Western Birds Journal

Volume 52, No. 1

Published January 1, 2021

Issue description

Volume 52, number 1 of Western Birds, published 2021

Articles

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    THOMAS A. BENSON, DEBORAH J. HOUSE, GUY McCASKIE, ALEX M. RINKERT, ADAM J. SEARCY, RYAN S. TERRILL (Author)

    THE 45TH ANNUAL REPORT OF THE CALIFORNIA BIRD RECORDS COMMITTEE: 2019 RECORDS

     From its last report through 2019, the California Bird Records Committee reached decisions on 204 records involving 225 individuals of 62 species and one species group, endorsing 176 records of 197 individuals. These include the first accepted state record of the Yellow-browed Warbler (Phylloscopus inornatus), bringing California’s total list of accepted species to 676, of which 13 represent established introductions. Other especially notable records detailed in this report include the state’s third Common Eider (Somateria mollissima), third Common Ringed Plover (Charadrius hiaticula), fourth and fifth Red-flanked Bluetail (Tarsiger cyanurus), a significant incursion of Cassin’s Sparrows (Peucaea cassinii) into the eastern Mojave Desert, and the first Spotted Redshank (Tringa erythropus) in 30 years.

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    SKIP AMBROSE, CHRISTINE FLORIAN, JUSTIN OLNES, JOHN MACDONALD, THERESE HARTMAN (Author)

    SAGEBRUSH SOUNDSCAPES AND THE EFFECTS OF GAS-FIELD SOUNDS ON GREATER SAGE-GROUSE

     Greater Sage-Grouse (Centrocercus urophasianus) use elaborate acoustic and visual displays to attract and select mates, and females and chicks depend on acoustic communication during brood rearing. A potential threat to the grouse is sounds associated with human activity. During April, 2013–2020, we collected 17,825 hours of acoustic data in three different acoustic situations in the sagebrush of Wyoming: rural, undeveloped areas (6), at Greater Sage-Grouse leks in a natural-gas field (20), and near active machinery in that gas field (17). The average existing sound levels in undeveloped sagebrush areas were LAeq = 26 dB and LA50 = 20 dB, and the average background sound level was LA90 = 14 dB. These values are lower than previously reported, due in part to our use of more sensitive equipment as well as addressing the influence of the instruments’ electronic self-noise. LAeq and LA50 at leks in the gas field ranged from 25.5 to 33.7 dB and 20.5 to 31.3 dB, respectively, depending on the distance, number, and type of nearby activities. Sound levels at leks were correlated with trends in the number of grouse using the lek: the higher the sound level, the greater the likelihood of a decline. Thresholds above which declines occurred were L Aeq = 31 dB and LA50 = 26 dB. Leks with LAeq > 31 dB and LA50 >26 dB, 100% and 91%, respectively, had declining trends. Our findings suggest that the current policy of limiting sound levels at leks to LA50 < 10 dB (or LAeq < 15 dB) over the background sound level is appropriate, if an accurate background level is used.

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    DANIEL M. TAYLOR (Author)

    THE STATUS OF LOONS IN IDAHO

     This report summarizes and updates the population status and distribution of loons in Idaho. Formerly, the Common Loon bred in northern, central, and southeastern Idaho, probably widely. With only sporadic unsustained nesting in the last half century it has been essentially extirpated as a breeding species, but flocks of up to 200 migrating birds occur in spring and autumn. In spring, concentrations are most frequent in southeastern and south-central Idaho, but in autumn they are widespread. Common Loon migration peaks from mid-April to
    early May and from mid-October to mid-November. The species winters in numbers of up to 20 on large lakes in northern and southwestern Idaho. The Pacific Loon was not conclusively recorded in Idaho before 1974, but since the mid-1980s a few to dozens have occurred annually in autumn throughout the state, with concentrations of up to 30. Its autumn migration peaks from mid-October to late November. In most years a few now winter, primarily in northern Idaho. There have been a dozen spring and three summer records. Early in the 20th century the Red-throated Loon was recorded rarely in migration but since the 1980s it has been recorded most years, most frequently in autumn. First noted in 1979, the Yellow-billed Loon remains rare. In spring, summer, and winter it is recorded principally from large lakes in northern Idaho, but autumn records are widespread.

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    JESSICA J. POLLOCK, HEIDI WARE CARLISLE, HEATHER M. HAYES, BRYCE W. ROBINSON (Author)

    MONITORING THROUGH COMMUNITY SCIENCE: ANNA’S HUMMINGBIRD WINTER RANGE EXPANSION INTO IDAHO

     Increased urbanization and supplementary feeding are implicated in driving the expansion of the range of the Anna’s Hummingbird (Calypte anna). In many areas this range expansion has been well described, but the recent expansion of the northeastern limit of the nonbreeding distribution, in winter in Idaho, has not yet been summarized. Using data from the Idaho Bird Records Committee database and www.eBird.org from 1976 through 2020, we collated records for Idaho and supplemented them with data from a community-science program of monitoring by homeowners. Our additional effort to solicit records from the community shows that database records and feeder observations alone underestimate the number of individuals present in the state. Through banding and color-marking of 58 individual hummingbirds at private residences, we documented six instances of Anna’s Hummingbirds returning to a site in successive winters, found a roughly even sex ratio, and found a ratio of adults to juveniles of about 3:1. Anna’s Hummingbird may now be a sparse year-round resident in parts of Idaho.

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    JESSIE L. WiLLIAMSON, MATTHEW J. BAUMANN (Author)

    EVIDENCE OF BROOD PARASITISM AND QUANTIFICATION OF RANGEWIDE OVERLAP BETWEEN THE OLIVE WARBLER AND BROWN-HEADED COWBIRD

     Brood parasitism is a fascinating natural history phenomenon that Provides a window into the coevolution of antagonistic interactions. many ecological and evolutionary aspects of brood parasitism remain unknown, and new hosts of brood parasites are still being discovered. We document the second instance of brood parasitism of the olive Warbler (Peucedramus taeniatus) by the Brown-headed Cowbird (Molothrus ater). apparent lack of habitat and elevation overlap across the ranges of these two species prompted us to examine how frequently they come into contact. We analyzed >3 million olive Warbler and Brown-headed Cowbird occurrence records from two open-source repositories, eBird and GBiF, to examine both synchronous and asynchronous locality overlap during the breeding season. We found that the two species were documented together simultaneously in only 3.1% of analyzed instances, but that they co-occurred in similar habitat types and/or at similar elevations at 11.8% of localities analyzed across the olive Warbler’s range. additional research on aspects of ecology and evolution, such as host selection, the cowbird’s diurnal patterns of movement, and the dynamics of intracellular pathogens infecting brood parasites and their hosts, may shed light more broadly on the ecological interactions and mechanisms underlying brood parasitism.

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    BRYCE W. ROBINSON, JESSICA J. POLLOCK, HEIDI WARE CARLISLE, HEATHER M. HAYES, JANICE ENGLE (Author)

    FIRST DOCUMENTATION OF SUCCESSFUL BREEDING FOR THE ANNA’S HUMMINGBIRD IN IDAHO

     Currently, the Anna’s Hummingbird (Calypte anna) breeds along the west coast of North America from Baja California to British Columbia and east into inland areas of California, Arizona, New Mexico, Oregon, and Washington (Clark and Russell 2012). The current distribution is a result of 80 years of range expansion out of Baja and coastal California, largely facilitated by urbanization, landscaping with non-native plants, and supplementary feeding (Greig et al. 2017, Battey 2019). Pollock et al. (2021), summarizing the recent increase in the numbers wintering in Idaho, illustrated that the species’ range continues to expand. This increase in winter numbers over time mirrors the trend in Arizona in the 1960s, when the establishment of a breeding population followed wintering (Zimmerman 1973, Clark and Russell 2012). Pollock et al. (2021) further suggest that Anna’s Hummingbird may now be a sparse year-round resident in parts of Idaho, primarily the greater Boise metropolitan area. Given the recent trend in Idaho that includes an increase in summer numbers in the past three years (ibid.), the establishment of a breeding population in the state seems possible, even probable.

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    JAMES W. CORNETT (Author)

    APPARENT COMMENSALISM OF A RED-TAILED HAWK AND BADGER

     Hunting associations between the American Badger (Taxidea taxus) and Coyote (Canis latrans) have been well documented (Aughey 1884, Hawkins 1907, Cahalane 1950, Lehner 1981, Kiliaan et al. 1991, Minta et al. 1992). Coyotes have been observed capturing rodents flushed out of burrows by badgers (Minta et al. 1992).

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    W. DAVID SHUFORD (Author)

    BOOK REVIEW: Breeding Bird Atlas of Nevada County, California

     A biological atlas maps the distribution, and sometimes the abundance, of a group of species (most commonly breeding birds) within a defined geographic area during a set time period. These atlases have dramatically advanced distributional studies over earlier ones based on randomly collected specimens or anecdotal observations by attempting to obtain comparable coverage within each (or a random sample) of the equal-sized blocks in an atlas grid overlain on the study area. The first breeding bird atlases began in Britain and Ireland in the mid-1960s (Lord and Munns 1970, Sharrock 1976). The concept quickly spread throughout the world but has been applied mostly in the northern hemisphere (Dunn and Weston 2008). The first atlas project in North America, for two counties in Maryland, was initiated in 1971 (Klimkiewicz and Solem 1978), but most subsequent work has been conducted at larger scales. From 1979 to 2018, atlases have been completed for 9 of Canada’s 13 provinces and territories, of which 6 have completed second atlases. They have been completed for 41 of the 50 United States, of which 18 have completed second atlases (Beck et al. 2018).

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    P. ROSS GORMAN (Author)

    FEATURED PHOTO - DO NUTCRACKERS USE AUTOMOBILES AS NUTCRACKERS?

     While driving through Yellowstone National Park, Wyoming (at 44.9° N, 110.5° W, 2122 m elevation), on 22 April 2019, I came across a Clark’s Nutcracker (Nucifraga columbiana) standing in the opposing lane of traffic. The nutcracker had a live Western Tiger Salamander (Ambystoma mavortium) in its bill. Intrigued by the scene, I pulled into a nearby roadway turnout and began to photograph this interaction between predator and prey.