Site use and fidelity in the Common Guillemot Uria aalge

• Published in: Ibis
• Main Authors: HARRIS, M. P., WANLESS, S., BARTON, T. R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1996
• Subjects: common guillemot; Uria aalge; uria
• Online Access: http://dx.doi.org/10.1111/j.1474-919x.1996.tb08057.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1474-919X.1996.tb08057.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1474-919X.1996.tb08057.x

The site fidelity of 470 colour‐ringed Common Guillemots Uria aalge with at least 1 year of breeding experience was followed on the Isle of May from 1982 to 1993. On average, 85.7% of birds recorded breeding at a site in any year were present at the same site in the following season. Of those which did not retain their site, 35% had moved to another site, 25% were nonbreeders and 40% were not seen. Site‐ fidelity of birds which returned to the colony the next year was 91%. There were no significant age or sex effects, but there were significant (and unexplained) year and area effects. Most birds which changed sites moved less than 2 m. Some birds which obtained a new site improved their nesting success, but many others became nonbreeders; it is speculated that the former chose to move site, whilst the latter had been evicted.