Monitoring productivity with multiple mist-net stations

Abstract

We evaluated data from 22 mist-net capture stations operated over 5 to 13 years in northern California and southern Oregon, to help develop sampling designs for monitoring using mist nets. In summer, 2.6% of individuals were recaptured at other stations within 1 km of the original banding station, and in fall, 1.4% were recaptured nearby. We recommend that stations be established 1?5 km apart to promote independent sampling. Percent of young birds in the total captured was similar among stations, both in summer and fall, indicating that large numbers of stations might not be necessary to sample age structure for an entire region, at least for common species. We examined the percent of young captured in fall and summer to determine whether some stations consistently captured lower proportions of young across all species, and found no consistent pattern. Power analysis indicated that about 10 stations were required to detect a 50% change in percent young between years for the Song Sparrow (Melospiza melodia), a common species. To detect a 25% change, 10 stations still sufficed in fall, but about 3× more were required in summer. Summer results were similar for the Yellow-breasted Chat (Icteria virens). More stations would be needed to reach similar precision targets for uncommon species, and probably also in regions of more heterogeneous habitat. Although the capture rates at stations in our region increased during the study, the capture rates at individual stations declined significantly after the first year of operation.

Citation

Ralph, C. John; Hollinger, Kimberly; Miller, Sherri L. 2004. Monitoring productivity with multiple mist-net stations. Studies in Avian Biology No. 29:12?20