Influence of nest concealment and distance to habitat edge on depredation rates of simulated grassland bird nests in southeast Kansas

Many features appear to influence avian nest success, and nest concealment and distance to habitat edge are among the most influential. We placed simulated bird nests baited with House Sparrow (Passer domesticus) eggs in two riparian grasslands to document the influence of these two habitat characteristics on nest depredation rates. Over three trials, 49% of nests (n = 105) were depredated with a mean daily survival rate of 0.908 (± 0.012 SE). Side and overhead concealment of depredated and undisturbed nests did not differ in any consistent manner, and logistic regression models indicated that nest fate was not influenced by the amount of vegetative concealment surrounding a nest. Depredated simulated nests were closer to habitat edges than undisturbed nests during only one of three trials, suggesting nest depredation was not strongly influenced by habitat edges. Our results indicate that in simulated grassland bird nests baited with sparrow eggs, concealment may be more influential on nest fate than distance to habitat edges. We recommend that future studies of simulated songbird nests use songbird-sized eggs to insure that the potential suite of nest predators is sampled by simulated nests.