Western Birds Journal

Volume 37, No. 4

Published October 1, 2006

Issue description

Volume 37, number 4 of Western Birds, published 2006

Articles

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    ROBERT H. DAY (Author)

    SEABIRDS IN THE NORTHERN GULF OF ALASKA AND ADJACENT WATERS, OCTOBER TO MAY

    I studied the distribution and abundance of seabirds in the northern Gulf of Alaska and adjacent waters during 16 research cruises from October to May 1997–2001. I recorded 58 species of seabirds on transects, plus one off the transects. The avifauna was dominated numerically by tubenoses (50% of all birds) and alcids (29%), with much smaller numbers of larids (3%), shorebirds (phalaropes; 3%), waterfowl (2%), cormorants (1%), and loons (<1%). Five species each composed ≥5%, and collectively composed 74%, of the wintering avifauna: the Common Murre (Uria aalge; 21%), Northern Fulmar (Fulmarus glacialis; 19%), Fork-tailed Storm-Petrel (Oceanodroma furcata; 16%), Sooty Shearwater (Puffinus griseus; 11%), and Black-legged Kittiwake (Rissa tridactyla; 7%). Another nine species collectively composed ~19% of all birds, whereas the other 44 species collectively composed ~7% of all birds. I recorded from 10 to 37 species per cruise; both the number of species and total density of all birds combined decreased from October to March, then increased rapidly in April and (especially) May.

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    JAY D. CARLISLE, CHARLES H. TROST, SARAH L. STOCK, GREGORY S. KALTENECKER (Author)

    AUTUMN LANDBIRD COMMUNITIES IN THE BOISE FOOTHILLS AND OWYHEE MOUNTAINS OF SOUTHWESTERN IDAHO

    Identifying important stopover areas is a critical step in conservation and management of migratory birds, and relatively little effort has been directed toward this task in Idaho or the Intermountain West. We used mist-net captures to describe the relative abundance, species richness, and community similarity of autumn migrant landbirds in the Boise Foothills and Owyhee Mountains of southwestern Idaho, two mountain ranges separated by the Snake River Plain. We captured birds at three mist-net sites from August to October 1998. Two sites were situated in the Boise Foothills, one in deciduous mountain shrubland, the other in an adjacent willow-dominated riparian draw; the third site was at a riparian spring in the Owyhee Mountains. Capture rates for resident species, temperate-zone migrants, and irruptive migrants were highest at the Boise Foothills riparian site, whereas the Boise Foothills mountain shrubland site had the highest abundance of neotropical migrants. Species richness was highest at the two Boise Foothills sites, but at all sites diversity and evenness were similar. Among the three sites, the two Boise Foothills sites (mountain shrubland and willow riparian) had the most similar bird communities. Capture rates were high (>1 bird per mist-net hour) at all three sites, and these results demonstrate that many species of autumn migrants occur frequently in montane deciduous habitats across southwestern Idaho.

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    EDWARD R. PANDOLFINO, JEREMY KWOLEK, KIM KREITINGER (Author)

    EXPANSION OF THE BREEDING RANGE OF THE HOODED MERGANSER WITHIN CALIFORNIA

    Published records and data from the California Waterfowl Association’s program monitoring nest boxes show that the Hooded Merganser (Lophodytes cucullatus) has become a regular and widespread breeder in California. More than 100 recorded nestings between 1996 and 2004 were distributed over 20 counties and yielded more than 800 hatchlings. Nest-box data show a dramatic increase in successful nesting attempts by the Hooded Merganser over this period. Banding data show a high degree of nest-site fidelity among females. Christmas Bird Count data reveal a statistically significant increase in the winter abundance of the Hooded Merganser in California since the early 1980s. This expansion of the breeding range is probably due to some combination of increasing breeding habitat and nest boxes and an increase in the species’ population in the western portion of its range.

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    Peter Pyle (Author)

    BOOK REVIEWS: Handbook of Avian Hybrids of the World: by Eugene M. McCarthy. Oxford University Press. 583 pages, 20 black-and-white figures (15 maps, 5 charts). Hardback $94.00 (ISBN-13-978-0-19-518323-8).

    The importance of hybridism to ornithology has been debated. Certain hybrid combinations have critical implications to species conservation, for example, the swamping of the American Black Duck (Anas rubripes) and Hawaiian Duck (A. wyvilliana) by introgression with the Mallard (A. platyrhynchos). Others add insight to taxonomy and evolutionary biology, for example, contact among several closely related pairs of passerine species that have recently bridged the Great Plains. Whereas these and other cases of widespread hybridism are well studied, most avian hybrids seemingly have been produced by chance encounters, best viewed as anomalies. For the field ornithologist, such chance hybrids are at least an enlightening source of entertainment and may provoke in-depth discussions on species identification, plumage, vocalizations, molt, breeding behavior, and other aspects of avian natural history.

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    Steve N. G. Howell (Author)

    BOOK REVIEW: Birds of the World: Recommended English Names: by Frank Gill and Minturn Wright, on behalf of the International Ornithological Congress. 2006. Princeton University Press. 260 pages, Paperback plus CD, $19.95 (ISBN 0-691-12827-8).

    Language, essentially an agreement of meaning for shared sounds and written words, is the keystone of human society. Yet Great Egret, White Heron, Common Egret, Great White Egret, American Egret, Egretta alba, Ardea alba, and Casmerodius albus are all names for one species of wading bird, and all are used in books on my shelf. While persons versed in nomenclature and taxonomy can figure out this synonymy, such heterogeneity doesn’t really facilitate communication. Is there a solution? Does it really matter? Do you care?

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    STEVE N. G. HOWELL (Author)

    FEATURED PHOTO: PRIMARY MOLT IN THE BLACK-FOOTED ALBATROSS

    Molt is a critical part of every bird’s life history, but there is a limit to the rate feathers can grow, which is about 4 to 10 mm/day in large birds (Prevost 1983). Hence some large and long-winged birds may have insufficient time between breeding seasons for a complete molt of their wing feathers, particularly the primaries (Langston and Rohwer 1996, Rohwer 1999). Molt of the primaries in most birds is sequential, from the innermost (primary 1, or p1) out to the outermost (usually p10), but some variations on this theme have developed in long-winged birds, so that they can fly more efficiently during molt. For example, the molt of albatrosses involves splitting the primaries into series. In the Black-browed (Thalassarche melanophris) and Gray-headed (T. chrysostoma) albatrosses, the outer three primaries are molted every other year, and some inner and middle primaries are molted every year (Prince et al. 1993). In the Black-footed (Phoebastria nigripes) and Laysan (P. immutabilis) albatrosses, the outer three primaries are usually molted every year, along with no to all inner and middle primaries (Langston and Rohwer 1995; pers. obs.). Year-to-year differences in the extent of primary molt reflect combinations of variation in the bird’s age, breeding status, and food supply (Prince et al. 1993; Table 1).

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    SIEVERT ROHWER, ANN E. EDWARDS (Author)

    FEATURED PHOTO: REPLY TO HOWELL ON PRIMARY MOLT IN ALBATROSSES

    In the Laysan and Black-footed Albatrosses the inner and outer primaries are replaced in opposite directions, making it clear that they are part of separate molt series. Howell (2006) argues that Langston and Rohwer (1995) were wrong about the location of the division between these molt series. While Langston and Rohwer interpreted this division as lying between primaries 5 and 6 (P5/6), Howell (2006) suggests that this divide lies between P7 and 8. Howell further posits that the mode of feather replacement in the inner primary series is stepwise, meaning that multiple waves of active feather replacement sometimes proceed simultaneously through the inner primaries.