Western Birds Journal

Volume 43, No. 1

Published January 1, 2012

Issue description

Volume 43, number 1 of Western Birds, published 2012

Articles

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    JUDDSON D. SECHRIST, EBEN H. PAXTON, DARRELL D. AHLERS, ROBERT H. DOSTER, VICKY M. RYAN (Author)

    ONE YEAR OF MIGRATION DATA FOR A WESTERN YELLOW-BILLED CUCKOO

    In 2009, we studied the migration of the Western Yellow-billed Cuckoo by capturing 13 breeding birds on the middle Rio Grande, New Mexico, and attaching a 1.5-g Mk 14-S British Antarctic Survey geolocator to each bird. In 2010, we recaptured one of the cuckoos, enabling us to download its geolocation data. The cuckoo had flown approximately 9500 km during its southward migration, traveling through Central America to winter in portions of Bolivia, Brazil, Paraguay, and Argentina. The spring migration route differed somewhat from the fall route, with the cuckoo bypassing Central America to migrate through the Caribbean. Additionally, it moved between New Mexico and Mexico at the end of summer in 2009 and again in 2010 before being recaptured at its breeding site. Our results, albeit from one individual, hint at a dynamic migration strategy and have broad implications for the ecology and conservation of the Western Yellow-billed Cuckoo, a species of conservation concern.

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    JAY D. CARLISLE (Author)

    IRRUPTIVE MIGRATION OF CHESTNUT-BACKED CHICKADEES TO SOUTHWESTERN IDAHO

    I document irruptive movements of the Chestnut-backed Chickadee to Lucky Peak in southwestern Idaho, over 80 km from its regular range. Chestnut-backed Chickadees were captured and/or observed at Lucky Peak in 2000, 2004, and 2008. To evaluate the context for this phenomenon, I also examined data on capture of all chickades and other irruptive species at Lucky Peak and numbers of irruptive species recorded on Idaho Christmas Bird Counts (CBC) from 1997 to 2011. Though CBCs in the winter of 2004–05 (following the largest movement of Chestnut-backed Chickadees at Lucky Peak in fall 2004) found high numbers of many irruptive species, relatively low numbers of Chestnut-backed Chickadees were detected on Idaho CBCs that winter. Overall, I observed little correspondence between capture totals at Lucky Peak and Idaho CBC data for potentially irruptive species in general, and little correspondence between years with Chestnut-backed Chickadees and patterns of any irruptive species in CBC data for the subsequent winter. The seasonal movement patterns of this species, their regularity, and their causes warrant greater attention.

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    SADIE K. WRIGHT, DANIEL D. ROBY, ROBERT G. ANTHONY (Author)

    FACTORS AFFECTING THE BEHAVIOR OF BROWN PELICANS AT A POST-BREEDING ROOST

    We sought to determine how disturbance may influence the behavior of California Brown Pelicans (Pelecanus occidentalis californicus) at a major post-breeding roost. In addition to assessing the effects of natural and anthropogenic disturbance on Brown Pelican behavior, we investigated the effects of other potential explanatory variables, including year, date, time of day, weather, tide stage, and density of pelicans on time-activity budgets of pelicans roosting on East Sand Island in the Columbia River estuary from June to August, 2001 and 2002. We found that during the day, pelicans spent the great majority of time either resting (44%) or preening (41%). Time of day, density of pelicans, wind speed, precipitation, and disturbance accounted for 34% of the variation in resting behavior among pelicans; year, date, time of day, number of pelicans, and disturbance accounted for 27% of the variation in vigilant behavior. All three categories of disturbance (natural, research-related human, other human) were associated with significant increases in the proportion of vigilant behavior and reductions in the proportion of resting behavior. It took longer for pelicans to recover to baseline behavior following a research-related disturbance than after other types of disturbance. This is likely because research-related disturbances involved human activity on the island (i.e., land-based), whereas most other human disturbances were water- or air-based. The potential exists for human disturbance to significantly alter pelican behavior at roost sites. Therefore, restriction of human access to the pelican’s major roost sites and regulation of human activities at roosts should be considered to ensure that available sites support the continued recovery of this subspecies.

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    ROBERT A. HAMILTON, JUTTA C. BURGER, SUSAN H. ANON (Author)

    USE OF NEST BOXES BY CACTUS WRENS IN ORANGE COUNTY, CALIFORNIA

    Responding to studies identifying an apparent lack of suitable natural nesting sites for the Cactus Wren (Campylorhynchus brunneicapillus) in coastal southern California, we designed “cactus-like” nesting structures and nest boxes (1) to determine whether this wren would use such structures or boxes and (2) to assess the efficacy of different construction designs. Out of 32 nest boxes deployed, two supported Cactus Wren nests that successfully fledged young—one in 2010 and another in a different location in 2011. In fall 2010, another box in yet a third location was used for a brood nest. In contrast, we observed no nesting in the 13 cactus-like structures over three years of study. Our results provide “proof of concept” that Cactus Wrens will select and successfully use nest boxes even in areas of mature cactus scrub. Furthermore, all three boxes used by Cactus Wrens were mounted in a tilted position, in which the nest box was angled up to 45°, rather than level. In the summer of 2011, we retrieved the artificial structures and weathering nest boxes and mounted 21 new boxes in the tilted position and with a level floor inserted to prevent eggs from falling into the bottom. We expect that this and future experiments will evaluate the potential conservation value of nest boxes for Cactus Wrens in areas recovering from wildfire and at sites of cactus restoration.

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    ADAM HANNUKSELA, TERESA SKIBA, BENJAMIN ZYLA, AMANDA PROUDMAN (Author)

    EXTENSION OF THE BREEDING RANGE OF COSTA’S HUMMINGBIRD IN SOUTHERN SONORA

    As currently known, the breeding range of Costa’s Hummingbird (Calypte costae) extends from the southwestern United States into Baja California and south to central Sonora, while the winter range extends south to the state of Nayarit (Baltosser 1989, Baltosser and Scott 1996, AOU 1998). Russell and Monson (1998) considered Costa’s Hummingbird a "poorly known species" in Mexico and reported evidence of breeding in Sonora as far south as Guásimas (27° 53' N, 110° 35' W). Cody (1983) reported observations of the species during the breeding season at Huatabampo, Sonora (26° 50' N, 109° 38' W), but did not document nesting. We report here the first evidence of breeding from southern Sonora.

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    JOHN C. STERLING, MATT BRADY (Author)

    FEATURED PHOTO: EXTRALIMITAL SAGE SPARROWS ON THE CENTRAL VALLEY FLOOR NORTH OF THE TULARE BASIN WITH NOTES ON SUBSPECIES STATUS AND IDENTIFICATION

    The Sage Sparrow (Amphispiza belli) is a rare vagrant on the floor of California’s Central Valley north of Fresno County. The few sight records are augmented by specimens from the Central Valley catalogued as three subspecies in the Museum of Vertebrate Zoology (MVZ) at the University of California, Berkeley: Bell’s Sage Sparrow (A. b. belli) and two interior forms, A. b. canescens (breeding in the southern Central Valley and Mojave Desert) and A. b. nevadensis (breeding in the Great Basin). However, we follow Patten and Unitt’s (2002) revision of the subspecies by regarding canescens as a synonym of nevadensis, here referred to as Interior Sage Sparrow. Although the specimens have been identified to subspecies, some sight records have not. Of the 37 records we have located for the Central Valley north of Fresno County, seven were not identified to subspecies. We echo Tim Manolis’s appeal (editor’s note in Stovall 1998) that birders should photograph and/or identify each extralimital Sage Sparrow to subspecies in order to clarify the status of each in the Central Valley and elsewhere. In this paper we summarize the records and provide tips to encourage and facilitate identification of these two distinctive subspecies.