Retention of anti-predator behavior in breeding birds and the reintroduction of an endemic island nest predator

We evaluated the risks of a proposed reintroduction of the island scrub-jay (Aphelocoma insularis; hereafter jays) in California’s Channel Islands. Jays are found only on Santa Cruz Island; reintroducing them to nearby Santa Rosa Island would reduce extinction risk. However, jays are also generalist predators of bird nests and breeding birds on Santa Rosa Island may have become naïve to the risk posed by jays. To test for prey naivete, we conducted behavioral experiments with 11 species of breeding bird on Santa Rosa and Santa Cruz Islands. We compared behavioral responses to taxidermy models and vocalizations of jays to similar presentations of a familiar nest predator (common raven, Corvus corax; Santa Rosa only), a novel species (american woodcock, Scolopax minor; Santa Rosa only), and a control (house finch, Haemorhous mexicanus). We also compared behavioral responses of birds on Santa Rosa Island to responses from Santa Cruz birds.