DOI: 10.5061/dryad.c4v2r8v
title: Data from: How extreme is extreme? Demographic approaches inform the occurrence and ecological relevance of extreme events

description: Projected increases in the variability of both temperature and
 precipitation will result in the greater likelihood and magnitude of
 extreme weather (e.g., cold snaps, droughts, heat waves) with potential
 implications for animal populations. Despite the ecological consequences
 of extreme weather, there are several challenges in identifying extreme
 events and measuring their influence on key demographic processes in
 free-living animals. First, there is often a mismatch between the spatial
 and/or temporal resolution of biological and climate data, masking the
 ability to draw inferences about how species and populations respond to
 extreme events. Second, there are multiple approaches for identifying an
 extreme event ranging from statistical definitions (e.g., standardized
 deviates) to species-specific biological thresholds. Lastly, the impacts
 of extreme weather on species can vary as a function of differences in
 exposure and intrinsic sensitivity to climate variability. In the Northern
 Hemisphere, rapid warming has contributed to a “wobblier” jet stream that
 promotes the higher likelihood of unusually cold Artic air moving
 southward and leading to more extreme winter conditions. Due to these
 conditions, the Upper Midwest experienced two of the coldest winters in
 the past 35 years during 2014 and 2015. We combined radiofrequency
 identification technologies with fine-scale weather data and standard
 capture-mark-recapture analyses to estimate weekly and overwinter survival
 rates of a common winter passerine, the black-capped chickadee (Poecile
 atricapillus), in a near continuous fashion. Using both statistical and
 biological definitions of weather extremes, we found that declining
 ambient temperatures reduced survival (despite the presence of favorable
 microclimates), and that biologically-defined thresholds of extreme
 weather were better at explaining variation in survival than statistical
 ones. Moreover, habitat fragmentation interacted with temperature to
 modify the exposure of birds to extreme weather with survival
 consequences, but sensitivity, as measured by body condition, did not
 appear to play a significant role. These results provide a novel
 contribution to the understanding of how extreme weather may interact with
 local- and landscape features to influence the demography of species and
 populations, and suggest potential opportunities for climate change
 adaptation in human-dominated landscapes
description: BCCH_cap_hist_1415Capture history and site covariates, including winter microclimate variables. Variable abbreviations are as follows: ch = capture history; yr = year; spp = species; Ag = Age (0 = HY; 1 = AHY); treeden = density of trees/ha; disttourb = distance to urban center (km); Area = focal patch area (ha); hdd = cumulative degree-days (C); MeanT = Average winter temperature (C); MinT = Average minimum temperature (C); CVT = Coefficient of variation in minimum temperature; Snow = total accumulated snowfall (cm); Ncoldwet = Number of cold (below -18C) and wet (&gt; 1cm snowfall) days; Mi = Body condition index; ISI = Impervious surface (%); Pfor = Percent forest (%); For_ED = Forest Edge Density (m^2); For_ENN = Area-weighted mean Euclidean Nearest Neighbor distance between forest patches in the landscape (m^2); PA = Perimeter:Area ratio of focal forest patch.