Western Birds Journal

Volume 33, No. 4

Published October 1, 2002

Issue description

Volume 33, number 4 of Western Birds, published 2002

Articles

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    EMILIE A. STRAUSS, CHRISTINE A. RIBIC, W. DAVID SHUFORD (Author)

    ABUNDANCE AND DISTRIBUTION OF MIGRATORY SHOREBIRDS AT MONO LAKE, CALIFORNIA

    We counted migratory shorebirds and documented their patterns of shoreline distribution at Mono Lake in the Great Basin of California via annual spring and fall surveys from 1989 to 1995. We tallied a total of 30 species—29 in fall, 25 in spring, and 24 in both seasons. Median counts of all shorebirds were 31,432 (13,901–50,916) in fall and 7,792 (2,683–25,616) in spring. Median counts exceeded 5,000 each for the American Avocet and Wilson’s and Red-necked phalaropes in fall, and 1,000 for the Western and Least sandpipers in spring. Of nine species with median counts of >50 individuals, medians were more than 50% higher in fall than spring for the American Avocet, Wilson’s Phalarope, and Red-necked Phalarope; more than 50% higher in spring than fall for the Semipalmated Plover, Western Sandpiper, Least Sandpiper, and Dunlin; and similar in both seasons for the Snowy Plover and Killdeer.

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    ROBERTO CARMONA, GORGONIO RUIZ-CAMPOS, JOSE ALFREDO CASTILLO-GUERRERO, EFREN HERNANDEZ (Author)

    COMPOSITION OF RAPTORS ON ESPIRITU SANTO ISLAND, GULF OF CALIFORNIA, MEXICO

    We surveyed raptors on Espíritu Santo Island, Gulf of California, bimonthly from November 1998 to October 1999. Visual surveys averaged 64 hours per visit. We collected two Elf Owls by mist net. Of the ten species of raptors recorded, five are resident (Turkey Vulture, Osprey, Red-tailed Hawk, Great Horned Owl, and Elf Owl), two are common visitors (Peregrine Falcon and American Kestrel), and three are rare visitors (Northern Harrier, Harris’ Hawk, and Golden Eagle). Four species were previously unrecorded on the island (Northern Harrier, Harris’ Hawk, Golden Eagle, and Elf Owl). Of the ten species, three are protected by the Mexican government.

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    ERIC MELLINK, JOSE ALFREDO CASTILLO-GUERRERO, AIMEE de la CERDA (Author)

    NOTEWORTHY WATERBIRD RECORDS IN THE DELTA OF THE RIO COLORADO, MEXICO, 2002

    Surveys of the Río Colorado delta in summer 2002 revealed abandonment of one large heronry but the existence of another large and several small, inconspicuous heronries previously nonexistent or undetected. Most notable among these mixed-species colonies were two nests of the Tricolored Heron and two fledglings of the Reddish Egret, representing considerable northward extensions of these species’ breeding ranges.

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    MARCO ANTONIO GONZALEZ-BERNAL, ERIC MELLINK, JOSE ROBERTO FONG-MENDOZA (Author)

    NESTING BIRDS OF FARALLON DE SAN IGNACIO, SINALOA, MEXICO

    From 1999 to 2001 we made the first thorough bird surveys of Farallón de San Ignacio, an islet off Topolobampo, Sinaloa. The islet hosts 100–200 nesting pairs of the Red-tailed Tropicbird, about 1,200 Brown Boobies, 1,400–1,650 Blue-footed Boobies, and about 1,000 Heermann’s Gulls. The Double-crested Cormorant and Yellow-footed Gull nest irregularly in small numbers.

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    WILLIAM C. WEBB, NORMAN C. ELLSTRAND (Author)

    FIRST RECORD OF DOUBLE BROODING BY THE COMMON RAVEN

    The Common Raven (Corvus corax) ranges throughout the Holarctic, but many life-history attributes of this species, including mean lifespan, age at first breeding, age-specific fecundity, and other important variables, remain poorly documented (Boarman and Heinrich 1999). During the spring of 2001, we observed a single pair of ravens successfully rear two broods from a nest located on the campus of the University of California, Riverside. Prior to our observations, ravens had been known to produce only replacement clutches after loss of eggs (Bowles and Decker 1930) or nestlings (Stiehl 1985).

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    DAVID S. TINNIN (Author)

    A WESTERN SCRUB-JAY PREYING ON DEER MICE

    Scrub-jays of the genus Aphelocoma are known to be omnivorous and opportunistic in their feeding habits (Bent 1946). Stomach-content analyses of Florida Scrub-Jays (A. coerulescens) have shown that they feed predominantly on vegetable matter, but that they also take large quantities of insects as well as frogs and lizards (Sprunt 1946). Aphelocoma spp. are also well known for raiding nests of other birds (Bent 1946; Haemig 1988).

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    FERNANDO PUEBLA-OLIVARES, OCTAVIO R. ROJAS-SOTO, ADOLFO G. NAVARRO S. (Author)

    FIRST RECORD OF LEACH'S STORM-PETREL IN THE GULF OF CALIFORNIA, MEXICO

    Leach’s Storm-Petrel (Oceanodroma leucorhoa) is a widespread bird of the North Pacific and North Atlantic oceans; in the former it breeds south to islands off western Mexico (AOU 1998). Four populations, differing mainly in the color of the rump, have been identified in western Mexico, breeding on Los Coronados (variably white rump), islets off Guadalupe Island in both summer and winter (white rump), and the San Benito Islands (dark-rumped). Furthermore, nonbreeding migrants, possibly from much farther north, occur south in the Pacific Ocean to about 15°S, mainly over offshore waters.

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    Steve N. G. Howell (Author)

    BOOK REVIEW: A Complete Guide to Antarctic Wildlife: The Birds and Mammals of the Antarctic Continent and Southern Ocean

    Antarctica and the southern seas are among the last true wildernesses on Earth. Few are lucky enough to visit these areas, and, until now, no single guide has covered their wildlife in a modern format. For readers of Western Birds, this book’s main interest lies in the treatment of southern seabirds that have occurred, or could occur, in North American waters: 106 pages, 9 color plates, and 126 color photos (84 of albatrosses) are devoted to the Procellariiformes.

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    STEVE N. G. HOWELL, PETER PYLE (Author)

    FEATURED PHOTO: AGEING AND MOLT IN NONBREEDING BLACK-BELLIED PLOVERS

    The correct determination of a bird’s age, both in the hand and in the field, can be useful for population studies and necessitates an appreciation of molt patterns. Like most Northern Hemisphere shorebirds, adult Black-bellied Plovers (Pluvialis squatarola) undergo a complete prebasic molt from fall into winter, while juveniles have only a partial molt in their first winter. The literature, however, contains conflicting information on the timing and number of molts undertaken by first-year Black-bellied Plovers.