Natural History of Nesting American Dippers (Cinclus mexicanus) in Southeastern Alaska

Abstract

Abstract We studied American Dippers nesting near Juneau, AK, for 4 years. Few dippers in our area live long enough to breed in 3 or more seasons. The nest exterior is composed of a variety of moss species. Nest success ranged from 62 to 87% of first nesting attempts and was lowest in a cool, wet spring. Nesting phenology was delayed in years with cool, wet springs, at higher elevations, and on lowland stream reaches that supported few fish. Second broods were uncommon but were most often reared when 1st broods were early and on stream reaches with ready access to small fish. Hourly chick-feeding rates varied widely, from 0 to 35 trips/h. Fish were delivered to some nests, up to 17 fish/h per nest, especially by female parents. In a few cases a female nested successfully with the same male in 3 successive years. Most changes of mate and territory were associated with the disappearance of 1 member of a pair, and all changes of territory occurred within the same watershed. Females that lost their mates afte...