Vol. 10, No. 1, WESTERN BIRDS i Tih Inmrui ^Fw^ii-Tij Fii 1 1 L 0 I ii r I lM ■. F\v r. |ohn 5. . Lfiiihn IV. r- r Udkrit Ferettte R Wahl T h‘ii mw PhW.-SMaaHTt" i Mrmhprihip Sfntffa if-' . M si^u el riiitrff rtf Wrfrrfim- Phyllis 1-ivnu.m ,JJ>nnuf Priprtt fruMgrt |im5:i OHjrrry ifcfBthatt- taui mu i- r, Joamt A, Crmry. liftml F. dtSiiHt ‘Si^kn A, Liiymfm. Sobri S, Luther iltiy i jni*u-_ RnJrratLt W Stadli'iip; 1 tirnerR WaKIj j.iriin %V!iiT riu^i JjdDU* A bit VI ifcrffr- iumsitr hzlilbr, Mara A. Mwr.- jSStoj^j/ ftvtfftt Ruben Alidiewv, Aliili BahlrLtjRe. WlJlLuui H BrUlc* Andrew J . Bcrjpef . LwjrtwC Bi nfrrrd ; fCNinrum). J«n nr A f^iiry, pflvtd F frrtuiw Rkhiird Kmiwiw Joaepli GipciiSjciss- Joseph R. fHil. |i . Sms ft j^hn-hnjii Virginia p.Johmtsii, flrtrua ke^d, Charleys. Owspil Sjeplicfl A Ijiymmi, joftti S, LuOmr; fin-s tifatiHlit. Brian § M - (lair- n i.-uy McCaikhv M. Tuwctsy Myr«i Ftairv B Nthk. 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GJoasy, bludc and while photos nire acccr^ihlc; b;ilf wm serren size: 133 Urn' Pbom ready copy is reaueaEt!d. li ihii h not |hl\tifak, esirn. ior iyp«eLLjny; Will be nuuk j|S follow 1 ,- |l c full pn^c, tlfl half pafie,, $5 qnnrscr p«fr. firud copy with rnnittniw io Phil SchoefTer, 376 Qroefittood Beach Rand, Tl baron, CaJlfaraia 94920, Makc t:h<4kt payable eli Wesierrt Fidd Om 1 1 lioEflgbts . A 1S% commission in ,il lowed for WESTERN BIRDS Volume 10, Number 1, 1979 FALL MIGRATION OF DIURNAL RAPTORS AT PT. DIABLO, CALIFORNIA LAURENCE C. BINFORD, California Academy of Sciences, Golden Gate Park, San Francisco, California 94118 For several years prior to the fall of 1972, I noted raptors migrating past my office window at the east end of Golden Gate Park, San Francisco, California. Concluding that I was by chance positioned along a raptor flyway, I set out to find a location where the birds would be more concentrated and easily observed. An examination of contour maps indicated that the hills at and near the base of Pt. Diablo, overlooking the mouth of San Francisco Bay, in the Marin (Co.) Headlands portion of the Golden Gate National Recreation Area, might offer the desired characteristics. On 21 September 1972, after seeing several hawks from my window, I visited Pt. Diablo and was rewarded with 1 62 individuals of 10 species of raptors in 3. 1 7 hours of observation. That fall, on 29 partial days (102.33 hours), I recorded 4034 individuals of 14 species, thus establishing the importance of Pt. Diablo as the only known major hawk lookout in western North America. Additional counts were made sporadically by myself and other observers during the falls of 1 9 7 3- 7 7 . The primary purpose of this report is to present the data on relative abundance, timing and species diversity gathered during the six falls. A few comparisons are made with migration at Hawk Mountain, Pennsylvania. Thorough analysis of other aspects of the phenomenon must await data from continuous coverage. DESCRIPTION OF AREA The Pt. Diablo Hawk Lookout consists of two hills about 275 m high and 0.6 km apart and connected by a saddle-like ridge that runs southwest- northeast. The southwestern hill, which is honeycombed with old military bunkers, is called “Bunker Hill” by local birders and “Hill 129” by personnel of the Golden Gate National Recreation Area. Its top consists of cement bunkers and platforms on a short, narrow grassy ridge that peaks at the northeastern end. The northeastern hill, called “Cross Hill” by birders, is topped by an abandoned parking lot. The sides of Western Birds 10:1-16, 1979 1 RAPTORS AT PT. DIABLO both hills are covered with grass and low chaparral, and Bunker Hill has small patches of pines that attract migrant passerines and, occasionally, hunting accipiters. Bunker Hill is the better of the two hills for fall raptor observation, because it affords an unobstructed view to the west and northwest, whence come most of the birds. The flat top of Cross Hill makes observation more difficult; however, this seems to be the better observation point in spring. Binford (1977) gives highway directions to both hills. OBSERVATIONS Fall counts were conducted sporadically from 1972 through 1977. The earliest date was 1 5 August and the latest 6 December. Observadons totaled 262.6 hours distributed over 72 partial days as follows: August, 22.2 hours, 5 days; September, 123.2, 33; October, 78.2, 21; November, 38.0, 12; and December, 1.0, 1. The vast majority of observations were made between 1000 and 1400 (PST), the prime period for raptor migration. Most of the counts were made by B. J. McCaffery or myself; the 20 other observers who generously provided data are listed under Acknowledgments. The number of individual raptors observed at a lookout depends on, among other factors, the completeness of coverage on both a daily and seasonal basis. Continuous coverage of Pt. Diablo was impossible because of a military rifle range that, when active, necessitated closure of Bunker Hill. Because coverage was not continuous, neither the actual counts of individuals nor figures derived from them can be used to determine true abundance. They can, however, be used as approximate measures of relative abundance when combined for the six falls and converted into percentages of the total or into passing rates, i.e. the number of raptors per hour of observation. Percentages are shown in Table 1 and passing rates in Figures 1 B-6. Even these calculations cannot completely eliminate errors resulting from interspecific variation in seasonal or daily timing of migration. For instance, a species that routinely migrates early or late in the day or season, when coverage was least extensive, would have relatively lower totals. However, I believe that this type of error is minimal. RELATIVE ABUNDANCE During the 262.6 hours of observation, 8696 individual raptors were recorded. Table 1 gives the 18 species that have been recorded and the relative abundance of each. The actual number of individuals seen over the six-fall span is presented for each species, but because these figures are difficult to visualize as measures of relative abundance, I have converted them into percentages of the total 8696 birds. I have also applied classical terminology to indicate relative abundance because 2 RAPTORS AT PT. DIABLO percentages are difficult to remember, These terms are based on the number of individuals that would be expected to pass in one typical flight day during the species’ peak 1 0-day period, assuming twelve-hour days and 4 hours each at 10096, 5096 and 10% of the maximum 10-day passing rate. The periods and approximate passing rates are shown in Figures 2-6. The scale is as follows: abundant , 62 5 + -H individuals per day; very common, 125+-625; common, 25 + -125; fairly common 5 + -25; uncommon , 0-5 per day, averaging 5 + + per fall season; rare, 0-5, 1- 5; occasional, 0-1 per day, averaging once per l + -5 years; casual, 0-1, 5 + - 25; accidental, 0-1, 25 + -h Species in the first six categories occur annually, whereas the others do not. Superscript “plus” signs indicate fractions. In these classical terms, two species are considered very common, two common, three fairly common, four uncommon, three rare, three occasional, and one accidental. The three commonest species were Red- tailed, Sharp- shinned, and Cooper’s hawks. Their respective percent- ages of the total raptors, based only on identified individuals, were 28.25, 28.22, and 19.9696. However, 517 (5.9496) unidentified accipiters were observed. If these are allocated according to the same ratio (1:1.41) noted for identified Cooper’s and Sharp-shinned hawks (disregarding Gos- hawk and the five unidentified buteos), there were about 2758.5 (31 .7296) Sharp-shinned and 1948.5 (22.4196) Cooper’s. Thus the Sharp-shinned was the most common species, surpassing even the Red-tailed, and these three species accounted for approximately 82.3896 (7164 birds) of the total. Four other species accounted for an additional 15.7296; Turkey Vulture (9.8196), American Kestrel (3.17), Marsh Hawk (1.60), and Red- shouldered Hawk (1.14). Thus seven species, termed very common to fairly common in relative abundance and each occurring probably every suitable day during its peak period, accounted for about 98. 1096 of the total individuals. The remaining 1 1 species, considered uncommon to accidental, accounted for less than 196 each and only about 1.9096 together. TIMING OF MIGRATION To demonstrate timing of fall migration at Pt. Diablo, I present histograms based on passing rates (Figures IB-6). Despite the paucity of data, the rarer species (except Mississippi Kite) are included because in most cases their dates of occurrence fit patterns I have noted elsewhere in northern California. Periods of peak abundance for some species can be determined from gross inspection of the histograms, but for other species (e.g., Marsh Hawk, White-tailed Kite) histograms are not adequate. Therefore, I calculated “average dates” based on actual dates of occurrence weighted by abundance (in terms of passing rates, pr) according to the formula: $(pr • date) ■+■ $pr. 3 RAPTORS AT PT. DIABLO Table 1. Relative abundance, in terms of the number of individuals seen, percent of total and classical terminology {see text), of migrating diurnal raptors recorded at Pt. Diablo, California, during 262.6 hours of timed observations in six falls, 1972-77. Numbers in parentheses reflect allocation of the 517 unidentified accipiters between Cooper’s and Sharp-shinned hawks according to the ratio 1:1.41 observed for identified birds. Figures in brackets represent additional records obtained outside timed periods (see Species Accounts). Number of Percent Classical individuals of total terminology Turkey Vulture (Cathartes aura) 853 9.81 Common White-tailed Kite (Elanus leucurus) 30 .34 Uncommon Mississippi Kite (Ictinia mississippiensis) 0 [1] .00 [+] Accidental Goshawk (Accipiter gentilisj 1 [+1] .01 Occasional Sharp-shinned Hawk 2454 28.22 (A. striatus) (2758.5) (31.72) Very Common Cooper’s Hawk 1736 19.96 (A. cooperii) (1948.5) (22.41) Common Red- tailed Hawk (Buteo jamaicensis) 2457 28.25 Very Common Red-shouldered Hawk (B. lineatus) 99 1.14 Fairly Common Broad-winged Hawk (B. platypterus) 65 [+11] .75 Uncommon Swainson’s Hawk (B. swainsoni) 3 .03 Rare Rough-legged Hawk (B. lagopus) 3 .03 Rare Ferruginous Hawk (B. regalis ) Golden Eagle 4 .05 Rare (Aqvila chrysaetos) 9 .10 Uncommon Marsh Hawk (Circus cyaneus) 139 1.60 Fairly Common Osprey ( Pandion haliaetus) 41 .47 Uncommon Prairie Falcon ( Falco mexicanus) 1 .01 Occasional Peregrine Falcon (F. peregrinus) 1 [+1] .01 Occasional American Kestrel (F. sparverius) 276 3.17 Fairly Common Accipiter sp. 517 (0) 5.94 (0.00) Buteo sp. 5 .06 Falco sp. 2 .02 Totals: 8696 (8696) 99.97 (99.98) 4 RAPTORS AT PI . DIABLO Patterns of abundance. The raptors as a whole, as well as the individual species, exhibited distinct patterns of increase and decrease with time. For all species together (Figure IB), migration progressed at a low intensity during the last two-thirds of August, increased rather abruptly in the first 10 days of September, reached a peak in the last 10 days of September, maintained a somewhat lower but fairly constant level through the end of October, and then decreased rather abruptly, reaching a low level in late November. Histograms for the three commonest species, the Red-tailed, Sharp-shinned and Cooper’s hawks, demonstrate that the fairly constant level for the last third of September through October was primarily a result of coincident decreases in the two accipiters and an increase in the Red-tailed. The increase from the first to the second periods of November was a result of an influx of Red- tailed Hawks and may have reflected the arrival of adults, which averaged later than immatures (pers. obs.). Histograms for the eleven commonest species show three rather distinct patterns of abundance: (1) The Turkey Vulture and American Kestrel increased gradually to a rounded peak, then decreased gradually. (2) The Red-tailed Hawk, Marsh Hawk and perhaps White-tailed Kite also increased gradually but reached a sharp peak and then decreased rather abruptly. (3) The Sharp-shinned, Cooper’s, Broad-winged and Red-shouldered hawks. Golden Eagle and Osprey increased rather abruptly to a sharp peak followed by a gradual decrease. More data are needed to test the validity of these patterns. Even though passing rates based on less than continuous coverage are not measures of true abundance, I offer the following figures so that visitors will gain some idea of what to expect on days with good visibility and during the best times of day (ca. 1000-1400 PST) and year (ca. 21 Sep. -31 Oct.). The maximum daily passing rate recorded was 129.65 birds per hour ( 1 bird per 28 sec.) during a 4.25-hour period on 22 Sep. 1977; 458 (88.996) of the total 515 birds were accipiters. Passing rates exceeded 60 birds per hour (1 per min.) on 10 (13,996) of the 72 partial days of observation, all between 21 Sep. and 28 Oct. The average during the very best period, 21 Sep.- 10 Oct., was 49.92 birds per hour (1 per 1 min., 1 2 sec.), while the average for all 72 partial days was 33. 1 5 per hour (1 per 1 min., 49 sec.). Sequence of occurrence. The sequence in which the 1 7 non-accidental species occurred may be determined by comparing peak periods and “average dates” shown in Figs. 2-6. The Swainson’s Hawk, Osprey and perhaps Prairie Falcon were early migrants; the first two had peak periods and “average dates” in mid-September, and their migration was largely over before 1 October. The White-tailed Kite averaged slightly later but may also be termed an early migrant; its migration was over by late October. Seven species had “average dates” and peak periods close 5 RAPTORS AT PT. DIABLO 1 1 1 1 1 1 l l l l 1 1 AUG ' SEP ' 'oct' l NOV | DEC ' 20 31 10 20 30 10 20 31 10 20 30 o I CN •— CN I CN Figure 1. Temporal species diversity (A) and temporal distribution (B) of migrating diurnal raptors recorded at Pt. Diablo, California, during the six-fall period 1972-77. The histogram for species diversity includes all records for the 1 8 species (see Species Accounts), while that for distribution is based on the 8696 individuals seen during 262.6 hours of timed observations. 6 RAPTORS AT FT. DIABLO to 1 October and can be considered late-September through October, or mid-term migrants: American Kestrel, Sharp-shinned, Cooper’s, Broad- winged and Red-shouldered hawks, and probably Peregrine Falcon and Ferruginous Hawk. The Turkey Vulture and Marsh Hawk were some- what later, still with “average dates” in early October but with peak periods in mid- to late October. The Red-tailed Hawk and Golden Eagle were even later, averaging mid- October, and the Rough-legged Hawk and Goshawk were the latest, with “average dates” in November. Duration. Migration was in progress at very low intensities when both the earliest (15 August) and latest (6 December) observations were made (Figure IB). The extreme limits of the migration period probably are early August and late December. PRAIRIE FALCON ;i 5-r i* 11 i 1 SWAINSON'S HAWK z> O x .4 — . 3 - - .2 + o ee * .1 + o-L - i 1 6 OSPREY 1 | | 1 | | | AUG SEP OCT NOV DEC o — o o o O O — o o o o i 1 CN _ CN CN — 1 1 1 — CN CO 1 1 1 — CN CO 1 1 1 — CN — CN — CN — CN Figure 6. Temporal distribution of migrating diurnal raptors recorded at Pt. Diablo, California, during 262.6 hours of observation in the six-fall period 1972-77. Specific dates are “average dates” of occurrence weighted by passing rates (see text). 11 RAPTORS AT PT. DIABLO partly an artifact of incomplete coverage. Daily species totals varied from 0 to 1 1 , with an overall average of 6.49. For the very best period, 2 1 Sep.- 10 Oct., totals ranged from 5 to 11 and averaged 8.15. Continuous coverage would, of course, affect these figures. SPECIES ACCOUNTS Prior to this study, neither the White-tailed Kite nor Red- shouldered Hawk was known to be migratory in California (Small 1974). Their abundance, annual regularity and southward movement at Pt. Diablo suggest true migration rather than random post-breeding dispersal, but corresponding spring data are needed for confirmation. The regular occurrence of the Broad-winged Hawk was most unexpected, as there were only about 15 previous records for the entire state. Details for this and the seven rare to accidental species are presented below; data for the commoner species are contained in Table 1 and Figures 2-6. Mississippi Kite. Accidental fall visitant. A single adult was seen well by W. M. Pursell and A. Mericourt on 13 Sep, 1976 (Winter and Erickson 1977). This was only the second record for northern California; the first was an immature seen by B. Clow 3 miles east of Cape Mendocino, Humboldt Co., on 6 Sep. 1975 (Stallcup and Winter 1976); the closeness of the two dates is perhaps significant. Goshawk. Occasional fall transient here and elsewhere on the coast of northern California. Two records: one immature seen by L. C. Binford on 17 Nov. 1972 during an invasion year for numerous northern or montane species, and one adult observed by W. M. Pursell on 20 Oct. 1974 (Stallcup et al. 1975). Broad-winged Hawk. Uncommon fall transient. At least 76 individuals were observed atPt. Diablo in the falls of 1972-77. Extreme dates were 15 Sep. (1975) and 5 Nov. (1975). The true average date for all records was 4 Oct., and the “average date” weighted by passing rate, based on the 65 birds recorded during timed periods, was 1 Oct. The maximum daily count was 1 4 on 30 Sep. 1974 (L. C. B,), ofwdiich eight were in sight at one time. Three immatures of the very rare dark phase were seen: 4 Oct. 1974 (L. C. B.), 6 Oct. 1974 (S. F. Bailey) and 28 Oct. 1972 (L. C. B.). This suggests that Pt. Diablo Broad-winged Hawks originate in the northwestern part of the species’ range, where the melanistic morph seems to occur most often. Swainson’s Hawk. Rare fall transient here and elsewhere along the coast of northern California. Three records, all for single immatures: 4 and 23 Sep. 1 975 (L. C. B.) and 7 Sep. 1976 (B. J. McCaffery). The last bird was wing-tagged as a juvenile near Richland, Benton Co., southeastern Washington in 1975 or 1976 (McCaffery pers. comm.; Winter and Erickson 1977). Rough-legged Hawk. Rare fall transient; possibly increases to uncommon status during some invasion years. Probably has been seen at Pt. Diablo more often than the three times for which I have data: single birds on 30 Sep. 1977 (B. D. Parmeter, W. M. Pursell et al.) and on 5 and 17 Nov. 1972 (L. C. B.). Ferruginous Hawk. Rare fall transient here and elsewhere on the coast of northern California. Four records: 21 Sep. 1977 (J. W. Shipman and L. Compagno), 30 Sep. 1977 (B. D. Parmeter, W. M. Pursell et al ), 1 Oct. 1977 (S. F. Bailey) and 7 Oct. 1972 (L. C. B.). 12 RAPTORS AT PT. DIABLO Prairie Falcon. Occasional fall transient here and elsewhere on the coast of northern California. One record: a single bird seen by B. A. Sorrie on 15 Aug. 1977. Peregrine Falcon. Occasional fall transient. Two records: one seen by S. F. Bailey etal. on 1 Oct. 1977 and one photographed bvj- W. Shipman and L. Compagnoon6 Oct. 1977. The scarcity of the Peregrine Falcon and apparent absence of the Merlin (Falco columbarius ) , despite their regularity elsewhere on the northern Califor- nia coast, may reflect behavioral responses to local geography, Both species are direct flyers that show little avoidance of water barriers or dependence on updrafts, and in fact seem to favor outer beaches where available (pers. obs.); possibly Marin Co. birds cut directly across the extreme mouth of San Francisco Bay rather than detouring eastward to Bunker and Cross hills. As support for this theory. Peregrine Falcons are seen with more regularity to the west of Bunker Hill over Rodeo Lagoon, and even the bird seen from Bunker Hill on 1 Oct. 1977 was described by Bailey (pers. comm.) as “far to the west-northwest and northwest.” COMPARISONS WITH THE EASTERN UNITED STATES I have compared certain aspects of migration at Pt. Diablo with data given by Haugh (1972) for Hawk Mountain, which is near Allentown, Pennsylvania, and is on a latitude about 320 km north of San Francisco. Although detailed comparisons of abundance must await data from continuous coverage of Pt. Diablo, some statements are warranted. Certainly, the Broad-winged Hawk is much less numerous and the Cooper’s Hawk much more so at Pt. Diablo. Aside from the western species (Swainson’s Hawk, Ferruginous Hawk and Prairie Falcon), only one other species, the Turkey Vulture, is clearly more common at Pt. Diablo. On the other hand, seven species occur in larger numbers at Hawk Mountain: Goshawk, Red- shouldered Hawk, Bald Eagle, Osprey, Peregrine Falcon and Merlin; the eagle and Merlin have not been recorded at Pt. Diablo, but should occur in small numbers. The patterns of abundance for individual species at Hawk Mountain are similar to the three noted at Pt. Diablo, except that the two accipiters decrease abruptly and the Golden Eagle increases gradually to a rounded peak. The duration of the fall migratory period is similar at the two lookouts, both having low intensities of movement in the last half of August and first part of December. The relative durations for individual species are also fairly similar, with the Red- tailed Hawk, Cooper’s Hawk, Marsh Hawk and American Kestrel spending about 3 months on migration, the Sharp-shinned Hawk, Red-shouldered Hawkand Osprey about 2.5 months, and the Broad-winged Hawk about 1.5 months. The Golden Eagle, however, has an extended period of about 3.5 months, rather than 1 month, at Hawk Mountain. In timing of peak periods, the most striking differences are that at Pt. Diablo the Broad- winged Hawk peaks about 2 weeks later and the Red- 13 RAPTORS AT PT. DIABLO shouldered Hawk somewhat over 3 weeks earlier than at Hawk Moun- tain. The Red-tailed Hawk, Golden Eagle, Sharp-shinned Hawk and Cooper’s Hawk also peak earlier at Pt. Diablo, by about 2 weeks for the first two species and 1 week for the accipiters. The Marsh Hawk, Osprey and American Kestrel peak at about the same time at the two lookouts, but the first two species seem to average a few days earlier and the American Kestrel a few days later at Pt. Diablo. Three additional species, for which data are few, the Rough-legged Hawk, Peregrine Falcon and Goshawk, also appear to occur a few days earlier. Thus with the notable exception of the Broad-winged Hawk and possibly the American Kestrel, migration is earlier at Pt. Diablo than at Hawk Mountain, in spite of the 320-km difference in latitude. Distance to the nearest breeding grounds, which are in central Alberta about 1750 km from Pt. Diablo, may account for the lateness of the Broad-winged Hawk. SOURCE OF RAPTORS Several factors probably contribute to the concentration of raptors at Pt. Diablo. Perhaps most important is the juxtaposition of the ocean and bay. The ocean shore of Marin Co. runs northwest- southeast, while the northwestern shore of the northern arm of San Francisco Bay runs approximately north-south. The land between thus forms a funnel culminating at Pt. Diablo. Both shorelines probably form leading lines, especially for those species such as buteos that hesitate to cross large bodies of water. In addition, the mountain ranges in this area form long northwest-southeast ridges, the most important of which is Bolinas Ridge, extendingfor some 55 km from Tomales to the Marin Headlands. Other long ridges form a series of lines parallel to the coast and extend nearly from the Oregon border. The importance of Bolinas Ridge is suggested by the fact that many raptors approach Bunker Hill from the northwest and especially west, with the latter birds originating in the northwest but being forced to follow the eastward curve of the ^arin Peninsula. Very likely many of the raptors observed at Pt. Diablo in fall originate in the northwestern coast belt of North America. However, evidence demonstrates that some come from the Great Basin and Great Plains; these birds could take a westward or southwestward course to the coast much in the manner of certain water birds, such as the California Gull (Larus califomicus) and Western Grebe (Aechmophorus occidentalis ) , and then turn to follow the coast southward. A Swainson’s Hawk wing- tagged near Richland, Washington, east of the Cascade Range, was seen at Pt. Diablo. The Broad-winged Hawk is not known to breed west of central Alberta, whence probably came at least the three dark phase birds observed at Pt. Diablo. Finally, the Ferruginous Hawks could have come only from their breeding grounds to the northeast. 14 RAPTORS AT PT. DIABLO SUMMARY Pt. Diablo, located just north of San Francisco, California, is the only known major hawk lookout in western North America. Since its discovery in the fall of 1972, 18 species of diurnal raptors have been recorded. Sporadic observations totaling 262.6 hours over 72 days in the falls of 1972 through 1977 produced 8696 individual birds. The relative abundance of each species is given. Seven species, termed very common to fairly common, accounted for about 98.10% of the total. The most numerous three, the Sharp-shinned (~3 1.7296), Red-tailed (28.25), and Cooper’s (~22.41) hawks, produced about 82.3896 of the total. Raptor migration begins in earnest about the first of September, reaches a peak in number of individuals in the end of September, and tapers off to a low level in late November. Limited migration takes place at least as early as mid-August and as late as early December. Peak periods and “average dates,” which together provide a sequence of occurrence, are presented for each species, and three patterns of abundance are postulated. The temporal pattern for species diversity is similar to that for abundance. Separate accounts are presented for the rarer species. The White-tailed Kite and Red-shouldered Hawk, previously thought to be sedentary in California, are shown to be migratory in fall. The Broad- winged Hawk, believed to be a casual vagrant in the state, is an uncommon fall transient at Pt. Diablo. Most individuals at Pt. Diablo probably originate in the northwestern coastal areas of North America and use northwest- southeast ridges, the Pacific coast, and locally the shore of San Francisco Bay as leading lines and sources of updrafts, but some birds come from northeast of the Cascades. Only two species (Turkey Vulture and Cooper’s Hawk) are more common at Pt. Diablo than at Hawk Mountain, Pennsylvania, while seven are more common at the latter. Most species peak earlier at Pt. Diablo. In most other aspects studied, migration is rather similar at the two lookouts. AC KN OWLED GMENTS I thank the following people who generously provided their migra- tion notes from Pt. Diablo: Stephen F. Bailey, Gordon Beebe, Leonard Compagno, Richard DeCoster, William Dillon, Bruce G. Elliott, Bud Fry, Ronald LeValley, Brian J. McCaffery, Alice Mericourt, John and Benjamin D. Parmeter, William M. Pursell, J. Van Remsen, Don Roberson, Mary Louise Rosegay, John W. Shipman, Bruce A. Some, Richard W. Stallcup, and Robert Sutherland. Nancy M. Poh typed the manuscript. 15 RAPTORS AT PT. DIABLO LITERATURE CITED Binford, L. C. 1977. California, Pt. Diablo. Birding 9:29-30. Haugh, J. R. 1972. A study of hawk migration in eastern North America. Search, Agriculture 2(1 6): 1-59. Small, A, 1974. The birds of California. Winchester Press, New York. Stallcup, R., D. DeSante and R. Greenberg. 1975. Middle Pacific coast region. Am. Birds 29:112-119. Stallcup, R. andj. Winter. 1976. Middle Pacific coast region. Am. Birds 30:1 18-124. Winter, J. and D. Erickson. 1977. Middle Pacific coast region. Am. Birds 31:216-221. Accepted 15 December 1978 Sketch by F. J. Watson 16 SIZE SELECTIVE PREDATION AND FOOD HABITS OF TWO CALIFORNIA TERNS DONALD M. BALTZ, Moss Landing Marine Laboratories, P.O. Box 223, Moss Landing, California 95039 (present address: Department of Wildlife and Fisheries Biology, University of California, Davis, California 95616) G. VICTOR MOREJOHN, Moss Landing Marine Laboratories, P.O, Box 223, Moss Landing, California 95039 BROOKE S. ANTRIM, Moss Landing Marine Laboratories, P.O. Box 223, Moss Landing, California 95039 Evidence for size selective predation by seabirds is anecdotal or, at best, qualitative; however, several studies suggest that prey size selection is a fairly common phenomenon partitioning the food resource among sympatric seabirds (Bourne 1955, Ashmole 1968, B6dard 1969, Baltz and Morejohn 1977). The present study documents size selection of prey species by two species of seabirds, the Caspian Tern (Sterna caspia) and the Forster’s Tern (S. forsteri ) . These two seabirds, although differing greatly in size, have broadly overlapping breeding seasons and similar foraging strate- gies. The study was done in Elkhorn Slough, Monterey County, California, where the fish fauna is well known (Cailliet et al. 1977); both terns forage in the slough and breed nearby. Since size differences are greater than 130:100 (culmen 174:100; gape width 191:100; weight 459:100), the terns were expected to exploit different elements of the prey community, as predicted by Hutchinson (1959) and MacArthur and Levins (1964). METHODS Six specimens of both species of terns were collected on 1 1 July 1975. On 28 July 1977,5 Caspian Terns and 9 Forster’s Terns were collected. A total of 11 Caspian Terns and 15 Forster’s Terns thus were utilized. Weights and measurements were taken from fresh specimens following Ashmole (1968). Contents of the proventriculus and ventriculus were removed and sorted. Otoliths were washed and stored dry as recom- mended by Fitch and Brownell (1968). Other contents such as fish flesh and bones were preserved in formalin and then stored in 40% isopropyl alcohol. The minimum number of prey represented by otoliths was taken to be the greatest number of right or left otoliths of similar size. Weights and standard lengths (SL) of Shiner Perch (Cymatogaster aggregata) represented by otoliths were estimated from regressions on specimens collected in Elkhorn Slough (formulae available from au- thors). Two otoliths, one representing a juvenile and the other an adult Shiner Perch taken by a Forster’s Tern and a Caspian Tern, respectively, were too eroded to determine prey size and were excluded from Western Birds 10: 17-24, 1979 17 TERN PREY SELECTION statistical tests. For Northern Anchovy (Engraulis mordax ), lengths and weights were calculated from otolith measurements using relationships provided by Clark and Phillips (1952) and Spratt (1975). Sizes of other prey species were measured or estimated from reference collection specimens at Moss Landing Marine Laboratories. Many of the prey items were represented only by otoliths. Some were represented by identifiable, partially digested whole fish. Since analysis on a gravimetric basis would have overestimated the importance of prey represented by partially digested or undigested items, the diets were compared numerically. Analyses of the stomach contents of terns collected in 1 97 5 and 1977 were combined and are summarized in Table 1 . The distribution and abundance of fishes in Elkhorn Slough and adjoining Bennett Slough were the subject of concurrent studies by Cailliet et al. (1977) and Antrim (unpubl. data). Fishes were collected from several areas before, during and after terns were collected. Bennett Slough is shallow and was sampled with a small beach seine (15.2 x 1.4 m). The main channel in Elkhorn Slough was sampled at several stations with a small otter trawl having a 4.9 m headrope with 38 mm stretch mesh in the body and a 32 mm stretch mesh liner in the codend. RESULTS Forster’s Terns were observed foraging over the entire area of the slough, but primarily over mudflats covered at flood tide where the water depth was 1 m or less. Schools of small fish were observed in the clear, shallow water covering the mudflats; when startled, the schools quickly disappeared in one of the many smaller channels which meander through the mudflats. Caspian Terns foraged over the main channel and, to a lesser extent, over the shallows. Both species collected on 1 1 July 1975 were preying heavily on the same fish, the Shiner Perch, although other fishes were taken as well. Stomachs of all specimens contained identifiable contents. The Shiner Perch was ranked first overall in abundance throughout the slough from August 1974 to June 1976 (Cailliet et al. 1977). Size distributions of Shiner Perch found in the stomachs of both tern species represent opposite ends of the bimodal distribution of Shiner Perch trawled in Elkhorn Slough in July 1975 (Figure 1). Caspian Terns preyed primarily on adult Shiner Perch, whereas Forster’s Terns preyed primarily on young-of-the-year. Mean prey lengths (Shiner Perch only) were significantly different between tern species (t-test, 19 d.f., P < .001). These differences are probably related to the large differences in predator size. Specimens collected on 28 July 1977 were not preying as heavily on Shiner Perch, but differences in the size of prey were apparent. Stomachs of two of the Forster’s Terns and one of the Caspian Terns did not contain identifiable food items. Forster’s Terns preyed on juvenile 18 TERN PREY SELECTION Table 1 . Summary of stomach contents of Caspian Terns (Sterna caspia) and Forster’s Terns (S. for steri) collected in Elkhorn Slough, Monterey Co., California, in July of 1975 and 1977. CASPIAN TERNS FORSTER’S TERNS (N=10) (N=15) PREY ITEMS A B C A B C Shiner Perch, Cymatogaster aggregata adult 20 80.0 80.0 1 1.6 6.7 juvenile 1 4.0 10.0 27 42.2 40.0 Northern Anchovy, Engraulis mordax adult 4 16.0 20.0 2 3.1 13.3 juvenile 21 32.8 53.3 Night Smelt, Spirinchus starksi juvenile 1 1.6 6.7 Top Smelt, Atherinops affinis juvenile 1 1.6 6.7 Arrow Goby, Clevelandia ios adult 8 12.5 13.3 Unidentified gobies 3 4.7 13.3 Gill Lice 1 Lironeca vulgaris 2 20.0 1 6.7 A=Total number of items in each category. B=Percentage of total individuals by number. C=Percent frequency of occurrence of various prey items in stomachs. 1 Gill Lice were probably acquired indirecdy from parasitized fishes; they are parasitic on many fishes and range from Washington to Baja California (Schultz 1969); lice are omitted from computation of percentage of total individuals. Northern Anchovy, juvenile Shiner Perch and Arrow Gobies (Cleve- landia ios), whereas Caspian Terns preyed on adult Shiner Perch and adult Northern Anchovy. Size of prey taken in 1977 again reflected the large size difference between the terns; however, measurable prey items in Caspian Terns were too few for statistical testing. Comparisons of prey length in samples comprised of more than one species were deemed inappropriate due to the variety offish body forms (Swennen and Duiven 1977); therefore, weights were used to compare prey size. Mean weights of all prey taken in 1975 were significantly different (t-test, 22 d.f., P<. 001, as were combined collections (Figure 2) from 1975 and 1977 on a mean weight basis (t-test, 23 d.f., P<.001). 19 TERN PREY SELECTION DISCUSSION The highly significant differences in the sizes of prey taken by the tern species were anticipated, since Salt and Willard (1971) reported that Caspian Terns . . consistendy captured much larger fish in the same water than any taken by Forster’s Tern.” However, the almost exclusive predation on different age classes of the same prey species, Shiner Perch Figure 1 . Size distributions of Shiner Perch ( Cymatogaster aggregate) in the stomach contents of Caspian Terns (Sterna caspia ) and Forster’s Terns (S. forsteri) and in Elkhorn Slough. Numbers of Shiner Perch are in parentheses. Mean size taken by terns is indicated by arrow. 20 TERN PREY SELECTION and Northern Anchovy, was unexpected. Whether this pattern contin- ues thoughout the stay of both species in the study area is unknown, since the food habits of both terns have not been examined in Elkhorn Slough during months other than July. Notwithstanding the great size differ- ences between the tern species, both species probably respond similarly in an opportunistic manner to the most available prey species. Bent (1921) summarized information which suggests that both Forster’s and Caspian terns are opportunistic feeders and may utilize a variety of prey other than fishes; however, Salt and Willard (1971) and Salt (pers. comm.) studied nearby San Francisco Bay area populations of Caspian and Forster’s terns which preyed exclusively on fishes while on the study area (April-January). During a 23-month study of the distribution and abundance of fishes in Elkhorn Slough, the Shiner Perch was ranked first in overall PREY WEIGHT (grams) Figure 2. Size distributions by weight of all prey taken by Caspian Terns ( Sterna caspia) and Forster’s Terns (S.forsteri) in Elkhorn Slough in 1 975 and 1 977. Numbers of prey organisms are in parentheses. 21 TERN PREY SELECTION abundance, whereas the Arrow Goby was ranked first in Bennett Slough, similar to the mudflat habitat in Elkhorn Slough ( Cailliet et al. 1 9 7 7) . The size distribution of Shiner Perch in the 1975 trawl catch was bimodal (Figure 1) due to the presence of numerous young-of-the-year and five older age classes. The Shiner Perch is viviparous and females give birth from early May through late June, with young ranging from 26 to 36 mm SL; young-of- the-year reach peak abundance in July in Elkhorn Slough (Antrim unpubl. data). The importance of Shiner Perch in the diets of Caspian and Forster’s terns reflects their abundance in the slough. Shiner Perch have also been found to be important prey of other seabirds and dominate many marine and estuarine habitats on the Pacific coast (Martini 1964, Sealy 1972, Gill 1976). Presence of otoliths from a juvenile Shiner Perch in the stomach contents of a Caspian Tern was probably due to predation on a pregnant female Shiner Perch. Cannibalism by Shiner Perch is an unlikely explanation, since adults are not piscivorous (Antrim unpubl. data). Alternatively, inexperienced terns might be expected to take prey of unusual size (Buckley and Buckley 1974); however, the tern in question was an adult. Inexperience might also account for the two largest fishes taken by Forster’s Terns. Salt and Willard (1971) found that the mean size of fishes taken by Forster’s Terns declined from spring to fall and that Forster’s Terns preyed most effectively on fishes of 75 mm total length (TL) or longer. They suggested that the observed decline in mean prey size was due to the passage of an age class begond the range of vulnerability. Our data support their suggestion.' Shiner Perch were present in their study area and were probably important prey. Age one- plus Shiner Perch in the 75 mm TL (58 mm SL) size range constituted a minor portion of the population in Elkhorn Slough in July 1975 (Figure 1). Information on the growth rate of the one-plus age class is lacking for the Elkhorn Slough population, but individuals in the Navarro River Estuary grow from a mean of 83.7 mm TL (72.6 mm SL) in early April to a mean of 98.4 mm TL (85.5 mm SL) in late July and early August (Varoujean pers. comm.). The maximum size of prey that Forster’s Terns have been observed to take is about 87 mm TL (75.6 mm SL) (Salt and Willard 1971). Assuming that growth rates are similar in both populations, it appears that the one- plus age class is much less vulnerable to attack by Forster’s Terns by early summer. The decline in mean prey size observed by Salt and Willard (1971) is probably the result of the increasing availability of young-of- the-year and the declining abundance and increasing cost in handling time of age one-plus Shiner Perch. Other piscivorous birds prefer prey slightly smaller than half the maximum size manageable (Swennen and Duiven 1977). This suggests that Forster’s Terns are quite capable of 22 TERN PREY SELECTION preying on fishes much larger than the mean size taken in this study (37.5 mm SL). The occurrence of Northern Anchovy was sporadic throughout the study, as was the occurrence of lesser prey species. The unidentified gobies recovered from Forster’s Terns in 1975 were possibly Arrow Gobies; however, five other species of gobies occur in Elkhorn Slough (Brothers 1975, Cailliet et al. 1977). The Arrow Goby was the most abundant fish in beach seine catches in the extensive mudflat area of Bennett Slough throughout most of the year and is probably the most abundant fish on mudflats throughout the sloughs, but mudflats in Elkhorn Slough were not sampled. The shallowness and clarity of the water over the mudflats probably enable terns to track their prey more effectively than is possible over deeper waters. Small fishes such as gobies are particularly vulnerable in shallow water to attack by Forster’s Terns which can capture prey to a maximum depth of 30 cm below the surface (Salt and Willard 1971). Forster’s Terns forage extensively over covered mudflats where small prey are abundant and more vulnerable. Caspian Terns also forage over covered mudflats, but concentrate their activity over deeper channels where larger prey are more abundant. ACKNOWLEDGMENTS We thankjohn E. Fitch for kindly identifying the otoliths used in this study and for consultation on related matters. James T. Harvey assisted in the collection of birds and fishes. Gregor M. Cailliet and Daniel H. Varoujean made several helpful suggestions and provided useful data. This report is part of a study concerned with feeding habits of marine fishes, seabirds and marine mammals sponsored by NOAA, Office of Sea Grant, Department of Commerce, under Grant No. NOAA-04-5- 158-20. LITERATURE CITED Ashmole, N. P. 1 968. Body size, prey size and ecological segregation in five sympatric tropical terns (AvesrLaridae). Syst. Zool. 17:292-304. Baltz, D. M. and G. V. Morejohn. 1977. Food habits and niche overlap of seabirds wintering on Monterey Bay, California. Auk 94:526-543. Bfedard, J. 1969. Adaptive radiation in Alcidae. Ibis 111:189-198. Bent, A. C. 1921. Life histories of North American gulls and terns. U. S. Natl. Mus. Bull. 113. Bourne, W. R. P. 1955. The birds of the Cape Verde Islands. Ibis 97:508-556. Brothers, E. B. 1975. The comparative ecology and behavior of three sympatric California gobies. PhD thesis, Univ. California, San Diego. Buckley, F. G. and P. A. Buckley. 1974. Comparative feeding ecology of wintering adult and juvenile Royal Terns (Aves: Laridae, Sternae). Ecology 55:1053-1063. 23 TERN PREY SELECTION Cailliet, G. M., B. Antrim, D. Ambrose, S, Pace and M. Stevenson. 1977. Species composition, abundance and ecological studies of fishes, larval fishes and zooplankton in Elkhorn Slough. Pages 216-386 in Nybakken, J., G. Cailliet and W. Broenkow, Ecological and hydrographic studies of Elkhorn Slough, Moss Landing Harbor and nearshore coastal waters July 1974 to June 1976. Moss Landing Marine Lab. Tech. Rep. Clark, F. N. andj. B. Phillips, 1952. The Northern Anchovy (Engraulis mordax) in the California fishery. California Fish and Game 38:189-207. Fitch, J. E. and R. L. Brownell. 1968. Fish otoliths in cetacean stomachs and their importance in interpreting feeding habits. J. Fish Res. Bd. Canada 25:2561-2574. Gill, R. E. 1976. Notes on the foraging of nesting Caspian Terns Hydroprogne caspia (Pallas). California Fish and Game 62:155. Hutchinson, G. E. 1959. Homage to Santa Rosalia, or why are there so many kinds of animals? Am. Nat. 93:145-159. MacArthur, R. and R. Levins. 1964. Competition, habitat selection and character displacement in a patchy environment. Proc. Natl. Acad. Sci. 51:1207-1210. Martini, E. 1964. Otolithen in Gewollen der Raubsee schwalbe (Hydroprogne caspia) . Bonner. Zool. Beitr. 15:59-71. Salt, G. W. and D. E. Willard. 1971. The hunting behavior and success of Forster’s Tern. Ecology 52:989-998. Schultz, G. A. 1 969. How to know the marine isopod crustaceans. Wm. C. Brown Co., Dubuque, Iowa. Sealy, S. G. 1972. Adaptive differences in breeding biology in the marine bird family Alcidae. PhD thesis, Univ. Michigan, Ann Arbor. Spratt, J. D. 1 975. Growth rate of the Northern Anchovy, Engraulis mordax in southern California waters, calculated from otoliths. California Fish and Game 61:116-126. Swennen, C. and P. Duiven. 1977. Size of food objects of three fish-eating seabird species: Uria aalge, Aka torda and Fratercula arctica (Aves: Alcidae). Netherlands J. Sea Res. 1 1:92-98. Accepted 18 December 1978 24 POST-HATCHING MOVEMENTS OF YOUNG ANCIENT MURRELETS SPENCER G. SEALY, Department of Zoology, University of Manitoba, Winnipeg, Manitoba R3T 2N2 R. WAYNE CAMPBELL, Vertebrate Zoology Section, British Columbia Provincial Museum, Victoria, British Columbia V8W 1X4 Precocial development in truly marine birds is exhibited by only four species, all alcids. Other species in the family are semi-precocial or exhibit a developmental pattern intermediate between these two (Ricklefs 1973, Sealy 1973, Birkhead 1977). The movement of newly hatched murrelets away from the colonies permits them to use what appears to be a patchily distributed food supply at sea (Lack 1968, Sealy 1975a, 1975b, 1976). The young of most other marine birds that exploit patchily distributed food or distant food resources develop slowly in their nest sites because they are fed infrequently (Ashmole 1971). COMPOSITION OF FAMILY GROUPS Most Ancient Murrelet (Synthiiboramphus antiquus) family groups consist of two adults with two young (Table 1). Adults of both Craven’s Murrelet (Endomychura craven) and Xantus’ Murrelet (E. hypoleuca) ac- company their two chicks at sea (De Weese and Anderson 1976, George L. Hunt pers. comm.). Single young of Common Murres (Uria aalge), which leave the nest site at 3 weeks of age, are accompanied usually by the adult male (Scott 1973). MOVEMENTS OF FAMILY GROUPS Little is known of the behavior and movements of precocial murrelets during their post-hatching development. Two-day-old Ancient Mur- relets leave their concealed nest burrows at night, often in great numbers (Willett 1915, Guiguet 1953a, Sealy pers. obs.), and are gone by sun-up from the colonies and surrounding waters. This exodus occurs from late May to late June on Langara Island, Queen Charlotte Islands, British Columbia (Sealy 1976). Duringthis period in 1970 and 1971, Sealy never saw Ancient Murrelet family groups within the 15-20 km radius off Langara Island that he regularly covered. Discussions with fishermen who had fished that area for many years revealed that only an occasional family group was seen, usually west of Langara Island and north of Frederick Island. Charles J. Guiguet (pers. comm.) believes, based on many years of at-sea observations in British Columbia, that these family groups move directly to offshore waters where the young grow. He saw adults and downy young only once nearshore, on 1 June 1959 (Table 1). Bartonek and Gibson (1972) saw families with downy young from 30 to over 40 miles from shore off the Alaska Peninsula. George L. Hunt (pers. comm.) radio-tracked a Xantus’ Murrelet with brood from its nesting site on Santa Barbara Island, California, and lost contact 16 km offshore. Western Birds 10: 25-30, 1979 25 YOUNG ANCIENT MURRELETS The dearth of sight records of Ancient Murrelet family groups is puzzling. Vermeer and Vermeer (1975) indicated that 190,000 pairs of Ancient Murrelets nest in British Columbiaat 22 colonies (the number of known nesting colonies is now 30 with the completion of the British Columbia Provincial Museum west coast seabird colony survey). Sight- ings of family groups are very few despite the thousands that must be at sea in June and July each year. Therefore these groups probably disperse widely after leaving the colonies. As well as moving offshore, some family groups move southward (see observations offVancouver Island, Table 1) to areas where Ancient Murrelets are not known to nest. The Vancouver Island sightings were made 2-6 weeks after young on Langara Island have started to leave the colony. Ancient Murrelets gradually build up in numbers in Barkley Sound, Vancouver Island, beginning in mid-July (Hatler et al. 1978). The southward movement continues in late fall and winter until they reach northern and central California (Grinnell and Miller 1944, Ainley 1976). In mid-July many young Ancient Murrelets, now about adult size and in juvenal plumage, begin moving back to inshore waters. Sealy first saw such young near Langara Island on 10 July 1971, and their numbers increased after that time. Eight such young averaged 208 g in weight (extremes, 1 83.9 and 220.3 g) and were similar to breeding adults (Sealy 1976). Except for one observation on 18July 197 1 (Table 1), these young were not accompanied by adults. The adults possibly stay offshore in mid-July and molt. Table 1. Location and composition of Ancient Murrelet family groups observed at sea. AREA DATE FAMILY GROUP 1 OBSERVERS ALASKA Between Forester and Dali islands Bristol Bay 21 July 1920 20-26 July 1969 2A, 2Y 8A, 8DY Willett (1920) Bartonek and Gibson (1972) QUEEN CHARLOTTE ISLANDS S.W. Moresby I. (1.6 km offshore) Egeria Bay, Langara I. Hecate Strait Hecate Strait 1 June 1959 18 July 1971 16 June 1972 22 July 1973 1A, 2DY 1A, 2Y 2A, 1Y 2A, 1Y Drent and Guiguet (1961) Sealy (1976) P. W. Martin P. W. Martin 26 YOUNG ANCIENT MURRELETS Table 1 (Cont.) FAMILY AREA DATE GROUP 1 OBSERVERS BRITISH COLUMBIA MAINLAND COAST 28-32 km W. Goose I. 13 June 1945 2A, 2DY Guiguet (1953b) Goose I. Banks 8 June 1947 several Martin and Myres (1969) Goose I. Banks 6, 8 June 1972 2A, 1Y P. W. Martin Goose I. Banks 30 June 1972 2A, 1Y P. W. Martin Off Blackney I. 19June 1976 2A, 1Y R. W. Campbell, M. S. Rodway Off Goose I. 21 June 1976 7A, 4DY R. W. Campbell, M. S. Rodway Off Simonds Group 21 June 1976 2A, 1DY R. W. Campbell, M. S. Rodway W. Limit I. 21 June 1976 1A, 1DY H. R. Carter, K. Taylor Moore Island 25 June 1976 4A, 2DY R. W. Campbell, M. S. Rodway VANCOUVER ISLAND 2 * Triangle Island 24-30 June 1949 2A, 2Y G. C. Carl, C. J. Guiguet Quatsino Sound 16 July 1949 2Y Martin and Myres (1969) Quatsino Sound 31 July 1949 increasing Martin and no. of imms. Myres (1969) Triangle Island 29June 1972 4 A, 4DY C. J. Guiguet 3 Triangle Island 16June 1974 3A, 1Y K. R. Summers Triangle Island 2July 1974 2A, 1Y Vermeer et al. (1976) TOTALS 4 49A, 37(DY & Y) 1 A: adult; DY: downy young; Y: young in juvenal plumage. 2 Observations off Vancouver Island, where Ancient Murrelets do not nest, indicate that the presence of family groups does not imply that nesting occurred nearbv (but see Vermeer et al. 1976). s Two downy young collected (British ColumbiaProvincial Museum 1 1899, 1 1900). 4 Data include 49 adults, 37 young (young without adults not included), 21 adult- chick groups. Young per adult=1.3; young per group=1.8. 27 YOUNG ANCIENT MURRELETS Evidence indicates that Ancient Murrelets prefer colder waters. Ainley (1976) found that they arrived in northern California in Novem- ber coincident with the decrease in surface temperatures. Also, the species was present in greatest numbers off California during winters of low water temperature (9°C-10°C). Departure from California occurs suddenly in March (Ainley 1976), when adults begin returning to the vicinity of nesting colonies on the Queen Charlotte Islands (Sealy 1976). Water temperatures near Langara Island average 7°C in March and rise to 1 1°C in June (Dodimead et al. 1963), when family groups are moving away from the colonies. DISCUSSION Why are vulnerable, downy young Ancient Murrelets moved out to sea away from the protection of burrows in the nesting colonies? The answer appears to lie in the use by this species of available food resources. All other alcids, except murrelets of the genus Endomychura, rear their young in nest sites and bring them food from the sea, at least during their first few weeks. The Ancient Murrelet’ s breeding strategy differs from that of semi-precocial alcids in that its incubation shifts are 72 hours (long for an alcid) and young are not fed during their 2 days in the nest (Sealy 1972, 1976). Long incubation shifts and the eventual long intervals between chick feedings suggest that food is either far from the colonies, as happens with many procellariiforms (see Ashmole 1971), or is patchily distributed and requires much time to locate. Evidence indicates the latter situation exists with Xantus’ Murrelet (Eppley and Schwartz 1976), Also, the precocial murrelets lack specialized morpho- logical apparatus, seen in plankton-feeding auklets (Bedard 1969a, Speich and Manuwal 1974) and fish-feeders (Bedard 1969b), which would facilitate the transport of economically feasible amounts of food to the two young in the nest. Scott (1973) postulated that the number of Common Murre parents that accompany their single chicks varies with the availability of food. Presence of the usual family group, with the male accompanying the young, reveals normal feeding conditions in which only one parent is needed to obtain enough food for the developing young. The adult female murre possibly spends more time protecting the chick on the open cliff ledge or feeding it during its 3-week period in the nest (see Birkhead 1977). It may be advantageous for adult males and their fledglings to move away from the colonies, thereby reducing competi- tion with females for food. Two Ancient Murrelet parents, however, may be needed to locate and obtain enough food for both young. The observations in Table 1 suggest that family groups are isolated from one another and are dispersed widely at sea. This isolation contrasts with the gregarious habits of Ancient Murrelets in winter and at 28 YOUNG ANCIENT MURRELETS breeding colonies. In a precocial species such as the Ancient Murrelet, if the food supply is uniformly distributed, adults and their young should remain rather evenly spaced throughout their environment. Avoidance of other groups would have the advantage of not attracting predators. Capture rates should average higher if another group has not foraged recently over the same area. On the other hand, when food is highly clumped, distribution of adults and young should reflect the uneven distribution of the food supply (Lack 1968, Orians 1971). ACKNOWLEDGMENTS We extend our thanks to those observers who provided unpublished observations. The Ecological Reserves Unit, Department of Environ- ment, Victoria, British Columbia, provided support during field work. Sealv’s work on murrelets was funded by grants from the National Science Foundation for work in Systematic and Evolutionary Biology at the University of Michigan and by the Frank M. Chapman Memorial Fund of the American Museum of Natural History 7 . LITERATURE CITED Ainley, D. G. 1976. The occurrence of seabirds in the coastal region of California. West. Birds 7:33-68. Ashmole, N. P. 1971. Sea bird ecology and the marine environment. Pages 223-286 in D. S. Farner and J. R. King eds. Avian biology, Vol. 1. Academic Press, New York. Bartonek, J. C. and D. D. Gibson. 1972. Summer distribution of pelagic birds in Bristol Bay, Alaska. Condor 74:416-422. Bedard, J. 1969a. Feeding of the Least, Crested, and Parakeet auklets around St. Lawrence Island, Alaska. Can. J. Zool. 47:1025-1050. Bedard, J. 1969b. Adaptive radiation in Alcidae. Ibis 111:189-198. Birkhead, T. R. 1977. Adaptive significance of the nestling period of Guillemots Uria aalge. Ibis 1 19:544-549. DeWeese, L. R. and D. W. Anderson. 1976. Distribution and breeding biology of Craveri’s Murrelet. San Diego Soc. Nat. Hist., Trans. 18(9): 155- 168. Drent, R. H. and C. J. Guiguet. 1961. A catalogue of British Columbia sea-bird colonies. Occ. Pap. Brit. Col. Prov. Mus. No. 12. Dodimead, A. J., F. Favorite and T. Hirano. 1963. Review of oceanography of the subarctic Pacific region. Int. N. Pac. Fish. Comm. Bull. 13:1-195. Eppley, Z. A. and D. B. Schwartz. 1976. The breeding biology ofXantus* Murrelet. J. LIndergrad. Res. Biol. Sci- , Univ. Calif. Irvine 6:240-250. Grinned, J. and A. H. Miller. 1944. The distribution of the birds of California. Pac. Coast Avif. 27. Guiguet, C. J. 1953a. The Ancient Murrelet. Victoria Nat. 10:68-70. Guiguet, C. J. 1953b. An ecological study of Goose Island, British Columbia, with special reference to mammals and birds. Occ. Pap. Brit. Col. Prov. Mus. No. 10. Hatler, D, F,, R. W. Campbell and A. Dorst. 1978. Birds of Pacific Rim National Park. Occ. Pap. Brit. Col. Prov. Mus. No. 20. Lack, D. 1968. Ecological adaptations for breeding in birds. Methuen, London. Martin, P. W. and M. T. Myres. 1 969. Observations on the distribution and migration of some seabirds off the outer coasts of British Columbia and Washington State, 1946-1949. Syesis 2:241-256. 29 YOUNG ANCIENT MURRELETS Orians, G. H. 1971. Ecological aspects of behavior in birds. Pages 513-546 in D. S. Farner and J. R. King eds. Avian biology, Vol. I. Academic Press, New York. Ricklefs, R. E. 1973. Patterns of growth in birds. II. Growth rate and mode of development. Ibis 115:177-201. Scott, J. M. 1973. Resource allocation in four syntopic species of marine diving birds. Ph.D. thesis, Oregon State Univ., Corvallis. Sealy, S. G. 1 972. Adaptive differences in breeding biology in the marine bird family Alcidae. Ph.D. thesis, Univ. Michigan, Ann Arbor. Sealy, S. G. 1973. Adaptive significance of post-hatching developmental patterns and growth rates in the Alcidae. Ornis Scandinavica 4:113-121. Sealy, S. G. 1975a. Egg size of murrelets. Condor 77:500-501. Sealy, S. G. 1975b. Feeding ecology of the Ancient and Marbled murrelets near Langara Island, British Columbia. Can. J. Zool. 53:418-433. Sealy, S. G. 1976. Biology of nesting Ancient Murrelets. Condor 78:294-306. Speich, S. and D. A. Manuwal. 1974. Gular pouch development and population structure of Cassin’s Auklet. Auk 91:291-306. Vermeer, K. and R. Vermeer. 1975. Oil threat to birds on the Canadian west coast. Can. Field-Nat. 89:278-298. Vermeer, K., K. R. Summers and S. Bingham. 1976. Birds observed at Triangle Island, British Columbia, 1974 and 1975. Murrelet 57:35-42. Willett, G. 1915. Summer birds of Forrester Island, Alaska. Auk 32:295-305. Willett, G. 1 920. Additional notes on the avifauna of Forrester Island, Alaska. Condor 22:138-139. Accepted 1 1 December 1978 ^^Ancierit" TViurreJet'" Sketch by Narca Moore 30 INCREASING POPULATIONS OF RING-BILLED AND CALIFORNIA GULLS IN WASHINGTON STATE MICHAEL R. CONOVER, Department of Zoology, Washington State University, Pullman, Washington 99164 (present address: Department of Ecology and Climatol- ogy, Connecticut Agricultural Experiment Station, Box 1 106, New Haven, Connecti- cut 06504) BRUCE C. THOMPSON, Washington Department of Game, 600 N. Capitol Way, Olympia, Washington 98504 RICHARD E. FITZNER, Ecosystems Department, Battelle Northwest, P.O. Box 999, Richland, Washington 99352 DON E. MILLER, Department of Zoology, Washington State University, Pullman, Washington 99164 The number of breeding Ring-billed Gulls (Larus delaivarensis) has been rapidly growing in at least one region of their broad range, that of the Great Lakes (Ludwig 1974). Several factors have been proposed to account for this increase, including greater availability of nesting sites, introductions of exotic fish, increased utilization of insects by the gulls and decreased human predation (Ludwig 1974, Jarvis and Southern 1976). In this report we examine the status of the Ring-billed Gull in the State of Washington, comparing current and past records of breeding colonies in the state. We also provide similar information on the California Gull (L. califomicus) which often occupies colony sites with the Ring-billed Gull. At the turn of the century the Ring-billed Gull was considered an infrequent visitor in Washington State and a sighting was considered worth reporting (Dawson and Bowles 1909). The first breeding record in Washington was apparently Kitchin’s (1930) sighting at Moses Lake. Slightly later, Decker and Bowles (1932) reported a colony of California Gulls nesting on the Columbia River, somewhere in Benton County. The distributional list of Hudson and Yocom (1954) mentioned four colonies: on Moses Lake (both species), Sprague Lake (Ring- billed Gull), Twelve-mile Slough (Ring-billed Gull) and the Columbia River near Pasco (Ring-billed Gull). By 1954 the Moses Lake colony apparently had been abandoned, and a new colony started on the sand-dune islands of the Potholes Reservoir, immediately south of Moses Lake (Johnsgard 1954). In 1956 two new mixed-species colonies were established on the Columbia River at Ringold and Coyote Rapids, presumably from the abandonment of the Pasco colony (Hanson 1963). That same year another colony consisting entirely of Ring-billed Gulls was found on the Columbia River near Boardman, Oregon (Broadbooks 1961). Hence by the late 1 950s at least five, and perhaps six, active colonies existed in the state. Unfortunately, data on colony sizes are available for only three of the colonies, the Boardman colony containing 300 breeding adults Western Birds 10: 31-36, 1979 31 GULLS IN WASHINGTON (Broadbooks 1961), Ringold colony 2,072 (Hanson 1963) and the Coyote Rapids colony 2,310 (Hanson 1963) averaging 1,561 per colony. Table 1 lists all former known Ring-billed and California gull colonies in the state that are now abandoned. To obtain data on the current population, we surveyed the Ring- billed and California gulls in the State of Washington and along the adjacent Columbia River during the 1976 and 1977 breeding seasons. The number of breeding birds was determined by a direct count of nests in all but one colony (Three-mile Canyon colony) where the number of nests was estimated using a strip census method. Location, number of breeding adults, and year of first establishment for 1 1 currendy active colonies are presented in Table 2. During our survey we located nine active Ring-billed and California gull colonies ranging in size from 254 to 8,760 breeding adults and averaging 2,942 per colony. In addition, Penland and Jeffries (1977) reported that 44 Ring-billed Gulls nested in two areas along the Washington coast. Altogether at least 17,468 Ring- billed and 9,052 California gulls nested in the state in 1977. Conceivably the present colonies are smaller in size than previously; however, the average number of breeding adults per colony calculated from our counts is above the largest of the three late- 1 950 colonies where numbers were reported. Indications are, therefore, that the total breeding population in the state has continued to rise during the last 2 decades. Notably, of the 1 1 current colonies, only the colonies on Sprague Lake and Potholes Reservoir were mentioned by earlier authors. Moreover, 8 of 10 colonies existing earlier than the mid-1960s have since been abandoned. Evidendy Ring-billed and California gulls shift colony sites ffequendy. Ring-billed Gulls also are expanding their breeding range in the Northwest. In recent years they have started breeding along the Washington coast (Penland and Jeffries 1977) and in British Columbia (Merilees 1974). Also, in 1976 and 1977, we observed 20-40 Ring-billed Gulls unsuccessfully attempting to nest in northern Idaho on a small, periodically-flooded island in Lake Coeur D’Alene. We can only speculate on the factors underlying the population increase of Ring-billed and California gulls in Washington since the early 1900s. Ludwig (1974) suggested that a similar population explosion of Ring-billed Gulls in the Great Lakes region resulted from a period of lowering water levels, which increased the nesting habitat, and from the establishment of alewives in the Great Lakes, which increased the gulls’ food resources. It is unlikely that either of these reasons can account for the increase of Ring-billed and California gulls in Washington. In most parts of the state nesting habitat has been reduced because of the damming of the rivers. There also has been no introduction of exotic fish which could have substantially increased the food available to gulls. 32 Table 1. Ring-billed and California gull colonies in Washington State that are now abandoned. GULLS IN WASHINGTON 05 u u CO !hO ui d 01 2 *u f 3 E & c c -c CO LO d 00 co p o' OJ P -X OJ N k— 1 c 0 O c Oi G CO IT) O O E re 1 — 1 £ E Os W V 3 O -Q T 3 U 3 0 u c 0 c 0 G O 0 u c 0 0 u c g re n 2 c /5 -S in c c« C If) u m C u IE cj O u qj 3 ' re D re qj 4—1 O 03 P Oj X X a O- E a 5 £ cd "T K E q £ o O u CO s~ o d CM >o CD »o o> X o u a. a. eg Cl CO CT) >- 2 O J o u < [D >- Q W E co J 03 £ GO W o 05 05 ^0 co i—l f, 10 to © CO © H 2 w co W Pi Ph co W U w Oh CO ■a © -O be _c 2 "O u be c IB -a m c ii bje^: G Ci 2 <-> *8 .a — c -9 <1 bc-g C re 2 u ■B .sa = c •r re f <° be^o c re 5 u "O © be _C 2 ■S.s 03 C ■3 c -Q o * C+H be 33 c re >- 2 O J o u Uh O 2 O HH h < U O J Q 2 < w 2 < 2 re D > 5 £ o re be 13 Si E O 3 o U c re -C T 3 U d O P 3 6 £ £ u S t- c 0 1 >- c o o c re E "O re re o 03 a, 3 E u D _> u D 2 D (-H _> be re 3 qj > 2 3 re E ^ cd J5 = 2 E 0 3 u 2 £ 3 O u > -£ > 0 u u D r- 1 c *re 0 0 S 1 '3 >, « C 2 J2 >. 0 3 u 2 re u 3 2 1/1 c v ‘E -5 U — ou, re c O ! > . C o 6 o H , , <« CJ re Oh 0 7^ u fa w re re d o, c c O 1 >, c J2 "C u & "D -S O & be u c re •-3 D Pi C re 1’ J3 O a c u 2 D D -C J= 3 o D X re J D o 2 D U O c c O fa CJ LD - a T3 3 c 0 0 0 0 0 u 5. E 0 D re _x CO . -X re hJ V CO >. qj a 1- E 0 .> 0 u o< u in V in 0 2 u O C qj — 1 ro u C HJ c ' re V d 2 jz o H c 33 e Slough Colony - 12 km Ring-billed Before 1954 Unknown Hudson and Yocom 1954 GULLS IN WASHINGTON Table 2. Ring-billed and California gull colonies in Washington State during the 1977 breeding season. NAME AND LOCATION SPECIES AND NUMBER YEAR COLONY OF COLONY OF BREEDING ADULTS ESTABLISHED Little Memaloose Island Colony- On the Columbia River 5 km upstream from the Dalles Dam. California 856 Unknown Miller Rocks Colony- On the Columbia River 3 km upstream from the Deschutes River. Ring-billed 960 California 60 Unknown Three-mile Canyon Colony- On the Columbia River between Arlington and Boardman, Oregon. Ring-billed 4380 California 4380 After 1968 Richland Colony- On the Columbia River by the municipal boat ramp in Richland. Ring-billed 678 California 772 1970 Island 18 Colony- On the Columbia River 4-5 km upstream from the Richland colony. Ring-billed 1726 California 426 1971 Cabin Island Colony- On the Columbia River 1 km upstream from Priest Rapids. Ring-billed 250 California 4 Early 1970s Banks Lake Colony- On the southern end of Banks Lake. Ring-billed 5436 California 1690 Early 1970s Sprague Lake Colony- On the western end of Sprague Lake. Ring-billed 1702 California 428 Late 1940s Potholes Reservoir- On several sand dune islands in the Potholes Reservoir. Ring-billed 2292 California 436 1952-1953 Whitcomb Island Colony- In Grays Harbor {Peniand and Jeffries 1977). Ring-billed 4 1976 Willapa Bay Colony- Ring-billed 40 First located in 1976 In Willapa Bay (Peniand and Jeffries 1977). Table 3. Population, total cropland acreage, and irrigated cropland acreage in eastern Washington since 1900. HUMAN TOTAL IRRIGATED YEAR POPULATION CROPLAND CROPLAND 1900 191,513 - - 1920 437,191 5,578,307 - 1940 509,845 6,361,946 - 1950 695,553 6,832,541 716,340 1960 813,857 4,033,226 1,093,709 1970 839,018 7,339,039 1,189,361 34 GULLS IN WASHINGTON Jarvis and Southern (1976) have suggested that feeding on insects, particularly air-borne ones, is a recent innovation by the Ring-billed Gull that, in part, explains the population increase in the Great Lakes region. However, the taking of insects may not be a recent phenomenon because Bent (1921) reported that Ring-billed Gulls commonly feed on worms and insects, and Baird etal. (1884) reported an observation of this species hawking insects. We consider the increase in Washington more likely to have resulted from decreased human predation on gulls and their eggs, and, probably more importantly, from increased food resources brought about by man’s activities. Both farming and garbage depositories probably have dramatically increased the food resources available for these two gull species, which feed in both aquatic and terrestrial habitats. In addition, the creation of many reservoirs and irrigation canals has increased the total area of aquatic habitats, perhaps increasing some of the fish and aquatic insect populations on which these gulls feed. Farming, especially irrigated farming, also has increased greatly in Washington during the past 50 years (Table 3), and some farming practices expose rodents, worms, insects and other prey that otherwise would remain concealed or inaccessible. Our observations of gulls following farm implements indicate that these gulls feed in cultivated fields and may be more adapted to do so than other birds which have more localized feeding areas. The social behavior and foraging strategies of gulls are adapted for obtaining food resources, such as fish schools, that are abundant in localized clumps but temporally unpredictable as to location. The sudden appearance of plentiful prey in variously located fields would correspond to this type of distributional pattern. The human population in eastern Washington has also increased over the last 50 years (Table 3), and several of the current colonies in the state are located near towns or cities with municipal garbage dumps. Our observations of gulls congregated at dump sites and of food items delivered by adults to their young indicate that man-processed food at least supplements the natural diet and for some individuals may be a primary food source. This research was partially funded by grants from the National Science Foundation and the Walla Walla District of the U.S. Corps of Engineers. We thank Bob J. Mickelson, Director, Washington State Department of Agriculture, for providing census record data for Table 3. LITERATURE CITED Baird, S. F., T. M. Brewer and R. Ridgway. 1884. The water birds of North America. Mem. Mus. Comp. Zool. Harvard 13:246-247. Bent, A. C. 1921. Life histories of North American gulls and terns. U. S. Natl. Mus. Bull. 113. 35 GULLS IN WASHINGTON Broadbooks, H. E, 1961. Ring-billed Gulls nesting on Columbia River islands. Murrelet 42:7-8. Dawson, W. L. and J. H. Bowles. 1 909. The birds ofWashington. Occidental Publ. Co. Seattle, Washington. Decker, F. R. and J. H. Bowles. 1932. Two new breeding colonies for the State of Washington. Murrelet 13:53. Hanson, W. C. 1963. Census of Ring-billed and California gull colonies in eastern Washington. Condor 65:163-164. Harris, S. W. and C. F. Yocom. 1952. Birds of the lower Grand Coulee and Potholes area, Grant County, Washington. Murrelet 33:18-28. Hudson, G. E. and C. F. Yocom. 1 954. A distributional list of the birds of southeastern Washington. Res. Stud. State Coll. Washington 22:1-56. Jarvis, W. L. and W. E. Southern. 1976. Food habits of Ring-billed Gulls breeding in the Great Lakes region. Wilson Bull. 88:621-631. Johnsgard, P. A. 1954. Birds observed in the Potholes region during 1953-1954. Murrelet 35:25-31. Kitchin, E. A. 1930. Nesting observations at Moses Lake in May. Murrelet 1 1:55-59. Ludwig, J. P. 1974. Recent changes in the Ring- billed Gull population and biology in the Laurentian Great Lakes. Auk 91:575-594. Merilees, W. J. 1974. Ring-billed and California gull nesting colony in south central British Columbia. Can. Field-Nat, 88:484-485. Penland, S. T. and S.J. Jeffries. 1977. New breeding records for the Ring-billed Guilin Washington. Murrelet 58:86-87. Accepted 22 January 1979 CATTLE EGRET IN COLORADO GARY C. MILLER, Monongahela National Forest, Richwood, West Virginia 26261 RONALD A. RYDER, Department of Fishery and Wildlife Biology, Colorado State University, Fort Collins, Colorado 80523 The ancestral breeding range of Cattle Egrets ( Bubidcus ibis) probably was Africa where the species evolved to exploit a foraging niche in the terrestrial-aquatic ecotone, later entering into its well known association with large ungulates (Siegfried 1978). The species’ ability to colonize new areas and its range extension through the western hemisphere have been well documented (Blaker 1971, Browder 1973, Crosby 1972, Davis 1960, Hancock and Elliott 1978, Lint 1962, Meyerriecks 1960, Siegfried 1978). Cattle Egrets were first noted in the continental United States in the 1940s (Palmer 1962) and generally have extended their range inland from coastal regions (Ogden 1978). Our observations plus those of others who have reported sightings of Cattle Egrets in Colorado to the Colorado Field Ornithologists have allowed us to summarize, on a smaller scale, the range extension of this species along the four major river drainages of the state, from the first reported sighting to its present status as a breeding bird (Kingery and Graul 1978). The Arkansas, Colorado, PlattefSouth Platte), and Rio Grande rivers have at least a large part of their origins within Colorado. EARLY RECORDS As shown in Table 1, the first recorded sighting of a Cattle Egret in Colorado took place in 1 964 near the South Platte River at Denver (Bailey and Ni^Hrach 1965). The next record confirmed by the Colorado Field Ornithologists Official Records Committee was from the Animas River, a tributary of the Colorado, in April 1968. Cattle Egrets were first confirmed on the Arkansas River drainage in 1 968 also, seen on different parts of the river in April and May. In May 1973 the first record from the Rio Grande drainage occurred (Reddall 1976). Nearly 9 years had elapsed between the first sighting and confirmed sightings on all of Colorado’s major river systems. Of 43 Cattle Egrets seen prior to 1977 (26 records), only 8 (3 records) occurred between 1 June and 1 September when nesting residents would be expected, and no evidence of nesting was found. Two nesting season records were of single individuals seen on one occasion each. The third was of a group numbering as many as 6, seen on several occasions between mid-August and late September 1975 at Lower Latham Reservoir on the South Platte drainage. Herman J. Griese studied that site intensively in 1975-76 and found no evidence of Cattle Egrets nesting. Thirty-one of 43 egrets seen prior to 1 977 ( 1 6 of 26 records) were on the South Platte drainage, but that drainage was probably more intensively observed than the others. Western Birds 10: 37-41, 1979 37 CATTLE EGRET IN COLORADO Table 1. Number of Cattle Egrets (Bubulcus ibis ) recorded in Colorado, 1964-1978, listed by drainage and year. Superscript indicates observations not reported to Colorado Field Ornithologists Official Records Committee. Year Drainage 1964 65-67 68 69 70 71 72 73 74 75 76 77 78 Total Arkansas 2 1 3 1 1 1 10b 19 Colorado 2 l a 2 2 C 7 Rio Grande 1 1 4 6 South Platte 1 2 4 9 8 7 8 29 d 68 Total 1 0 4 0 I 2 7 1 10 9 8 12 45 100 aBy Gustav A. Swanson, 21 May 1975 near Craig, Moffat County. bBv Bryant Will, 27 April 1978, about 15 km southwest of Campo, Baca County. cBy Warner P. Gorenzel, 23 May 1978, Brown’s Park, Moffat County, concludes sighting of 23 by Warner P. Gorenzel, 18 August 1975, Weld County. NESTING AND RECENT RECORDS In 1977 the first known nesting of a pair of Cattle Egrets in Colorado was observed at Pelican Island (40°20'N, 104°16'W, elevation 1472 m), Riverside Reservoir, near the South Platte River in Weld County (Miller 1978). The area, which received little human use and was nearly surrounded by cattle grazing lands, had been studied intensively by Miller in 1976, and visited yearly since 1962 by Ryder and Colorado Division of Wildlife personnel (Ryder and Torres 1974), and Cattle Egrets had not been seen before. Ranchers of the area expressed interest in the egrets and readily noticed them in 1977, but stated they Ptad not seen them before. We believe, therefore, that 1977 was the first year in which Cattle Egrets nested at Riverside Reservoir. As shown in Table 1, Cattle Egrets were seen in all drainages in 1977. Those sightings on the Arkansas and Colorado were made prior to 1 June, and might be considered migrants. On 6 June Miller saw six in alternate plumage at Milton Reservoir (South Platte drainage), about 30 km southwest of Riverside Reservoir. On 25 June Ryder and Mark Strong captured and banded an individual in basic plumage at Adams Lake on the Rio Grande drainage. This was the first Cattle Egret banded in the state. Cattle Egrets nested on the Rio Grande drainage of Colorado in 1977, but the fact was not revealed until 1978. In 1977 a nestling egret was banded and identified as a Snowy Egret ( Egretta thula) during the annual banding of young in a large colony of Snowy Egrets and Black-crowned Night Herons (Nycticorax nycticorax) at Russell Lakes, Saguache County. The bird, recovered in 1978, was a Cattle Egret (specimen in collections of the Department of Fishery and Wildlife Biology, Colorado State University, Fort Collins). 38 CATTLE EGRET IN COLORADO In 1978 at least two pairs of Cattle Egrets nested at Riverside Reservoir. Miller saw two adults in alternate plumage in a stand of flooded willows (Salix sp.J on 29 May, and Ryder found two nests at the same site on 11 July 1978. On 26 July those nests contained seven young Cattle Egrets. One dead adult in alternate plumage was found near one nest. Cattle Egrets may have nested in the Lower Latham or Milton Reservoir area of the South Platte in 1978. Records on 30 May and 2 July by Robert Andrews and others were from Lower Latham, and on 18 August Warner P. Gorenzel saw 23 Cattle Egrets, at least 6 of which were immatures, at a point between the two reservoirs. Lower Latham and Milton reservoirs are about 10 km apart, and both are 30 km from Riverside. Both reservoirs are fairly inaccessible to humans, contain colonies of ardeids, and are adjacent to cattle grazing areas. As shown in Table 1, Cattle Egrets were seen on all drainages in 1978. In addition to the South Platte observations previously mentioned, egrets were seen on the Arkansas drainage ( 1 0 in late April), the Colorado drainage (2 in late May), and the Rio Grande drainage ( 1 in late April, 1 in early June). The nesting status of Cattle Egrets on the Rio Grande in 1978 was not verified although at least one adult was seen in a Snowy Egret nesting colony (Walter Graul pers. comm.). EXTENSION OF KNOWN BREEDING RANGE Prior to nesting at Pelican Island in 1977, Cattle Egrets had not been known to nest along the 750 km of Platte River drainage between Riverside Reservoir and its confluence with the Missouri River. They have been seen fairly regularly as far west as Crescent Lake National Wildlife Refuge in Nebraska (Anonymous 1978) and have nested on the Missouri drainage as far west as J. Clark Salyer and Lone Lake National Wildlife Refuges in North Dakota (Rodney Schmitt pers. comm.). Prior to nesting at Russell Lakes in 1977, the northernmost known limit of nesting Cattle Egrets on the Rio Grande drainage was Elephant Butte Lake, New Mexico, first noted in 1975 (Witzeman et al. 1975). The Russell Lakes record represents an inland range extension of 550 km. Although still not known to nest on the Arkansas and Colorado drainages in Colorado, Cattle Egrets nest near these rivers outside the state. In 1974 they nested as far west on the Arkansas drainage as Cheyenne Bottoms, Kansas, 330 km downstream from the Colorado border (Martinez and Schwilling 1974). In the vicinity of the Colorado River drainage, they have nested as far inland as the north end of the Salton Sea in California (Kelso 1979). SUMMARY The first confirmed sighting of a Cattle Egret in Colorado occurred in 1 964, but nearly 9 years elapsed before they were recorded on all of the 39 CATTLE EGRET IN COLORADO major river systems of the state. In 1977, 12 nesting seasons after the initial sighting, they were first confirmed as nesting in the state, doing so on the South Platte and Rio Grande drainages. Cattle Egrets again nested on the South Platte in 1978, but their status on the Rio Grande was not ascertained, and Cattle Egrets were still not known to nest on the Arkansas and Colorado River drainages. Between September 1964 and September 1978, 100 Cattle Egrets were noted in 39 Colorado records. The observation of nesting at Riverside Reservoir in 1 97 7 was the first known for Cattle Egrets on the entire Platte River system from its confluence with the Missouri River and represents a known breeding range extension of 750 km inland. The Russell Lakes nesting represented a 550 km inland extension of known breeding range along the Rio Grande drainage. Cattle Egrets nest on the Arkansas River drainage in Kansas and near the Colorado River in California, and we may expect their breeding range extension to continue upstream to Colorado in the future. ACKNOWLEDGMENTS The observations and assistance of Robert Andrews, Warner P. Gorenzel, HermanJ. Griese, MarkA. Strong, Gustav A. Swanson, Bryant Will and many other observers who reported Catde Egret sightings were instrumental in making this study. Research activities of the senior author were funded by Colorado State University, Colorado Division of Wildlife and the National Audubon Society. The cooperation of the Colorado Field Ornithologists, Riverside Club Company and Bureau of Land Management is appreciated. LITERATURE CITED Anonymous. 1978. 1977 (twentieth) fall occurrence report. Nebraska Bird Rev. 46(2):23-35. Bailey, A. M. and R. J. Niedrach. 1965. Birds of Colorado. Vol. 1. Denver Mus. Nat. Hist., Denver. Blaker. D. 1971. Range expansion of the Cattle Egret. Ostrich Suppl. 9:27-30. Browder, J. A. 1973. Long-distance movements of Cattle Egrets. Bird-Banding 44:158-170. Crosbv, G. T. 1972. Spread of the Cattle Egret in the western hemisphere. Bird- Banding 43:205-21 1. Davis, D. E. 1960. The spread of the Cattle Egret in the United States. Auk 77:421- 424. Hancock, J. andH. Elliott. 1978. The herons of the world. Harper & Row, New York. Kelso, S. A. 1979. First records of Cattle Egrets nesting in northern California. West Birds in press. Kingerv, H. E. and W. D. Graul. 1978. Colorado bird distribution latilong study. Colorado Field Ornithol., Denver. 58 pp. Lint, K. C. 1962. Cattle Egret expands range. Auk 79:483. Martinez, E. F. and M. D. Schwilling. 1974. Cattle Egret nests at Cheyenne Bottoms. Bull. Kansas Ornithol. Soc. 25(3): 18-19. 40 CATTLE EGRET IN COLORADO Meyerriecks, A. J. 1960. Success story of a pioneering bird. Nat. Hist. 69(7):46-57. Miller, G. C. 1978. Riverside Reservoir, Colorado. 1977. Nesting season report. C.F.O. Journal 33:19-20. Ogden, J. C. 1978. Recent population trends of colonial wading birds on the Atlantic and Gulf coastal plains. Pages 137-153 in A. Sprunt IV, J. C. Ogden and S. Winckler, eds. Wading birds. Res. Rep. 7, Natl. Audubon Soc., New York. Palmer, R. S. 1962. Handbook of North American birds. Vol. 1. YaleUniv. Press, New Haven, CT, Reddall, j. 1976. Colorado Field Ornithologists Official Records Committee report 1972 through 1975. West. Birds 7:81-97. Ryder, R. A. and J. R. Torres. 1974. Research and management of some nongame waterbirds in Colorado. J. Colorado- Wyoming Acad. Sci. 7(5):76. Siegfried, W. R. 1978. Habitat and the modern range expansion of the Cattle Egret. Pages 315-324 in A. Sprunt IV, J. C. Ogden and S. Winckler, eds. Wading birds. Res. Rep. 7, Natl. Audubon Soc., New York. Witzeman, J., J. P. Hubbard and K. Kaufman. 1975. Southwest region. Am. Birds 29:1014-1018. Accepted 24 February 1979 Sketch by Narca Moore 41 Ring-billed Gull ■ l.arm dehuvarensis ; San Diego. California. April 1079. Yashica T. L.. Electro “X". Vivitar 70-150 Zoom. 1 / 5 0 0 r h sec. at fS. Photo b\ Bill Millington 42 NOTES ROBBERY OF NESTING MATERIALS BY THE CALLIOPE HUMMINGBIRD JONATHAN L. ATWOOD, 2218 San Anseline #6, Long Beach, California 90815 On 27 May 1978, while looking for birds in the White Mountains near Tollhouse Springs, Inyo County, California, I located an active Blue-gray Gnatcatcher (Polioptila caerulea) nest which was placed approximately 1 m high near the top of a low sagebrush (Artemesia tndentata) shrub. While Judy Atwood, Thomas LaRoque and I were observing the female gnatcatcher on the nest, we were rather startled to see a female Calliope Hummingbird (Stellula calliope) fly to the gnatcatcher nest and, while hovering, remove nesting material from the outside of the nest cup. Although the female gnatcatcher appeared to watch the pilfering hummingbird during the several seconds it was present at the nest, the gnatcatcher continued to incubate and made no effort to drive the hummingbird away. The male Blue-gray Gnatcatcher was not observed near the nest until several minutes after the hummingbird had departed. We flushed the female gnatcatcher from her nest and found three eggs in it. The Calliope Hummingbird’s direct, unhesitating flight to the gnatcatcher nest, despite our presence within 1 m of the site, suggests that the hummingbird had previously made similar piratic visits. Both species use similar materials in the construction of their nests (Harrison 1978). Considering the energy expenditure involved in gathering nest-building materials, it is perhaps not surprising that the hummingbird would make repeated thefts from this concentrated and apparently poorly defended source of nesting materials. Welty (1962) summarized a number of examples of intraspecific robbery of nesting materials, and cited this behavior as being quite common among colonially nesting birds such as penguins, cormorants, pelicans, storks and Rooks ( Cotvus jrugilegus). Brown (1963) noted frequent intraspecific nest robbing in cooperatively breeding Mexican Jays (Aphelocoma ultramarina), and Biaggi (1955) observed similar behavior in Bananaquits (Coereba flaveola ). Bent (1940) did not mention any such piratic behavior by North American hummingbird species. However, Wagner (1945) regularly observed a Mexican hummingbird, the Green Violetear ( Colibri thalassinus ) , constructing its nest with material stolen from active, but unattended, nests of the White-eared Hummingbird (Hylocharis leucotis); sometimes such behavior completely destroyed the latter species’ nest. In summary, intraspecific robbing of nesting materials has been reported relatively frequently, and instances of intrafamilial (Trochilidae) theft have also been observed. The robbery of nesting materials from an active Blue- gray Gnatcatcher nest by a female Calliope Hummingbird represents an interordinal (Apodiformes and Passeriformes) example of such behavior. LITERATURE CITED Biaggi, V. 1 955. The Puerto Rican Honeycreeper, Coereba flaveola portoricensis (Bryant). Spec. Bull., Univ. Puerto Rico Agric. Stn. Bent, A. C. 1940. Life histories of North American cuckoos, goatsuckers, humming- birds and their allies. U.S. Natl. Mus. Bull. 176. Western Birds 10: 43-44, 1979 43 NOTES Brown, J. L. 1963. Social organization and behavior of the Mexican Jay. Condor 65:126-153. Harrison, C. 1978. A field guide to the nests, eggs and nestlings of North American birds. C. Harrison, Cleveland, Ohio. Wagner, H. O. 1 945. Notes on the life history of the Mexican Violet-ear. Wilson Bull. 57:165-187. Welty, J. C. 1962. The life of birds. W'. B. Saunders Co., Philadelphia. Accepted 19 April 1979 RAPTOR RESEARCH FOUNDATION ANNUAL MEETING The annual meeting of the Raptor Research Foundation will be held 9-12 November 1979 at U.C. Davis Tennis Club, Davis, California. The meeting will in- clude a two-day symposium on California raptors, a day of workshops, and two days of general papers and invited lecturers. Non-members wishing to receive registration and agenda information can write to David L. Harlow, U.S. Fish and Wildlife Service, Sacramento Endangered Species Office, 2800 Cottage Way Room W-2527, Sacramento, CA 95825. COLOR-MARKED CANADA GEESE Plastic neck collars have been put on 1000 Canada Geese on their breeding grounds in northeastern California to more accurately determine the relationship between local breeding areas and wintering grounds. The collars are red with black numerals, a K followed by three digits. Any reports of these collared birds, whether or not the numbers can be read, will be appreciated. Please send reports to: California Department of Fish and Game, 1416 Ninth St., Sacramento, CA 95814 (916-445- 6896) or P. O. Box 758, Gridley, CA 95948 (916-846-3569). All reports will be acknowledged. WFO ANNUAL MEETING 16 - 18 February 1980 Santa Barbara Natural History Museum, Santa Barbara, California Don’t miss it! 44 NOTES FIRST RECORDS OF THE RACE SCOTTII OF THE RUFOUS-CROWNED SPARROW IN CALIFORNIA J. V. REMSEN, JR., Museum of Zoology, Louisiana State University, Baton Rouge, Louisiana 70893 STEVEN CARDIFF, San Bernardino County Museum, 2024 Orange Tree Lane, Redlands, California 92373 On 22 May 1976 Remsen heard a singing Rufous-crowned Sparrow (Aimophila ruficeps) at 6000 ft (1825 m) in Live Oak Canyon, New York Mountains, northeastern San Bernardino County', California, about 1 9 km from the Nevada border. Attempts to see the bird failed. On 28 and 29 July 1976 Remsen returned to the area and again located a Rufous-crowned Sparrow, singing from the same slope as in the May observation. This time the bird was seen and studied in detail (McCaskie 1976). In late May 1977 at least three singing birds were found in the Keystone Canyon- Live Oak Canyon area of the New York Mountains by Stephen F. and Karen L. Bailey, Cardiff and Remsen. The authors found one still present on 20 June 1977, when Cardiff succeeded in obtaining a specimen (male with enlarged testes; San Bernardino County Museum 30001). It was subsequently identified as A. r. scottii by Ned K. Johnson and Remsen by comparison with the large series of North American races of this sparrow at the Museum of Vertebrate Zoology. The dates of occurrence and consistent presence of singing birds at a single locality indicate local nesting, although no direct evidence was obtained. This is the first record from California of A. r. scottii, which breeds from northwestern and north-central Arizona and southwestern New Mexico south to south-central Arizona, northeastern Sonora, and northwestern Chihuahua (AOU Check-list 1957; Phillips, Marshall and Monson 1964). Small populations of scottii have also been found in the Zion area of southwestern Utah (Wauer 1965, Hayward et al. 1976), and there are several sight records from southern Nevada (C. S. Lawson pers. comm.), presumably of scottii. There have been two previous sight and one photographic record of Rufous-crowned Sparrows from east of the Sierra Nevada in California: one photographed on 25 Nov. 1972 by E. H. and Donna Johnson on the trail to Crystal Spring (about 43 km southwest of Live Oak Canyon) near the headquarters of Mitchell Caverns State Park, Providence Mountains, San Bernardino Co. (photos on file at San Bernardino Co. Museum); two in a canyon just north of the headquarters of Mitchell Caverns State Park on 25 March 1975 by Steve Forsell (McCaskie 1976); and one at Scotty’s Castle, Death Valley National Monument, Inyo Co., on 8 May 1974 by Richard Stallcup (McCaskie 1974). The subspecies involved in these sightings is unknown, but scottii is the most likely. The other races occurring in California ( ruficeps , canescens and obscura) are highly sedentary and have never been recorded east of the Sierra (Grinnell and Miller 1 944). The race rupicoia , a southwest- ern Arizona form darker and grayer than scottii , could also potentially occur in California. In the Live Oak Canyon- Keystone Canyon area. Rufous-crowned Sparrows were found singing from 5440 to 6000 ft (1650 to 1825 m) on steep slopes with open Singleleaf Pinyon (Pinus monophylla) woodland, scattered, small, rock outcrops, and open areas with patches of grass 30-100 cm in height. A sparse layer of small shrubs was irregularly distributed on the slopes. In the gullies at the foot of the slopes were dense thickets of Scrub Oak (Quercus dumosa). Canyon Live Oak (Quercus chrysolepis ) , Desert Almond (Prunus fasciculata) , and Ashy Silk-tassel (Garrya flavescens). Most observations were on south- facing slopes. Permanent water was found within 1 km at Keystone Spring and Live Oak Spring. The most common breeding birds at this locality were (in approximate descending order of abundance): Bewick’s Wren (Thryo- Western Birds 10: 45-46, 1979 45 NOTES manes beunckii), Blue-gray Gnatcatcher ( Polioptila caerulea). Plain Titmouse (Parus inomatus), Bushtit (Psaltriparus minimus ), Gray Vireo (Vireo vicinior) , Black-throated Gray Warbler (Dendraica nigrescens) and Scrub Jay (Aphdocoma coerulescens) , We have spent hundreds of hours in other areas of the New York Mountains and the adjacent Mid Hills without finding Rufous-crowned Sparrows. R. Kentjohnson (pers. comm.) spent over 3 months in the nearby Granite Mountains and did not see this species, nor have moderate amounts of field work in the Clark and Kingston ranges to the north of the New York Mountains by Ned K. Johnson, the authors, and many others produced any records. Thus we are reasonably certain that the Rufous-crowned Sparrow is not present, or at least not widespread, elsewhere in the region, although little informa- tion is available from the Providence Mountains, the location of two of the previous records. Two possible explanations for the apparent restriction of Rufous-crowned Sparrows to the Live Oak Canyon- Keystone Canyon area are: (1) this is the only area suitable for this species, and (2) this species has only recently begun to colonize the region. We do not favor the first hypothesis. Habitat seemingly identical to that on the slopes of these canyons is widespread throughout the mountain ranges mentioned above as well as elsewhere in the New Yorks. Many of these localities have water permanently available at springs. Live Oak and Keystone canyons do have extensive patches of oaks, which are not present at most other localities; however, other canyons with oaks, such as Sagamore, Caruthers and Fourth of July, all in the New York Mountains, lack Rufous-crowned Sparrows. Furthermore, this species was never noted in the oaks themselves. Recent colonization seems to be a more plausible explanation. Cardiffhad visited this area during May and June several times during the previous 10 years without noting this species. Several other species of southwestern birds are currently in the process of extending their ranges northward and westward (Johnson and Garrett 1974), and the Rufous-crowned Sparrow may be part of this general pattern. Perhaps it is not coincidental that the Live Oak Canyon-Keystone Canyon area is at the extreme eastern edge of the New York Mountains, making it the closest locality in California to source populations in Arizona. We thank Ned K. Johnson for aid in subspecific identification of the specimen, and we are grateful to H. Douglas Pratt and Alan M. Craig for comments on the manuscript. Field work in northeastern San Bernardino County was funded by the Bureau of Land Management through Kristin H. Berry. LITERATURE CITED American Ornithologists’ Union. 1957. Check-list of North American birds, 5th ed. Am. Ornithol. Union, Baltimore, MD. Grinnell, J. and A. H. Miller. 1944. The distribution of the birds of California. Pag. Coast Avif. No. 27. Hayward, C. L., C. Cottam, A. M. Woodbury and H. H. Frost. 1976. Birds of Utah. Great Basin Nat. Mem. No. 1. Johnson, N. K. and K. L. Garrett. 1974. Interior bird species expand breeding ranges into southern California. West. Birds 5:45-56. McCaskie, G. 1974. The spring migration. Southern Pacific Coast region. Am. Birds 28:851-854. McCaskie, G. 1976. The nesting season. Southern Pacific Coast region. Am. Birds 30:1002-1005. Phillips, A., J. Marshall and G. Monson. 1964. The birds of Arizona. Univ. Arizona Press, Tucson. Wauer, R. H. 1965. Wintering Rufous- crowned Sparrows found in Utah. Condor 67:447. Accepted 15 March 1979 46 REVIEW The Complete Outfitting 8c Source Book For Birdwatching. Michael Scofield. 1978. 192 p. The Great Outdoors Trading Company, Marshall, California. $6.95 paper; $12.95 hardcover. This good basic source book covers six major categories: history, equipment, publications (books and periodicals), clubs and organizations, best birding sites and tours and expeditions. Its appendices list zoos and natural history museums, rare bird alert phone numbers, birds’ favorite plants, a birdlist based on the AOU check-list and specifications for building bird houses. Its casual, conversational style is entertaining, and it is amply illustrated with black-and-white photographs and etchings. One of the book’s more valuable features is its basic equipment section which covers binoculars, scopes, telephoto lenses, tripods, tape recorders and microphones. Explanations of criteria used in comparing different models are very lucid and helpful. Interna] workings of binoculars, scopes and lenses are brieflv explained. Buying tips are offered. Birders traveling in North America and abroad will be pleased with the list of bird- related organizations, which details activities and publications of each group as well as giving a local contact person, address and phone number. Covered are 38 states, 8 Canadian provinces and 23 foreign countries representing all continents. Also for the traveling birder, the tour and expedition section discusses how to choose a tour and lists in detail tours to all continents. Unfortunately, this otherwise excellent book is marred by a few glaring instances of misleading statements and misinformation: e.g., “songbirds and hawks attack owls in the daytime - they know he can’t see.” Omissions also occur (though the compilers made every effort to be complete), usually because organizations failed to respond to queries. However, I would hope that a next edition includes such listings as Robbins’ field guide Birds of North America , Pentax telephoto lenses, Denver Museum of Natural History under museums, and groups such as Colorado Field Ornithologists. The section on birding sites is good for its scope. Addresses and phone numbers are listed for further information on each site, and reference books are given for those desiring greater coverage. Unfortunately, this section could also benefit from more thorough research. The description of Aransas Refuge in Texas alerts the birder to watch for Sandhill Cranes, but makes no mention of Aransas’ star attraction, the Whooping Crane. Also most visitors to Hawaii Volcanoes National Park will be interested in other birds than the Cardinal and House Finch, two of the three species listed. Occasional omissions and misinformation aside, The Complete Outfitting & Source Book for Birdwatching is the most complete source book available and is a valuable reference addition to birders’ libraries. I particularly commend its ethical and responsible attitude. The book points out that plaving a tape near nesting birds mav cause the parents to desert, mentions bits of birding etiquette, and generally fosters concern and respect for birds and our mutual environment. -Narca A. Moore Western Birds 10: 47, 1979 47 TREASURER’S REPORT WESTERN FIELD ORNITHOLOGISTS Cash Flow Statement 1 January 1978 to 31 December 1978 Cash on hand 1 January 1978 Gibralter Savings & Loan (savings) $3,846.92 Crocker National Bank (checking) 7,080.95 RECEIPTS Membership $9,008.47 Boat Trips 7,144.50 Annual Meeting - 1978 1,431.05 Special Publications (1) 1,000.00 Back Issues 931.76 Reprints 764.84 Interest 469.33 Advertising 70.00 Sales Tax Received 52.12 Donations 25.00 DISBURSEMENTS Western Birds (2) $6,590.85 Boat Trips 5,438.33 Annual Meeting— 1978 1,689.27 Annual Meeting - 1979 220.00 Postage (3) 808.02 Reprints 626.56 Special Publications (1) 557.99 Miscellaneous 220.67 Promotion 144.22 Sales Tax Paid 62.88 Bird Records Committee Cash on hand 31 December 1978 Gibralter Savings & Loan (savings) $13,550.28 Crocker National Bank (checking) 1,874.96 (prepared without audit) (1) California Department of Fish & Game Report: “Species of Special Concern” (2) Includes Journal mailing costs (3) Other than Journal mailing $10,927.87 $20,897.07 $31,824.94 $16,399.70 $15,425.24 Philip P. Schaeffer, Treasurer 48 Volume 10 * Number l f ! 9?9 Fall Migration uf piurruil K.ipto^ai Pi, Diablo, GtHformi J L&inrmx C Bin ford Si$p ScU ■ Nv< Pml in- ill 5 tn.il Foml Habiu ol Tw* Cahfi nisi - Ttjm* Dwtelfl M Britts G. rfafa* Aitfrej.efe and Brooke J Atfriw 17 K 31 Cudir Egret in Colunicltt Miller /mi Rwnjfd A- Rtdtr 37 NOTES Robbery oF Nr* ling Mflirriitb by ifre CcdlTopp Hummingbird J/fflftihtin L Atwti&d 4 S ptni RffCnrd> ul rbr Knitt k of tl|r ftiifviuwnotnrd Sparrow m Culifumia / I foem&K r Jr &nd Stewm Cardiff 45 REVIEW A 'are® A. 47 Trtj_surtTs Report Philip P L Stftneffrt 4 H M&nqaEdfk^ dioidd foe ittg In AJatrftl CiSig r WiniRlll Wfi>\ Gah&khid, CA Wirh } r *ir mall rtf of ^ryir f.tiniuli In f.Wrrf-tiJViTi to H/rfrcir |hn& fc pp. Irtmico Avwblblcftl iHmiUlr Edilii-j : .tnd ik&rmt SMyrt Styk Mitn m. i lHi I'+’S .tVliSiil? fmm Arm m n- i ■ i - r u mi ol Hi«i,ngical Sorum* 1^01 Wilnhn ill- iiilriAFd. Ai iiiiyiuii. VA 2241.I 1 ? l*»r fit J.iHli. Papm are Lifted I bit arc upon fielu iruilnnf pf biftlt. that art bctli un-dri nutuMdc and useful in JFiawun. -imt t-hul 211 ake a ni/mfliifai •n-niNhisrinr Ctt fcicimbc literature* AppruprilTc Uf ra induitr d hiiuh uUrm. migrultin. NMtiu. falMvifir, ecology,. pufmlntion dynaunks, habitat rcE|idrcmctlt*, rhe effect* nZ pollution, And lecfraiLfuci. r'nr identify! ng t round recording ami ;i I i.o; . p^phlftg \ Jird.* in ihc field Pi pm of gene * j I mieteK will he Gpiwickfrd r«r^Brvile« ■i| ' ben ^eograjiiik oitgiii, hut p utrdciiiiJPiy deseed iirr pn ,ier^ dealing with Mihi’- 1 jerotnp I tied m or heating on. R(eky Mouiitijin sUsiro ami provthfcA lA’cstwanJ induduig AMi and Hawaii ( ■ijjaumi partis flf the Pacific OccAD and .Mexico; arid WeM'ern Tcxa*; l \zi r h I "rt jre raided 50 Imk rrpnr.U of r*vh pjpe; AddiUumii repriiila od photD^rfLph.* Of raw m*\ ufiouiial bird^ uiwormjva nred hv an article hur n h rupoiMl I mduding «|Knich. ttal.e, Ick^Niv and other pcilineni inform .izmo^ jdiould br tuhniriird El) Sfeplien A* Uymcm, Mm Ackley Ptoad Ukeptm, ( A M455 pi a* i - H ntchmg M ov rm cup ot 'I r>ii ng A nriv m M 1 1 rrelet Spewer G 5Vj2A and Jfc Vfofm CampHU fnertasing FupuljJicMis of Ring-hjlie*! ^iwi C^tftirnii G^tlh in WjLiii ingiDri Stau- Mu had M Cendwr, < C m^rr.