A Watershed-Scale Survey for Stream-Foraging Birds in Northern California
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Our objective was to develop a survey technique and watershed-scale design to monitor trends of population size and habitat associations in stream-foraging birds. The resulting methods and design will be used to examine the efficacy of quantifying the association of stream and watershed quality with bird abundance. We surveyed 60 randomly selected 2-km stream reaches of all stream orders in the Smith River watershed in northern California. In addition to counts and foraging activity of American Dippers (Cinclus mexicanus) and other bird species that forage in the stream, we collected a large variety of physical and biological measurements of the stream and bank habitats to identify the factors most related to abundance. We found highest dipper densities on larger streams and main stems of the river, and they were present in cascades significantly more often than expected. We also conducted an intensive color-banding and census effort along one creek where we banded most of the resident breeding population over four years. By surveying about once per month between April and November, we have located nests, documented triple-clutching, nest fidelity, and feeding of nestlings by three or more birds at one nest.