Queuing for Preferred Territories: Delayed Dispersal of Siberian Jays

1. Siberian jays (Perisoreus infaustus) can acquire breeding status along two routes. Some offspring dispersed in their first summer of life, but one-third of birds ringed as nestlings (39 of 117; 40 broods) postponed dispersal beyond their first winter and up to 3 years of age. 2. Birds dispersing in their first summer were able to settle in flocks outside their natal territory, while retained offspring appeared to be queuing for territorial vacancies in high-quality habitat rather than claiming one of the currently available vacancies of low quality. 3. Males dispersing in their first year acquired territories close to human settlements, and with few low spruces. Reproductive success was low in those territories. Males with delayed dispersal acquired territories further away from human settlements and with a high density of low spruces (< 15 m). Reproductive success was high in such territories. 4. A preference of all birds for territories characterized by high reproductive success, regardless of their timing of dispersal, suggests a causal relationship to habitat characteristics. A non-breeding surplus of retained offspring had priority to vacancies at high densities and these birds claimed territories where reproductive success was high. At low densities and without a non-breeding surplus it was possible for birds dispersing as yearlings to shift territory, and acquire vacant sites of higher quality. It was birds settled in the territories with lowest reproductive success which shifted, and at low population density their territories remained vacant. 5. Siberian jays postponed dispersal as a strategic trade-off, where they forego dispersal options of low quality while queuing for high-quality habitat. However, a nepotistic parental behaviour towards retained offspring implies that fitness gains of delayed dispersal is not only a question of habitat quality.