Reproductive Success and Nest Depredation of the Florida Scrub-jay

—The Florida Scrub-jay (Aphelocoma coerulescens) is listed as a threatened species primarily because of habitat loss throughout much of its range. The Ocala National Forest in Florida contains one of three main subpopulations that must be stable or increasing before the species can be considered for removal from federal listing. However, little information is available on Florida Scrub-jay reproductive success or predation pressure on this forest. I used video cameras during 2002 and 2003 to identify nest predators and timing of predation events. The presence of the video system did not significantly affect the rate of nest abandonment. Thirteen nests were video-monitored of which one was abandoned, five experienced no predation, three were partially depredated, and four had total loss of nest contents. Snakes were responsible for more losses from predation than either mammals or birds. I monitored 195 other scrub-jay nests (no video-monitoring) and measured the mean number of eggs, nestlings, and fledglings produced per breeding pair. No significant difference in reproductive success was detected between years or between year and helper status. Groups with helpers produced significantly more fledglings (0.5 per breeding pair) and had higher daily survival rates of nests in the egg stage, nestling stage, and the entire breeding season than groups lacking helpers. Received 15 July 2005. Accepted 7 October 2006. The Florida Scrub-jay (Aphelocoma coerulescens), federally listed as a threatened species, occurs primarily on lands containing fine, well-drained soils along Florida’s coastline, and on ancient sand dune ridges in the interior of peninsular Florida. They are monogamous cooperative breeders living in groups on year-round territories. Groups contain a mated pair and as many as six helpers that may be related to one or both members of the breeding pair (Sprunt 1946, Woolfenden 1978). Helpers do not build nests, incubate, feed the incubating female, or brood, but do feed nestlings and fledglings, and also participate in mobbing possible predators (Woolfenden and Fitzpatrick 1984). Pairs will renest if the nest is lost in an effort to produce one brood of fledglings per breeding season (Woolfenden and Fitzpatrick 1984). Preferred habitat consists of dense thickets of scrub oaks (Quercus spp.) 3 m tall with bare sand substrate between them and may develop after land has been burned, harvested, or otherwise cleared. The amount of new habitat currently is inadequate and, coupled with conversion of existing habitat for silviculture, agriculture, commercial as well as residential develop1 USDA, Southern Research Station, Southern Appalachian Mountains Cooperative Ecosystems Studies Unit, Department of Forestry, Wildlife, and Fisheries, University of Tennessee, Knoxville, TN 37996, USA; e-mail: [email protected] ment, has led to an overall reduction in the amount of suitable scrub-jay habitat (Fitzpat-