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

1. 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 lifecycle. Environmental conditions
experienced in the non-breeding season may have downstream effects on the
other stages of the annual lifecycle. Not investigating such effects may
potentially lead to erroneous inferences about population dynamics. 2.
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 if variation in the foraging behaviour and timing of spring
migration influenced subsequent reproductive performance. 3. 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. 4. 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.