WILSON PHALAROPE NEST SUCCESS IS NOT INFLUENCED BY VEGETATION CONCEALMENT

I examined vegetation characteristics at nests of Wilson's Phalaropes (Phalaropus tricolor) to evaluate the null hypothesis that nest success was independent of concealment from predators. During 1983 and 1984, 28% (n = 25) and 18% (n = 60) of phalarope clutches successfully hatched chicks; both years predation caused most (60%) clutch failures. No relationship obtained between nesting success and vegetation density, height and heterogeneity, but plant communities differed between successful and depredated nests in 1983. These results do not support the hypothesis that clutch concealment deters predation; rather they suggest that other, perhaps multiple, factors should be examined as forces shaping nest-site selection of ground-nesting birds.