Skipped breeding in common guillemots in a changing climate: restraint or constraint?

Abstract

Climate change may have demographic consequences for marine top predators if it leads to altered rates of skipped breeding. Here we examine variation in skipping propensity at both the population and individual levels in common guillemots Uria aalge in relation to climate and oceanographic variables and explore the extent to which skipping may be adaptive or an unavoidable consequence of ecological or social constraints. We assumed a detection probability for birds present in the colony of 1.00 and skipping events were defined to include both resightings of non-breeders and failures to resight individuals known to be alive (not present at the colony but resighted in future years). Skipping frequency was higher in years where sea surface temperatures (SST) were higher in winter (both in the current and previous year), when guillemots from our study colony disperse widely across the southern North Sea. Individuals differed consistently in their average skipping propensity and their responses to SST. Males and females were equally likely to skip on average and the frequency of skipping increased in the oldest age classes. Birds that skipped in year t had lower breeding success in year t + 1 if they laid an egg, compared to birds that did not skip in year t. Lifetime reproductive output was negatively related to individual skipping frequency. These results imply that skipping is driven by individual-specific constraints, although we cannot rule out the possibility that birds benefit from skipping when environmental (or internal) signals indicate that breeding in poor years could be detrimental to their residual reproductive value. While future climate change might lead to guillemots skipping more often due to carry-over effects from wintering to breeding periods, the net demographic impacts may be subtle as the absolute frequency of skipping may remain low and individuals will not be equally affected.

Forecasting ocean warming impacts on seabird demography: a case study on the European storm petrel

“…Thus, birds are more likely to skip breeding after cold winters and in cold prebreeding periods. Our findings that the western Mediterranean basin conditions during winter and spring affect the probability of breeding in the Mediterranean storm petrel is in agreement with studies on other species (Reed et al 2015).…”

“…Due to the high costs of reproduction, seabirds often skip reproduction as an adaptive strategy in response to environmental constraints that favours their own survival and future reproduction (Jenouvrier et al 2005b, Giudici et al 2010, Cubaynes et al 2011, Reed et al 2015. Intermittent breeding is actually a widely observed phenomenon, which can be modelled based on the cost of reproduction (Shaw & Levin 2013).…”

Use of state‐space modelling to identify ecological covariates associated with trends in pinniped demography

“…Environmental conditions seem to impact fecundity more than survival ( This is consistent with life history theory that suggests that long-lived capital breeders 'prioritize' survival over breeding (Gaillard, Festa-Bianchet, & Yoccoz, 1998;Reed, Harris, & Wanless, 2015;Stenson, Buren, & Koen-Alonso, 2016). While trends in survival were stable, varying only owing to strong short-term action such as culling, temporal trends in fecundity were more variable.…”

Editorial: Climate Change and Marine Top Predators

“…In common terns (Sterna hirundo), Szostek et al (2015) find that arrival date and mass at the breeding colony were related to climatic conditions and food availability in wintering and staging areas, but that age groups differed in their reaction to climate. Reed et al (2015) show that the probability of skipping breeding in common guillemots was higher after warm winters, and that individuals differed in both mean skipping propensity and their response to temperature.…”