Age structure of Black-backed Woodpecker populations in burned forests

Abstract

ABSTRACT Population age structure is important for understanding population dynamics, but can be difficult to resolve in landbirds due to the limited number of age classes discernible by examining plumage. In forests of western North America, Black-backed Woodpeckers (Picoides articus) typically colonize burned areas shortly after fire, but densities decline within 6–10 yr. This pattern is often assumed to result from adult Black-backed Woodpeckers abandoning territories when food resources wane, yet long-distance breeding dispersal is relatively rare in birds, whereas long-distance natal dispersal is more common. To determine whether colonization of newly burned areas is driven primarily by breeding dispersal of adults or natal dispersal by young birds, we captured 57 adult Black-backed Woodpeckers in 6 burned areas in California between 1 and 8 yr after fire. We used patterns of multiple feather generations retained among primary coverts, secondaries, and secondary coverts to assign birds to 1 of 5 age ...