Predation of small eggs in artificial nests: Effects of nest position, edge, and potential predator abundance in extensive forest

After photographic observations in the field and laboratory tests indicated that small rodents might be significant predators on small eggs, we conduc ted a field study in central Massachusetts to compare predation of House Sp arrow (Passer domesticus) eggs in artificial nests near to (5-15 m) and far from (100-120 m) forest edges and between ground and shrub nests. As in ea rlier studies in managed northeastern forest landscapes that used larger qu ail eggs, predation rates on small eggs in nests at the forest edge did not differ (P > 0.05) from those in the forest interior for either ground nest s (edge = 0.80 vs interior = 0.90) or shrub nests (edge = 0.38 vs interior = 0.28) after 12 days of exposure. However predation rates on eggs in groun d nests were significantly higher (P < 0.001) than in shrub nests at both t he edge and interior. There were no significant (P > 0.05) differences in t he frequency of capture of the 6 most common small mammal species between f orest edge and interior. Logistic regression analyses indicated a highly si gnificant (P < 0.001) nest placement effect but very little location or sma ll mammal effect. Predation of small eggs by small-mouthed ground predators such as white-footed mice (Peromyscus leucopus) has nor been documented as a major factor in egg predation studies, but use of appropriately-sized eg gs and quantification of predator species presence and abundance seems esse ntial to future studies.