The performance of 2 nonparametric estimators of species richness, the bootstrap (S(B)) and kth-order jackknife (S(Jk)), are compared using simulated parasite communities. The parameters of the simulation match those of an earlier comparison that favored S(B) as an estimator but did not include S(Jk). S(Jk) is the least biased of the 2 estimators. Whereas the bias of S(B) is significantly affected by true species richness and the proportion of rare species, the bias of S(Jk) is relatively insensitive to changes in these parameters, and is, therefore, recommended as a robust estimator of species richness.