Western Birds Journal

Volume 32, No. 2

Published April 1, 2001

Issue description

Volume 32, number 2 of Western Birds, published 2001

Articles

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    CHARLES T. LaRUE, LARA L. DICKSON, NIKOLLE L. BROWN, JOHN R. SPENCE, LAWRENCE E. STEVENS (Author)

    RECENT BIRD RECORDS FROM THE GRAND CANYON REGION, 1974-2000

    We report information on 100 species from the Grand Canyon region from 1974 to 2000; of these, 98 are from the Colorado River, and 18 species are new to the Grand Canyon region. We compiled new seasonal information on 33 species and breeding information on 11 species. Changes are due, among other factors, to a change in habitats resulting from the construction and operation of Glen Canyon Dam. Flow regulation from the dam increased water clarity, and numbers of many waterbirds (primarily Anseriformes) subsequently increased. For example, the Common Goldeneye did not occur in Grand Canyon before the late 1980s, but since then it has become the most abundant wintering waterfowl. Stabilization of the river's flow has also allowed the growth and expansion of riparian vegetation. Birds we believe are responding to this increase in vegetation include Bell's Vireo, Sharp-shinned Hawk, and wintering Empidonax flycatchers and sparrows. Also, there has been an increase in coverage (e.g., bird-monitoring river trips in winter).

     

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    SASHA EARNHEART-GOLD , PETER PYLE (Author)

    OCCURRENCE PATTERNS OF PEREGRINE FALCONS ON SOUTHEAST FARALLON ISLAND, CALIFORNIA, BY SUBSPECIES, AGE, AND SEX

    We summarize observations of 201 Peregrine Falcons (Falco peregrinus) at Southeast Farallon Island during the fall and winter from 1990 to 1999, categorized by age, sex, and subspecies. The northwestern subspecies (F. p. pealei) and the continental subspecies (F. p. anatum) occurred with roughly equal frequency. We recorded 10 individuals of the arctic subspecies (F. p. tundrius). During fall, adults occurred significantly earlier than immatures. Males tended to occur earlier than females, and anatumtended to occur earlier than pealei. Four to six birds per year (of both anatum and pealei) remained through the winter. Under the assumption that wintering individuals returned each year to the maximum extent possible allowed by the observed variation by age, sex, and subspecies, their survival rate was 0.78.

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    BRIAN D. C. WILLIAMS (Author)

    NOTES : LOW-ELEVATION NESTING BY CALLIOPE HUMMINGBIRDS IN THE WESTERN SIERRA NEVADA FOOTHILLS

    The Calliope Hummingbird breeds uncommonly to fairly commonly in the Sierra Nevada and other high mountain ranges in California. In the Sierra, it typically nests above 4,000 feet elevation (Grinnell and Miller 1944; Gaines 1992; pers. obs.), usually near moist meadows or other relatively level and wet sites with a mixture of deciduous and coniferous trees, shrubs, and flowering plants (Grinnell and Miller 1944; Verner et al. 1980; Gaines 1992; pers. obs.).

    Although it can be locally fairly common as a migrant in the more arid lowlands during spring migration (pers. obs.), it generally avoids dense forests, dry ridges, or other relatively exposed and hot sites for breeding. Consequently, I was quite surprised to find a Calliope Hummingbird raising young in relatively arid Blue Oak (Quercus douglasii) woodland well below 1,000 feet elevation.

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    ANN SCARFE, J. CAM FINLAY (Author)

    RAPID SECOND NESTING BY ANNA'S HUMMINGBIRD NEAR ITS NORTHERN BREEDING LIMITS

    Anna's Hummingbirds (Calypte anna) were first reported in Victoria, British Columbia, in December 1944 and again each winter until 13 January 1947. Sightings continued through the 1950s (Taylor and Harper 1987), increased in number each year, and by 1970 the first individual was noted on the Victoria Christmas Bird Count. Numbers increased on subsequent counts, with 177 noted in 1998 (D. Pearce, pers. comm.).

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    JUAN CERVANTES-SANCHE, ERIC MELLINK (Author)

    NOTES : NESTING OF BRANDT'S CORMORANTS IN THE NORTHERN GULF OF CALIFORNIA

    In Mexico, Brandt's Cormorant (Phalacrocorax penicillatus) breeds mostly on islands and offshore rocks along the Pacific coast of the Baja California peninsula (Everett and Anderson 1991; Grinnell 1928; Wilbur 1987). The southernmost known colony on the Pacific coast is at the north end of Isla Margarita (approximately 24°30' N, 112°W; Guzman in Everett and Anderson 1991). Colonies in the Pacific can contain thousands of individuals.

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    GUSTAVO ARNAUD, EDGAR AMADOR, MARCOS ACEVEDO (Author)

    NOTES : A POTENTIAL THREAT TO BALD EAGLES IN BAJA CALIFORNIA SUR, MEXICO

    The Southern Bald Eagle (Haliaeetus leucocephalus leucocephalus) is a resident species in the state of Baja California Sur (Grinnell 1928), occurring mainly in coastal habitats. Nesting is now known only from Bahía Magdalena–Almejas on the west coast (Henny et al. 1993; Amador-Silva and Guzmán-Poo 1994; Rodríguez-Estrella et al. 1995), where no more than three pairs are found annually.

    The physiography of Baja California Sur is composed of extensive plains and hills. The principal mountain ranges are the Sierras la Giganta and la Laguna, and the predominant vegetation is desert scrub, which covers 92% of the state area (INEGI 1995). Freshwater habitats are scarce and largely temporary across the state.

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    Howard L. Cogswell (Author)

    BOOK REVIEW : The California Condor , A Saga of Natural History and Conservation

    This nearly folio-sized book of 4¼ pounds is aptly subtitled, given the history of the major study and conservation programs directed toward this species since the 1940s. A prologue tells of the authors’ first experience with California Condors and expresses the book’s goal: "to give the reader an appreciation of both the basic biology of the condor and the dynamics of condor conservation from a viewpoint mainly inside the conservation and research program."

    The book is then organized into six “parts,” the first of which is “Historical and Background Matters.” Chapter 1, on “Perspectives,” summarizes the species’ natural history and compares it with that of the Andean Condor and several Old World vultures. Chapter 2 provides an excellent account of the ceremonial and other uses made of California and Andean Condors by native peoples within their ranges.

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    WALTER WEHTJE (Author)

    FEATURED PHOTO :RANGE EXPANSION OF THE GREAT-TAILED GRACKLE IN WESTERN NORTH AMERICA

    The spread of the Great-tailed Grackle (Quiscalus mexicanus) is one of the most impressive range expansions to occur in North America during the 20th century. The U.S. breeding range was limited to southernmost Texas in 1900 (Ridgway 1902), but a century later, Great-tailed Grackles breed in 19 states, from Arkansas in the East, north to Minnesota, and west to California and Oregon (Dinsmore and Dinsmore 1993; Scheuering and Ivey 1995; Price 1997; Granlund 1999), with sightings in Washington, British Columbia, Montana, North Dakota, Wisconsin, and Ontario (Dinsmore and Dinsmore 1993; Granlund 1999).