Linking oceanographic conditions, migratory schedules and foraging behaviour during the non‐breeding season to reproductive performance in a long‐lived seabird

Abstract

Studies of the mechanisms underlying climate‐induced population changes are critically needed to better understand and accurately predict population responses to climate change. Long‐lived migratory species might be particularly vulnerable to climate change as they are constrained by different climate conditions and energetic requirements during the breeding and non‐breeding seasons. Yet, most studies primarily focus on the breeding season of these species life cycle. Environmental conditions experienced in the non‐breeding season may have downstream effects on the other stages of the annual life cycle. Not investigating such effects may potentially lead to erroneous inferences about population dynamics. Combining demographic and tracking data collected between 2006 and 2013 at Kerguelen Island on a long‐lived migratory seabird, the Black‐Browed Albatross (Thalassarche melanophris), we investigated the links between sea surface temperature during the non‐breeding season and behavioural and phenological traits (at‐sea behaviour and migratory schedules) while accounting for different responses between birds of different sex and reproductive status (previously failed or successful breeders). We then explored whether variation in the foraging behaviour and timing of spring migration influenced subsequent reproductive performance. Our results showed that foraging activity and migratory schedules varied by both sex and reproductive status suggesting different energetic requirements and constraints among individuals. Higher sea surface temperatures during late winter, assumed to reflect poor winter conditions, were associated with an earlier departure from the wintering grounds and an extended pre‐breeding period. However, an earlier spring migration and an earlier return to Kerguelen grounds were associated with a lower breeding success. Our results highlighted that behaviour during some periods of the non‐breeding season, particularly towards the end of the wintering period and the pre‐breeding period, had a significant effect on the subsequent reproductive success. Therefore, caution needs to be given to all stages of the annual cycle when predicting the influence of climate on population dynamics. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13117/suppinfo is available for this article.

Climate change and functional traits affect population dynamics of a long‐lived seabird

“…Among climate variables, sea surface temperature (SST) is known to influence primary and secondary production in several marine ecosystems (Behrenfeld et al., ) and has been linked to various demographic rates in several seabird species (Barbraud et al., ). In BBAs breeding at Kerguelen Island, SST during various phases of the life cycle influences their migratory schedule, survival, breeding and success probabilities (Desprez, Jenouvrier, Barbraud, Delord, & Weimerskirch, ; Nevoux, Weimerskirch, & Barbraud, ; Pinaud & Weimerskirch, ; Rolland, Barbraud, & Weimerskirch, ). Juvenile BBA migrates from Kerguelen to the coasts of Australia, moving progressively from the south‐western coasts along to the south‐eastern coasts (De Grissac, Börger, Guitteaud, & Weimerskirch, ).…”

“…Juvenile BBA migrates from Kerguelen to the coasts of Australia, moving progressively from the south‐western coasts along to the south‐eastern coasts (De Grissac, Börger, Guitteaud, & Weimerskirch, ). Adults from Kerguelen migrate in this sector as well during the non‐breeding season (Desprez et al., ). Consequently, the SST in this wintering sector affects demographic rates and functional traits of both juveniles and adults.…”

“…Furthermore, higher SST during the breeding season over the eastern Kerguelen shelf—the main foraging area of this BBA population—positively influenced breeding success (Nevoux et al., ; Pinaud & Weimerskirch, ; Rolland, Barbraud, & Weimerskirch, ). Finally, larger fledging body size positively affected both juvenile survival and recruitment probabilities (Supporting Information, R. Fay, M. Desprez, S. Jenouvrier, C. Barbraud, K. Delord, & H. Weimerskirch, unpublished data), and both timing of arrival on the pre‐breeding grounds and foraging behaviours in the pre‐breeding grounds affected future breeding success (Desprez et al., ).…”

“…The effects of SST and foraging behaviours depend on individual breeding experience and status at the previous breeding season (Desprez et al., ; Nevoux et al., ; Rolland, Barbraud, & Weimerskirch, ). In BBA, like in many seabirds, individuals breeding successfully in a given year have a higher probability of reproducing and successfully raising a chick in the following year compared to failed breeders and non‐breeders (individuals that skipped reproduction in a given year; Cam & Monnat, ; Jenouvrier, Péron, & Weimerskirch, ).…”

“…In BBA, like in many seabirds, individuals breeding successfully in a given year have a higher probability of reproducing and successfully raising a chick in the following year compared to failed breeders and non‐breeders (individuals that skipped reproduction in a given year; Cam & Monnat, ; Jenouvrier, Péron, & Weimerskirch, ). In addition, failed breeders return earlier to pre‐breeding grounds and have extended winter and pre‐breeding periods, suggesting that they require longer foraging periods to build the energetic reserves necessary to reproduce compared to successful breeders (Desprez et al., ). These differences in functional traits and demographic rates between failed and successful breeders may indicate a lower intrinsic quality of failed breeders (sensu Wilson & Nussey, ).…”