The Gull

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Volume 22

SAN FRANCISCO, AUGUST, 1940

Number 8

The Status and Preservation of the White-tailed Kite in California

The National Association of Audubon Societies suggested, in October, 1938,
that an attempt be made to discover something about the status of the White-
tailed Kite in California with a view to possible protective measures. I undertook
to make a beginning for such a study, and on May 4, 1940, submitted to the
National Association a report of 44 typed pages which included a survey of the
situation up to January 1, 1940. I did not mean to imply by this report that con-
clusive facts were presented or that the way is clear for Kite preservation.
Rather, it is to be considered as a sort of outline for a badly needed thorough
investigation of the matter.

In the February, 1939, issue of The Gull, a notice of this project was printed
with a request that any sort of a record of Kites that readers might have be
forwarded to me. I strongly suggested that no definite data as to nesting localities
be broadcast and I tried to make it clear that all such information given to me
would be held as confidential and that “if there should be any sort of release of
material gathered, it would be couched in such general terms that no identifica-
tion of locality could be made.” It was necessary to make this admonition and
promise because of the continued existence of illegal traffic in Kite eggs. The
co-operation of correspondents has been most gratifying. Their letters, together
with many interviews with persons in authority and with those who have had
experience with the species, yielded 136 records (occurrence and breeding).
These, added to material gleaned from 109 titles found in the literature, have
formed the basis for the report. In it I have refrained from mentioning names of
correspondents so that there could be no possibility of linking a name with a
definite locality. It was not deemed necessary to be cautious in quoting from
already-published records.

For the benefit of members of the Audubon Association of the Pacific I sub-
mit the following brief arrangement of the report:

Status. Space allows but the briefest treatment here. Suffice it to say that the
earliest record for Kites found in the literature was that of Gambel who took
three specimens sometime prior to 1846 in the vicinity of the Mission San Juan
Bautista. Other early mentions are those of Heermann and Belding. The former
wrote in 1859 (Pac. R. R. Rep., X, p. 33) that “the extensive marshes of Suisun,
Napa, and Sacramento Valleys are the favorite resort of these birds, more espe-
cially during the winter season, as they find a plentiful supply of insects and
mice, their principal nourishment. They generally range over their feeding
grounds in small flocks, from a single pair up to six or seven pairs together. . . .”
Belding, during his collecting experience near Stockton in 1877-78 (Proc. U. S.
Nat’l Mus., I, 1879, p. 435), saw as many as twenty at the same moment within a
circle of half a mile.

The most northern record of occurrence is at Burney Falls, Shasta County,
two seen on April 29, 1937 (as published by Ingles, Condor, XXXIX, p. 222). It has

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also been recorded by Clay (Condor, XXVIII, p. 98) a£ Miranda, on the South
Fork of the Eel River, on August 6, 1924. (There is no indication that the bird
occurs regularly at either of these localities, however.) The most southern record
is for Tia Juana Marsh, San Diego County (Huey, Auk, XLVIII, p. 620). There is
a single record as far inland as Yosemite National Park (Grinned, “Animal Life
in the Yosemite,” p. 281).

There appear to be various areas where records for the species are more
numerous. These are the Russian River Valley, the San Francisco Bay area, the
Suisun Marshes and the Sacramento-San Joaquin Delta area, Santa Clara County,
southern Santa Cruz and northern Monterey Counties, parts of Santa Barbara
County, and the Santa Clara River Valley of Ventura County. Although the south
arm of San Francisco Bay and Santa Clara County has had at times a rather
heavy population (as Kites go), the most important area probably is the Suisun
Marshes and Sacramento-San Joaquin Delta region. This might even be con-
sidered the center of distribution for the species on the Pacific Coast. In 1936
nine nesting pairs were definitely discovered in an area of ten square miles in the
Suisun Marshes and 25 to 30 pairs estimated for the entire marsh area. In the
spring of 1940, ten nesting pairs were discovered along 5.8 miles of an island-filled
slough in the Stockton district (although this last item exceeds the time limit of
the report, it is of such interest that it could not be excluded).

Santa Clara County has had as many as eight to ten pairs in one season
(1928). However, since that time there does not appear to have been more than
about two pairs known to be nesting at different points in the county.

An old resident of northern Monterey County says that Kites have fluctuated
in numbers since his first experience with them there in 1896, decreasing for ten
or fifteen years, then increasing, and that they are now on a decline again.
Ventura County has had a Kite history since 1880.

More work must be done on the subject before we can arrive at even an
approximate conclusion as to the actual numbers of White-tailed Kites in Califor-
nia at present and be able to compare them with those of the past. However, I
have tried to ascertain some sort of minimum figure by making a compilation
based on breeding records. These were divided into two classifications, definite
and probable. Those records concerning nests in use, i.e., being built, or with eggs
or young, were put in the first group; while those referring to pairs that were
habitually seen at one place during the breeding season were included in the
second. Records for pairs seen often at one place but not in the breeding season,
or seen only once, were excluded. There is a total of 93 definite and 50 probable
breeding records for the state from 1878 (the year of the first record) up to and
including 1939 (records for pairs breeding for consecutive years at one place are
considered as one record). As there is no one year in which all the important Kite
regions are mentioned, it is difficult to select a year which might indicate a pop-
ulation total at any one time. Because the period 1935-39 contained records in all
the regions, these records were selected as a sort of indicator of the present
population. This five-year period yielded a total of 32 definite and 39 probable
breeding pairs. That this figure represents about one-third of the total records
going back for 61 years is not to be taken as an indication of increase. In recent
years there has, of course, been a great increase in observers which might
account for the comparatively larger figure.

Possibly the Kite never has been an abundant, or even very common species
in the state. It is probably true that it never has “within historical times
predominated as such raptorial birds as the Desert Sparrow Hawk or the Red-
tailed Hawk for instance” (Pickwell, Condor, XXXII, p. 239). No statement as to
its actual increase or decrease is justified at the present; nor could we say
whether the bird is holding its own.

Certain Characteristics of Kite Behavior. The Kite nests in two rather distinct
types of habitat, the willow and marsh or river-bottom type, and the level or
slightly rolling or foothill country, where live oaks grow. There seem to be

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more records of general occurrence for the former type of country. They have a
habit of sometimes nesting rather close together. Pickwell (Condor, op. cit.)
found three nests within 320 yards of each other. Also ten pairs were found within
5.8 miles in the Stockton region (referred to above). Hatching a second brood
after fledging the first has been observed by Hawbecker (Condor, XLII, p. 106)
in southern Santa Cruz County. I had previously suspected, but never was able
to prove, this sort of behavior in Monterey County. Such close proximity of nests
and the hatching of two broods in a season would seem to be rather unusual be-
havior for a raptorial bird.

Another feature of behavior which is of great importance when we try to
record the Kite’s numbers, or its increase or decline, is the sudden appearance at
a particular place of several nesting pairs, their nesting there for several years,
and then their equally abrupt cessation as a breeder in that area. This sort of
thing has been recorded in Santa Barbara County, Santa Clara County, and
southern Santa Cruz County.

Food. The feeding habits of the Kite are entirely in its favor. All the definitely
substantiated records (stomach and pellet analyses) have shown the bird to be a
small mammal eater with the meadow mouse (Microtus) forming about 90%
of its diet. Obviously, every effort should be made to protect it for this reason if
for none other.

Preservation of the Kite. Allow me to quote from two articles by Jean M.
Linsdale, of the Museum of Vertebrate Zoology (Condor, XXXII, p. 105, and
XXXIX, p. 198) on conservation of certain California birds. He says that the evi-
dence indicates that the Kite (and the Prairie Falcon, Duck Hawk, Red-bellied
Hawk, Golden Eagle, Bald Eagle and Osprey) is “not in immediate danger of ex-
tinction in California but that the prospects are not good for [its] holding out un-
less our present attitude toward [it] is changed.” Most people believe that a
“hawk’s a hawk” and should be shot and Dr. Linsdale believes that these birds
“appear particularly likely to suffer in California because their habitats are re-
stricted in extent and consequently their numbers are always small. Any program
to protect these species should involve an effort to preserve as much as possible of
the habitats now occupied.” He also says that an important danger to these spe-
cies is the “competitive zeal of egg collectors.” He here makes the distinction be-
tween the scientific oologist and the collector who is interested particularly in
“exchange value”. The former does no permanent harm, but “half a dozen expert
collectors of eggs for exchange are able to affect harmfully the welfare of im-
portant bird species.”

There is no doubt that there is a considerable demand for Kite eggs among
this latter type of collector. And even though Kites have been protected by law in
California since 1905, when it became illegal to take the bird or its eggs even for
scientific purposes, Kites still are occasionally shot and, I am reliably told, there
is still traffic in sets of eggs. The price is sufficiently high to make the risk worth-
while.

Other adverse factors are: (1) The indications are that the breeding stock
at present is small. If there is now a decline any increase in its rate, or any
sharp decline setting in in the near future, might be fatal to the species.
(One authority, having read the full report, commented, “The total number of
pairs observed, namely during the years 1935 to 1939, even when additional
unobserved ones are included, does not indicate a great probability of survival
for the Kite.”) (2) The Kite is extremely conspicuous and easily shot. Its white
plumage is readily noted against the dark green foliage of oaks or willows. It
hovers in a stationary position at a low altitude. It often seems unaware of the
nearby presence of human beings. It inhabits areas such as duck-hunting marshes,
where men are armed and, according to some writers, are ready to shoot them
when game is scarce (cf. Grinnell, Condor, XVI, p. 41). However, one ornithologist
correspondent who is thoroughly familiar with certain duck-kite areas, says that
“rarely, a Kite is shot by a duck hunter”). There are four definite cases in the

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literature of a bird being shot1 in recent times (Huey, Auk, XLVIII, p. 620;
Stoner, Condor, XXXV, p. 121, and XLI, p. 120; Neff, Condor, XXXVI, p. 218).
Two other actual shootings in addition to those in the literature are known to
me. There are also museum specimens which had been shot “by mistake," and
by small boys, etc. (four specimens in C.A.S.). (3) Because of their rarity, Kite
eggs are decidedly a “collector’s item” and the bird is therefore menaced by
unscrupulous commercial collectors. (4) Because of the sometimes erratic move-
ments of the Kite it may be difficult to foresee an exterminating decline, if and
when it does set in. (5) Their marsh habitat is becoming more and more re-
stricted, being drained for more intense cultivation, or otherwise affected.

Favorable factors are: (1) It is not restricted to any one area in the state,
as is the Condor at the present time, and the Kite seems capable of moving about
to a certain extent at least. (2) To the best of our scientific knowledge it is
utterly harmless and even beneficial. (3) Above all it is attractive in appearance
and would be capable of a wide popular appeal, if properly understood by the
general public.

Suggestions for conservation measures have been numerous and space does
not permit a discussion of them here (the report contained five pages on this
aspect of the matter). I am very grateful for the suggestions submitted to me.
They have all been transmitted to the National Association.

In concluding this resume I should like to take the opportunity to thank
Dr. John T. Emlen, Jr., for his help on this project and Miss Margaret W.
Wythe, of the Museum of Vertebrate Zoology, for her kind help in arranging the
material from the literature. Also, my thanks are due to the California Academy
of Sciences and the Museum of Vertebrate Zoology for allowing me to use data
from the labels of specimens as well as giving me access to their libraries. Most
of all, I want to thank those correspondents, Audubon members as well as others,
who so kindly sent me their Kite records.

Laidlaw Williams, Carmel, California. July 13, 1940.

£

Audubon Notes

August Meeting: The regular meet-
ing will be held on Thursday evening,
the 8th, in the Ferry Building.

The evening will be devoted to vaca-
tion experiences by members. Please
come prepared to help out.

August Field Trip will be taken on
Sunday, the 11th, to Golden Gate Park,
San Francisco. Take car No. 5 and meet
at Fulton and Stanyan Streets at 10 : 00
a. m. Bring luncheon.

Audubon Association of the Pacific

Organized January 25, 1917

For the Study and the Protection of Birds

President Mr. B. K. Dunshee.— Room 714, 245 Market St., San Francisco

Corresponding Secretary _ Mr. Joseph J. Webb 519 California St., San Francisco

Treasurer . Mrs. A. B. Stephens 1695 Filbert St., San Francisco

Monthly meeting second Thursday, 8 P. M., Ferry Building.

Address Bulletin correspondence to Mrs. A. B. Stephens, Editor, 1695 Filbert St., San Francisco.

Membership dues, payable January 1st, $3.00 per year.

Student memberships, $1.50 per year. Life memberships, $50.00.

Members are responsible for dues until written notice of resignation is received by Treasurer.

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