The effects of management practices on grassland birds—Brewer’s Sparrow (&lt;i&gt;Spizella breweri breweri&lt;/i&gt;)

Walker, Brett L.; Igl, Lawrence D.; Shaffer, Jill A.

doi:10.3133/pp1842aa

Cited by 5 publications

(9 citation statements)

References 42 publications

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“…We recorded information on the pairing status of male Brewer's sparrows during spot mapping visits via the unique vocalizations of paired versus unpaired individuals. Male Brewer's sparrows sing distinctly longer, more elaborate songs after successfully pairing (Walker, 2000; A. Chalfoun, unpublished data). Indeed, altered vocalization patterns and increased frequency of singing is a somewhat widespread strategy among passerines to reduce cuckoldry (Moller, 1991).…”

Section: Methodsmentioning

confidence: 99%

Congruence among multiple indices of habitat preference for species facing human‐induced rapid environmental change: A case study using the Brewer's sparrow

Carlin

Chalfoun

2022

Ecol Sol and Evidence

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Accurate evaluations of habitat preference are key to understanding optimal conditions for wildlife survival and reproduction. Habitat selection, however, usually is evaluated using a single index of preference, and congruence among multiple, relevant indices of preference is examined rarely. We assessed the concordance between patterns of habitat preference using three different indices of breeding site preference in a migratory songbird. Specifically, we compared the chronology of territorial establishment, pair formation and reproductive initiation of the Brewer's sparrow (Spizella breweri) along a gradient of surface disturbance associated with natural gas development in Wyoming, USA during 2019. We expected all three indices to demonstrate a preference for breeding sites with less surface disturbance, where reproductive success typically is higher. By contrast, all indices suggested suboptimal preference with respect to surface disturbance, with some discrepancy among them. The chronology of settlement and pairing did not vary across the disturbance gradient, whereas nest initiation tended to occur earlier at sites with more disturbance. If the pattern of suboptimal selection of breeding sites that we identified is generalizable across other populations of migratory birds affected by energy development, the resultant lower fitness in those areas may exacerbate population declines. Our results suggest that traditional, single‐index approaches to the study of habitat selection, if chosen carefully, may provide adequate inference on habitat preferences. Different metrics, however, can lead to at least subtle differences in patterns of habitat selection. The simultaneous examination of multiple indices of preference across a diversity of systems would help clarify the contexts under which preference metrics can become decoupled.

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Section: Methodsmentioning

confidence: 99%

Congruence among multiple indices of habitat preference for species facing human‐induced rapid environmental change: A case study using the Brewer's sparrow

Carlin

Chalfoun

2022

Ecol Sol and Evidence

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Section: Songmentioning

confidence: 99%

“…Male Brewer's Sparrows sing two categories of song types, short songs and long songs, but each male typically gives only one short song type, rarely two or three (Walker 2000, Rich 2002. Males generally only give short songs when unpaired, so short songs are thought to play a key role in mate attraction (Walker 2000) and, therefore, in the potential for reproductive isolation between subspecies (Mayr and Johnson 2001). Acoustic elements of taverneri songs are reported to have lower maximum frequencies, higher minimum frequencies, and, therefore, cover a narrower range of frequencies than those of breweri (Klicka et al 1999, Walker 2024).…”

Section: Songmentioning

confidence: 99%

“…We added one recording from a public repository of a male singing short songs in willows in the Flattops Wilderness in Colorado to our alpine sample (XenoCanto 14188). Following Walker (2024), we used the selection tool to select (a) the entire song, (b) each section of the song, (c) one representative syllable type within each section, and (d) each note type within each selected syllable type. For each song, we measured song duration, total number of syllable types, and total number of note types.…”

Section: Songmentioning

confidence: 99%

“…At each site, we surveyed for, counted, and recorded singing males, documented habitat features, looked for evidence of breeding, and captured birds to obtain morphological data, photographs, and blood and feather samples. Finally, we compared external morphology, acoustic structure of songs, plumage and maxilla color, and mitochondrial and nuclear DNA sequences between alpine birds and sagebrush breweri and against published data for each subspecies (Klicka et al 1999, Walker 2024 to determine the taxonomic affiliation of alpine birds.…”

Section: Introductionmentioning

confidence: 99%

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Field research guided by citizen science and monitoring data reveal a novel alpine breeding distribution and vegetation associations of a declining, habitat-specialist songbird in Colorado, USA

Walker,

Yappert,

Brennan

et al. 2024

ACE

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Documenting the breeding habitat and distribution of migratory songbirds is essential for accurately assessing their conservation status. The "sagebrush" subspecies of the Brewer's Sparrow (Spizella breweri breweri) breeds in greatest abundance in sagebrush-dominated (Artemisia spp.) shrublands of western North America, and the "timberline" subspecies (S. b. taverneri) breeds in shrubs or krummholz at or above the tree line in mountain ranges from Alaska to Montana. Brewer's Sparrows have also been reported at alpine sites in summer in mountain ranges across the western United States, but their taxonomic affiliation and breeding status are unknown. We reviewed monitoring, citizen science, and specimen data for Colorado and identified 186 historical summer observations of Brewer's Sparrows at 59 alpine sites (3334-4288 m elevation). We surveyed 39 alpine sites in June-July 2021-2023, detected a total of 100 adults (mostly singing males) at 26 alpine sites (3395-3754 m elevation), and confirmed breeding at three sites. Males occupied mixed-species willow patches 0.9-1.8 m tall, often intermixed with sparse conifer krummholz. We recorded songs and captured, measured, photographed, and collected blood and feather samples from birds at a subset of alpine sites and nearby, lowerelevation sagebrush sites in May-July 2021. Vegetation associations and timing of breeding at alpine sites closely matched those of taverneri, but short songs, external morphology, coloration, and genetics of alpine birds overlapped with sagebrush birds and more closely matched those of range-wide breweri. Our results indicate that western Colorado supports a widely-distributed, but poorlydocumented, population of alpine breweri breeding in willows with sparse conifer krummholz within a relatively narrow elevation band at or above the tree line. Whether alpine birds are itinerant breeders that first nested in sagebrush remains unknown. Our results complicate interpretation of differences in breeding habitat and breeding phenology as supporting criteria for subspecific identification and taxonomic delineation in this species. La recherche sur le terrain guidée par la science citoyenne et les données de suivi révèlent une nouvelle répartition de nidification en milieu alpin et les associations végétales d'un passereau spécialiste en baisse, au Colorado, États-UnisRÉSUMÉ. Il est essentiel de caractériser l'habitat de nidification et la répartition des passereaux migrateurs pour évaluer avec précision leur situation. La sous-espèce « breweri » du Bruant de Brewer (Spizella breweri breweri) niche en plus grand nombre dans les régions arbustives dominées par les armoises (Artemisia sp.) de l'ouest de l'Amérique du Nord, et la sous-espèce « taverneri » (S. b. taverneri) niche dans les arbustes ou les krummholz à la limite des arbres ou au-dessus de celle-ci dans les chaînes de montagnes de l'Alaska au Montana. Des Bruants de Brewer ont également été signalés sur des sites alpins en été dans les chaînes de montagnes de l'ouest des États-Unis, mais leur ...

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Rangeland Songbirds

Chalfoun,

Johnson,

Shaffer

2023

Rangeland Wildlife Ecology and Conservation

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Songbirds that occur across the diverse types of North American rangelands constitute many families within the Order Passeriformes, and hundreds of species. Most are declining, and many are considered potential indicator species for rangeland ecosystems. We synthesized information on the natural and life history, habitat requirements, conservation status, and responses to management of songbirds associated with North American grasslands and sagebrush steppe, two of the most geographically extensive types of rangelands. We provide a more targeted examination of the habitat associations and management considerations for two focal species, the grassland-obligate grasshopper sparrow (Ammodramus savannarum) and sagebrush-obligate Brewer’s sparrow (Spizella breweri). Grassland- and sagebrush-obligate species rely on expansive stands of grasslands and sagebrush, respectively, and we discuss how key ecological processes and rangeland management approaches—grazing, fire, and mechanical treatments—influence rangeland songbirds. Rangeland management practices can affect breeding songbirds considerably, primarily through the resultant structure and composition of vegetation, which influences the availability of preferred nesting substrates, refugia from predators, and foraging success. Optimal management strategies to limit negative consequences to rangeland songbirds will depend on the target species and local topoedaphic and climatic conditions. The maintenance of large, contiguous patches of native habitats and restoration of previously degraded areas will help facilitate the population persistence of rangeland-associated songbirds. Maintaining structural heterogeneity of habitats within landscapes, moreover, can facilitate local species diversity. Information pertaining to periods outside of the nesting stage is severely lacking for most species, which is concerning because effective management necessitates understanding of threats and limiting factors across the full annual life cycle. Moreover, information on disease effects and prevalence, the effects of a changing climate, and how both may interact with management strategies, also comprise key gaps in knowledge.

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The effects of management practices on grassland birds—Brewer’s Sparrow (<i>Spizella breweri breweri</i>)

Cited by 5 publications

References 42 publications

Congruence among multiple indices of habitat preference for species facing human‐induced rapid environmental change: A case study using the Brewer's sparrow

Congruence among multiple indices of habitat preference for species facing human‐induced rapid environmental change: A case study using the Brewer's sparrow

Field research guided by citizen science and monitoring data reveal a novel alpine breeding distribution and vegetation associations of a declining, habitat-specialist songbird in Colorado, USA

Rangeland Songbirds

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