A simple trail camera modification reveals red-bellied woodpeckers as important egg predators of box-nesting wood ducks

Abstract

Artificial nesting structures have been used to aid the recovery and maintenance of certain avian populations such as the wood duck (Aix sponsa). The success of nest boxes for wood ducks relies on excluding common nest predators such as raccoons (Procyon lotor) and rat snakes (Pantherophis spp.) via the use of predator guards; however, woodpeckers cannot be excluded. Red-bellied woodpeckers (Melanerpes carolinus) are foraging generalists and have been anecdotally observed preying on wood duck eggs where documenting predation events is difficult to accomplish through traditional nest box monitoring. Here, we used custom-modified trail cameras to document egg depredations and foraging events by red-bellied woodpeckers and the removal of damaged eggs by wood ducks during the laying and incubation periods. We captured 35,686 videos and documented 1173 different events consisting of 608 (51.8%) videos of red-bellied woodpeckers and 565 (48.2%) of wood ducks. We determined 38 (30.6%) eggs were depredated during the laying period and 14 (11.3%) during incubation. Wood ducks removed 23 (60.5%) eggs depredated during the laying period and 13 (92.9%) depredated during incubation. We found no difference in the daily number of times red-bellied woodpeckers visited boxes with nests in the laying or incubation period (t = −0.967, df = 14.699, P = 0.349). Red-bellied woodpeckers depredated 1.0 ± 0.2 eggs during each event and returned to forage on previously depredated eggs 5.3 ± 4.4 times each day spending 2.1 ± 1.1 min during each return. Our results suggest that red-bellied woodpeckers forage on eggs when nests are unguarded, and they have previously been under-recognized in the literature as predators of wood duck eggs. Future nest box programs should consider the impact red-bellied woodpeckers have on wood duck egg loss and nest survival.