Western Birds Journal

Volume 54, No. 2

Published April 1, 2023

Issue description

Volume 54, number 2 of Western Birds, published 2023

Articles

  1. Cover image V54(2)

    DANIEL D. GIBSON, THEODORE G. TOBISH, AARON J. LANG, JACK J. WITHROW, LUCAS H. DeCICCO, NICHOLAS R. HAJDUKOVICH, ROBERT L. SCHER (Author)

    THE FIFTH REPORT OF THE ALASKA CHECKLIST COMMITTEE ADDS 21 SPECIES TO THE CHECKLIST OF ALASKA BIRDS FROM THE FIVE YEARS 2018–2022

     The fifth report of the Alaska Checklist Committee adds 21 species to the Checklist of Alaska Birds from the five years 2018–2022, a net total that includes the addition of two species formerly maintained as subspecies—Stejneger’s Scoter (Melanitta stejnegeri) and the Short-billed Gull (Larus brachyrhynchus)—and the deletion of one species (Northwestern Crow) currently maintained as a subspecies of the American Crow, Corvus brachyrhynchos caurinus. At the close of 2022 we recognize 541 species and 118 additional subspecies as occurring, or having occurred, naturally in Alaska.

  2. Cover image V54(2)

    EDWARD R. PANDOLFINO, LILY A. DOUGLAS, PETER PYLE (Author)

    VOCALIZATIONS AND BILL MEASUREMENTS MAY RESOLVE SOME QUESTIONS ABOUT TAXONOMIC RELATIONSHIPS WITHIN THE FOX SPARROW COMPLEX

     The many described subspecies of the Fox Sparrow (Passerella iliaca) have been parsed into four groups, the Red (iliaca group, two or three subspecies), Sooty (unalaschcensis group, seven subspecies), Thick-billed (megarhyncha group, five subspecies) and Slate-colored (schistacea group, four subspecies). Intermediate populations and contact areas between these groups play a role in answering the question whether any of the groups should be considered separate species. P. i. canescens of the Slate-colored group shows genetic characters of both the Slate-colored and Thick-billed groups. As currently classified it comprises two disjunct populations, one breeding in the White Mountains of California and Nevada, the other in the Toiyabe Range of central Nevada. We analyzed the vocalizations and bill sizes of these two populations to see if this might shed light on their taxonomic relationships. Our analyses of song, call, and bill measurements, along with a re-examination of previously published morphologic and genetic data, suggest that the two disjunct populations currently assigned to P. i. canescens represent different subspecies: the central Nevada population P. i. schistacea (in the Slate-colored group) and the White Mountains population P. i. megarhyncha (in the Thick-billed group), thus eliminating P. i. canescens as a synonym. Our findings may have implications for any future proposals to split the Fox Sparrow groups into distinct species. If that split results in the Slate-colored and Thick-billed groups assigned to separate species, our results would include the White Mountains population in the Thick-billed species and the central Nevada population in the Slate-colored species.

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    DESMOND E. SIEBURTH, RYAN TERRILL, PETER PYLE (Author)

    THE POTENTIAL IDENTIFICATION AND DISTRIBUTION OF AINLEY’S STORM-PETREL AT SEA BY TIMING OF MOLT

     In 2016, the American Ornithologists’ Union split the Leach’s Storm-Petrel into three species: Leach’s Storm-Petrel (Hydrobates leucorhous), Townsend’s Storm-Petrel (H. soccoroensis), and Ainley’s Storm-Petrel (H. cheimomnestes). Leach’s breeds around the Northern Hemisphere during the boreal summer, while both Townsend’s and Ainley’s breed on islets off Guadalupe Island, Mexico, the former in summer and the latter in winter. Although morphological differences between Leach’s and Ainley’s are slight at best, we hypothesized that the difference in breeding schedule may result in a difference between the species in molt schedule, allowing identification of some birds at sea. We examined 528 specimens and hundreds of photographs for molt of primaries, aging each bird by its having juvenile vs. basic flight feathers and the presence of molt clines, and scoring molt by the number of primaries replaced. Using threshold models, we identified ten birds whose timing of molt suggested Ainley’s, most occurring off central-to-southern Mexico. In Leach’s and/or Townsend’s storm-petrels, primaries were being replaced in the second prebasic molt from 21 February (p2) to 15 December (p8) and in the definitive prebasic molt from 24 October (p3) to 22 February (p8). In the smaller sample of Ainley’s, these dates were 23 November (p6) to 22 February (p8) and 11 June (p3) to 7 November (p8), respectively. Thus the timing of molt may help identify Ainley’s at sea, important for the management of this vulnerable species. Genetic analysis of the specimens may confirm our identifications and the applicability of our technique.

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    PHILLIP J. CAPITOLO, BARBARA DOE (Author)

    NEST-BOX USE AND APPARENT DOUBLE BROODING BY RED-BREASTED NUTHATCHES IN CALIFORNIA

     We documented Red-breasted Nuthatches (Sitta canadensis) in the Berkeley Hills of coastal central California successfully using a nest box in 2021 and 2022, and successfully double brooding in 2022. Although we can’t be certain the individuals responsible for the two broods in 2022 were the same, we never saw more than two adults. In both years, we also observed the nuthatches applying resin to the outside of the box, most conspicuously to create a mass that included some grass at the base of the entrance hole, somewhat reducing its diameter (Figure 1).

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    JEFFERY T. WILCOX, LUC MYERS, IAN JACKSON, JEFF A. ALVAREZ (Author)

    APPARENT OBJECT PLAY IN THE NORTHERN HARRIER

     Animal play is notoriously difficult to describe, particularly in birds (Ficken 1977). Play is most common in the young of a species (Loizos 1966), a life stage when conflicting environmental pressures are reduced by parental care. In 11 of the 13 orders of birds for which play has been reported, the young are altricial (Ortega and Beckoff 1987). Beckoff and Byers (1981) classified avian play into three categories: locomotor play (primarily play in flight), object play, and social play. Play with objects, reported for eight avian orders (Ortega and Beckoff 1987), is widespread in wild populations of birds of prey (see Ficken 1977) and may involve manipulating prey animals or inanimate objects such as twigs or stones. During play, an object is often carried into the air, dropped, and then caught with the feet, with the act repeated many times (Ficken 1977). We report here on object play by the Northern Harrier (Circus hudsonius). Ours is not the first report of play in the Northern Harrier (Sumner 1931), nor of harriers playing with inanimate objects (Bildstein and
    Hamerstrom 1980, Bildstein 1992). We describe repeated acts that constitute the first report of play by a Northern Harrier with an unknown inanimate object, and speculate on why this activity may lend fitness to an individual harrier.