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

Chmura, Helen; Krause, Jesse; Pérez, Jonathan; Asmus, Ashley; Sweet, Shannan; Hunt, Kathleen ; Meddle, Simone; McElreath, Richard; Boelman, Natalie; Gough, Laura; Wingfield, John

10 June 2018

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 gambellii), 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 years (2012-2016). Our results indicate that snowfall and cold temperatures decrease 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.