The Ability of the Razorbill Alca torda to Raise an Additional Chick to Fledging

Publisher Website
Google Scholar
Abstract
A 2nd chick was introduced to 14 razorbill nest sites on Skokholm [Wales, United Kingdom] the day after the true chick hatched. All sites were under boulders so twinned chicks could be weighed each day. Control observations were on nests with single chicks elsewhere on the island. Feeding rates and amount of food per nest-site per day were increased in pairs with twins, although twinned chicks grew significantly slower than the controls. In only 2 of 14 sites did both chicks survive to fledging, giving a breeding productivity of 0.83 young/nest, compared with 0.64 for single chicks. Failure of the 2nd chick was the result of unsuccessful competition for food (9 cases), and due to the apparent breakdown in the normal fledging behavior of 1 of the adults (5 cases).

This publication has 0 references indexed in Scilit: