Measurements and weights of British puffins

Abstract

Puffins continue to grow and become heavier until they have at least two fully-developed bill grooves. Both adults and immatures become lighter during the breeding season, but show weight increases after the young have fledged. Birds from St Kilda were significantly smaller and lighter than those from the Isle of May. A survey of measurements of Puffins from other colonies showed a marked difference in size between those nesting in the east and west of Britain, which is associated with differences in the ecology of the populations. Most birds found dead in the winter were probably from British colonies. © 1979 Taylor & Francis Group, LLC.