Simulation Models of Female Choice in Red-Winged Blackbirds

We used three models to simulate female choice in red-winged blackbirds. Fidelity of females to the territories on which they nested in the preceding year was insufficient to account for the observed levels of consistency in settlement patterns when first-breeding females and females not faithful to their sites chose randomly among the available territories. In contrast, use of an agreed-upon ranking of suitability by nonfaithful and first-breeding females, in conjunction with empirical levels of site fidelity, produced levels of consistency similar to those observed. However, the addition of strong density dependence reduced levels of consistency considerably. We conclude that settlement patterns of female redwinged blackbirds are likely to be affected by the relative suitability of the available territories and that a strong density-dependent effect is unlikely to influence female choice in this species.