LOW NESTING SUCCESS OF LOGGERHEAD SHRIKES IN AN AGRICULTURAL LANDSCAPE

Southeastern Illinois is dominated by cropland, and the remaining pastures or grasslands are marginally suitable for breeding Loggerhead Shrikes (Lanius ludovicianus), owing, in part, to limited nest sites. From 1998 through 2000, we recorded poor nest success (26%) among shrikes, although results of earlier studies (1967-1972) in this region indicated that nest success was 72 to 80%. Clutch size (5.7 eggs) and fledglings/ successful nest (4.4 young/successful nest) were similar to those reported in previous studies. During our study, generalist mammalian predators were abundant, and most nest failures (88%) were caused by predation. We suggest that the loss of grassland habitat and agricultural intensification has resulted in reduced nest success, and this may be true in other areas of the species' range as well.