White-crowned Sparrow (Zonotrichia leucophrys)

Chilton, Glen; Baker, Megan C.; Barrentine, C. D.; Cunningham, Michael

doi:10.2173/bow.whcspa.01

Cited by 13 publications

(17 citation statements)

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“…Since the 1980s there have been a few changes in the composition of the nesting bird community on the east end of Herschel Island, characterised by a loss of two species currently facing population declines (Zöckler et al 2013) and particularly associated with brackish and freshwater ponds (RNPH and RUTU), and a gain of some species more typically associated, at least west of the Mackenzie River, with boreal and subarctic habitats [sandhill crane (SACR), LESA, and white-crowned sparrow (WCSP)] (Chilton et al 1995;Nebel and Cooper 2008;Eckert 2012;Gerber et al 2014). Increasing sea level, coupled with greater variability associated with more frequent and intense storm surges, have resulted in increased flooding of significant portions of the beach and alluvial fan habitats each summer (Pollard et al 2012).…”

Section: Breeding Bird Communitymentioning

confidence: 99%

Phenology of hatching and food in low Arctic passerines and shorebirds: is there a mismatch?

Leung¹,

Bolduc

Doyle³

et al. 2018

Arctic Science

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The warming climate is driving earlier spring snow melt and longer growing seasons in tundra regions of northwestern North America, thereby changing the timing of ecological processes. On Herschel Island, Yukon, Canada, we investigated changes in the migratory bird community, and the potential for phenological mismatch of egg hatching with the pulses in abundance of arthropod prey on which young birds depend for growth. We found an apparent reduction in abundance or loss of some species dependent on freshwater ponds or sparsely vegetated upland tundra. Tracking hatch dates of passerines and shorebirds along with the changes in biomass of mobile life history stages of arthropods (principally Araneae, Tipulidae, Carabidae, Muscidae, Chironomidae, Mycetophilidae, and Ichneumonidae), we found no evidence for phenological mismatch in the 2007–2009 time period. Most nests hatched, and the period of most rapid chick growth occurred, in advance of the highest availability of arthropod biomass. Shorebirds hatched significantly later than passerines, less in advance of the peak abundances of arthropods. They are most at risk of future mismatch, given likely trend to earlier onset of arthropod availability and longer migration routes. Herschel Island is a well-studied site warranting further monitoring to assess changes in the Arctic tundra ecosystem.

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Section: Breeding Bird Communitymentioning

confidence: 99%

Phenology of hatching and food in low Arctic passerines and shorebirds: is there a mismatch?

Leung¹,

Bolduc

Doyle³

et al. 2018

Arctic Science

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“…It overwinters in the mid‐western United States and southern Canada (Hussell and Montgomerie ). The Gambel's white‐crowned sparrow occurs only in western North America, where it breeds in Alaska and Canada (though sometimes as far south as northern Washington State) and overwinters in California, Arizona, New Mexico, Texas and northern Mexico (Chilton et al ). Both species nest on the ground.…”

Section: Methodsmentioning

confidence: 99%

“…Both species nest on the ground. Lapland longspurs nest in the sides of tussock‐forming sedges, while Gambel's white‐crowned sparrows nest at the base of shrubs (Chilton et al , Boelman et al , 2017). At our study sites, both species arrive on the breeding grounds in mid‐May and quickly establish territories.…”

Section: Methodsmentioning

confidence: 99%

“…At our study sites, both species arrive on the breeding grounds in mid‐May and quickly establish territories. Clutch initiation may continue from late‐May to mid‐June and nestlings typically hatch by mid‐June (Boelman et al ) and fledge 8–11 d later (Chilton et al , Hussell and Montgomerie ). Diet of nestling Lapland longspurs and Gambel's white‐crowned sparrows at our sites includes crane flies Tipula cariniform , sawflies (Tenthredinidae), midges (Chironomidae), muscoid flies (Muscidae), beetles (Coleoptera), spiders (Araneida), caterpillars (Lepidoptera), true bugs (Hemiptera) and other insects (Boelman et al ).…”

Section: Methodsmentioning

confidence: 99%

“…Ground‐dwelling arthropods were sampled weekly throughout the breeding season (clutch initiation to several weeks beyond fledging) at all transects using pitfall traps (Robel et al ) using a monitoring scheme described in detail by Rich et al (). Briefly, for pitfall traps, from late‐May to late‐July we placed clear plastic cups in the ground flush with the soil surface at 10 fixed locations along each 100‐m transect.…”

Section: Methodsmentioning

confidence: 99%

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Late‐season snowfall is associated with decreased offspring survival in two migratory arctic‐breeding songbird species

Chmura

Krause

Pérez

et al. 2018

Journal of Avian Biology

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While the effect of weather on reproduction has been studied for many years in avian taxa, the rapid pace of climate change in arctic regions has added urgency to this question by changing the weather conditions species experience during breeding. Given this, it is important to understand how factors such as temperature, rain, snowfall, and wind affect reproduction both directly and indirectly (e.g. through their effects on food availability). In this study, we ask how weather factors and food availability influence daily survival rates of clutches in two arctic‐breeding migratory songbirds: the Lapland longspur Calcarius lapponicus, a circumpolar breeder, and Gambel's white‐crowned sparrow Zonotrichia leucophrys gambelii, which breeds in shrubby habitats across tundra, boreal and continental climates. To do this, we monitored clutch survival in these two species from egg‐lay through fledge at field sites located near Toolik Field Station (North Slope, Alaska) across 5 yr (2012–2016). Our results indicate that snowfall and cold temperatures decreased offspring survival rates in both species; although Lapland longspurs were more susceptible to snowfall. Food availability, quantified by pitfall sampling and sweep‐net sampling methods, had minimal effects on offspring survival. Some climate models predict increased precipitation for the Arctic with global warming, and in the Toolik region, total snow accumulation may be increasing. Placed in this context, our results suggest that changes in snow storms with climate change could have substantial consequences for reproduction in migratory songbirds breeding in the North American Arctic.

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Late breeding season definitive prebasic molt in males, and late breeding season brood care by females, in central California Wilson’s warblers

Gilbert

2022

Ecology and Evolution

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I made observations of a central California population of Wilson's Warbler, Cardellina pusilla, after July 1 over 10 breeding seasons. I sighted males in definitive prebasic molt from July 4 (in 2007) to September 1 (in 1999). Most territorial males molted on their breeding territories, and individual molt lasted up to 46 days. Following prebasic molt, territorial males engaged in subdued “post‐molt singing,” which lasted about 7 days in some males, and which I first heard on August 13 (in 2004) and last heard on September 6 (in 1999). I sighted no female in definitive prebasic molt, or in fresh basic plumage, during the study. Of 13 females sighted ≥ July 21, 11 were in late breeding season uniparental brood care, and I could not rule out late brood care for the other two. Most, and possibly all, females not engaged in late season uniparental brood care apparently vacated their breeding territories before July 21. This departure was much earlier than for resident males, the last of which I sighted on September 10 (in 1999). Early‐departing females presumably underwent prebasic molt after July 21 at locations not known. Remaining late‐nesting females must have molted much later than resident males and likely later than early‐departing females, and at locations unknown. I last sighted two uniparental brood‐tending females, still in worn plumage, on August 26 and 29, respectively. Two unique findings of this study are a male/female difference in location of prebasic molt, and a likely dichotomy of prebasic molt timing between females leaving their breeding territories early and those remaining in uniparental brood care. Another finding, post‐molt singing in most and possible all territorial males, is a largely unrecognized behavior, but one previously reported in several passerine species. Post‐molt singing may reliably indicate completion of prebasic molt.

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White-crowned Sparrow (Zonotrichia leucophrys)

Cited by 13 publications

References 0 publications

Phenology of hatching and food in low Arctic passerines and shorebirds: is there a mismatch?

Phenology of hatching and food in low Arctic passerines and shorebirds: is there a mismatch?

Late‐season snowfall is associated with decreased offspring survival in two migratory arctic‐breeding songbird species

Late breeding season definitive prebasic molt in males, and late breeding season brood care by females, in central California Wilson’s warblers

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