FORAGING PATTERNS OF VESPER SPARROWS (POOECETES-GRAMINEUS) BREEDING IN CROPLAND

Effects of seasonal changes in the plant and animal communities of cropland on foraging patterns of vesper sparrows (Pooecetes gramineus) were studied during April-August in 1979 and 1980. individuals breeding in cornfields and soybean fields were observed from elevated blinds situated in fencerows to determine where they foraged. Vesper sparrows foraged primarily in or near uncropped areas (e.g., fencerows) or weedy areas within cropped fields throughout the season, but proportionately more foraging occurred away from these areas as the season progressed. Where vesper sparrow territories included part of both a cornfield and a soybean field, the sparrows preferred to forage in the field with the most crop residue, usually a soybean field with corn residue from the previous season. These results suggest (1) that vesper sparrows can be protected, in part, from the harmful effects of pesticides by limiting pesticide use in areas where foraging is concentrated, and (2) that foraging opportunities for this species may be enhanced by reduced tillage farming methods.