Western Birds Journal

Volume 10, No. 1

Published January 1, 1979

Issue description

Volume 10, number 1 of Western Birds, published 1979

Articles

  1. Cover image V10 (1)

    LAURENCE C. BINFORD (Author)

    FALL MIGRATION OF DIURNAL RAPTORS AT PT. DIABLO, CALIFORNIA

    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 162 individuals of 10 species of raptors in 3.17 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.

  2. Cover image V10 (1)

    DONALD M. BALTZ, G. VICTOR MOREJOHN, BROOKE S. ANTRIM (Author)

    SIZE SELECTIVE PREDATION AND FOOD HABITS OF TWO CALIFORNIA TERNS

    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, Bédard 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 strategies. 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).

  3. Cover image V10 (1)

    SPENCER G. SEALY, R. WAYNE CAMPBELL (Author)

    POST-HATCHING MOVEMENTS OF YOUNG ANCIENT MURRELETS

    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).

  4. Cover image V10 (1)

    MICHAEL R. CONOVER, BRUCE C. THOMPSON, RICHARD E. FITZNER, DON E. MILLER (Author)

    INCREASING POPULATIONS OF RING-BILLED AND CALIFORNIA GULLS IN WASHINGTON STATE

    The number of breeding Ring-billed Gulls (Larus delawarensis) 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. californicus) which often occupies colony sites with the Ring-billed Gull.

  5. Cover image V10 (1)

    GARY C. MILLER, RONALD A. RYDER (Author)

    CATTLE EGRET IN COLORADO

    The ancestral breeding range of Cattle Egrets (Bubulcus 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, Platte (South Platte), and Rio Grande rivers have at least a large part of their origins within Colorado.

  6. Cover image V10 (1)

    JONATHAN L. ATWOOD (Author)

    NOTES: ROBBERY OF NESTING MATERIALS BY THE CALLIOPE HUMMINGBIRD

    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 tridentata) 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.

  7. Cover image V10 (1)

    J. V. REMSEN, JR., STEVEN CARDIFF (Author)

    NOTES: FIRST RECORDS OF THE RACE SCOTTII OF THE RUFOUS-CROWNED SPARROW IN CALIFORNIA

    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 19 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.

  8. Cover image V10 (1)

    Narca A. Moore (Author)

    REVIEW: The Complete Outfitting & 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.