Western Birds Journal

Volume 16, No. 3

Published July 1, 1985

Issue description

Volume 16, number 3 of Western Birds, published 1985

Articles

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    JOSEPH MORLAN (Author)

    EIGHTH REPORT OF THE CALIFORNIA BIRD RECORDS COMMITTEE

    This report contains 154 records of 63 species, documented by 109 contributors. Only 18 records are unaccepted, for an acceptance rate of 88.4%, the highest since 1975. Particularly encouraging is the high number of contributors. In fact, the ratio of total contributors to total records is 0.71, the highest since the committee began. This ratio, I believe, reflects a realization on the part of many birders of the value and importance of participating in the committee review process.

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    MICHAEL D. McCRARY, ROBERT L. McKERNAN, WILLIAM D. WAGNER, ROSS E. LANDRY (Author)

    ROADSIDE RAPTOR CENSUS IN THE SAN JACINTO VALLEY OF SOUTHERN CALIFORNIA

    In recent years much emphasis has been placed on the conservation of raptors, which are generally low in numbers and tend to be highly sensitive to human activities such as shooting, pesticide use and habitat alteration (for a review see Newton 1979). Although the alteration and destruction of breeding habitat may currently be the greatest detriment to many bird species, the work of Fretwell (1977) on Dickcissels (Spiza americana) suggests that the loss of wintering habitat may, in some cases, be equally important. However, this aspect of raptor research has received comparatively little attention.

    In 1981 we initiated a 2-year fall and winter study of raptors in the San Jacinto Valley to provide baseline data on populations in southern California and to quantify the importance of this valley as a wintering area for raptors.

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    DOROTHY H. MILES (Author)

    WHITE TERNS ON OAHU PRODUCE SIBLINGS FIVE MONTHS APART

    White Terns (Gygis alba) commonly breed on remote atolls and islands in tropical and subtropical regions, including the Northwestern Hawaiian Islands (NWHI). In 1961 a pair of these seabirds was reported to be breeding at Koko Head on Oahu (Ord 1961), the only main Hawaiian Island where they have been found. Since then the terns have expanded their nesting area some 16 km to the civic center of Honolulu. Harrison et al. (1984) estimated 50–100 pairs in the main Hawaiian Islands.

    Dorward (1963) found that the White Tern was one of the few species on Ascension Island to have a distinct annual breeding season, laying about January. Individual pairs laid on the same ledge in successive seasons with an interval of close to a year. On Christmas Island in the Central Pacific Ocean Ashmole (1968) found that incubation and chick-rearing took about 5 months and molt about 5.5 to 7 months. Howell (1978) found the incubation period to be 35 days. Pettit et al. (1981) found the White Tern to be one of only two terns with prolonged incubation and to have the longest incubation in relation to its egg mass of any tern. A single egg is laid but no nest is built.

    Here I present the results of my study of White Tern breeding biology on Oahu. I describe differences occurring in individual breeding pairs; these previously undescribed differences concern the lengths of intervals between breeding which, in turn, affect the number of offspring produced in one year.

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    GARY RITCHISON (Author)

    NOTES: VOCALIZATIONS OF THE BLACK-HEADED GROSBEAK

    Although the breeding biology and singing behavior of the Black-headed Grosbeak (Pheucticus melanocephalus) have been examined (Weston 1947; Ritchison 1983a, b; 1985), little information is available concerning grosbeak vocalizations. The purpose of this note is to describe the vocalizations of the Black-headed Grosbeak and briefly indicate the context(s) in which the vocalizations were uttered.

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    DAVID HAYES (Author)

    NOTES: UNUSUAL WESTERN BLUEBIRD EGGS

    Usually bluebirds (Sialia spp.) lay unmarked light blue eggs (Bent 1949). Albinistic eggs have been reported for all three North American species (Musselman 1935, Laskey 1939, Power 1966, Eltzroth 1983), but are considered unusual. The fertility of albinistic eggs has been confirmed for the Eastern Bluebird (S. sialis; Musselman 1935, Laskey 1939) and the Mountain Bluebird (S. currucoides; Power 1966, Munro et al. 1981) but not the Western Bluebird (S. mexicana).

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    MICHAEL H. TOVE (Author)

    NOTES: FIRST UTAH RECORDS OF THAYER’S AND MEW GULLS, WITH COMMENTS ON THEIR REGIONAL DISTRIBUTION AND STATUS

    Over the last few decades, there has been a generally widespread increase in North American gull populations (e.g., see Conover et al. 1979, Am. Birds regional reports). Although this trend principally involves the commoner species, a number of extralimital species (i.e., “rarities”) also have been documented. However, the apparent increase in reported rarities exceeds that of the commoner species. This apparent increase is at least partly due to an increase in the number and expertise of field observers (see Fussell et al. 1982). A significant proportion (majority?) of these “rarities” are immature birds, notable in being difficult to identify (Fussell et al. 1982, Grant 1982, Farrand 1983). Recent identification articles (e.g. Gosselin and David 1975, Lehman 1980, Lauro and Spencer 1980) as well as the newer “sophisticated” field guides (e.g. Farrand 1983, Scott 1983) have greatly contributed to heightened observer awareness, resulting in increased discoveries of “rarities.” Thus, it should not be surprising to find that previously unrecorded species “suddenly” occur with regularity in small numbers. However, apparently sudden changes in status and distribution of a given species should be viewed with caution and, for each case, supported by a particular explanation should be provided.

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    CARROLL D. LITTLEFIELD (Author)

    NOTES: A RECORD OF PRETERRITORIAL COPULATION BY SANDHILL CRANES

    The Malheur-Harney Lakes Basin, Harney Co., Oregon, is an important traditional spring stopover area for the Pacific Flyway Population of Lesser Sandhill Cranes (Grus canadensis canadensis). Located in southeast Oregon, mowed and flooded meadows south and east of Burns provide excellent feeding, loafing, and roosting habitat for a majority of the 20,000 to 23,000 cranes in the population (Littlefield and Thompson, Proc. Crane Workshop 3:288-294, 1981). Individual birds remain in the basin from several days to a few weeks before continuing north to nesting regions in southwest Alaska.