TEMPORAL PATTERNS OF PREDATION ON ARTIFICIAL NESTS IN THE SOUTHERN BOREAL FOREST

We examined temporal and spatial patterns of nest predation using arti ficial nests containing a timing device. On a daily basis, predation w as bimodally distributed with peaks of activity occurring 3 hours afte r sunrise and 2 hours before sunset. The average times when nests were destroyed by mice, squirrels, and corvids differed significantly Dail y nest survival over a 12-day ''incubation'' period was not constant, as 58% of all predation occurred within the first 3 days. Experimenter visits to nests may have influenced predation, because 8% of all pred ation occurred less than 1 hour after observers left nests. The probab ility that nearest-neighbor nests were destroyed within 1 hour of each other was significantly greater than expected if nests were destroyed randomly. Artificial nests containing timing devices provide useful d ata on patterns of nest predation that cannot be obtained if nests are checked infrequently.