Abstract

Personality is relevant in shaping the way animals respond to environmental conditions. Some personality traits may be disadvantageous under non-optimal environmental conditions, reducing foraging success and breeding performance in the long term. In this study we tested whether individual personality plays a role in determining shifts in seabirds' foraging behaviour and habitat use when environmental conditions are poor. We used GPS-tracking information from chick-rearing Cory's Shearwaters (Calonectris borealis) during eight consecutive years. Boldness was measured by the response of the tracked individuals to a novel object presented at their nest. Foraging habitat was identified as the environment within geographic points where birds were flying at low speed with high turning rates. We found that bold individuals displayed more foraging habitat consistency and boldness influenced foraging habitat during years of poor environmental conditions. Bold individuals tended to remain closer to the colony under poor environmental conditions, while shy individuals dispersed considerably farther from the colony. However, there was no influence of the personality on breeding success, and the whole population tended to have a lower probability of breeding success during years of poor conditions. During adverse environmental conditions, shy birds shifted habitat, probably as consequence of exploitative competition with the bold birds, but this has no effect on the birds' ability to successfully raise a chick.