Large barnacle goose males can overcome the social costs of natal dispersal

• Published in: Behavioral Ecology
• Main Author: Jeugd, Henk P. van der
• Format: Text
• Language: English
• Published: Oxford University Press 2001
• Subjects: Articles; Barnacle goose
• Online Access: http://beheco.oxfordjournals.org/cgi/content/short/12/3/275; https://doi.org/10.1093/beheco/12.3.275

The decision to disperse is influenced by a trade-off between the costs and benefits of moving to a new area, and the optimal dispersal tactic is likely to differ among different individuals. I studied natal dispersal of barnacle geese in relation to fledging characteristics such as body weight and body size. I classified birds as having dispersed when they were known to be alive at the age of 5 years, the maximum age of first breeding, but had not recruited into their natal colony. I assumed that those birds were breeding elsewhere. Because survival was registered on the wintering grounds, survival estimates were not dependent on the size of the study area during breeding. The probability of successful dispersal increased with increasing body weight and tarsus length in males, but not in females. Heavy or large males also won more aggressive interactions with territory owners when returning to their natal colony as 1 year olds, and were therefore probably at a competitive advantage when settling. Individuals that settled in an unfamiliar environment suffered more attacks by territory owners, and as a result, they started reproduction at a later age than birds remaining in the natal colony. Surprisingly, dispersing males did not seem to benefit from their choice to disperse in terms of enhanced reproductive success. The views that dispersal in birds generally results from poor-quality individuals being expelled from their natal area and that low return rates of heavy individuals result from stabilizing selection need to be revised.