DOI: 10.5061/dryad.f7h4614
title: Data from: Flexible response to short-term weather in a cold-adapted songbird

description: To improve survival during winter, temperate species use a variety of
 behavioural and physiological adaptations. Among songbirds, the
 maintenance of lipid reserves is a widely-used strategy to cope with the
 severity of winter; however, little is known regarding how multiple
 synchronously acting environmental mechanisms work together to drive these
 effects. In a context where temperate winter conditions are becoming more
 variable, it is important to widen our understanding regarding the
 flexible adaptations that may allow wintering species to adjust to
 projected climate change. Using a long-term dataset collected across
 multiple wintering populations (7 years; 8 locations), we analyzed the
 effects of daily variation in weather (e.g., temperature, snowfall) on the
 variation in energy reserves (i.e., fat stores) of wintering snow buntings
 (Plectrophenax nivalis). Our results support the prediction that birds
 carry more reserves to increase the safety margin against starvation when
 conditions are energy-demanding and access to food is unpredictable (i.e.,
 colder, snowier conditions). Birds responded to daily changes in weather
 by increasing their reserves as conditions deteriorated, with maximal
 temperatures and snow depth being the most important predictors of
 fattening decisions. We also found that females consistently exhibited
 higher fat reserves than males relative to their body size, suggesting
 that differential physiological adaptations among sexes or social
 dominance may play an additional role in explaining variation in energy
 reserves across individuals in this species. Overall, our findings
 increase knowledge on phenotypic adjustments used by species wintering in
 temperate zones to match variation in their environment.
description: Snow bunting winter
 banding data and associated daily weather variables for each individual
 captureSnow bunting winter (Nov
 1 to Mar 20) banding data (including age, sex, banding location, body
 mass, wing chord, fat score and time of capture) merged to associated
 daily weather data (including mean temperature, minimal temperature,
 maximal temperature, snow depth, total snowfall, absolute humidity,
 maximal wing gust and cloud cover (for the period 2009-2015 for 8
 locations in eastern Canada. Banding data were obtained from both the
 Canadian bird banding office and the citizen science project Canadian Snow
 Bunting Network. Daily weather variables were merged to banding data and
 were extracted from the following three sources : 1) environment and
 climate change weather office online, 2) ministère du développement
 durable de l'environnement et de la lutte contre les changements
 climatiques et 3) National snow and ice data center. Only individual
 record for which a complete set of information was available for every
 individual (i.e. sex, age, wing chord, fat score, body mass, time of
 capture) and only banding entries with an associated complete set of
 weather variables were kept in the dataset. Excel was used to calculate
 weather averaged over the three days preceding capture. R Software (3.2.1)
 was used to create the datafile and do all other
 manipulations.snbudata.csv