Hazards of Tail-First Fish-Swallowing by Young Terns

Publisher Website
Google Scholar
Abstract
Young common terns (Sterna hirundo) were fed small fish by their parents during the pre-flying or pre-fledgling period, and thereafter until they had mastered the skills involved in fishing for themselves. Almost invariably the young birds swallow the fish head-first. In the laboratory it was possible to cause young terns to swallow fish tail-first by presenting them a fish with the tail toward their beak. Tail-first swallowing attempts usually failed. Even when successful, tail-first attempts required more time and effort on the part of the chick and increased the possibility of having a fish stolen by another bird. The disadvantages observed in the feeding experiments are adequate to explain the rarity of tail-first swallowing in nature. They indicate why chicks learn to swallow fish head-first, almost without errors, by the time they are about 1 wk old. The cues involved in this learning process remain to be determined.

This publication has 0 references indexed in Scilit: