Differential response of nest predators to the presence of a decoy parent in artificial nests

Capsule Mammalian and avian predators respond differently to decoys. Aims To investigate if parental attendance, which is often not accounted for in artificial nest studies, could alter predator guilds and predation rates. Methods To analyze the effects of simulated parental attendance on nest predation trends we implemented decoys of mounted American Robin Turdus migratorius specimens. We set up 22 nest-sites in an Illinois (USA) forest with control (no decoy) and experimental (with decoy) nests, the latter of which simulated parental attendance. Motion-sensitive cameras and bite-mark impressions on plasticine eggs and quail eggs identified predators. Results We found that simulated parental attendance significantly reduced nest predation rates: 61% of the 22 paired treatments were totally depredated, and more control nests (77.3%) were depredated in comparison with nests with decoys (9.1%). Mammalian predators predominantly attacked nests with decoys and avian predators predominantly attacked control nests. Conclusions Using taxidermic decoys in artificial nest experiments may improve the emulation of predation trends of natural nests, while revealing that parental attendance differentially affects predators.