Western Birds Journal

Volume 48, No. 2

Published April 1, 2017

Issue description

Volume 48, number 2 of Western Birds, published 2017

Articles

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    GARY H. ROSENBERG, KURT RADAMAKER, DAVID VANDER PLUYM (Author)

    ARIZONA BIRD COMMITTEE REPORT, 2010–2014 RECORDS

     In this its eighth report, the Arizona Bird Committee reviews 677 records and updates the Arizona bird list through 2014, adding seven species: the Baikal Teal (Anas formosa), Hawaiian Petrel (Pterodroma sandwichensis), Ivory Gull (Pagophila eburnea), Little Gull (Hydrocoloeus minutus), Rosy-faced Lovebird (Agapornis roseicollis, an introduced species now well established), Sedge Wren (Cistothorus platensis), and Common Redpoll (Acanthis flammea). These bring the Arizona state list to 555 species.

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    JOSEPH C. ORTEGA, CATHERINE P. ORTEGA (Author)

    AGE STRUCTURE OF ADULT BROWN-HEADED COWBIRDS IN SOUTHWEST COLORADO

     We live-trapped and banded Brown-headed Cowbirds (Molothrus ater) in La Plata County, southwest Colorado, during the breeding seasons of 1992 to 1999. We captured a total of 1034 adult males and 386 adult females. Although we could not determine the exact ages of newly captured males older than one year (after second year; ASY) and of newly captured adult females, we identified the minimum possible age of each bird captured or recaptured each year. We found that most cowbirds of either sex were 1 or 2 years old, though we recaptured some older individuals. The percentage of recaptured females ≥2 years old increased through the study but appeared to stabilize during the last three years, implying that these older individuals constituted a quarter to a third of the population. The mean estimated minimum age of adult males was significantly greater than that of adult females in 1997 but not in 1998 or 1999. The ratio of yearling to older males varied significantly by year with yearlings becoming more common in the later years of study. Incorporating the age structure of a Brown-headed Cowbird population, especially of females, may increase the utility of various models concerning host populations subjected to cowbird brood parasitism, and this information is relevant to estimating the number of cowbird eggs expected to be laid in an area during a breeding season.

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    DANIEL A. COOPER, JENNIFER MONGOLO, CHRIS DELLITH (Author)

    STATUS OF THE CALIFORNIA GNATCATCHER AT THE NORTHERN EDGE OF ITS RANGE

    At the northern edge of its range, the California Gnatcatcher has long been known to occur from eastern Ventura County east into northwestern Los Angeles County, but the current status of birds in these areas is not well understood. We review historical and recent sources of information and draw two main conclusions: first, that the California Gnatcatcher population that once existed from the lower Santa Clara River Valley in Ventura County east/upstream to Santa Paula and Simi Valley has likely contracted to the southeast. Second, that the current, consistent range of the species in Los Angeles County does not extend north of the San Gabriel Valley. The California Gnatcatcher is evidently extirpated from the San Fernando Valley and never occurred regularly in the Santa Clarita area to the northwest. Dispersing and even occasionally nesting birds in northwestern Los Angeles County have not resulted in a stable, consistent population there. Misinterpretation of seasonal movements and isolated sightings of the California Gnatcatcher here may have led to a misunderstanding of the boundaries of its normal range, as well as the misapplication of critical habitat as defined under the Endangered Species Act. As a result, we recommend that immediate conservation efforts be focused in areas where birds are conclusively known to occur, namely, the Thousand Oaks/Moorpark area of Ventura County, and that coastal sage scrub at low elevations in the Santa Clarita and especially the northeastern San Fernando Valley areas of Los Angeles County be systematically searched to locate any remaining populations.

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    ISAAC J. HELMERICKS (Author)

    FIRST RECORDS OF THE ASIAN ROSY-FINCH IN ALASKA AND NORTH AMERICA

    On 30 December 2011 I found and photographed an Asian Rosy-Finch (Leucosticte arctoa) on Adak Island, in the central Aleutian Islands, Alaska. At that time and for the next five years this bird provided the only record of the species for North America. In 2016, however, a photo surfaced of a bird that had been seen in October 2008 at Gambell, St. Lawrence Island, revealing it too to have been an Asian Rosy-Finch. Thus at the close of 2016 there were two records of this species within the political limits of Alaska and North America.

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    BRYCE W. ROBINSON, LUCAS H. DeCICCO, AARON BOWMAN, SCOTT HAUSER, JOHN M. WRIGHT (Author)

    FIRST RECORD OF THE EASTERN PHOEBE BREEDING IN ALASKA: EXTRALIMITAL BY 2000 KM

    The Eastern Phoebe (Sayornis phoebe) nests across much of North America east of the Rocky Mountains (Sinclair et al. 2003, Van Damme 2010, Weeks 2011). Although Alberta represents the western extreme of the species’ regular breeding distribution, extralimital nesting occasionally occurs west to southeastern Yukon Territory and northeastern British Columbia (Sinclair et al. 2003, Van Damme 2010). In Alaska, the Eastern Phoebe is a casual visitor with no previous nesting records (see Gibson and Withrow 2015; Table 1). Here we document the first record of the Eastern Phoebe nesting in the state of Alaska, the westernmost breeding record for the species and extralimital by 2000 km.

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    Eugene Hunn (Author)

    BOOK REVIEW: Birds of the Pacific Northwest: A Photographic Guide

    This new regional guide is one of many covering all or part of the “Pacific Northwest” (or “the Pacific Southwest” if you’re from north of the Canadian border). I confess to having felt inundated by the annual flood of new bird guides. So my first question was, “What’s new here?” The authors confront this issue head-on: “Our working concept was to fill a niche between, on the one hand, the scientifically intense state and provincial ‘Birds of …’ tomes, … and, on the other hand, the widely used North American field guides which … depict ranges and seasonal movements only at a broad continental scale (p. 6).” Their book also complements a plethora of guides limited to one or another local county and beginners’ guides to one section or another of the Pacific Northwest. This guide is definitely not just for beginners. It builds on three previously published more narrowly focused regional guides by these same authors (Birds of the Willamette Valley Region, R. W. Morse Co., 2004; Birds of the Puget Sound Region, R. W. Morse Co., 2004; and Birds of Southwestern British Columbia, Heritage House, 2010). Aversa and Opperman are based in western Washington, where they have devoted careful attention to the local avifauna for several decades each, while Cannings is of a family of highly accomplished British Columbia naturalists. They know the region and its bird life exceptionally well, which they define to include Oregon, Washington, Idaho, western Montana, and southern British Columbia from the continental divide to the continental shelf. To cover this broad region better, they enlisted advice from experts from Oregon, Idaho, and Montana to complement their first-hand knowledge.

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    PETE SOLE (Author)

    PEREGRINE FALCONS ATTACK A ROSS’S GULL IN CENTRAL COASTAL CALIFORNIA

    On 12 January 2017, Don Pendleton discovered a Ross’s Gull (Rhodostethia rosea) near Pillar Point Harbor, Half Moon Bay, San Mateo County, California. He contacted Donna Pomeroy, who joined him to help confirm the identification. They noted key identification points including the gull’s rather small size, pink blush on the breast and belly, dark spot behind the ear, small black bill, and red legs. One of Pomeroy’s photos is featured on this issue’s back cover. Over the next 3 days, hundreds of birders watched and photographed the Ross’s Gull. The gull often foraged alone in parking lots, open fields, and along California Highway 1. All reports were within a 3.5-km radius of the Half Moon Bay Airport (www.eBird.org)