The post-fledging survival of young Guillemots Uria aalge in relation to hatching date and growth

The post‐fledging survival of a total of 1277 young Guillemots Uria aalge ringed in 6 years was assessed using sightings of 267 individuals back at the natal colony and recoveries of 46 ringed birds. In two years there was a significant decline in survival prospects with estimated hatching date, the first time such a trend has been demonstrated in the Alcidae. In these years pairs breeding early had a 2–3 times greater chance of having a young...