Breeding Success in Relation to Parent Size and Experience in a Population of the Hooded Crow

A population of wing-tagged Hooded Crows Corvus corone cornix was studied for five breeding seasons. Pairs that bred in the first year that they occupied a territory laid smaller clutches and bred later than experienced pairs. Some pairs bred for the first time in the second year that they occupied a territory. In this year their breeding success was similar to that of experienced pairs. Pairs with one experienced partner and one that bred for the first time had a breeding success that was similar to that of experienced pairs. A pair's territory increased in area after the first year of occupation. Experienced pairs differed with respect to egg weight, breeding time, and clutch size but not with respect to rate of predation on eggs and nestlings. Large females (measured as bill length plus foot length) and heavy females laid heavy eggs. Heavy females and females in good condition (heavy in relation to their size) bred early.