DESPOTIC DISTRIBUTION, UNEQUAL REPRODUCTIVE SUCCESS, AND POPULATION REGULATION IN THE JAY GARRULUS-GLANDARIUS L

Jays in S-central Sweden occupied territories in most forest habitats, but with a strong preference for dense forest characterized by trees >10 yr and a composition of >30% Norway spruce Picea abies. Individuals having territories in this preferred habitat exhibited the highest breeding success. This supports the Fretwell-Lucas model of ideal-despotic distribution. Differences in nest predation, and perhaps also in food abundance and adult predation, caused higher breeding success in forest dominated by spruce than in other forests. Despots were not distinguished by size, but age might be more important in such a long-lived species. Territoriality means that certain individuals monopolize some resources at the expense of other individuals, which results in unequal resource partitioning. The effect of having the preferred habitat unequally divided among individuals, which will result in a density-dependent breeding output is discussed. -from Author