Western Birds Journal

Volume 46, No. 3

Published July 1, 2015

Issue description

Volume 46, number 3 of Western Birds, published 2015

Articles

  1. Cover image V46(3)

    ISRAEL MORENO-CONTRERAS, HÉCTOR GÓMEZ DE SILVA, ADRIáN TORRES-VIVANCO, NOHEMI VILLALPANDO-NAVARRETE, ALEJANDRO BOTELLO (Author)

    AVIFAUNA OF JUÁREZ MUNICIPALITY, CHIHUAHUA, MEXICO

    We provide the results of avifaunal inventories in Juárez Municipality, a poorly known part of the relatively under-birded Mexican state of Chihuahua. Patterns observed are highly consistent with published literature on the avifauna of westernmost Texas. Our findings modify the status of some species, including the addition of rare migrants (Grace’s Warbler and Zone-tailed Hawk), first records for Chihuahua (Downy Woodpecker, Blue-headed Vireo, Pine Warbler, and Rose-breasted Grosbeak), range expansions (Neotropic Cormorant, Eurasian Collared-Dove, American Crow), and changes of seasonal status (Great Blue Heron, Vermilion Flycatcher, and Cassin’s Kingbird).

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    DOUGLAS W. FAULKNER (Author)

    COLORADO BIRD RECORDS COMMITTEE REPORT: 1986–2013

    Since 1985, 58 species have been added to the Colorado list, 49 confirmed as new to the state, 8 to reclassification of subspecies as species, and 1 to description of a new species (the Gunnison Sage-Grouse, Centrocercus minimus). The changes include discovery of a resident population of the Ruffed Grouse (Bonasa umbellus), transitory colonization of the Inca Dove (Columbina inca), marginal colonization of the Acorn Woodpecker (Melanerpes formicivorus), the Glossy Ibis (Plegadis falcinellus) becoming a regular spring migrant, massive colonization of the Eurasian Collared-Dove (Streptopelia decaocto), vagrancy of four species of Old World origin, and vagrancy of one species of Southern Hemisphere origin, the Kelp Gull (Larus dominicanus).

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    CLAIT E. BRAUN, SARTOR O. WILLIAMS III (Author)

    HISTORY AND STATUS OF THE WHITE-TAILED PTARMIGAN IN NEW MEXICO

    We reviewed the literature and observations of the occurrence and status of the White-tailed Ptarmigan (Lagopus leucura) in New Mexico. Historical reports were infrequent, likely because of an inadequate system for recording observations from the public, although by 1928 biologists had a good understanding of the distribution and status of the species in the state. By 1980, ptarmigan persisted in small numbers in the northern portion of the New Mexico range but were uncommon or absent in the southern portion of the range, prompting a transplant of White-tailed Ptarmigan from Colorado into the southern area in 1981. Following that successful transplant, observations initially increased and subsequently continued at a relatively low level with most reports coming from the southern portion but including others from throughout the historical range. White-tailed Ptarmigan are localized in suitable habitats, but their abundance in New Mexico may be affected by the decreasing size of alpine snowfields in summer, grazing in areas dominated by willow (Salix spp.), and the shift to a warmer and drier climate.

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    SHANNON E. MCNEIL, DIANE TRACY, CAROLINE D. CAPPELLO (Author)

    LOOP MIGRATION BY A WESTERN YELLOW-BILLED CUCKOO WINTERING IN THE GRAN CHACO

    A lack of information on the full life cycle of long-distance migrants, including nonbreeding periods, may hinder the recovery of threatened populations. In 2010, on the middle Rio Grande, Sechrist et al. (2012) recaptured a Yellow-billed Cuckoo (Coccyzus americanus) fitted with a light-level geolocator, revealing for the first time wintering grounds and migration routes of an individual of this species. To further this knowledge, in 2011 we placed light-level geolocators on eight Western Yellow-billed Cuckoos at breeding sites on the lower Colorado River in Arizona and California. We recaptured one female in July 2012 at her previous capture site and analyzed the stored light data. During fall migration the bird flew ~9500–9900 km, passing through the Caribbean region. It wintered from mid-November to late April in the Gran Chaco of central South America, around the junction of Paraguay, Bolivia, and Argentina. The more direct spring route back to the breeding grounds passed through Peru and Central America. Following recapture, we discovered the bird was nesting while wearing the geolocator, and she later fledged young from two nests. Before and after migration, the bird appeared to pause in southern Arizona or Sonora, paralleling the first tracked Western Yellow-billed Cuckoo, suggesting this monsoonal region may be important to the western population during these stages of the life cycle. The bird’s migration timing and loop route, though reversed in direction, were also strikingly similar to those of the first bird tracked, and their overlapping wintering grounds suggests the possibility of a distinct winter range for the western population. Given the continuing expansion of agriculture into natural areas throughout this large region of South America, conservation of these forested areas is essential.

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    ASHLEY M. LONG, HEATHER A. MATHEWSON, DIANNE H. ROBINSON, JOSEPH A. GRZYBOWSKI, MICHAEL L. MORRISON (Author)

    BLACK-CAPPED VIREO BREEDING HABITAT IN NORTH-CENTRAL TEXAS

    The Black-capped Vireo (Vireo atricapilla), listed as endangered by the U.S. Fish and Wildlife Service, breeds in southwestern Oklahoma, central Texas, and northern Mexico (Grzybowski 1995, Wilkins et al. 2006). Its breeding habitat is typically composed of low, deciduous shrubs and trees of irregular heights, heterogeneity that may result from local environmental conditions (e.g., soil type, climate) or must be maintained by periodic disturbance (e.g., wildfire, prescribed burning) (Graber 1961, Grzybowski 1995). Habitat loss (e.g., land-use conversion, vegetation succession), habitat degradation (e.g., grazing by domestic livestock, browsing by wild herbivores), and nest parasitism by the Brown-headed Cowbird (Molothrus ater) precipitated the species’ decline (Ratzlaff 1987). Since the vireo’s listing as endangered (Ratzlaff 1987), most of its management (e.g., cowbird removal, habitat manipulation) and research has taken place at a few prioritized study sites in Texas (e.g., Grzybowski et al. 1994, Stake and Cimprich 2003, Pope et al. 2013) and Oklahoma (e.g., Grzybowski et al. 1994). Smith et al. (2012) added to our understanding of vireo-habitat relationships in the southwestern portion of the breeding range in Texas. Information regarding the vireo’s occurrence, abundance, and reproductive status in relation to habitat characteristics is still lacking for north-central Texas.

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    MELANIE R. COLÓN, RONNISHA S. HOLDEN, MICHAEL L. MORRISON, TIFFANY M. MCFARLAND, HEATHER A. MATHEWSON (Author)

    GOLDEN-CHEEKED WARBLER: NEW MAXIMUM LONGEVITY RECORD

    The Golden-cheeked Warbler (Setophaga chrysoparia) breeds exclusively in juniper–oak woodlands in central Texas (Ladd and Gass 1999). It was listed as endangered in 1990 because of habitat loss and fragmentation (Smith 1990). Much of the research on the Golden-cheeked Warbler’s demography has been part of long-term monitoring at Fort Hood Military Reservation and at Balcones Canyonlands Preserve (see Groce et al. 2010). The species has been banded and monitored at other locations as well, including Kerr Wildlife Management Area (WMA), Kerr County.

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    KEN R. SCHNEIDER (Author)

    HYPERMELANISTIC AMERICAN PIPIT RETURNS TO WINTER IN CENTRAL CALIFORNIA

    On 1 December 2013, I observed a hypermelanistic American Pipit (Anthus rubescens) at Bedwell Bayfront Park in San Mateo County, California (Schneider 2014). This rather striking individual remained there through at least 4 January 2014. Almost a year later, on 5 November 2014, I found a similar pipit at the same location, where it remained through at least 28 January 2015. The bird was judged by photos to be in its first year when observed in 2013. Photographs of the bird in 2014–2015 again show a rather uniform medium-brown plumage with pale edging on the wing coverts and tertials and a blackish bill and legs, and the shape of the primary coverts, as well as other features of the plumage, made it possible to age the bird then as an adult. As the bird was not captured and banded in winter 2013–2014, it is difficult to prove that the pipit the following winter was in fact the same bird, but the rarity of this plumage abnormality in pipits, the similar overall appearance from one winter to the next, and the same location argue strongly that this was indeed the same bird. The progression in the apparent age of the bird from first year to adult also lends support to this conclusion.

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    PAUL G. LEVESQUE, JAMIE FENNEMAN, JEREMIAH KENNEDY (Author)

    FIRST OCCURRENCE OF THE CAVE SWALLOW IN BRITISH COLUMBIA

    On 11 November 2012 we observed a group of four swallows foraging over a freshwater pond at Iona Island Regional Park in Richmond, British Columbia (49° 21´ N 123° 21´ W). At a distance of 100 m, we quickly identified three of them as Barn Swallows (Hirundo rustica), while the fourth appeared at first to be a Cliff Swallow (Petrochelidon pyrrhonota). When it got closer to the observers, we identified the fourth bird—by its dark cinnamon-orange forehead, pale cinnamon-orange throat and chin, and dark cinnamon-orange rump—as a Cave Swallow (Petrochelidon fulva) (Figures 1 and 2), a species previously unknown in British Columbia. The bird remained at Iona Island for nine days (to 19 November), during which period it was seen and photographed by many. Photographs show that the bird was undergoing primary molt and that it had replaced primaries 1 through 6 (Figure 1). The prebasic molt of adult Cave Swallows begins promptly after breeding, with flight feathers being replaced from June through September. In contrast, the preformative molt of immature birds occurs later, in the fall and winter, with flight-feather replacement from September through March (Pyle 1997). Given the date of our observation and the extent of primary replacement, we aged the bird as an immature in preformative molt.

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    ARAN MEYER, NATHANIAL WARNING, LAURYN BENEDICT (Author)

    DIRECT REMOVAL OF FECAL SACS BY ROCK WRENS

    Removal of fecal sacs from nests during nestlings’ development is an adaptive behavior shared by most species of passerines (Skutch 1976, Welty 1982, Weatherhead 1984). The selective forces that have shaped nest-sanitation behavior remain unclear, but clean nests are thought to be less likely to attract predators (Petit and Petit 1987, Petit et al. 1989; but see Ibáñez-Álamo et al. 2014a). Nest-sanitation behavior also appears to improve a host’s rejection of a brood parasite’s eggs (Moskat et al. 2003, Guigueno and Sealy 2012). In many studies nest sanitation is linked explicitly to measures of parental investment, including feeding rates (Ricklefs 1977, Gustafsson and Sutherland 1988, Markman et al. 2002). All of these studies indicate that the removal of fecal sacs can improve reproductive success for the parents, but fewer studies have focused on the role of nestlings’ behavior in nest sanitation, particularly in coordination with parental actions. Such behaviors have been known for some time. For example, Blair and Tucker (1941) described “active cooperation” behaviors, in which nestlings of multiple species with varied nest types were observed making deliberate movements to facilitate removal of their feces. Selection for behaviors that facilitate efficient removal of fecal material should be beneficial because they prevent nest contamination and decrease the time and energy expenditure given to nest sanitation (Thomson 1935, Spencer 2005, Ibáñez-Álamo et al. 2013). Nestlings of a few passerine species have been observed to raise their tails in response to adults’ visits to the nest in order to facilitate cloacal stimulation, after which the adults pick up the fecal sacs and either remove them from the nest or eat them (Selous 1933, Smith 1942, Davis 1978). Other researchers describe parent birds waiting near nestlings to remove fecal sacs from the nest floor (Gabrielson 1912, Laskey 1948, Ley and Williams 1998). In the House Wren (Troglodytes aedon) in Surinam, Haverschmidt (1952) described parents removing fecal sacs directly from the cloacae of nestlings, a behavior also described by Dobbs et al. (2001) in the Scaled Antpitta (Grallaria guatimalensis). This direct removal of fecal sacs likely eliminates a parent bird’s need to search for and pick up feces during the time of maximum provisioning effort, and it could limit the amount of potentially harmful bacteria within nests (Ibáñez-Álamo et al. 2014b). Direct removal of fecal sacs can be difficult to observe, particularly in cavity nests or nest boxes, and may therefore go underreported and undescribed. To date there have been few accounts of nestlings cooperating with parents to remove feces in species nesting in rock cavities, and even fewer photos or videos documenting such coordinated sanitation behaviors.

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    DALE W. STAHLECKER (Author)

    PROLONGED INCUBATION AND TWO CLUTCHES IN A NEW MEXICO GREAT HORNED OWL NEST: 2011–2012

    Widely spread across the phylogenetic tree in three avian orders, birds of prey are linked by their food habits and convergent evolution of talons and strong beaks. Second clutches/broods are rare among raptors; instead, a tendency to extend incubation beyond the time required for hatching has been documented in 12 species of the Accipitriformes, four of the Falconiformes, but only two of the Strigiformes (Margalida et al. 2006). With an average incubation period of 33 days (Arturo et al. 2014), the Great Horned Owl (Bubo virginianus) has not previously been reported to extend incubation. Furthermore, the species was previously known to lay a second clutch only after the death of the male early in incubation of the first clutch (Marti 1969).

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    STEVE ZAMEK, EDWARD R. PANDOLFINO (Author)

    INTERSPECIFIC FEEDING OF MOUNTAIN BLUEBIRD NESTLINGS BY A PYGMY NUTHATCH

    On 17 June and 20 June 2014 Zamek and his sister, J. Zamek, observed an adult Pygmy Nuthatch (Sitta pygmaea) feeding Mountain Bluebird (Sialia currucoides) nestlings near Prosser Creek Reservoir, Nevada County, California. The bluebirds’ nest cavity was approximately 2 m above the ground in a large snag. An active Pygmy Nuthatch nest with nestlings was in a cavity in the same snag approximately 2 m above the bluebird nest. There were other nest holes in this snag, but they did not appear to contain active nests. During approximately two hours of observation in late afternoon on 17 June and three hours in early morning on 20 June, a female Mountain Bluebird frequently fed the three bluebird nestlings. A male Mountain Bluebird was also present and remained close to the nest most of the time but visited the nest only four times on 17 June and twice on 20 June. A Pygmy Nuthatch also fed the Mountain Bluebird nestlings at least ten times on 17 June and at least nine times on 20 June. The Pygmy Nuthatch also reached into the Mountain Bluebird nest and removed fecal sacs two times on 20 June. Zamek obtained photographs of the bluebirds and the nuthatch feeding the bluebird nestlings and removing a fecal sac (see this issue’s back cover), making this one of very few photographically documented examples of interspecific feeding of nestlings and nest maintenance.