Old burns as source habitats for Lewis's woodpeckers breeding in the Black Hills of South Dakota

摘要

Crown-burned pine forests are an important breeding habitat for many cavity-nesting birds, and can serve as a source habitat for some woodpecker species. However, it is unclear if this function continues with postburn succession as predators recolonize burned habitats and snag density declines. Lewis's Woodpeckers (Melanerpes lewis) are considered "burn specialists" and are a species of conservation concern. We monitored Lewis's Woodpeckers nesting in ponderosa pine (Pinus ponderosa) forests to determine the source or sink function of old-burn habitats in the Black Hills of South Dakota (study units burned in 1988 and 1991); concurrently, we examined avian and mammalian predator communities within burned and unburned areas. Between 2002 and 2005 we found 55 Lewis's Woodpecker nests, 51 of which were successful. Using adult and juvenile mortality rates for other melanerpine species taken from the literature, we determined that the old-burn habitats we sampled were acting as sources for Lewis's Woodpeckers. Point Counts and tracking tube surveys suggested that both avian and mammalian predators had successfully recolonized these old-burn habitats, as both groups were common in old burns and in unburned forests. The unusually high nesting success of Lewis's Woodpeckers in the Black Hills is likely due to the absence of some common nest predators. While the high success rates might continue, we suggest that the overall contribution of young to the region from these burned sites will decline as suitable habitat components (such as snags) decline with the continuation of postfire succession.