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"The causes, consequences and conservation implications of individual specialisation in seabirds"

Final Report Summary - ALBASPECIALISATION (The causes, consequences and conservation implications of individual specialisation in seabirds)

The research project was split into three main themes:

• Quantify the degree of consistency in individual foraging strategy

This theme focused on measuring foraging behaviour and assessing the degree to which individuals are consistent in this behaviour

• The causes of individual variation in foraging strategy, developing measures of individual personalities in albatrosses

This theme focused on quantifying individual differences in personality and linking this to foraging behaviour

• Determine the conservation implications of individual variation

This theme focused on examining the fitness consequences of both personality variation and foraging strategy, particularly in relationship to fisheries, which are known to be a widespread threat to albatross populations.

• A description of the main S&T results/foregrounds (not exceeding 25 pages)

Summary of results

Individual personalities

We used a series of tests to quantify personality differences for the first time in two species of albatross; Black browed and Wandering. Using a novel object test, the approach of a person and heart rate measures, we identified that both species showed repeatable personality differences and that these were heritable in wandering albatross (sample size insufficient for black browed). We also found that the response to a novel object was correlated with the response to an approaching person, suggesting they are measuring similar variation. Having quantified these measures of personality, using a standard axis of boldness, we developed new measures, assessing foraging personality.

Consistency in foraging behaviour

While previous studies have found that individuals display consistent foraging behaviours, we were the first to consider foraging behaviour itself as a personality trait. Using the same methods we employed for our measure of boldness in response to a novel object, we collapsed foraging traits into one measure using a principal components analysis. Our measure of foraging personality was found to be highly repeatable between individuals, suggesting it too can be considered to be a personality trait.

Linking boldness and foraging

Our measure of foraging personality correlated with boldness, suggesting evidence of a behavioural syndrome. We found strong evidence that bolder birds forage nearer the colony where competition is thought to be higher. However, despite predictions that personality may correlate with the overlap with fisheries, we found no evidence of this.

Consequences of personality differences

Our results showing that boldness does not predict the overlap with fisheries suggests that the risk of bycatch in fishing lines is perhaps not linked to personality. However, we find strong support that there are fitness consequences to personality differences and that these are linked to foraging. In black browed albatross, it appears that there is a highly sex specific fitness benefit to personality differences. Bolder females have a higher fitness but this result is reversed in males, and instead shyer males have higher fitness. In addition it appears to always be beneficial for males to forage close to the colony, but for females the benefit of this strategy depends on food availability. In wandering albatross, the relationship with personality is both sex and age dependent. As males get older they show reproductive senescence, but this is much stronger in shy males than bolder males. Bold males appear to change their foraging behaviour as they get older, making longer trips and gaining more mass during these than their shy counter parts. Boldness does not seem to impact on female fitness in this species. These differences between the two species may be due their foraging ecology. Results from black browed albatross were collected during chick brooding, where birds make short trips close to the colony, under high competition. The results from wandering albatross were from incubation, where birds make long trips, with little overlap between individuals.

These questions have been addressed in more detail in a series of publications.

Details of Publications

Patrick, S.C. and Weimerskirch, H. Senescence rates are strongly influenced by personality in a long lived seabird. In review Proceedings of the National Academy of Sciences.
Patrick, S.C. and Weimerskirch, H. Personality, foraging and fitness consequences in a long lived seabird. In Press PLoS One.
Weimerskirch, H. Cherel, Y., Delord, K., Jaeger, A., Patrick, S.C. Riotte-Lambert, L. 2014 Lifetime foraging patterns of the wandering albatross: life on the move! Journal of Experimental Marine Biology and Ecology 450, 68-78.
Patrick, S.C Charmantier, A., and Weimerskirch, H. 2013. Differences in boldness are repeatable and heritable in a long-lived marine predator. Ecology and Evolution 3(13), 4291-4299