the prey items were Hymenoptera,
Diptera about 31%.
B. Foraging areas
Grinnell and Miller (1944), "foraging is conducted beneath
the crowns of the trees." In a Colorado aspen-conifer
forest, Beaver and Baldwin (1975) found these flycatchers
feeding mostly from ground level to 9 m. Myers (1911)
noted Western Flycatchers feeding "quite near the nest in
a damp place under the bank." Verbeek (1975a) found in a
California study that "The Western Flycatcher. .. is strictly
fa canopy species, preferring the inner parts of trees."
Miller and Stebbins (1964) saw this species "foraging under
and about the foliage canopy" at Joshua Tree.
»
*
Empidonax difficilis (con't.)
C. Foraging strategies
Dawson (1923) describes foraging behavior; the birds select
perches bare of vegetation through the middle heights of a
forest where they usually "sally flycatch." Oberholser
(1914) notes feeding behavior in Texas--MIt f lits. .. through
shady openings beneath the tree canopy where it snaps up
winged insects from the air and plucks caterpillars from
tree trunks." LaRivers (1941) noted that Western Fly-
catchers were unable to kill large crickets. Verbeek
(1975b) found that this species used the "hawking" method
to feed 60% of the time, and "gleaning" about 40"%,.
D. Feeding phenology
Bent (1963) reported that ladybird beetles made up about
7% of the diet in August, but the average dropped to about
2% for the year. Lepidopterans were not present in the diet
for March, but totaled about 7% for the year.
E. Energy requirements
Beaver and Baldwin (1975) found that Lepidopterans provide
Western Flycatchers with 65% of the total dry weight in _
their diet, although these insects account for only 22% i £
of all prey items taken.
VI REPRODUCTION
A. Age at first breeding
Johnson (1974) states that first-year Western Flycatchers
are known to breed.
B. Territorial behavior
Beaver and Baldwin (1975) found that most interspecific
territorial disputes between Western Flycatchers and other
species take place early in territory establishment. Davis
et al . (1963), "The Western Flycatcher has an alert, aggres-
sive, snappish nature and reacts to intruders with a swift
chase, usually accompanied by threat notes..."
C. Courtship and mating behavior
Davis et al . (1963) give a detailed account of vocalization
and courtship--"Mated males have only a dawn song. Unmated
males sing at dawn and during much of the day as well. Song
appears to function primarily in mate attraction."
&
>
Em-pi donax difficilis (con't.)
D. Nesting phenology
Dawson (1923) states that 2 broods are raised in southern
California, one elsewhere; season ranges from April to June.
Wheelock (1904) gives California season as 1 May to 15 July.
Willet (1933) noted Western Flycatchers breeding mostly in
late May and early June in California. Davis et al . (1963)
found that in California, the nesting cycle begins in late
April or early May and second nestings may continue well
into July. California egg dates from Bent (1963): 57 records,
6 May to 17 June, indicating height of season.
E. Length of incubation period
Davis et al. (1963) found that in California "The incubation
period is 14 or 15 days, with 15 days the usual period.
Incubation is performed by... the female." Rodeck (1947)
found that the incubation period lasted as long as 19 days
(Colorado). Williams (1942) reported a 15 day period in
California.
F. Length of nestling period
Davis et al . (1963), studying the Western Flycatcher in
California, found that "The duration of the nestling period
ranged from 14.5 to 17.5 days."
G. Growth rates
Wheelock (1904) states the young are fed by regurgitation
until they are 4 or 5 days old. Davis et al . (1963) gives
a detailed description of the nestling period, including
feeding and growth rates. They found that at hatching,
young weigh about 1.5 g. Young gain 0.6 to 1.5 g per day
through the first 9 days of life, after which the rate slows.
Average fledging weight is about 10.0 g.
H. Post-breeding behavior
Swarth (1904), in noting the behavior of this species in
Arizona--"Af ter the breeding season they descend the moun-
tains to a lower altitude, and after the first of August
young and old are fairly abundant in the oaks of the foot-
hills, and along the washes as in the spring." In Calif-
ornia, Davis et al . (1963) found that the final break-up
of a family group is the result of a gradual drifting apart
as the young move farther and farther away from the original
territory; no young were seen on their parents territory
30 days after fledging.
Empidonax difficilis (con't.)
VII POPULATION PARAMETERS
A. Clutch size
Peterson (1961), "Eggs (3-4) spotted." Davis et al. (1963)
found that clutch size "consisted of from three to at least
five eggs." Bent (1963) reports a clutch as containing 3
or 4 eggs.
B. Fledging success
In Colorado, Beaver and Baldwin (1975) found that of 28
nestlings, 18 or 64% survived the first week out of the
nest. Davis et al. (1963) found in a California study-
that "13 young were fledged from five nests, an average
of 2.6 fledglings per nest."
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
Davis et al . (1963) noted that in California, "there is a
noticeable decrease in numbers by the end of August, followed
by occasional records in September and early October .. .records
from mid-September on pertain to transients from the North."
F. Habitat density figures
In California, Grinnell and Miller (1944) concluded that
the center of abundance of Western Flycatchers lies within
the coast belt along the entire length of the State. In
an aspen-conifer habitat in Colorado, Beaver and Baldwin
(1975) found breeding densities ranging from 1.2 birds per
10 ha to 6.9 birds per 10 ha.
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Bent (1963) stated that Empidonax flycatchers, like all
other small birds, are preyed upon by many predatory birds
and mammal s .
B. Competition
"We have shown that differences in foraging microhabitat
are probably not sufficient to prevent competition between
E. hammondii and E. difficilis in our study area." (Beaver
and Baldwin 1975) (Colorado). Verbeek (1975b), in a study
>
»
Empidonax difficilis (con't.)
of Black Phoebes, Western Wood Pewees, and Western Flycatchers
in California, showed that "Potential competition among
these flycatchers appears to be reduced by interspecific
differences in nest site selection, nest height, breeding
season, foraging tactics, and the choice of perch sites."
C. Parasitism
Friedmann (1963), "Unknown as a cowbird host until 1934,
the Western Flycatcher appears to be in the process of be-
coming a fairly regular victim in California, where the
parasite is extending its range." Friedmann et al . (1963)
felt, however, that this species choice of nest sites-
cliffs and manmade structures — renders it relatively immune
from cowbird parasitism (possibly as low as 3.8% of all
nests parasitized). Benson and Russell (1934) noted cow-
bird parasitism of Western Flycatchers in California.
IX STATUS
A. Past population trends
Grinnell and Miller (1944) called this species "common"
throughout its California range.
B. Present population status
Peterson (1961) called this species "The most frequently
encountered Empidonax in most parts of western United
States."
C. Population limiting factors
Grinnell and Miller (1944) felt that the lack of shade and
water prevents these flycatchers from expanding into south-
east California.
D. Environmental quality: adverse impacts
E. Potential for endangered status
9
10
Empidonax dif ficllis (con't.)
XI LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. 5th edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bailey, F. M. 1906. A nest of Empidonax difficilis in New
Mexico. Condor 8:108.
Beaver, D. L. and P. H. Baldwin. 1975. Ecological overlap
and the problem of competition and sympatry in the Western
and Hammond's flycatchers. Condor 77:1-13.
Benson, S. B. and W. C. Russell. 1934. The cowbird breeds
in Berkeley. Condor 36:219.
Bent, A. C. 1942. Life histories of North American flycatchers,
larks, swallows, and their allies. U.S. Nat. Mus. Bull.
179:1-555.
Brodkorb, P. 1949. Variation in the North American forms of
Western Flycatcher. Condor 51:35-39.
Carter, F. 1937. Bird life at Twentynine Palms. Condor 39:
210-219.
Davis, J., G. F. Fisler and B. S. Davis. 1963. The breeding
biology of the Western Flycatcher. Condor 65:337-382.
Dawson, W. L. 1923. The birds of California. Vol. 2. South
Moulton Co., San Francisco.
Friedmann, H. 1963. Host relations of the parasitic cowbirds.
U.S. Nat. Mus. Bull. 233:1-276.
Friedmann, H. , L. F. Kiff and S. I. Rothstein. 1977. A further
contribution to knowledge of the host relations of the para-
sitic cowbirds. Smithsonian Contrib. Zool. No. 235. 75 pp.
Grinnell, J. 1908. The biota of the San Bernardino Mountains.
Univ. California Publ. Zool. 5:1-170.
Grinnell, J. 1914. An account of the mammals and birds of
the lower Colorado Valley. Univ. California Publ. Zool.
12:51-294.
Grinnell, J. and A. H. Miller. 1944. The distribution of
the birds of California. Pacific Coast Avifauna. No. 27.
608 pp.
11
Empidonax dif ficilis (con't.)
Grinnell, J. and H. S. Swarth. 1913. An account of the birds
and mammals of the San Jacinto area of southern California.
Univ. California Publ. Zool. 10:197-406.
Hellmayr, C. E. 1927. Catalogue of birds of the Americas and
the adjacent islands. Part 5. Field Mus. Nat. Hist. Zool.
Ser. Publ. 242, Vol. 13.
Johnson, D. H. , M. D. Bryant and A. H. Miller. 1948. Verte-
brate animals of the Providence Mountains area of Calif-
ornia. Univ. California Publ. Zool. 48:221-376.
Johnson, N. K. 1963. Comparative molt cycles in the tyrannid
genus Empidonax. Proc. Intern. Ornithol. Congr. 13:870-
883.
Johnson, N. K. 1974. Molt and age determination in Western
and Yellowish flycatchers. Auk 91:111-131."
LaRivers, I. 1941. The Mormon cricket as food for birds.
Condor 43:65-69.
Miller, A. H. and R. C. Stebbins. 1964. The lives of desert
animals in Joshua Tree National Monument. Univ. California
Press, Berkeley. 452 pp.
Moore, R. T. 1940. Notes on middle American Empidonaces.
Auk 57:349-389.
Myers, H. W. 1911. Nesting habits of the Western Flycatcher.
Condor 13:87-89.
Oberholser, H. C. 1974. The bird life of Texas. Vol. 2.
Univ. Texas Press, Austin.
Peterson, R. T. 1961. A field guide to western birds.
Houghton Mifflin Co. , Boston. 366 pp.
Phillips, A., J. Marshall and G. Monson. 1964. The birds of
Arizona. Univ. Arizona Press, Tucson. 212 pp.
Rodeck, H. G. 1947. Incubation in the Western Flycatcher.
Condor 49:86.
Ridgway, R. 1907. The birds of North and Middle America.
Part 4. Bull. U.S. Nat. Mus. No. 50.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Storer, T. I. 1914. Return of a Western Flycatcher to a
particular locality. Condor 16:144.
12
Empidonax dif ficilis ( con ' t . )
Swarth, H. S. 1904. Birds of the Huachuca Mountains, Arizona.
Pacific Coast Avifauna No. 4. 70 pp.
Van Rossem, A. J. 1936. Birds of the Charleston Mountains,
Nevada. Pacific Coast Avifauna. No. 24. 65 pp.
Verbeek, N. A. M. 1975a. Northern wintering of flycatchers
and residency of Black Phoebes in California. Auk 92:737-
749.
Verbeek, N. A. M. 1975b. Comparative feeding behavior of three
coexisting tyrannid flycatchers. Wilson Bull. 87:231-240.
Wauer, R. H. 1962. A survey of the birds of Death Valley.
Condor 64:220-233.
Wheelock, I. G. 1904. Birds of California. A. C. McClurg
and Co. , Chicago. 578 pp.
Weske, J. S. 1976. Western Flycatcher in Oklahoma. Auk 93:
655-656.
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna No. 21. 204 pp.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. No. 6. 39 pp.
Williams, L. 1942. Interrelations in a nesting group of four
species of birds. Wilson Bull. 54:238-249.
<
ft
WESTERN KINGBIRD
Tyrannus verticalis
I TAXONOMY
A. Type description
Tyrannus verticalis - AOU (1957)
Mountains , vo 1 . 2, 1823, p. 60.
Mts. = near La Junta, Colorado.)
B. Current systematic treatments
Say,
(Ash
in Long, Exped. Rocky
River, near Rocky
•
AOU (1957) lists the Western Kingbird as a member of the
avian Order Passeriformes, Suborder Tyranni, Superfamily
Tyrannoidea, and Family Tyrannidae (Tyrant Flycatchers) ;
this species is monotypic. Hellmayr (1927) also lists this
species as monotypic. Davis and Webster (1970) feel that
the existence of a hybrid Western Kingbird X Scissor-tailed
Flycatcher, demonstrates the phylogenetic proximity of the
two species.
C. Synonomies of scientific nomenclature
Ridgway (1907), Muscicapa verticalis ; Laphyctes verticalis.
D. Synonomies of vernacular nomenclature
Hellmayr (1927), Arkansas Kingbird. Grinnell and Miller
(1944) add Arkansas Flycatcher.
II DESCRIPTION
A. External morphology of adults
Ridgway (1907) gives detailed description of plumages; the
crown with a large concealed patch of reddish orange;
back, wings, add rump plain yellowish gray; tail black,
the outer web and shaft of outermost rectrix wholly white:
iris brown, legs and feet brownish black. Peterson (1961),
"Smaller than Robin, with pale gray head and back, pale
yellow belly. .. 8. 5-9 inches."
B. External morphology of subadult age class
Ridgway (1907) describes the young as being essentially
like adults, but without the crown patch, more drab-gray,
and yellow of under parts paler. Wheelock (1904), "Young
like adults, but crown patch wanting, and wing-coverts
edged with buff."
Tyr annus verticalis (con't.) ^~
C. Distinguishing characteristics ^9
Interspecific - Peterson (1961), "In this species the black
tail has a narrow white edging on each side. . . Ash- throated
and Wied's Crested Flycatchers have wing bars, rufous tails."
Phillips et al. (1964) calls this species a "paler edition"
of the Cassin's Kingbird.
Intraspecific - Ridgway (1907) describes the female as
similar to the adult male; adult male-- length 206 mm; wing
130.1 mm; tail 93.5 mm and adult female-- length 196 mm;
wing 122.3 mm tail 86.9 mm.
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), range of species - "Breeds from western Oregon,
western Washington, east of the coast ranges, southern
British Columbia, southern Alberta, southern Saskatchewan,
southern Manitoba, and western Minnesota, rarely to southern
Wisconsin, southern Michigan, southernmost Ontario, and
northwestern Ohio; south to northern Baja California, Sonora,
northwestern Chihuahua, southern New Mexico, west-central
Texas, northeastern Oklahoma, central eastern Kansas, and
rarely, north-central Missouri." Hellmayr (1927), "Western
North America, breeding from southern British Columbia,
Alberta, and Saskatchewan south to northern Lower California
and Chihuahua, east to western Minnesota, western Iowa,
central Kansas, and western Texas; wintering from western
Mexico to Guatemala..."
B. California distribution of the species
Grinnell and Miller (1944) describe the California range
of the Western Kingbird as "In general, almost entire area
of State not heavily forested and below 5000 feet in altitude
However, rare, or absent some at migration time, on open
deserts and in northern humid coast belt... in migration
the species has been recorded from Farallon and most of
Santa Barbara Islands." Small (1974) gives range in Calif-
ornia as "length of state but absent from northwest coastal
forests and southeastern deserts."
C. California desert distribution
Grinnell and Miller (1944) list important California records,
including Death Valley (April) and the Salton Sea (summer).
Johnson et al. (1948), while working in the Providence
Mtns. of California, found Western Kingbirds most numerous
near Cima, San Bernardino County (13 May, in pairs).
Grinnell (1914) noted the possible nesting of this species
•
^k Tyrannus verticalis (con't.)
i
near Ehrenberg, Arizona (opposite Blythe, California).
Grinnell and Swarth (1913) recount sightings of Western
Kingbirds in the San Jacinto area, which include -- Kenworthy,
Cabezon, and Banning in June, and Hemet Lake in August.
Wauer (1964) found this species breeding in the upper canyons
between 3000 and 4000 feet elevation on the Panamint Moun-
tains, Death Valley. Carter (1937) noted the Western King-
bird at Twentynine Palms during March, April, and May; not
breeding. Pierce and Summer (1927) called Western King-
birds "an abundant breeder on the desert" near the San
Bernardino Mountains. Lamb (1912) found this species nest-
ing near Daggett, San Bernardino Co. During the summer,
Stevens (1903) noted Western Kingbirds at Twentynine Palms,
Needles, Ehrenberg, and several other California and Arizona
desert locations. Miller and Stebbins (1964) described
this species as "Transient and also summer resident from
late March to early September" in the Joshua Tree National
Monument. They called Western Kingbirds scarce and local
in the Monument, and list several breeding records (Quail
Spring). Willett (1951) found this species breeding along
the Colorado River and nearby desert regions of southern
California. Hollister (1908; found this species nesting
near Needles in May.
D. Seasonal variations in distribution
A0U (1957) states that Western Kingbirds winter in small
numbers from the coast of South Carolina to Florida, but
chiefly in Middle America from Guerrero and Morelos to northern
Nicaragua- -migrates in small numbers to the east coast.
Grinnell and Miller (1944) describe Western Kingbirds as
"summer residents, late March to early September" in Calif-
ornia. Small (1974) gives seasonal status as "common
transient and summer visitor, late March to September. . .
no satisfactory winter records." Willett (1933) noted that
Western Kingbirds usually arrived in California in March
and left the state in September. Bent (1963) describes
the winter range as "chiefly in the western parts of Central
America, north to Sonora, and south to southern Guatemala."
He lists date of spring arrival in California as 15 March.
IV HABITAT
A. Biotopic affinities
Peterson (1961) describes the habitat of this kingbird as
"Open country with scattered trees, farms, roadsides."
Grinnell and Miller (1944), "Dry open situations. .Woodlands
must be of far- scattered trees, to harbor this kingbird;
oaks, cottonwoods, digger pines and tree-yuccas are attractive,
if not growing too thickly." Small (1974) gives California
Tyr annus verticalis (con't.)
habitat as "open country such as savannah, agricultural
lands bordered by trees, plain." Phillips et al. (1964),
"This is the common kingbird of the Lower Sonoran Zone."
Willett (1933) called this species a common summer resident
of lowlands and mesas in California. Grinnell (1914) found
that this species prefers cottonwoods along the lower
Colorado River. In Washington, Kennedy (1914) found that
agriculture, with the associated increase in irrigation,
caused an increase in kingbird numbers.
B. Altitudinal range
Grinnell and Miller (1944), "Altitudes of summer residence
extend from below sea level, as near Salton Sea, up to over
6400 feet." Willett (1933) found this species "occasional
up to 7000 feet in mountains" of California. Johnson et al,
(1948) found Western Kingbirds at elevations between 3300
and 5100 feet in the Providence Mountains, California,
during summer.
C. Home range size
D. Territory requirements
Perch sites - Grinnell and Miller (1944) list living and
dead trees, derricks, windmills, power poles, and fence-
posts as roost sites. Johnson et al. (1948), in the Pro-
vidence Mountains area of California, gave perch sites as
utility poles, fence posts, Joshua trees, and junipers.
Courtship and mating sites - Smith (1966) found that males
"have a nest-site-showing display." Bent (1963) recounts
several aerial displays performed by male kingbirds.
Nest sites - Dawson (1923), "placed at moderate heights
in bushes or trees, or, as frequently, on beams and ledges
of barns or other outbuildings." Phillips et al. (1964),
"nests primarily in broad- leaved deciduous trees, such as
cottonwoods and mesquites. It is not adverse to placing
its nests on exposed telephone poles." Johnson et al.
(1948) found Western Kingbird nests in Joshua trees in the
Providence Mountains of California. Quigley (1944) found
a pair of Western Kingbirds utilizing a Northern Oriole
nest in Kern Co., California (nest held young kingbirds).
Robertson (1931) noted the use of eucalyptus trees as
kingbird nest sites in southern California.
E. Special habitat requirements
Grinnell and Miller (1944) conclude that this species re-
quires expansive open areas around perch and nest sites.
^ Tyrannus verticalis (con't.)
F. Seasonal changes in habitat requirements
Grinnell and Swarth (1913) found that Western Kingbirds
moved to higher elevations during late summer in the San
Jacinto region of California, with numerous 8000 feet
sightings.
V FOOD
A. Food preferences
Tyler (1913) notes that these kingbirds usually prey upon
grasshoppers, butterflies, bees, and various other insects
in California. In the Chihuahuan Desert of New Mexico,
Raitt and Pimm (1976) found that grasshoppers were the most
important food source. La Rivers (1941) found this species
feeding on crickets in Nevada. Knowlton and Harmston (1943)
reported that "of 55 stomachs. .. 48 of them contained 110
grasshoppers. .. six stomachs contained eight field crickets"
(Utah). Martin et al. (1951) found that bees and wasps,
grasshoppers, beetles, bugs, and flies were the most im-
portant food items taken in the West. In Joshua Tree National
Monument, Miller and Stebbins (1964) found that "Large
insects flying in the open are the food resource for this
kingbird..." In Texas, Ohlendorf (1974) found that in
terms of relative frequency, Coleoptera were the most often
captured prey, followed by Hymenoptera, Hemiptera, and
Orthoptera.
B. Foraging areas
Tyler (1913) found these kingbirds hunting (f lycatching)
from a wire fence along an alfalfa field in California.
Grinnell and Swarth (1913) noted this species feeding in
the open meadows surrounding Hemet Lake (southern California)
during August. Smith (1966), "T. verticalis was partial to
much more open desert shrub and grass areas, and foraged
very little along the sides of the canyons."
C. Foraging strategies
Guillion (1948) noted that a Western Kingbird feeding along
the edge of an orchard in Oregon was doing most of its
flycatching within four feet of the ground. Although it
would drop to the ground for an insect, it remained there
for only a moment. La Rivers (1941) noted that this species
often flew to the ground from a fence or utility pole to
capture an insect.
Tyrannus verticalis ( con ' t . )
D. Feeding phenology-
Stone (1941) noted Western Kingbirds feeding on elderberries
during June in Lake Co., California. Martin et al. (1951)
found that elderberries were the only plant food found in
appreciable amounts in the stomachs of 139 kingbirds col-
lected mainly in California during summer and fall.
E. Energy requirements
Miller and Stebbins (1964) found that in the deserts of
California, Western Kingbirds do not require water, although
its presence, as at oasis, probably results in a better
food supply. Ohlendorf (1974) showed that although they
were not the most frequently captured prey, Orthopterans
were the most important food item in terms of expressed
as percent of total prey volume (supply most energy to
bird).
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Dawson (1923) states that kingbirds show the highest levels
of territory defense during courtship; hawks, crows, jays
and magpies are often driven away from nests.
C. Courtship and mating behavior
Tyler (1913) noted that these kingbirds often spend several
days in "noisy discussion" when choosing a nest site.
Smith (1966) gives a detailed account of courtship behavior,
including descriptions of vocalizations, tumble flight,
wing and tail displays, and various other activities per-
formed by both sexes.
D. Nesting phenology
In California, Dawson (1923) gives laying period as early
May to mid-June. California breeding season of 1 May to
25 June given by Wheelock (1904). Willett (1933), "Breeds
mostly in May and early June" in California. Tyler (1913)
found that it took almost exactly 4 weeks for a pair to
complete a nest, lay eggs, and fledge young. California
egg dates, as given by Bent (1963), are: 106 records, 17
April to 9 July; 53 records, 10 May to 4 June.
E. Length of incubation period
Dawson (1923) lists an incubation period of 12-13 days.
Wheelock (1904) states that incubation lasts 13 days in
California. Bent (1963) gives incubation as lasting 12-14
days.
B Tyr annus verticalis (con't.)
F. Length of nestling period
A 2 week nestling period was given by Dawson (1923).
Wheelock (1904) reports that nestlings begin their first
flights at 2 weeks of age.
G. Growth rates
Wheelock (1904), in describing young development, "At first
they are fed by regurgitation, but after the third day
large insects are torn apart and given fresh."
H. Post-breeding behavior
Grinnell and Miller (1944) state that "Post-breeding move-
ment carries individuals up to 8500 feet" (California).
VII POPULATION PARAMETERS
A. Clutch size
Peterson (1961), "Eggs (3-5; 7) boldly spotted." Bent
(1963) gives the average clutch as 3-5 eggs, occasionally
up to 6 or 7.
»
B. Fledging success
&
C. Mortality rates per age class
D. Longevity
E. Seasonal abundance
In the San Jacinto area of California, Grinnell and Swarth
(1913) found that "In late summer they became still more
numerous, and more widely spread." Lamb (1912) called this
species "Very abundant everywhere during August and September,
after which they left to reappear April 2," near Daggett,
on the Mojave Desert of California.
F. Habitat density figures
Balda (1970) found a breeding density of 3 pairs of Western
Kingbirds per 100 acres in oak woodland (Arizona). Near
Buena Vista Lake, Kern Co., California, Lamb and Howell
(1913) found one Western Kingbird nest on about every fourth
telegraph pole. Stewart and Kantrud (1972) gave an average
range of 2.30 to 4.03 pair of Western Kingbirds per square
in North Dakota, with a maximum density of 24 pairs/square
mile. In a cottonwood-willow habitat of California, Ingles
(1950) discovered 7 pair of nesting kingbirds on a 33 acre
\ 4
Tyrannus verticalis (con't.)
study area. In Montana, Walcheck (1970) found 3 pairs
per 100 acres in a pine- juniper woodland, and 13 pairs per
100 acres in a cottonwood forest; kingbirds were absent in
sagebrush habitat. In riparian habitat in the Sacramento
Valley, California, Gaines (1974) found 26 to 38 territorial
male Western Kingbirds per square km.
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Hamilton (1941) found the remains of Western Kingbirds at
Burrowing Owl nests near Denver, Colorado. Bent (1963)
feels that "These kingbirds and their eggs and young are
doubtless preyed upon by the ordinary mammalian and avian
predators. . .but they are valiant and often successful in
driving their enemies away."
B. Competition
Dawson (1923) states that Western and Cassin Kingbirds
often nest close to one another without adverse interactions.
Swarth (1904) has noted these two kingbirds migrating together
in Arizona. However, DeBenedictis and McCaskie (1967)
found that intense fighting may occur between Western and
Cassin' s Kingbirds, especially near the nest site--"these
two species may be as interspecif ically territorial as
they are intraspecif ically territorial." In Arizona, Gil-
man (1915) found a Bendire Thrasher trying to drive a pair
of Western Kingbirds from their nest: the kingbirds kept
the site. In Texas, Ohlendorf (1974) showed that between
Western and Cassin' s Kingbirds, "There was no apparent
interspecific defense of feeding areas, although the nest
sites were defended." Hespenheide (1964) discusses several
factors that prevent serious interspecific competititon
in kingbirds.
C. Parasitism
Friedmann (1963) notes the infrequent parasitism of Western
Kingbird nests by cowbirds. Friedmann et al. (1977) state
that although this kingbird has raised cowbird young, it
usually "rejects" the eggs. Smith (1972) followed a king-
bird pair that fledged one cowbird and one kingbird in
Nebraska.
IX STATUS
A. Past population trends
Grinnell and Miller (1944) called this species locally com- /fr *
mon to abundant in interior valleys of California. Hollister v^,
(1908) found this species "abundant along the Colorado River"
near Needles, California.
Tyrannus verticalis (con't.)
B. Present population status
Small (1974) describes this species as common in California
during summer. Davis and Webster (1970) state that Western
Kingbirds have been expanding their breeding range eastward
(Texas). Smith (1966) felt that "its recent range expansion
has probably been much influenced by the plantings settlers
made on the plains."
C. Population limiting factors
Grinnell and Miller (1944) found that "Woodland must be of
far-scattered trees to harbor this kingbird."
D. Environmental quality: adverse impacts
E. Potential for endangered status
Tyrannus verticalis (con't.) XI LITERATURE CITED 10
American Ornithologists' Union. 1957. Checklist of North
American birds. 5th edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Balda, R. P. 1970. Effects of spring leaf-fall on composi-
tion and density of breeding birds in two southern
Arizona woodlands. Condor 72:325-331.
Bent, A. C. 1942. Life histories of North American flycatchers,
larks, swallows, and their allies. U. S. Nat. Mus. Bull.
179:1-555.
Carter, F. 1937. Bird life at Twentynine Palms. Condor
39:210-219.
Davis, L. I., and F. S. Webster, Jr. 1970. An intergeneric
hybrid flycatcher (Tyrannus x Muscivora) . Condor 72:37-42.
Dawson, W. L. 1923. The birds of California. Vol. 2. South
Moulton Co., San Francisco.
DeBenedictis, P. and R. G. McCaskie. 1967. Cassin's Kingbird
and plumbeous Solitary Vireo in the White Mountains of
California. Condor 69:424-425.
Friedmann, H. 1963. Host relations of the parasitic cowbirds.
U.S. Nat. Mus. Bull. 233:1-276.
Friedmann, H. , L. F. Kiff and S. I. Rothstein. 1977. A
further contribution to knowledge of the host relations
of the parasitic cowbirds. Smithsonian Contrib. Zool.
No. 235. 75 pp.
Gaines, D. 1974. A new look at the nesting riparian avifauna
of the Sacramento Valley, California. Western Birds 5:
61-80.
Gilman, M. F. 1915. A forty acre bird census at Sacaton,
Arizona. Condor 17:86-90.
Grinnell, J. 1914. An account of the mammals and birds of
the lower Colorado Valley. Univ. California Publ. Zool.
12:51-294.
Grinnell, J. and A. H. Miller. 1944. The distribution of
the birds of California. Pacific Coast Avifauna No. 27.
008 pp.
Grinnell, J. and H. S. Swarth. 1913. An account of the birds
and mammals of the San Jacinto area of southern California.
Univ. California Publ. Zool. 10:197-406.
11
Tyr annus verticalis (con't.)
Gullion, G. W. 1948. An early record of the Western Kingbird
in Lane County, Oregon. Condor 50:46.
Hamilton, W. J., Jr. 1941. A note on the food of the western
Burrowing Owl. Condor 43:74.
Hellmayr, C. E. 1927. Catalogue of birds of the Americas and
the adjacent islands. Part 5. Field Mus. Nat. Hist. Zool.
Ser. Publ. 242, Vol. 13.
Hespenheide, H. 1964. Competition and the Genus Tyrannus .
Wilson Bull. 76:265-281.
Hollister, N. 1908. Birds of the region about Needles, Calif-
ornia. Auk 25:455-462.
Hunter, J. S. 1905. Double nest of Arkansas Kingbird. Condor
7:53.
Ingles, L. G. 1950. Nesting birds of the willow-cottonwood
community in California. Auk 67:325-332.
Johnson, D. H. , M. D. Bryant and A. H. Miller. 1948. Verte-
brate animals of the Providence Mountains area of California.
Univ. California Publ. Zool. 48:221-376.
Kennedy, C. H. 1914. The effects of irrigation on bird life
in the Yakima Valley, Washington. Condor 16:250-255.
Knowlton, G. F. and F. C. Harms ton. 1943. Grasshoppers and
crickets eaten by Utah birds. Auk 60:589-591.
Lamb, C. 1912. Birds of a Mohave Desert oasis. Condor 14:
32-40.
Lamb, C. and A. B. Howell. 1913. Notes from Buena Vista Lake
and Fort Tejon. Condor 15:115-120.
LaRivers, I. 1941. The Mormon cricket as food for birds.
Condor 43:65-69.
Martin, A. C. , H. S. Zim and A. L. Nelson. 1951. American
wildlife and plants. McGraw Hill Book Co., Inc., N.Y.
Miller, A. H. and R. C. Stebbins. 1964. The lives of desert
animals in Joshua Tree National Monument. Univ. California
Press, Berkeley. 452 pp.
Ohlendorf, H. M. 1974. Competitive relationships among king-
birds (Tyrannus) in Trans-Pecos Texas. Wilson Bull. 86:
357-373.
12
Tyrannus verticalis (con't.)
Peterson, R. T. 1961. A field guide to western birds. Houghton
Mifflin Co.. Boston. 366 pp.
Phillips, A., J. Marshall and G. Monson. 1964. The birds of
Arizona. Univ. Arizona Press, Tucson. 212 pp.
Pierce, W. M. and E. L. Sumner, Jr. 1927. New records from
Big Bear Lake, San Bernardino Mountains, California.
Condor 29:82.
Pinckney, A. J. 1938. A hand-reared Arkansas Kingbird. Wilson
Bull. 50:290-291.
Quigley, R. , Jr. 1944. Unusual nest site of the Western King-
bird. Condor 46:206
Raitt, R. J. and S. L. Pimm. 1976. Dynamics of bird communi-
ties in the Chihuahuan Desert, New Mexico. Condor 78:427-
442.
Ridgway, R. 1907. The birds of North and Middle America.
Part 4. Bull. U.S. Nat. Mus. No. 50.
Robertson, J. McB. 1931. Birds and eucalyptus trees. Condor
33:137-139.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Smith, T. S. 1972. Cowbird parasitism of Western Kingbird
and Baltimore Oriole nests. Wilson Bull. 84:497.
Smith, W. J. 1966. Communication and relationships in the
Genus Tyrannus . Publ. Nuttall. Ornithol. Club No. 6, 250 pp.
Stevens, F. 1903. Bird notes from eastern California and
Western Arizona. Condor 5:75-78; 100-105.
Stewart, R. E. and H. A. Kantrud. 1972. Population estimates
of breeding birds in North Dakota. Auk 89:766-788.
Stone, N. W. 1941. Elderberries as food for birds. Condor
43:121.
Swarth, H. S. 1904. Birds of the Huachuca Mountains, Arizona.
Pacific Coast Avifauna No. 4. 70 pp.
Tyler J. G. 1913. Some birds of the Fresno District, Calif-
ornia. Pacific Coast Avifauna No. 9. 114 pp.
Walcheck, K. C. 1970. Nesting bird ecology of four plant
communities in the Missouri River Breaks, Montana. Wilson
Bull. 82:370-382.
(J
13
W
Tyr annus verticalis (con't.)
Wauer, R. H. 1962. A survey of the birds of Death Valley.
Condor 64:220-233.
Wauer, R. H. 1964. Ecological distribution of the birds of
the Panamint Mountains, California. Condor 66:287-301.
Whedon, A. D. 1938. Nesting behavior of Kingbirds. Wilson
Bull. 50:288-290.
Wheelock, I. G. 1904. Birds of California. A. C. McClurg
and Co., Chicago. 578 pp.
Willett, G. 1933. A revised list of the birds of southwestern
California. Pacific Coast Avifauna No. 21. 204 pp.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. No. 6. 39 pp.
»
fr
u
WESTERN MEADOWLARK
m Sturnella neglecta
I TAXONOMY
A. Type description
AOU (1957) Sturnella neglecta confluenta Rathbun, Auk, 36,
no. 1, Jan. 1917, p. 68. (Seattle, Washington.)
Sturnella neglecta neglecta: Sturnella neglecta Audubon,
Birds Amer. (octavo ea.), vol" T, 1884, p. 339, pi. 489.
(Missouri River about Fort Crogan = Old Fort Union, North
Dakota. )
B. Current systematic treatments
AOU (1957) places Sturnella neglecta in the Order Passeri-
formes. Family Icteridae with two subspecies. Mayr and
Short (1970) note that S. neglecta and S. magna hybridize
in their zone of overlap and should be "Further studied to
determine their relationship. They are considered sibling
species. Oberholser (1974) considers S. neglecta, S_.
ludoviciana, as does Kincaid (1974). This is based on a
name assigned by Brisson, prior to Audubon describing the
species.
C. Synonomies of scientific nomenclature
Grinnell and Miller (1944), Sturnella hippocrepus, Sturnella
magna neglecta, Sturnella magna. Oberholser (19 74), S.
luctoviciana. Kincaid (1974), S. ludoviciana.
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), Western Meadowlark, Meadow Lark,
Missouri Meadowlark, Western Lark.
II DESCRIPTION
A. External morphology of adults
Dawson (1923): "Adult male. General color of underparts
black-brown, modified by much tawny and buffy-gray edgings
of feathers, which throw the black into stripes and bars
with a suggestion of herring-bone pattern; the tawny heaviest
on secondaries and upper-tail feathers, where taking the form
of partial bands; a median crown stripe and posterior por-
tion of superciliary sordid white or buffy; anterior portion
of superciliary, lower cheeks, chin, upper throat, breast,
middle belly, and edge of wing, rich yellow; a large black
crescent on upper breast; sides and flanks black- streaked,
i
»
Stumella neglecta (con't.)
and spotted with pale brown on a buffy whitish ground. Bill
variegated, tawny black and white. Female, Like male but
smaller and paler, with some substitutions of brown for
black in streaking; black of jugulum veiled by grayish tips
of feathers; yellow of breast, etc., duller."
Baird et al . (1905): "Feathers above, dark brown, margined
with brownish- white, with a terminal blotch of pale reddish-
brown. Exposed portion on wings and tail with transverse
band, which in the latter are completely isolated from each
other, narrow and linear. Beneath yellow, with a black
pectoral crescent. The yellow of the throat extending on
the sides of the maxilla. Sides, crissum, and tibiae very
pale reddish-brown, or nearly white, streaked with blackish.
Head with a light median and superciliary stripe, the latter
yellow in front of the eye; a blackish line behind it. The
transverse lines on the feathers above with a tendency to
become confluent near the exterior margin.
B. External morphology of subadult age classes
Dawson (1923): "Immature birds resemble parents but are
grayer with pale yellow more confined and they lack the
jugular crescent. Bent (1958) says the young are practically
indistinguishable from the adults once they get their first
winter plumage.
C. Distinguishing characteristics
Interspecific - Baird et al. (1905) describes the differences
between ;S. neglecta and S^. magna the eastern species. Dawson
(1923) describes the eastern species as lacking the yellow
on lower cheek. Robbins et al . (1966) say the western species
can be told from the eastern by its paler back and tail.
Kincaid (1974): "Similar to Lilian's Eastern Meadowlark,
S. magna lilianae, but wing and tail longer, sides of head
more whitish, yellow of lower surface lighter," in reference
to S. neglecta. Bent (1958): "These two species Ceastern
and western] can be easily recognized by their white lateral
tail feathers, yellow breast, and black crescent," but it
is very difficult to tell them apart.
Intraspecific - Bent (1958) describes conf luenta as similar
to neglecta but the bars on the tail and tertials are broader
and much more confluent; upper parts are darker throughout
and the black areas more extensive; yellow of underparts
darker. Kincaid (1974), S. n. conf luenta: "Resembling _S. n.
neglecta but upper parts more deeply colored with black
markings broader; bars on tertials and tail wider; yellow
of lower parts a little darker."
f>
e
Sturnella neglecta (con't.)
^ GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) Sturnella neglecta in general: "Central British
Columbia, central Alberta, central Saskatchewan, southern
Manitoba, western and southern Ontario, northern Michigan,
and northwestern Ohio south to Baja California, Zacatecas,
Nuevo Leon, central Texas and Louisiana."
Sturnella neglecta conf luenta: "Breeds from southwestern and
central British Columbia south through Washington, western
Idaho, and Oregon to southern California, intergrading with
S. n. neglecta in central Idaho, Death Valley, and San Diego
County, California."
Sturnella neglecta neglecta: "Breeds from southern British
Columbia, central Alberta, central Saskatchewan, southern
Manitoba, western Ontario, northeastern Minnesota, northern
Wisconsin, northern Michigan, southern Ontario, northwestern
Ohio south through western Montana, eastern Idaho, Nevada,
southeastern California to northwestern Baja California,
northwestern Sonora, central and southeastern Arizona, eastern
Sonora, Sinaloa, Jalisco, northwestern Durango, Guanajuato,
southeastern Coahuila, central Texas, northwestern Louisiana,
northwestern Arkansas, central and eastern Missouri, south-
western Tennessee, southern Illinois, southern Michigan,
and central Ohio."
Gullion et al . (1959): "Noted as a common resident in the
valleys and sagebrush areas... but also found to be common
throughout the year on desert areas, particularly in desert
grassland and creosote-bush." Lanyon (1956) describes the
sympatric distribution of Meadowlarks in the north-central
states.
B. California distribution of the species
Grinnell and Miller (1944): "Occurs throughout the state
with exception of most arid and barren tracts of deserts,
roughest mountains and densest forests. Included are all
coastal islands, and many high points in the Sierra Nevada
reached by vagrants. Life-zones occupied in breeding season;
Lower and Upper Sonoran, and Transition."
Dawson (1923): "Resident and general distribution throughout
state, save arid portions of the desert, broken mountain
sections, and the dense forests. Breeds from Lower Sonoran
to Lower Boreal." Small (1974) calls S. neglecta a common
resident. in the state.
Sturnella neglecta (con't.)
C. California desert distribution
Grinnell and Miller (1944) say that breeding populations
are rare in the desert but that on southeastern deserts
numbers have increased with the development of oases and
irrigated lands. They give records for San Bernardino
Mountains, San Jacinto Mountains, Owens Valley, Inyo Moun-
tains, Panamint and Death Valleys, San Bernardino County,
Riverside County and Imperial County. Dawson (1923) lists
Colorado deserts at Indio and Inyo County as breeding sites.
Willett (1951) calls S. neglecta a scattered resident in the
southern desert. PhiTlips et al . (1964): "In occasional
years heavy winter or spring rains on the desert will bring
up a stand of grass which will become inhabited with Western
Meadowlarks. "
D. Seasonal variations in distribution
AOU (1957), S. n. confluenta: "Winters from Vancouver Island
and the adjacent mainland southward. Migrant, in part,
in the northeastern section of its range."
_S. n. neglecta: "Winters north to southern Alberta, southern
Saskatchewan , southern Manitoba, and southern Wisconsin;
south to southern Baja California, Michoacan Mexico, Tamaulipas,
southern Texas, Louisiana, and Mississippi. Casual in
Alaskan northern British Columbia, Mackenzie, northern
Alberta and Kentucky.
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944): "Life-zones occupied in breed-
ing; Lower Sonoran, Upper Sonoran, Transition." Habitat
in grassy plains, hillslopes and meadowlands, may be mod-
erately intermixed with bushes. Peterson (1961): "Open
fields, meadows, grassy plains, prairies." Kincaid (1974):
"...in habits prairies, meadows, and fields. Habit details
frequently differ however." Walcheck (1970) in a study in
the Missouri River Breaks, Montana, found S. neglecta
associated with greasewood- sagebrush shrubTand, sagebrush
grassland, and pine- juniper woodland. Lanyon (1957) notes
that neglecta selects drier environments than _S. magna.
B. Altitudinal range
Grinnell and Miller (1944) - 200 feet to 11,000 feet. Dawson
(1923) - up to 11,000 feet. Bent (1958) - about 8,000 feet
is the highest in California.
<*
#
Sturnella neglecta (con't.)
•
»
C. Home range size
Bent (1958) - 10 to 32 acres. Lanyon (1957) - 3 to 15 acres.
These areas were found to undergo changes in shape through
the season. Kendeigh (1941) in 50 acres of priarie noted
6 S. neglecta nesting and feeding in the area.
D. Territory requirements
Perch sites - Bent (1958) says the males have singing perches
on trees or posts in their territory.
Courtship and mating sites
Nest sites - Baird et al. (1905) state that they build their
nest in a slight depression under a bunch of grass, and
concealed by it. Dawson (1923): "On ground, chiefly in
meadows or pastures, in thick grass or weeds. Peterson
(1961): "A grassy saucer, partially domed, among grass."
Bent (1958) describes a nest placed in a growth of low grass
that was arched over with strips of dry bark. Roseberry
and Klimstra (1970) in a study of S. magna note pastures to
be the favored nest site and then Hayfields.
E. Special habitat requirements
F. Seasonal changes in habitat requirements
Kincaid (1974): "During spring and summer the western nests
on uplands where grass is comparatively short and dry; in
winter habitat preferences are less marked... the western is
more likely to forage on bare, desert-like ground.
V FOOD
A. Food preferences
Baird et al . (1905) say they feed chiefly on insects, seeds
and grain. Bent (1958; says the diet consists of grass-
hoppers, beetles, crickets; 70% animal matter to 30% vege-
table. Kincaid (1974): "The vegetable portions of its diet
consists of grain (corn, oats, wheat, barley), a little
fruit pulp, and weed seeds." Bryant (1914) found meadowlarks
to eat 63.3% animal food and 36.77D vegetable food; grain
was the largest by volume.
B. Foraging areas
Grinnell and Miller (1944) give foraging areas as matted
grass tangles, living vegetation, in cultivated lands.
$
Stumella neglecta (con't.)
C. Foraging strategies
Grinnell and Miller (1944) say that much food is obtained
from the ground surface by turning over clods and by drill-
ing the soil.
D. Feeding phenology
Bryant (1914) found vegetable food to make up the largest
part of the diet in January through March and October
through December. Animal food made up the largest percent
in April through September.
E. Energy requirements
Dawson (1923) gives an estimate of 6 pounds of food needed
annually by an adult.
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
Bent (1958) prints an exerpt from a study by Kendeigh (1941):
"Territorial behavior is well established in this species,
although only the male defends the territory." They have
singing posts in the territory where they perch while singing.
Lanyon (1957): "Territories were established and maintained
solely by the males and defended for a period of up to 4
weeks before the arrival of the female. Maintenance of
territories continued until fledging of the final brood."
Species of a different genus were often tolerated in the
territory.
C. Courtship and mating behavior
Bent (1958): "It probably consists of song and plumages
display." Lanyon (1957) says that both male and female sing.
Lanyon (1957) found males that did not obtain a mate could
not maintain territories. Pair formation took place immediately
upon arrival of the female on the male's territory. 53%
of male S. neglecta had more than one mate.
D. Nesting phenology
Bent (1958) records egg dates from California from February
11 to June 10. Kincaid (1974) reports the nesting season
in Texas as mid-March to mid-August. Lanyon (1957) gives
18 April as the average date of egg-laying initiation;
last egg laid - 4 May.
e
Sturnella neglecta (con't.)
E. Length of incubation period
Bent (1958) - 13 days. Lanyon (1957) - 13 to 14 days,
occasionally 15 days.
F. Length of nestling period
Bent (1958) - about 4 weeks.
G. Growth rates
Bent (1958) gives a detailed description of each days growth
for the eastern species. By the eleventh or twelfth day
the young leave the nest at which time they can fly a little
if necessary.
H. Post-breeding behavior
Bent (1958) says the male chases his young out of his terri-
tory at about 1 month of age. "After the last brood of
young are... on the wing, old and young gather into groups...
and begin their late summer wanderings..." Lanyon (1957)
says that they become gregarious following the late- summer
molt.
POPULATION PARAMETERS
A. Clutch size
Dawson (1923) - 4 to 5, rarely 6 or 7. Peterson (1961) -
3 to 7. Bent (1958) - 3 to 7, 5 being the commonest.
B. Fledging success
Lanyon (1957) records 50% of nests fledging young.
C. Mortality rates per age class
D. Longevity
Kennard (1975) did not publish an age record from band
returns for the Western Meadowlark, but the oldest eastern
one he found was 8 years 8 months.
E. Seasonal abundance
Bent (1958): "...many birds winter on suitable portions of
the Colorado and Mohave deserts where this species is unknown
in the summer."
F. Habitat density figures
Sturnella neglecta (con't.)
II INTERSPECIFIC INTERACTIONS
A. Predation
Bent (1958): "Meadowlarks have many enemies, more especially
Golden Eagles, Prairie Falcons, Marsh Hawks, Red-tailed
Hawks," and also skunks, weasels, minks, raccoons, coyotes,
snakes and crows. "Some nests are probably trodden by
cattle or sheep. Roseberry and Klimstra (1970) attribute
losses to predation at 51% of total losses.
B. Competition
Kendeigh (1941) on a 50-acre priarie noted 16 species of
passerines using the area for feeding and/or nesting.
C. Parasitism
Friedmann et al . (1977) do not list the Western Meadowlark
as being a cowbird victim. The eastern species is, however.
IX STATUS
A. Past population trends
Baird et al . (1905) report the species to be abundant in
California. Lanyon (1957) notes a marked northeastward v~r
extension of the range of neglecta during the past 50 years.
*
B. Present population status
Lanyon (1957) notes the increasing range of both the eastern
and western species as a result of increased suitable habi-
tat due to greatly expanded agricultural activities. Bryant
(1914) gives a long discussion on the economic status of the
western meadowlark in California. This study was prompted
by the number of complaints against the meadowlark by farmers
who said they ate sprouting grain. The results of Bryant's
study (1914) indicate that the meadowlark actually does
more good than harm by eating cutworms and grasshoppers.
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
<Ji
Sturnella neglecta (con't.)
Sk LITERATURE CITED
American Ornithologists Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Baird, S. F. , T. M. Brewer and R. Ridgway. 1905. A history of
North American birds. Vol. 2. Little, Brown and Co.,
Boston.
Basket, J. N. 1896. Intergradation in song of Sturnella magna
and S. m. neglecta in Missouri. Auk 13:258-259.
Bent, A. C. 1958. Life histories of North American blackbirds,
orioles, tanapers, and allies. U.S. Natl. Mus. Bull. 211.
Bond, F. 1901. Song of the western meadowlark. Auk 18:108-
109.
Bryant, H. C. 1914. A determination of the economic status
of the western meadowlark in California. Univ. Calif.
Publ. Zool. 11:377-510.
Dawson, W. L. 1923. The birds of California. Vol. 1. South
Moulton Co., Los Angeles.
Friedmann, H. , L. F. Kiff and S. I. Rothstein. 1977. A further
contribution to knowledge of the host relations of the para-
sitic cowbirds. Smithsonian Contrib. Zool. No. 235. 75 pp.
Grinnell, J. and A. H. Miller. 1944. The distribution of the
birds of California. Pacific Coast Avifauna. No. 27.
608 pp.
Gullion, G. W., W. M. Pulich and F. G. Evenden. 1959. Notes
on the occurrence of birds in southern Nevada. Condor 61:
278-297.
Kendeigh, S. C. 1941. Birds of a prairie community. Condor
43:165-174.
Kennard, J. H. 1975. Longevity records of North American birds.
Bird-Banding 46:55-73.
Kincaid, E. B. Ed. 1974. The bird life of Texas. Vol. 2.
Univ. of Texas Press, Austin.
Knowlton, F. H. 1909. Birds of the world. Henry Holt and Co.,
New York. 873 pp.
Lane, G. W. 1933. The western meadowlark singing at night.
Condor 35:237.
10
Sturnella neglecta (con't.)
Lanyon, W. E. 1956. Ecological aspects of the sympatric dis-
tribution of rneadowlarks in the north-central states.
Ecology 37:98-108.
Lanyon, W. E. 1957. The comparative biology of rneadowlarks
(Sturnella) in Wisconsin. Publ . Nuttall Ornith. Club,
no"] TJ 67 p.
Mayr, E. and L. L. Short. 1970. Species taxa of North American
birds. Publ. Nuttall Ornith. Club, no. 9, 127 p.
McAtee, W. L. 1944. Meadowlark ranges. Auk 61:147-148.
Oberholser, H. C. 1974. The bird life of Texas. Vol. 2.
Univ. of Texas Press, Austin.
Peterson, R. T. 1961. A field guide to western birds. Houghton
Mifflin Co., Boston. 366 pp.
Phillips, A., L. Marshall and G. Monson. 1964. The birds of
Arizona. Univ. of Arizona Press, Tucson. 212 pp.
Pierce, F. J. 1921. The meadowlark as a conversationalist.
Wil. Bull. 33:154-155.
Robbins, C. S. , B. Bruun and H. S. Zim. 1966. Birds of North
American. Western Publ. Co., Wisconsin. 340 pp.
Roseberry, J. L. and W. D. Klimstra. 1970. The nesting ecology
and reproductive performance of the eastern meadowlark.
Wil. Bull. 82:243-267.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Walcheck, K. C. 1970. Nesting bird ecology of four plant
communities in the Missouri River Breaks, Montana. Wil.
Bull. 82:370-382.
Willett, G. 1951. Birds of the southern California deserts.
Los Angeles County Mus. Zool. Publ. No. 6. 39 pp.
<*^
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»
»
WESTERN WHITE-THROATED SWIFT
Aeronautes saxatalis
A. s. saxatalis
TAXONOMY
A. Type description
AOU (1957), Acanthylis saxatalis Woodhouse, in Sitgreaues,
Rep. Expd. Zuni and Colorado Rivers, 1853, p. 64. (Inscrip-
tion Rock, New Mexico).
B. Current systematic treatments
Lack (1956) Apodinae divided into five genera, one of which
is Aeronautes containing three New World species. "as
compared with Aeronautes, Panyptila has a white nape like
A. andecolus, white sides to the rump like A. andecolus
and A. saxatalis, a white throat and upper chest like A.
saxatalis, and white bases to the secondaries, like A.""
saxatalis, these resemblances are far too striking to be
due to chance. . . indicate that Panyptila and Aeronautes. . .
are closely related. . .with the transfer of andecolus from
Apus to Aeronautes, these two genera can no longer be dif-
f erentiated. . .by presence or absence of feathering on toes."
Order Apodiformes, family Apodidae.
C. Synonomies of scientific nomenclature
AOU (1957), Acanthylis saxatalis Woodhouse. Peters (1940),
Cypselus melanoleucus (Baird) . Ridgway (1911), Aeronautes
melanoleucus (Baird) . Grinnell (1944) Panyptila melanoleuca,
Micropus melanoleucus, Cypselus saxatilis
D. Synonomies of vernacular nomenclature
Dawson (1923), Rock Swift, Mountain Swift, Rocky Mountain
Swift, White- throated Rock Swift. Grinnell and Miller
(1944), White-bellied Swift.
II DESCRIPTION
A. External morphology of adults
Ridgway (1911), detailed description of adults, including
plumage, soft parts, and measurements. Peterson (1961),
"contrasting black and white pattern. . .underparts white
with black side patches." Dawson (1923), "Adults: chin,
throat, breast, middle line of belly, and a conspicuous
patch on flanks, white--also outer edge of first primary
and tips of secondaries; remaining plumage brownish black,
paling on forehead, shading on sides of head; a whorl of
stiffened feathers in front of eye black."
/
/
Aeronautes saxatalis (con't.)
B. External morphology of subadult age class
Ridgway (1911), "Similar to adults, but white of underparts
duller (more or less grayish or sooty) and blackish of
sides duller especially anteriorly, where more sooty grayish
and less strongly contrasted with whitish of throat, etc."
C. Distinguishing characteristics
Interspecific - Peterson (1961), 'Known as a swift by its
long, narrow, stiff wings and characteristic twinkling and
gliding flight; from other North American swifts by its
contrasting black and white pattern."
Intraspecif ic -
III GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), "From southern British Columbia and Southern
Alberta (possibly) to Montana and northwestern South Dakota,
south in the mountains to Guatemala and El Salvador." A.
s* saxatalis; "Breeds from southern British Columbia
XVaseaux Lake and Okanagon Valley), Idaho, western Colorado,
New Mexico, and western Texas (Davis and Chi so s Mountains)
south to the Cape region of Baja California (including the V. #
Santa Barbara Islands and Guadalupe Island), Sinaloa, and
Guanajuato." •
B. California distribution of the species
Small (1974), "more arid regions of the state east and south
of the northwest humid coastal belt." Dawson (1923),
"Resident in cliffs of Upper and Lower Sonoran life zones
in southern California, foraging to highest altitudes; also
breeding locally in Sonoran and Transition zones through-
out the state, except in the humid coastal districts from
Santa Cruz northward. Resident on the Santa Barbara Island."
C. California desert distribution
Dawson (1923), "Resident in cliffs of Upper and Lower Sonoran
life zones." Wauer (1964), found in lower canyons of Pana-
mint Mountains from mid-March to mid- summer. Wilson (1945),
Kettleman Hills area. Miller (1951), Inyo, Upper Kern
Basin, San Diego, Mojave, Colorado regions. Bent (1940),
nesting near San Pasqual, San Diego County, and on Slover
Mountain in the San Bernardino Valley. Grinnell (1944)
"Certain mountain ranges of Inyo County. .. Death Valley
and Salton Sink. .. San Bernardino Mountains."
Aeronautes saxatalis (con't.)
m D. Seasonal variations in distribution
»
AOU (1957), "Winters from San Francisco Bay region in central
California, central Arizona (Big Sandy and Phoenix), and
southwestern New Mexico (Hachita and Chloride) south to
south-central Mexico. Small (1974) "resident and summer
visitor (California), larger part of population leaves
state for winter (October to March)." Dawson (1923),
"Wintering birds from the north appear to rove about the
country in considerable companies. .. at other seasons...
appears to be much less sociable." Wauer (1964) "post-
nesting birds move (mid- summer) into higher canyons (Pana-
mint Mtns.) or to the low-desert oases such as Furnace
Creek Ranch and Eagle Borax Works." Grinnell and Miller
(1944) "part of population emigrates for winter, leaving
a part. .. remaining through winter at low altitudes, south-
erly."
IV HABITAT
A. Biotopic affinities
Miller (1951), Upper and Lower Sonoran , and Transition
zones. Grinnell and Miller (1944), "semi-arid and arid
parts of the State..."
P
B. Altitudinal range
Dawson (1923), "foraging to highest altitudes." Grinnell
and Miller (1944) "nests from within a few feet of sea
level... up probably to at least 6000 feet."
C. Home range size
Grinnell and Miller (1944), "probably the daily cruising
radius of this bird is greater than in any other species,
even the California Condor."
D. Territory requirements
Perch sites - Small (1974), "roosts in deep crevices in
cliffs, canyons, bluffs, and rocks."
Courtship and mating sites - Bent (1940) "performed largely,
if not wholly, on the wing." Dawson (1923; "the nuptial
embrace, appears to take place... in the air. In this the
birds come together from opposite directions, engage with
the axes of their bodies held at a decided angle laterally,
and begin to tumble slowly downward, turning over and over
the while for several seconds, or until earth impends,
where upon they separate. .. coition may take place in the
nesting crevices also."
Aeronautes saxatalis (con't)
Nest sites - Dawson (1923), "a shallow, often formless saucer {4&
of feathers glued together with saliva and placed at bottom
of inaccessible cranny or crevice on cliff." Describes a
number of efforts to reach such nests. Pitelka (1944),
on Life Science Euilding on Berkeley campus in a colony
of Cliff Swallows. Lack (1956), "builds (nests) in rock
crevices on steep cliffs... it has also taken to using holes
in buildings."
F. Seasonal changes in habitat requirements
V FOOD
A. Food preferences
Bent (1940), winged ants and other Hymenoptera, bugs, flies,
dung beetles, engraver beetles, clover root weevils, leaf-
hoppers. .. root maggots, long-legged flies (Dolichipodidae) ,
flesh flies, March flies, true bugs.
B. Foraging areas
Small (1974), "forages over deserts, foothills, mountains,
sea coast." Grinnell and Miller (1944), "air-ways. . .high
and low, over valleys and desert mesas, foothills and highest
mountains . " ^^
C. Foraging strategies
Bent (1940) "food. .. obtained wholly on the wing, it pro-
bably feeds on whatever small flying insects it can capture."
D. Feeding Phenology
E. Energy requirements
Bartholomew, Howell and Cade (1957), body temperatures,
respiratory rate, and behavior for entry torpor, and arousal
in captivity. Remained capable of effective, coordinated
movement at body temperatures as low as 25.8°C. "Reduced
body temperature and torpor provide a means of energy con-
servation and are associated with survival during long
periods of fasting."
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
C. Courtship and mating behavior
Aeronautes saxatalis (con't.)
m D. Nesting phenology
Dawson (1923), "April-June, varying with locality; one
brood."
E. Length of incubation period
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
VII POPULATION PARAMETERS
A. Clutch size
Dawson (1923), "4 or 5 elongate ovate; pure white."
B. Fledging success
C. Mortality rates per age class
D. Longevity
& E. Seasonal abundance
F. Habitat density figures
VIII INTERSPECIFIC INTERACTIONS
A. Predation
Arnold (1942), observed captured in flight by the smaller
of a pair of Falco peregrinus which had both pursued the
swift. Webster (1944) have, on occasion, seen the amazing
feet of a small Prairie Falcon taking white- throated swifts."
B. Competition
C. Parasitism
IX STATUS
A. Past population trends
Grinnell and Miller (1944), "Resident partially, within
State; .. .part of population emigrates for winters, leaving
part (the smaller) remaining through winter at low altitudes.
"Common in vicinity of colonial roosting and nesting re-
treats."
»
Aeronaut es saxatalis (con't.)
B. Present population status ,f^
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
~
Aeronautes saxatalis ( con ' t . )
XL LITERATURE CITED
American Ornithologists' Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Arnold, L. W. 1942. The aerial capture of a White-throated
Swift by a pair of falcons. Condor 44:280.
Bartholomew, G. A., T. R. Howell and T. J. Cade. 1957. Tor-
pidity in the White-throated Swift, Anna Hummingbird, and
Poor-will. Condor 59:145-155.
Bent, A. C. 1940. Life histories of North American cuckoos,
goatsuckers, hummingbirds and their allies. U.S. Nat. Mus.
Bull. No. 176.
Dawson, W. L. 1923. The birds of California Vol. 2. South
Moulton Co., San Francisco.
Grinnell, J. and A. H. Miller. 1944. The distribution of
birds of California. Pacific Coast Avifauna No. 27.
608 pp.
Lack, D. 1956. A review of the genera and nesting habits of
swifts. Auk 73:1-25.
Miller, A. H. 1951. An analysis of the distribution of the
birds of California. Univ. California Publ. Zool. 50:
531-624.
Peters, J. L. 1940. Checklist of birds of the world. Vol.
IV. Harvard Univ. Press, Cambridge, Massachusetts.
Peterson, R. T. 1961. A field guide to western birds. Hough-
ton Mifflin Co., Boston.
Pitelka, F. A. 1944. White-throated Swift breeding with Cliff
Swallows at Berkeley, California. Condor 46:34-35.
Ridgway, R. 1911. The birds of North and Middle America,
Part V. Bull. U.S. Nat. Mus. No. 50.
Small, A. 1974. The birds of California. Macmillan Co.,
New York.
Wauer, R. H. 1964. Ecological distribution of the birds of
the Panamint Mountains, California. Condor 66:287-301.
Webster, H. , Jr. 1944. A survey of the Prairie Falcon in
Colorado. Auk 61:609-616.
Aeronaut es saxatalis (con't.)
Wilson, I. D. 1945. Birds of the Kettleman Hills area, Calif-
ornia. Condor 47:149-153.
*
*
WILSON'S WARBLER
Wilsonia pusilla
TAXONOMY
A. Type description
AOU (1957), W. £. pusilla Wilson, Amer. Orn. , Vol. 3, 1811,
p. 103, pi. 26, figi Z~. CSouthern states, ... lower parts...
of New Jersey and Delaware = southern New Jersey. )
W. £. pileolata: Motacilla pileolata Pallas, 300 gr. Rosso-
Asiatica, vol. 1, 1811, P. 497. (ex insula kodiak = Kodiak
Island, Alaska.)
W. £. chryseola Ridgway, U.S. Nat. Mus. Bull. 50, pt. 2,
Oct. 16, 1902, pp. 705. 714. (Pacific Coast district =
Red Bluff, California.)
B. Current systematic treatments
AOU (1957), recognizes three species in the genus Wilsonia.
Subspecies are W. pusilla: W. £. pusilla, w. p_. pileolata,
W. £. chryseola. In the Family Parulidae: Wood Warblers.
Bent (1953) , dTvides the W. pusilla western representatives
into two subspecies, pileolata and chryseola. Mayr and
Short (1970) state that the species of this genus are quite
distinct and their relationships with other genera are un-
clear.
C. Synonomies of scientific nomenclature
AOU (1957), W. £. pileolata: Motacilla pileolata Pullas.
Grinnell and Miller (1944), pileolata, Myiodioctes
pusillus, Wilsonia pusilla, Sylvania pusilla pileolata. "
chryseoTa, "Sylvania pusilla, Setophaga wilsonii, Myiodioctes
pusillus. Ridgway (1915), Wilson s Warbler: Sylvania pusilla,
D. Synonomies of vernacular nomenclature
Grinnell and Miller (1944), pileolata: "Northern Pileolated
Warbler" and lists synonomies as "Green Black-cap Warbler,
Alaska Pileolated Warbler." chryseola, "Golden Pileolated
Warbler" and lists synonomies as Green Black- capped Fly-
catcher, Black-capped Warbler, Western Blackcap. ' Peterson
(1961), gives Wilson's Warbler the synonym, Pileolated
Warbler."
Wilsonia pusilla (con't.)
II DESCRIPTION
A. External morphology of adults
Bent (1953), describes chryseola as yellow of forehead and
superciliary region, inclining more or less to orange;
yellow of the underparts, olive-green upper parts and almost
yellow in extreme cases. Grinnell and Storer (1924) say
that chryseola is recognized by its black cap.
Dawson (1923) describes adult male pileolata as "A base
bright olive-green; forehead, sides of head, and under parts
bright yellow, shading on sides into color of back; crown
or cap lustrous black; wings and tail fuscous, edged with
olive-green and without peculiar marks. Bill dark above
and light below; feet light brown." The adult female is
similar "but the black cap sometimes wanting-dark olive
veiled" by warbler green tops instead." Dawson (1923) gives
the same description of chryseola as in Bent (1953).
B. External morphology of subadult age classes
Grinnell and Storer (1924), chryseola; young are said to
resemble female or young yellow throats, with no black cap.
Dawson (1923) describes immature pileolata as being "like
respective sex of parents, but black cap sometimes variously,
or even completely, veiled by olive-green."
C. Distinguishing characteristics
Interspecific - Peterson (1961), "yellow Warbler has yellow
spots in tail."
Intraspecif ic - Peterson (1961), "male: yellow warbler
with a round black cap. Females sometimes do, and immatures
do not, show traces of the cap. Olive above, bright yellow
below, no streaks or wing bars; with a yellow stripe above
the body black eye." Bent (1953), pileolata; "is much like
the eastern Wilson's Warbler, but is somewhat larger...
and its coloration is brighter. .. it is not, however, so
brightly colored as [chryseolal. " Dawson (1923) says that
pileolata is brighter than pusilla but not so bright as
chryseola, which is also smaller. Phillips, et al. (1964)
places the dullest birds in the east and the brightest
along the Pacific coast; the largest from the Rocky Moun-
tains and the smallest from the coast. W. p. pusilla is
the eastern bird, W. p_. pileolata is the middle range,
brighter bird, and chryseola is the coastal brightest
bird. Chapman ( 1907) ; chryseola is "similar to pileolata
but smaller and of a still brighter, deeper yellow.
^
»
I
»
Wilsonia pusilla (con't.)
J I GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957) Wilsonia pusilla: "Northern Alaska, northern
Yukon, northwest and central Mackenzie, northeast Manitoba,
northern Ontario, southern Labrodor, and Newfoundland south
to southern California, central Nevada, northern Utah,
northern New Mexico, central Saskatchewan, southern Manitoba,
northern Minnesota, southern Ontario, northern Vermont,
central Maine, and central Nova Scotia."
W. p_. pileolata: "Breeds from northern Alaska, northern
Yukon, and extreme northwestern Mackenzie south to southern
Alaska, northern British Columbia, and the mountains of
interior southern British Columbia, eastern Washington
and eastern Oregon, central eastern California, central
Nevada, northern Utah, southwestern Colorado, and north
central New Mexico; ranging east to western Alberta, central
Montana, and eastern Wyoming."
W. £. chryseola: "Breeds along coasts and coastal ranges
Trom southwestern British Columbia south to southern Calif-
ornia (San Bernardino Mountains, Escondido)."
Bent (1953), gives the breeding ranges of pileolata as,
"From the northern tree limit in Alaska, southward along
the coast. . .mainly in the mountain regions, at least as
far as New Mexico and perhaps central western Texas." It
is a common summer resident of the mountains of western
Montana. Probably breeds in eastern Oregon. Breeds commonly
along the timberline in Colorado, from 12,000 to 6,000 feet.
The breeding range of chryseola is given as being confined
"to the Pacific Coast district, from southern British Colum-
bia to southern California, mainly west of the mountain
ranges."
B. California distribution of the species
Grinnell (1928), W. p_. pileolata, rare fall and late spring
transient, in southern California. W. p_. chryseola, common
in migration through Baja and southern California. Grinnell
and Miller (1944), W. p. pileolata, "Summer resident along
eastern margin of California. Rare winter visitant." W. p_.
chryseola "Summer resident and migrant arriving by late
March in the lowlands and leaving principally in September.
As breeding, in general entire state from eastern edge of
Sierran forests westward. However, irregularly and locally
distributed within this range. .. sparse in arid lowlands.
Most abundant in humid coastal belt and in high meadows of
interior mountains." Dawson (1923), pileolata: "Fairly
Wilsonia pusilla (con't.)
common migrant through southern California especially east
of the desert divide. Also breeds in mountain ranges east
of the Sierras and for an undetermined distance northward.
Possibly the line of demarcation between pileolata and
chryseola should be set at the Sierran divide. " Chryseola,
according to Dawson (1923) is a summer resident chiefly
in semi-riparian associations in Lower Sonoran and Canadian
Zones, from the crest of the Sierras to the Pacific, and
from Oregon south to the San Bernardino Mountains. Small
(1974), "for breeding, length of state, irregularly dis-
tributed but absent from floor of Modoc Plateau, eastern
and southern deserts, floor of central valley."
C. California desert distribution
Grinnell and Miller (1944), W. p_. pileolata, "In migration...
most often detected in southern and eastern California.
Specific reports of summer residence; ... San Diego County;
Argus Mountains, Inyo County; Providence Mountains, San
Bernardino County; Colorado River Valley, Imperial County;
San Bernardino Mountains, 8,500 feet; San Diego County."
Small (1974) "reports W. pusilla as breeding throughout the
length of the state but absent from the floor of the Modoc
Plateau, eastern and southeastern deserts, and Central
Valley, and in migration, almost everywhere.
D. Seasonal variations in distribution
AOU (1957) "In winter, from southern Baja California,
southern Sonora, central Nuevo Leon and southern Texas
south to Costa Rica and western Panama. W. p_. pileolata:
"Winters from Guerrero, Morelos, Nuevo Leon, and south
Texas, south through Mexico (except the Yucatan Peninsula)
and Central America to west Panama; casually north to Calif-
ornia." W. p_. chryseola: "Winters from southern Baja Calif-
ornia and southern Sonora south through western Mexico and
Central America to western Panama; casually north to central
California. In migration east to Arizona and, casually,
to Veracruz."
Bent (1953), pileolata winters in Mexico and Central America.
Grinnell et al! ( 1930) , state that chryseola in the Larsen
Peak region of California is limited closely in summer
to alder and willow thickets bordering ponds, streams and
moist meadows. Chryseola is seen about the city in Seattle
as fall migration starts, Bent (1953). Dawson (1923),
chryseola; Winters in lower California, Sonora and Chihuahua;
occurs during migrations on the east side of the Sierra-
Cascade divide and in Arizona. Phillips et al. (1964),
gives southern Arizona migration dates for pileolata as
April 13 to June 3 and again from August 18 to November 6.
e?
Wilsonia pusilla (con't.)
i "It migrates later than chryseola." Chryseola is given as
f a common spring transient in southwestern Arizona, northeast
to the Tucson Valley. Southern Arizona migrations are from
March 9 to April 25, fall migrations from August 1 to
November 5.
IV HABITAT
A. Biotopic affinities
Grinnell and Miller (1944), pileolata, "Life zones in summer,
Transition and Canadian." cnryseolata, "Low, shaded plant
cover close to streams, meadows, . . .humidity high. Willows,
alders, dogwood, blackberries, poison oak and ferns..."
Bent (1953;, pileolata, "in its winter home... is chiefly
an inhabitant of low growth beneath the forest." Hines
(1963), pileolata; exhibits a definite affinity for alders
along the Noatak River in Alaska. Chapman (1907) cites
Walter Fisher as saying that chryseola frequent copsas
along the water courses in valleys or willow thickets and
moist meadows, in California. Chapman (1907) himself found
them in many anita chaparral.
B. Altitudinal range
Grinnell and Miller (1944), chryseola, "Altitudes of nesting
| range from near sea level up to at least 9,500 feet on east
slope of Mount Whitney, Inyo County."
C. Home range size
D. Territory requirements
Perch sites -
Courtship and mating sites -
Nest sites - Grinnell and Miller (1944), chryseola, "...found
on the ground or up two or three feet in tangles of vegeta-
tion. Bent (1953) gives the same placement of nests; low
in shrubs, and an elevation of vegetation, or in a depression
in the ground. Peterson (1961), "Nest a loose grass cup on
or near ground." Bent (1953), pileolata; Nesting in Alaska
is given as "found only in the vicinity of willow and alder
thickets. .. lower mountain slopes... in cleared defiles and
under matted dead grass it builds its home. The nest may
be sunken flush with the mossy sod or... in the center of a
large tuft of grass." In Colorado a nest is described as
"sunken in the ground on the eastern slope... of the swamp...
beneath the low, spreading branch of a willow." Chapmen
(1907) describes a nest in blackberry vines eight feet from
the ground.
Wilsonia pusilla (con't.)
E. Special habitat requirements
F. Seasonal changes in habitat requirements
Grinnell and Miller (1944), pileolata, "In migration. . .as
in summer." chryseola, "In seasons of migration, low thick
vegetation is preferred but not solely in the vicinity of
water."
V FOOD
A. Food preferences
Bent (1953), chryseola; In 52 stomach samples, animal matter
made up 93% and vegetable 1%. Hemiptera were 35% of the
former, and the rest was made up of wasps, ants, flies,
crane-flies, beetles of 6 different families and caterpillars.
Vegetable food was almost entirely fruit pulp.
B. Foraging areas
Grinnell and Miller (1944), pileolata, "tangles of stream
side vegetation over moist ground. . . stays close to the
ground." chryseola, "All activities take place within six
feet of the ground. Utilizes close-set branchwork of
thickets as forage beats... but also engages in considerable
f lycatching." Grinnell and Storer (1924; state that chryseola ^^
adheres closely to damp situations, "either over boggy
ground or within a few yards of a stream."
C. Foraging strategies
Grinnell and Storer (1924), chryseola; "The birds are noted
for their habit of darting out after flying insects."
D. Feeding phenology
Bent (1953), chryseola; Its vegetable food (fruit pulp)
consumed in the months of September and October.
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
C. Courtship and mating, behavior
Wilsonia pusilla (con't.)
D. Nesting phenology
Bent (1953), chryseola generally arrives on their breeding
grounds in March or early April in California and in western
Washington, about the first of May.
E. Length of incubation period
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
:i POPULATION PARAMETERS
A. Clutch size
Peterson (1961), "Eggs (3-6) dotted." Bent (1953), reports
5 nests of pileolata in Alaska with 6 eggs each, but that
farther south there were 3 to 5 in a clutch, 4 being the
most common. For chryseola, 3 to 5 eggs, most often 4,
and raises 2 broods a year. Dawson (1923), chryseola;
clutch size is given as, 3 or 4. Chapman (190/) gives
pileolata clutch size as 4 to 6, usually 4 or 5.
B. Fledging success
C. Mortality rates per age class
D. Longevity
Kennard (1975) in a summary of longevity records from band
recoveries does not have a record for W. pusilla, but gives
7 years, 11 months as the record for W. canadensis.
E. Seasonal abundance
Grinnell and Miller (1944), "in spring on the southeastern
deserts W. p_. pileolata outnumbers chryseola. " chryseola,
"Common as a breeding species... in the lowlands. Bent
(1953), pileolata was reported as being "a rather common
winter visitor between the elevations of 3,500 and 8,500
feet." Land (1963), pileolata; Reported it as abundant
in winter in Guatemala.
F. Habitat density figures
:i INTERSPECIFIC INTERACTIONS
A. Predation
Wilsonia pusilla (con't.)
B. Competition
Grinnell and Storer (1924), chryseola, is reported as feeding
with the Tolmie Warbler, but the Tolmie often forages into
drier chaparral which chryseola does not.
C. Parasitism
Friedmann (1934) says chryseola is not an uncommon victim
of the Dwarf Cowbird in southern California. Friedmann
et al., (1977) found recent evidence that W. pusilla must
be a fairly regular host for cowbirds, especially m southern
California. The subpsecies affected most was W. p. chryseola.
IX STATUS
A. Past population trends
Chapman (1907) cites Cooke as saying that W. p_. pileolata
is the most numerous insect-eating bird just above the
timberline in Colorado, and Nelson, as saying that pileolata
is one of the most common bush- frequenting species in
Alaska."
B. Present population status
C. Population limiting factors •Ofc
D. Environmental quality: adverse impacts
E. Potential for endangered status
.<•
Wilsonia pusilla (con't.)
[I LITERATURE CITED
American Ornithologists Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bent, Arthur Cleveland. 1953. Life histories of North American
Wood Warblers. Smithsonian Institution, United States
National Museum, 203:626-646.
Chapman, Frank M. 1907. The Warblers of North America. Third
Edition. D. Appleton & Co., New York.
Dawson, William Lear. 1923. The birds of California. Vol. 1
South Moulton Co., San Francisco.
Friedmann, Herbert. 1934. Further additions to the list of
birds victimized by the cowbird. Wilson Bulletin, 46:25-
36, 104-114.
Friedmann, H. , L. F. Kiff and S. L. Rothstein. 1977. A further
contribution to knowledge of the host relations of the para-
sitic cowbirds. Smithsonian Contrib. Zool. No. 235. 75 pp.
Grinnell, Joseph. 1928. A distributional summation of the
ornithology of lower California. University of California
Publications in Zoology, 32:1-300.
Grinnell, Joseph, Joseph Dixon and Jean Myron Linsdale. 1930.
Vertebrate natural history of a section of northern Calif-
ornia through the Lassen Peak region. Univ. of California
Publications in Zoology, 35:1-594.
Grinnell, Joseph and Alden H. Miller. 1944. The distribution
of the birds of California. Cooper Ornithological Club,
Berkeley, California.
Grinnell, Joseph and Tracy I. Storer. 1924. Animal life in
the Yosemite. Contr. Museum of Vertebrate Zoology, Univ.
of California.
Hines, John Q. 1963. Birds of the Noatak River, Alaska.
Condor 65:410-425.
Kennard, John H. 1975. Longevity records of North American
birds. Bird-Banding 46:55-73.
Land, Hugh C. 1963. A collection of birds from the Caribbean
Lowlands of Guatemala. Condor 65:49-65.
Mayr, Ernst and Lester Short. 1970. Species taxa of North
American birds. Publication of the Nuttall Ornithological
Club, No. 9. Cambridge.
10
Wilsonia pusilla (con't.)
Peterson, Roger Tory. 1961. A field guide to Western Birds.
Houghton Mifflin Co., Boston, 366 pp.
Phillips, Allan, Joe Marshall and Gale Monson. 1964. The
birds of Arizona. University of Arizona Press, Tucson.
212 pp.
Ridgway, Robert. 1915. A Manual of North American birds.
Fourth Edition. J. B. Lippincott Company, Philadelphia.
653 pp.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Stewart, Robert M. , L. Richard Mewaldt and Susan Kaiser. 1974.
Age ratios of coastal and inland fall migrant passerines
in central California. Bird-Banding 45:46-57.
Willett, George. 1933. A revised list of the birds of south-
western California. Pacific Coast Avifauna. No. 21.
204 pp.
*•
<•
YELLOW- RUMPED WARBLER
Dendroica coronata
I TAXONOMY
A. Type description
AOU (1957), D. c. coronota (Linnaeus). Motacilla corona tus
Linneaus, Syst. Nat. , ed. 12, vol. 1, 1766, pT 333. Based
on Golden crowned Flycatcher of Edwards, Gleanings, 187.
(in Pennsylvania = Philadelphia, Pa.)
D. c. hooveri McGregor, Bull. Cooper Orn. Club, 1, no. 2,
Mar. 15, 1899, p. 32. (Palo Alto, California.)
D. c. auduboni : Sylvia auduboni J. K. Townsend, Journ. Acad.
Nat. Sci. Philadelphia, 7, pt. 2 (Nov. 21), 1837, p. 191.
(forests of the Columbia river [near Fort Vancouver, Washing-
ton] . )
D. c. memo rabi lis: D. auduboni memo rabi lis Oberholser, Ohio
Journ. Sci., 21, May (June 6), 1921, p. 243. (Ward, Boulder
County, Colorado.)
B. Current systematic treatments
Grinnell and Miller (1944), say it is inadvisable to recog-
nize a large race, D. c. memorabilis, from Rocky Mountain
region, even though there is a graded increase in size interior-
ward . "
AOU (1957), recognizes 20 species in the genus Dendroica,
and four subspecies of D. coronata. In the family Parulidae:
Wood Warblers.
Peterson (1961), compares Audubon's and Myrtle as two separate
species, as does Hubbard (1970), who recommends that they
be conspecies.
Bent (1953) gives Dendroica coronata two subspecies, coronata
and hooveri, and D. auduboni two subspecies, auduboni and
nigrifrons. Mayr and Short (1970), "The auduboni group
comprises several races, but the eastern coronata group is
monotypic." These two species hybridize in the northwest.
C. Synonomies of scientific nomenclature
AOU (1957), D. c. auduboni : D. auduboni and Sylvia auduboni
J. K. Townsend.
D. c. memorabilis: D. auduboni memorabilis Oberholser. Bent
X1933) D. auduboni auduboni . Ridgway (1915), D. auduboni.
Dendroica coronata ( con ' t . )
D. Synonomies of vernacular nomenclature
AOU (1957), Myrtle Warbler, D. coronata; Audubon's Warbler
D. c. auduboni.
Grinnell (1928), Alaska Myrtle Warbler, D. c. hooveri;
Rocky Mountain Audubon Warbler, D. c. memo rabi lis. Phillips
et al. (1964) give three common names for D. coronata,
Yellow-rumped, Myrtle, and Audubon's.
II DESCRIPTION
A. External morphology of adults
Peterson (1961), "male in spring: Blue-gray above; heavy
black breast patch, throat yellow or white, crown yellow;
2 narrow white wing patches or one broader. Female in spring,
brown; 2 white wing bars. Bent (1953), auduboni ; In winter
the old and young, males and females are very similar.
"Hybrids. . .occur occasionally between the different races...
especially where their ranges approach or overlap." Adult
male auduboni are described by Dawson (1923): "throat rich
yellow^ black cheeks. . .bluish gray over auriculars; .. .white
on middle and greater wing coverts. .. tail with white sub-
terminal blotches on inner webs of 4 or 5 outer feathers...
Adult female similar to adult male but duller. . .white of
wing patch nearly obsolete. . .yellow of throat paler and often
displaced by white." Hubbard (1970) describes auduboni,
"in breeding plumage, males from north of the Mexican border
are gray above streaked with black, and white below with
the breast streaked to solidly black. The loral and anterior-
most auricular areas are blackish, and the areas posterior
to the auriculars and posterior to the yellow crown patch
are gray or grayish white. Over much of the western United
States, southwestern Canada, and Baja California this plumage
varies only slightly, with males from the southern Rockies
and Black Hills southward averaging somewhat more extensively
black on the underparts than those to the north and west. . .
in the southernmost Southwest a marked increase occurs in
the extent of black. Females resemble first year males
and in breeding plumage show a pattern of geographic varia-
tion that parallels that of the breeding plumage of males
and winter plumages. Hubbard (1970) also describes geographic
variation in the amount of white in the outer retrices of
auduboni . He gives details of mensural characters. Yarbrough
and Johnston (1965) compare mensural characters of hooveri
and coronata.
»
Dendroica coronata (con't.)
B. External morphology of subadult age classes
Peterson (1961), "Brownish above, whitish below, streaked;
throat yellowish or white, rump yellow. Bent (1953),
auduboni, "Juvenile is brown above streaked with black and
white, and white below, streaked with black; sexes are alike.
As a subadult the plumage is browner, the yellow areas
paler and less pronounced, the black streaks less prominent.
Dawson (1923) describes the young males (rarely) and females
as losing the yellow throat in winter. Hubbard (1970)
describes first-year males as browner, less gray above
and have the ventral black markings as streaks. He also
gives the same geographic variation as in females.
C. Distinguishing characteristics
Interspecific - Phillips et al. (1964) say that Yellow-
rumped Warblers can be recognized by their yellow rump
and similar yellow on the crown and sides, pale throats
and white tails patches that do not reach the tip of the
tail. Hubbard (1970) says that memorabilis (applied to the
breeding birds in the southern Rockies) is not recognizable
because of broad intergradation in wing length and plumage
characters with northwestern populations.
Intraspecific - Bent (1953), wings of California males
average .15 inch longer than those of eastern birds (D. c.
coronata), tails .14 inch longer. "It appears to be a finely
drawn subspecies." The western subspecies differs from the
eastern in being "larger in size and more solidly black
breast in the male. Audubon's and Myrtle Warbler juveniles
...are almost indistinguishable though there is always more
white in the tail feathers of the western bird." Dawson
(1923), auduboni ; "Similar to hooveri but throat rich yellow,
black cheeks reduced by encroachment of bluish gray over
auriculars." Phillips et al. (1964), "Geographic variation
in the species. . .consists of increase in the amount of
black and larger size to the south. The Myrtle group is
northern. .. the eastern race is small and dark (coronata)
with a brownish suffusion over the back." Audubon ' s is
to the south and the winter basic plumage shows no cheek
pattern, the unstreaked breast is clouded with brown.
Ill GEOGRAPHICAL DISTRIBUTION
A. Overall distribution of the species
AOU (1957), "From northern Alaska, northern Yukon, western
and central Mackenzie, northern Manitoba, northern Ontario,
central Quebec, north- central Labrador, and Newfoundland
south to north and central British Columbia, south Alberta,
southwestern Saskatchewan, central and southeastern Montana,
northern Minnesota, northern Michigan, central Ontario,
»
»
Dendroica coronata ( con ' t . )
%
northeastern New York, Massachusetts, and Maine, from western
South Dakota south in the mountains to southern California,
northern Baja California, southern Arizona, and southern
New Mexico, and in the Sierra Madre Occidental to Durango."
D. c. auduboni : "Breeds from central British Columbia south
along the Pacific coast through the Cascade Mountains and
the Sierra Nevada to southern California and northern Baja
California. "
D. c. memorabilis: "Breeds from southeastern British Columbia,
southwestern Alberta, and southwestern Saskatchewan south,
east of the Cascade Mountains and the Sierra Nevada, to
central eastern California (White and Inyo Mountains) , south-
ern Nevada, southern Arizona, southern New Mexico, and
western Texas."
D. c. hooveri: "Breeds from north-central Alaska, northern
Yukon , and northwestern and central Mackenzie south to
southern Alaska, and northern British Columbia."
Bent (1953) "In the Atlin region of northern British Columbia
it (hooveri) , is a common species breeding mostly in low-
lands. " Bent also reports that the breeding ranges of
hooveri and auduboni may overlap in British Columbia.
Auduboni range is given as, "Western North America from
British Columbia to Guatemala."
B. California distribution of the species
Rett (1953), shot a D. coronata on Santa Rosa Island, Calif-
ornia 24 March 1951. Grinnell (1928), D. c. hooveri, mid-
winter visitant. D. c. auduboni , abundant and widespread
as a winter visitant over most of southern California, also
reaching most of the islands. D. c. memorabilis, "winter
visitant scatteringly, " through southern California and
Baja. Grinnell and Storer (1924), auduboni ; most widely
distributed and most abundant wood warbler found in the
Yosemite region. Dawson (1923), auduboni ; "A common breeder
of the mountainous sections in both Boreal and Transition
zones; found from the Santa Rosa to the San Jacinto Mountains
north along the Sierran ridge to Shasta, east upon the White
and Warner ranges; in the northwest in the Trinities, south
to Lake and Mendocino Counties and locally in Sonoma County.
Small (1974), lists the Myrtle Warbler as "fairly common
in northwest coastal region; less common to south and un-
common to rare in southern California, "and the Audubon's
Warbler, breeding range as "virtually all mountainous regions
of state except desert mountains of extreme eastern section
of San Bernardino County; in coast range, south to Monterey
Coast and in Peninsular Ranges, south to Santa Rosa Mountains;
otherwise, length of state. '
<-
j^p
»
I
Dendroica coronata (con't.)
C. California desert distribution
Grinnell and Miller (1944), give selected sightings and
dates. D. c. hooveri, Kern County, November 4; Los Angeles
County, November 13 to March 1, Death Valley in Inyo County,
April 10, northeastern San Diego County, March 10; Imperial
County, February 11.
D. c. auduboni , in the mountains of Riverside County in
breeding season; also Inyo Mountains. Eastern San Bernardino
County, possibly summer resident. Bent (1953), auduboni ;
one of the most abundant birds of the San Bernardino Moun-
tains, widely distributed from the Transition Zone up through
the Boreal.
D. Seasonal variations in distribution
AOU (1957), "Winters from Kansas, the southern Great Lakes
region, and southern New England through Mexico and Central
America to central Panama; also on Bermuda, Cuba, Jamaica,
the Bahamas, Hispaniola, Puerto Rico, the Virgin Islands,
and Antigua; and on the Pacific Coast from northwestern
Oregon south to northern Baja California, in the west from
southwestern British Columbia, central Washington, central
Nevada, southwestern Utah, central New Mexico, southern
Texas, through Mexico, Central America and Costa Rica."
Grinnell and Miller (1944), D. c. auduboni , "in winter
throughout low lands and lower mountains" in most of Calif-
ornia, "occurs widely on coastal islands." Bent (1953)
hooveri has been found in winter from California to south-
eastern Louisiana. . .and in northern Baja California, and
in southern Veracruz in Mexico:" auduboni , "is widely dis-
tributed in the lowlands only during winter, retiring to the
mountains for the breeding season." Dawson (1923) reports
the same for auduboni. Small (1974) says that "Myrtle"
Warbler is a winter visitor, October to late April. Phillips
et al. (1964) reports that Yellow- rumped Warblers are found
in or near southern Arizona away from the breeding grounds,
from September to late May, but that they are rare on the
desert before late September. They give the latest date
in the mountains as November 6. "Auduboni is a common
winter resident in Arizona. Hooveri is a rare winter vis-
itor to Lower Sonoran Zone rivers and farms in western and
southern Arizona. Memorabilis breeds in the highest moun-
tains of Arizona, migrates in fall and spring and winters
in parts of the state."
•
Dendroica coronata (con't)
IV HABITAT
A. Biotopic affinities
Williamson (1957), D. c. hooveri, found only in riparian
woodland in Napaskiak area of Alaska. Peterson (1961),
"coniferous and mixed forests." In winter varied; woods,
tree tops, brush, thickets, gardens. Grinnell and Miller
(1944), D. c. hooveri, "Distinctly varied. Deciduous or
evergreen. Frequently seen in gardens, orchards." D. c.
auduboni, Life- zones in summer, Transition, Canadian, Hud-
sonian. " In coniferous forests of wide variety. Hubbard
(1965), memorabilis, "common in fir and spruce-fir forests
and uncommon in other habitats." Bent (1953), auduboni,
"it's breeding range does not extend nearly as far north
as that of the Myrtle Warbler, it extends further south
and to considerably higher altitudes, breeding largely in
the Canadian Zone among the pines, spruces, and firs."
B. Altitudinal range
Miller (1955), reported D. c. auduboni only at 7000 foot
level in Sierra del Carmen area of northern Mexico in April.
Grinnell and Miller (1944), "Altitudes of known or probable
breeding range from 500 feet to 11,000 feet as at Cottonwood
Lakes, Inyo County, for D. c. auduboni . Bent (1953), audu-
boni; found breeding in the mountains of New Mexico at 7,500
to over 11,000 feet. Breeds at similar elevations in Colorado
In the San Bernardino Mountains from 9,000 to 10,500 feet.
Grinnell and Storer (1924), auduboni ; summer range from
Transition Zone yellow pines (3,300 feet) up through lodge
pole pines and other conifers to the upper limit of un-
stunted trees (10,000 feet).
C. Home range size
D. Territory requirements
Perch sites - Grinnell and Miller (1944), D. c. hooveri,
open branchwork, tops of trees and bushes.
Courtship and mating sites -
Nest sites - Peterson (1961), "in conifer." Grinnell and
Miller (1944), D. c. auduboni, "Nest emplacements range
from 3 or 4 feet up to 100 feet. . ." "rarely nesting occurs
in broad- leafed trees, in meadows or in orchards." Bent
(1953), hooveri , nesting 40 feet up, near the top of a
spruce. . . another nest was in a small jack pine in open woods
on the shore of Lake Atlin, in northern British Columbia.
Auduboni , in the Rocky Mountains in Utah, nests in almost
any tree, pine, spruce, fir, aspen or oak. Bent (1953),
J
»
I
»
Dendroica coronata (con't.)
auduboni ; Reported nesting in two different habitats: near
Seattle, Washington, in a fir tree, 30 feet up, and near
Ft. Sherman, Idaho, in deciduous trees and bushes. Generally
hidden inside the tree or bush. "Nests in tamarack, cedar,
and birch have been reported..." Ridgway (1915) reports
that D. coronata nests in pine or spruce trees."
E. Special habitat requirements
Bent (1953), reports hooveri being confined to heavier
spruce woods during breeding in Alaska. Small (1974) gives
the breeding habitat of Audubon's Warbler as "montane and
subalpine forests of Transition, Canadian, and Hudsonian
Life Zones."
F. Seasonal changes in habitat requirements
Grinnell and Miller (1944), D. c. auduboni , "in winter
habitat is highly varied." Bent (1953) , hooveri: during
winter they frequent spruce, birch and cottonwoods. Grinnell
and Storer (1924), auduboni ; during the summer it frequents
the main forested districts of the mountains in Yosemite,
in winter the deciduous trees and brush of the foothills
and valley country.
V FOOD
A. Food preferences
Bent (1953), auduboni; During a year-long survey in Calif-
ornia, food was found to consist of 85% animal matter and
15% vegetable matter (fruits and seeds). Spofford (1977)
observed Audubon's Warbler in southeastern Arizona eating
galls on poplar leaves which were caused by aphids.
B. Foraging areas
Grinnell and Miller (1944), D. c. hooveri, over open ground,
on ground surface and grass tops. D. c. auduboni , search
needle tufts of conifers. "Part of insect food is caught
on the wing." From ground to tops of trees. In winter,
flycatching in the open, ground foraging, berry eating,
sipping nectar, in addition to searching foliage surfaces.
Whitmore (1977) in a study on habitat partitioning states
that Audubon's Warbler (D. c. auduboni) is associated with
high canopy cover and many trees.
C. Foraging strategies
Grinnell and Miller (1944), D. c. auduboni , fly out from
edge of tree searching needle tufts and return to it. Bent
Dendroica coronata (con't.)
(1953), auduboni , Flies through the air searching for
insects, snapping them up as it goes. Makes "flycatcher
sallies" from a post of observation. Bent calls them
"versatile" feeders, describing their airborne feeding
and ground feeding.
D. Feeding phenology
Bent (1953), auduboni ; collect in great flocks in spring
to feed on oak worms in live oaks,aand they eat myrica
berries in the fall. Yarbrough and Johnston (1965) give
the feeding phenology of the eastern Myrtle Warbler.
E. Energy requirements
VI REPRODUCTION
A. Age at first breeding
B. Territorial behavior
C. Courtship and mating behavior
D. Nesting phenology
Bent (1953), hooveri ; reports a nest taken with five fresh
eggs on June 15. THey arrived at breeding grounds in north-
ern Alaska on 22 May in 1900. .. already in pairs. Auduboni ;
"general opinion seems to be that two broods are often
raised in a season." Gives the nesting season in the Sierra
cuchumatanes, nearly 11,000 feet high, as April to August.
Dates of arrival at breeding grounds; in Kansas, April 14;
in Colorado Springs, April 12; in Wyoming, April 21; in
Grass Valley, California, April 10; Idaho, April 16. Late
dates of departure from breeding grounds: Prospect, Oregon,
18 November; Bayview, Idaho, 26 October; Laramie, Wyoming,
9 November; Silver City, New Mexico, 10 November. Eggs
were reported in California from 11 May to 30 July. The
height of the season is given as 13 to 25 June.
E. Length of incubation period
Bent (1953), auduboni ; "probably between 12 and 13 days,
as with the Myrtle Warbler.
F. Length of nestling period
G. Growth rates
H. Post-breeding behavior
Bent (1953), auduboni ; Young birds are the first to leave
the nesting area and appear in the lowlands, probably driven
out by their parents.
¥
Dendroica coronata (con't.)
I POPULATION PARAMETERS
A. Clutch size
Peterson (1961), "Eggs (3-5) spotted." Bent (1953), audu-
boni ; 3-5 eggs, almost always 4. Slightly glossy, spotted.
Dawson (1923), gives auduboni clutch size as 3 to 5, usually
4, as does Chapman ( 1907J .
B. Fledging success
C. Mortality rates per age class
D. Longevity
Bent (1953), auduboni; A bird banded at Altadena, California,
on December 1~ 1935, was retrapped at the same station on
February 13, 1940, being nearly 5 years old at the least.
Kennard (1975) in a summary of longevity records from banded
birds gives 6 years, 8 months as the oldest Myrtle Warbler
(D. coronata) .
E. Seasonal abundance
Bent (1953), hooveri , "It may be commoner than is supposed,
as it is recognizable only with specimens in hand." A
southward exodus was at its height during the last week
in August and first week in September in northern British
Columbia, accompanied by a constant stream of Myrtle
Warblers. Hines (1963), hooveri, In the Noatak River area
in Alaska this race is abundant during the breeding season
in the willow understory of the spruce forest.
F. Habitat density figures
Phillips et al. (1964). refer to D. coronata as the most
abundant, hardiest warbler in Arizona.
ail INTERSPECIFIC INTERACTIONS
A. Predation
B. Competition
Grinnell and Storer (1924), auduboni ; nests with the Hermit
Warbler in the Transition and part of Canadian Zones of
Yosemite. At higher altitudes it is the only Warbler in
the evergreens. In Guatemala, auduboni has been reported
feeding with bluebirds (Sialia sialis guatemalae) . Whitmore
(1977), found Audubon's Warblers and Yellow Warblers to use
much of the same habitat in Utah and suggested they may be
competitive. Ficken and Ficken (1966), "...individual Myrtle
Warblers are quickly attracted to food sources, particularly
berries, where other species are feeding."
>
>
10
Dendroica coronata (con't.)
C. Parasitism
Friedmann et al. (1977) report five records of cowbirds
(m. ater artemisiae) laying in nests of D. c. auduboni ,
and two records of cowbirds laying in nests of D. c.
memo rabi lis.
IX STATUS
A. Past Population trends
Chapman (1907) refers to D. auduboni as one of the most
common warblers of the Pacific slope.
B. Present population status
r
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
11
Dendroica coronata (con't.)
LITERATURE CITED
American Ornithologists Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bent, Arthur Cleveland. 1953. Life histories of North Amer-
ican Wood Warblers. Smithsonian Institution, United States
National Museum. 302:258-282.
Chapman, Frank M. 1907. The Warblers of North America. Third
Edition. D. Appleton & Co. , New York.
Dawson, Willian Leon. 1923. The birds of California. Vol. 1.
South Moulton Co. , San Francisco.
Ficken, Millicent S. and Robert W. Ficken. 1966. Behavior of
Myrtle Warblers in Captivity. Bird-Banding 37:273-279.
Friedmann, H. , L. F. Kiff and S. L. Rothstein. 1977. A further
contribution to knowledge of the host relations of the para-
sitic cowbirds. Smithsonian Contrib. Zool. No. 235. 75 pp.
Grinnell, Joseph. 1928. A distributional summation of the
ornithology of lower California. University of California
Publications in Zoology 32:1-300.
Grinnell, Joseph and Alden H. Miller. 1944. The distribution
of the birds of California. Pacific Coast Avifauna No. 27.
608 pp.
Grinnell, Joseph and Tracy L. Storer. 1924. Animal life in
the Yosemite. Contr. Museum of Vertebrate Zoology, Univ.
of California.
Hines, John Q. 1963. Birds of the Noatak River, Alaska. Condor
65:410-425.
Hubbard, John P. 1965. The summer birds of the forests of
the Mogollon Mountains, New Mexico. Condor 67:404-415.
Hubbard, John P. 1969. The relationships and evolution of
the Dendroica coronata complex. Auk 86:393-432.
Hubbard, John P. 1970. Geographic variation in the Dendroica
coronata complex. Wilson Bulletin 82:355-369.
Kennard, John H. 1975. Longevity records of North American
birds. Bird-Banding 46:55-73.
Mayr, Ernst and Lester Short. 1970. Species taxa of North
American birds. Publication of the Nuttall Ornithological
Club, No. 9. Cambridge.
10
Dendroica coronata (con't.)
C. Parasitism
Friedmann et al. (1977) report five records of cowbirds
(m. ater artemisiae) laying in nests of D. c. auduboni ,
and two records of cowbirds laying in nests of D. c.
memo rabi lis.
IX STATUS
A. Past Population trends
Chapman (1907) refers to D. auduboni as one of the most
common warblers of the Pacific slope.
B. Present population status
C. Population limiting factors
D. Environmental quality: adverse impacts
E. Potential for endangered status
<m
~
11
Dendroica coronata (con't.)
XI LITERATURE CITED
American Ornithologists Union. 1957. Checklist of North
American birds. Fifth Edition. American Ornithologists'
Union, Baltimore, Maryland. 691 pp.
Bent, Arthur Cleveland. 1953. Life histories of North Amer-
ican Wood Warblers. Smithsonian Institution, United States
National Museum. 302:258-282.
Chapman, Frank M. 1907. The Warblers of North America. Third
Edition. D. Appleton & Co. , New York.
Dawson, Willian Leon. 1923. The birds of California. Vol. 1.
South Moulton Co., San Francisco.
Ficken, Millicent S. and Robert W. Ficken. 1966. Behavior of
Myrtle Warblers in Captivity. Bird-Banding 37:273-279.
Friedmann, H. , L. F. Kiff and S. L. Rothstein. 1977. A further
contribution to knowledge of the host relations of the para-
sitic cowbirds. Smithsonian Contrib. Zool. No. 235. 75 pp.
Grinnell, Joseph. 1928. A distributional summation of the
ornithology of lower California. University of California
Publications in Zoology 32:1-300.
Grinnell, Joseph and Alden H. Miller. 1944. The distribution
of the birds of California. Pacific Coast Avifauna No. 27.
608 pp.
Grinnell, Joseph and Tracy L. Storer. 1924. Animal life in
the Yosemite. Contr. Museum of Vertebrate Zoology, Univ.
of California.
Hines, John Q. 1963. Birds of the Noatak River, Alaska. Condor
65:410-425.
Hubbard, John P. 1965. The summer birds of the forests of
the Mogollon Mountains, New Mexico. Condor 67:404-415.
Hubbard, John P. 1969. The relationships and evolution of
the Dendroica coronata complex. Auk 86:393-432.
Hubbard, John P. 1970. Geographic variation in the Dendroica
coronata complex. Wilson Bulletin 82:355-369.
Kennard, John H. 1975. Longevity records of North American
birds. Bird-Banding 46:55-73.
Mayr, Ernst and Lester Short. 1970. Species taxa of North
American birds. Publication of the Nuttall Ornithological
Club, No. 9. Cambridge.
12
Dendroica coronata (con't.)
Miller, Alden H. 1953. The Avifauna of the Sierra del Carmen
of Coahuila, Mexico. Condor 55:154-178.
Peterson, R. T. 1961. A Field Guide to Western Birds.
Houghton Mifflin Co., Boston, pp. 366.
Phillips, Allan, Joe Marshall and Gale Monson. 1964. The
birds of Arizona. University of Ariz. Press, Tucson.
212 pp.
Rett, Egmont Z. 1953. Additional Notes on the birds of Santa
Rosa Island, California. Condor 55:156.
Ridgway, Robert. 1915. A manual of North American birds.
Fourth Edition. J. B. Lippincott Company, Philadelphia.
653 pp.
Small, A. 1974. The birds of California. Winchester Press,
New York. 310 pp.
Spofford, Sally Hoyt. 1977. Poplar leaf-stem gall insects
as food for Warblers and Woodpeckers. The Wilson Bulletin,
89:485.
Whitmore, Robert C. 1977. Habitat partitioning in a community
of passerine birds. Wilson Bulletin, 89:253-265.
Willett, George. 1933. A revised list of the birds of south-
western California. Pacific Coast Avifauna. No. 21.
204 pp.
Williamson, Francis S. L. 1957. Ecological distribution of
birds in the Napaskiak area of the Kuskokwim River Delta,
Alaska. Condor 59:317-338.
Yarbrough, Charles G. and David W. Johnston. 1965. Lipid
deposition in wintering and premigratory Myrtle Warblers.
Wilson Bulletin 77:175-191.
Land r ment
Libr
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Denver. CO 80225
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