Western Birds Journal

Volume 53, No. 1

Published January 1, 2022

Issue description

Volume 53, number 1 of Western Birds, published 2022

Articles

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    LYNN W. OLIPHANT, IAN G. WARKENTIN, KELLY KOZIJ, ADAM P. SCHMIDT (Author)

    MERLIN PARENTAL BEHAVIOR AND CHICK DEVELOPMENT AS REVEALED BY WEBCAM

     previous knowledge of the Merlin’s (Falco columbarius) nesting behavior was based on observation from the ground or data recorded during nest checks. Similarly, descriptions of chicks’ behavioral development were restricted to studies of captive birds. We used a webcam to observe adult prairie Merlins (F. c. richardsonii) and their four young on an artificial nest platform located in Weyburn, Saskatchewan, from 25 april to 22 July 2020. Our observations extended from prior to egg-laying until 12 days after fledging, being most intensive after hatching. activities revealed by the webcam largely confirmed previous ground-based observations and studies involving either nest visits or captive rearing. eggs were laid at roughly 2-day intervals followed by a 30-day incubation period and a 31-day nestling period. the female dominated activity at the nest until the chicks achieved homeothermy
    (7–10 days after hatching); the male was seldom seen except when delivering prey to the female. the female stopped brooding chicks during the night after day 14 and during daylight on day 16. the male began bringing food directly to the chicks starting 17 days after hatching. the chicks’ development matched published reports
    with constant competition for food among chicks but also apparent efforts by the adult female to ensure that each chick received sufficient food. the webcam enabled us to gather more detailed information about the Merlin’s behavior at the nest than previously possible and provided an opportunity for citizen science involving a common but little studied falcon.

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    STEPHANIE KLEIN, LARRY BAER, RYAN A. PHILLIPS (Author)

    BREEDING SWAINSON’S HAWKS IN THE CENTRAL COAST RANGE OF CALIFORNIA

     During the 20th century the Swainson’s Hawk (Buteo swainsoni) was an infrequent migrant through the central Coast Range of California with no breeding documented. Since 2005, however, several breeding pairs have established nest sites in the region. We studied Swainson’s Hawks during the breeding seasons of 2019 and 2020 in a portion of the central Coast Range to estimate their abundance and distribution there. We observed individual hawks systematically and monitored their nesting activity and breeding outcomes in suitable habitat in Alameda, Santa Clara, and San Benito counties within the Coast Range and sought to characterize the habitat of this small outlying population. From 2019 to 2020 the numbers of nesting pairs increased from 3 to 5, of young fledged from 1 to 6, and of individual adults from 15 to 22. Swainson’s Hawks were more closely associated with farmland
    than with grassland, and nests were located in areas that were closely associated with both grassland and farmland. The increase of this species in the central Coast Range and its use of agricultural areas is of conservation significance for land managers and wildlife and conservation agencies, given that the California Department of Fish and Wildlife has designated it as threatened.

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    JOCELYN HUDON, PETER PYLE (Author)

    DIET-RELATED PLUMAGE ERYTHRISM IN THE WESTERN TANAGER AND OTHER WESTERN NORTH AMERICAN BIRDS

     Consumption of the berries of two exotic bush honeysuckles (genus Lonicera) containing the red carotenoid pigment rhodoxanthin has resulted in abnormal erythristic plumages in several species of birds in eastern North America. Here we report 12 examples of plumage erythrism in the Western Tanager (Piranga ludoviciana), in both live birds (5) and museum specimens (7), that we suspect have the same etiology. The erythristic tanagers feature overtly orange to red feathers variously scattered on the head, rump, wing coverts, and/or underparts, areas of the plumage normally colored by carotenoid pigments. All were in their year of hatching, so the reddened feathers, including replaced median coverts with orange tips, represent formative plumage grown on or near the breeding grounds where berries containing rhodoxanthin are available. By contrast, adult Western Tanagers undergo body molt primarily in the Mexican monsoon region in fall and on their winter grounds in early spring where bush honeysuckles are nonexistent. We also report examples of Red-breasted Sapsuckers (Sphyrapicus ruber) with anomalous red pigmentation on their backs and of Cedar Waxwings (Bombycilla cedrorum) with orange tail bands, as previously documented in the East. In these species, the reddened areas are typically yellow or green, colors based on carotenoid pigments that can be altered through the consumption of fruits containing rhodoxanthin. We conclude that these reddened feathers are the result of the consumption of honeysuckle berries or possibly the red arils of the Pacific Yew (Taxus brevifolia), representing a first report of diet-related erythrism in western North America.

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    JOSEPH F. DI LIBERTO, MAYA R. STAHL, SILAS E. FISCHER, KATHY A. GRANILLO (Author)

    DO ATTRIBUTES OF GRAY VIREO NEST SITES INFLUENCE BROWN-HEADED COWBIRD BROOD PARASITISM?

     Brood parasitism can have major detrimental effects on the fitness of reproducing songbirds and often contributes to nest failure. As the Gray Vireo (Vireo vicinior) suffers high rates of brood parasitism by the Brown-headed Cowbird (Molothrus ater), we hypothesized that vireos might choose nest sites selectively to thwart cowbird parasitism. To investigate this question, we measured and compared vegetative and spatial attributes of nest sites in a known breeding population of the Gray Vireo on the Sevilleta National Wildlife Refuge, New Mexico, in 2017 and 2018. Specifically, we compared parasitized and unparasitized nests with respect to the nest’s height and the average height, diameter, and foliage density of the nest tree. We also compared the spatial attributes of the nearest neighboring nest, nearest parasitized nest, and the density of surrounding juniper trees within 50 m of a nest. Interestingly, among none of the variables measured did we find an association with the incidence of brood parasitism, suggesting that nest parasitism might be more strongly linked to other larger-scale ecological or behavioral variables.

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    HELEN L. LOFFLAND, LYNN N. SCHOFIELD, RODNEY B. SIEGEL, BETH CHRISTMAN (Author)

    SIERRA NEVADA WILLOW FLYCATCHER DECLINE CONTINUES BUT LOSSES ABATE AT TWO RESTORED MEADOWS

     Willow flycatcher (Empidonax traillii) populations have been declining across the western United States for decades. The Sierra Nevada–southern cascades population in California is especially vulnerable, with fewer than 200 pairs remaining. Hydrologic restoration has been recommended for conserving this population. other riparian songbirds have increased in response to restoration, but little is known about how restoration has affected the Willow flycatcher. The little Truckee River has long been a stronghold for the Willow flycatcher, and the demography of the population there was studied intensively from the late 1990s through 2010. Baseline data from that study provided an opportunity to gauge the species’ response
    to pond-and-plug restoration projects completed at two meadows within the study area in 2009 and 2010. We aggregated and analyzed data from Willow flycatcher surveys from 1997 through 2019 at the two restored meadows as well as nine nearby unrestored meadows with at least two Willow flycatcher territories at some time during the demographic study. at most meadows, the number and density of Willow flycatcher territories declined over the two-decade study period. However, losses at the unrestored meadows were significantly greater than at the restored meadows, where territory density clearly did not collapse following the disturbance caused by restoration and then remained largely stable thereafter. Within large meadows already occupied by Willow flycatchers, meadow restoration that restores hydrologic function and increases flooding over creekbanks may be an effective strategy for
    stabilizing declining Willow flycatcher populations in the Sierra Nevada.

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    RICHARD A. ERICKSON, RENÉ VALDÉS (Author)

    NOTES ON THE BREEDING BIOLOGY OF THE HOODED GROSBEAK (COCCOTHRAUSTES ABEILLEI)

     The Hooded Grosbeak (Coccothraustes abeillei) is endemic to evergreen montane forests from northern Mexico to northern Central America (Carter 2014). Like its two congeners the Hawfinch (C. coccothraustes) of Europe, Asia, and north Africa, and the Evening Grosbeak (C. vespertinus) of North America—the Hooded Grosbeak is generally quiet and inconspicuous when nesting (Komar 2002). Nearly 75 years passed between the formal naming of the Evening Grosbeak and the first descriptions of its nesting habits (Speirs 1968). Clement (2010) and Carter (2014) summarized what very little has been published concerning nesting of the Hooded Grosbeak, primarily on the basis of the work of Thurber et al. (1987; phenology), Howell and Webb (1995; brief description of nest site), and Komar (2002; phenology, nest description, and behavior). Carter (2014) noted further that “data on clutch size, egg color, and incubation have not been recorded.” Additional references to the timing and locations for “breeding” and juveniles collected were listed by Miller et al. (1957). We prepared this note in response to this paucity of information.

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    JONATHAN VARGAS, LILIANA ORTIZ-SERRATO, CÉSAR IVÁN MANRÍQUEZ-CASTRO, GORGONIO RUIZ-CAMPOS (Author)

    FIRST SPECIMEN OF THE NAZCA BOOBY (SULA GRANTI) FOR THE STATE OF BAJA CALIFORNIA, MEXICO

     On 16 June 2021, during the spring–summer monitoring for nesting shorebirds, we found a dead subadult male Nazca Booby (Sula granti, Figure 1) on the inner side of the sandbar at the mouth of the Estero Punta Banda, south of the city of Ensenada, Baja California, Mexico (31° 46ʹ 25˝ N, 116° 37ʹ 17˝ W). The specimen was found in a site with halophytic plants dominated by Abronia maritima and Carpobrotus edulis. The specimen was identified by its peculiar coral/pink bill with yellower tip in comparison with the yellowish bill color of the Masked Booby, Sula dactylatra (Cuccaro-Díaz et al. 2020). Also, a dorsal view of the central tail feathers shows the white extending from the base of the tail to beyond half its length (Figure 2).

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    ROBERT D. DORN, JANE L. DORN, CALVIN E. DYER (Author)

    NORTHERN CARDINAL NESTING IN WYOMING

     The Northern Cardinal (Cardinalis cardinalis) was first reported in Wyoming on the basis of John Clearwaters’ observation of a pair along Bear and Horse creeks near LaGrange, Goshen County, date not specified (Grave and Walker 1913). McCreary (1939) reported that cardinals were being brought into the state in cages by the Mexicans and some may have escaped or been released. The cardinal has been reported from Wyoming at least 19 times since 1957 about equally in all seasons except winter, for which there are only two reports (Scott 1957, 1962, Downing 1990, Faulkner 2010, https://wybirdrecordscommittee.wordpress.com). The observations cover most parts of the state. But there have been no reports of nesting. The species has been classified as a “rare, irregular, yearlong visitor” (Dorn and Dorn 1999) or a “rare visitor” (Scott 1993, Faulkner 2010, https://wybirdrecordscommittee. wordpress.com).

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    Daniel S Cooper (Author)

    BOOK REVIEW: LIFE UNDER THE FAST LANE: ECOLOGY AND CONSERVATION OF THE BRIDGE-NESTING PURPLE MARTINS IN URBAN SACRAMENTO

     For more than 20 years, field ornithologist and consultant Dan Airola has been studying and helping manage a unique population of the Purple Martin (Progne subis) nesting under freeway bridges in Sacramento, California. This monograph (the first in what is intended to be a series from the Central Valley Bird Club, edited by Airola), brings together two decades of insight into balancing human-oriented infrastructure with the needs of a threatened bird species making a living in this bustling, constantly changing city. Historically nesting throughout the Central Valley, western martins never took to artificial nest boxes like their eastern cousins, though roof-nesting was noted by the earliest ornithologists visiting Sacramento in the 1800s. This phenomenon lasted into the 1970s when martins switched from building roofs to cement freeway bridges, coinciding with the arrival of European Starlings (Sturnus vulgaris), which seem physically unable to nest in the same vertical “weep holes” on the undersurfaces of bridges (p. 10–11).

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    Robert A. Hamilton (Author)

    BOOK REVIEW:SACRAMENTO COUNTY BREEDING BIRDS

     In our hyperconnected era, torrents of fresh sightings gush through the computers of eBird editors and splash onto our screens. The sheer volume of data can create an illusion that repeatedly touching our lips to the mighty eBird firehose will somehow quench our thirst for knowledge, but the resulting depth of understanding tends to be rather shallow. Deeper aquifers of wisdom are tapped when local experts curate collections of observations and place them in proper historical and biogeographical contexts. From 1988 to 1993, Tim Manolis led a cutting-edge effort to collect the data for a Sacramento County breeding bird atlas (BBA) that was not published. In 2015, Ed Pandolfino, Manolis, Lily Douglas, and Chris Conard decided to reanimate the zombie information by transforming it into the baseline against which to compare a new batch of data, collected from 2016 to 2020. Thus, in 2021,
    Sacramento County became the first region of California to publish the results of two BBA projects (Sonoma County also completed its second round of field work in 2020, but the results are not yet published).

     

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    THANK YOU TO OUR SUPPORTERS

     The generosity of WFO’s members made a quantum leap this past year. Our first ever birdathon was a great success, bringing in $32,000. Then Ron Mallory’s challenge has so far brought in another $10,000, a figure still growing. The challenge is open until 15 May 2022, at which time Ron will match the final number. Thus even with inflation spiking and the covid-19 pandemic dragging on, WFO is in a strong position to sustain and even expand our publications and programs. The board of Western Field Ornithologists and the editorial team of Western Birds are deeply grateful to the following contributors for their financial support in 2021