BREEDING BIOLOGY OF SNOWY PLOVERS AT GREAT SALT LAKE, UTAH

摘要

I studied the breeding behavior of Snowy Plovers (Charadrius alexandrinus) in northern Utah from 1990-1993. Nests at Great Salt Lake were initiated over a 14-week period from mid-April to mid-July, and were more comparable to data from California than from Kansas. Breeding males were first resighted from late March through May, whereas females had a more prolonged arrival period from late March through mid-June (N = 256 color-banded adults). Renesting following nest loss was documented only twice, in part because birds often left the study sites. Most females departed immediately after nests hatched, while males exhibited uniparental care of broods. A similar mating system was described for coastal California, where sequential polyandry was documented regularly. During this study double-brooding and sequential polyandry were rarely observed, but both strategies were probably more common than I detected. Mayfield-method estimates of annual nest success ranged from 5.4% to 49.2%, with most nest failures apparently caused by mammalian predators. These results suggest that the breeding strategies of migratory plovers in Utah resemble those of resident and migratory birds nesting in California and Oregon, rather than migratory plovers nesting in the Great Plains.