Adoption of Strange Chicks by Herring Gulls, Larus argentatus L


Psychological Laboratory, University of St. Andrews, St. Andrews, Fife, Scotland, KY16 9JU, U.K.


Adoption of young by unrelated adults is expected to be rare in natural populations, yet a high incidence was observed in a population of Herring Gulls on the Isle of May, Scotland. The means whereby rejection was avoided, and the resulting costs and benefits to adopting parents and adopted chicks, are described.