Use of woody debris piles by birds and small mammals in a riparian corridor

Woody debris piles, a natural component of rivers draining the coastal fore sts of the Pacific Northwest, provide a unique resource in the riparian-riv er corridor. We describe the distribution of woody debris piles on the Skyk omish River, Washington, and examine their use by birds and small mammals. We found an average of one debris pile per 15 m of river bank; the inside o f these piles was significantly cooler than the ambient environment. Over s ixteen bird species were observed using the debris piles while other bird s pecies in the area were never observed on the debris piles. The overall spe cies richness of small mammals was greater at debris piles (9 species) than at reference sites in nearby areas without woody debris (I species). On co bble bars, there was a greater abundance of small mammals at debris piles t han at reference sites. We conclude that debris piles may provide valuable resources to both birds and small mammals particularly on otherwise barren cobble bars.