9310711 Winkler Mr. David G. Haskell's doctoral-dissertation research will investigate how variations in predation risk have affected the evolution of begging calls of nestling wood warblers (Parulidae). These diverse New World tropical migrants nest in a wide variety of sites, and Mr. Haskell's recent experiments show that nestlings begging from ground nests incur greater increases in the risk of predation than do nestlings begging from trees. Mr. Haskell will now test the hypothesis that ground-nesting species have begging calls that are harder to hear and to locate than the begging calls of tree-nesting species. This will be the first comparative study of nestling calls to use standardized recording protocols and to take into account the phylogenetic relationships of the species being compared. Predation is the major source of mortality for most nestling birds, an the results of this study should be of interest to biologists interested in the productivity of bird populations and the behaviors that have evolved to mitigate nestling mortality. The evolution of begging has also been the subject of considerable theoretical work, and this study should be of interest to biologists studying the evolution of parent-offspring interactions as well.
