REPRODUCTIVE SUCCESS AND NEST DEPREDATION OF THE FLORIDA SCRUB-JAY

Abstract

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.