The only avian species entirely restricted to Florida, the Florida Scrub-Jay was described in the eighteenth century ( Bosc 1795 ), a full century before the scrub-jays of western North America became known to science. Although this species lives in a habitat easily accessible to humans, and individual birds can become exceptionally tame, only anecdotal information regarding its life history was available until late in the twentieth century (e.g., Amadon 1944a ). Since 1969, however, this species has been the subject of intensive study by the authors, their students, and numerous colleagues.
Few North American birds rival the Florida Scrub-Jay for sedentariness or habitat restriction. Although many individuals live for more than ten years, most do not travel more than a few kilometers from their birthplace. This jay lives only in oak (Quercus) scrub, a fire-dominated shrub community unique to Florida and found only on well-drained sandy soils. Acceptable habitat occurs as isolated patches on sandy deposits, surrounded by vast expanses of pine (Pinus) woodlands, hammocks, and grasslands that are not used. The Florida oak scrub, a rare and relict habitat, has been converted throughout the twentieth century into citrus groves, improved pastures, and housing developments, with a concomitant decrease in this jay. In 1987 the U.S. Fish and Wildlife Service listed the species as Threatened.
Florida Scrub-Jays breed cooperatively. Each territory contains one monogamous breeding pair, and surviving offspring typically remain home and "help" the breeding pair during the next breeding season. These prebreeders help feed dependent young, detect and mob predators, and defend the group territory. Breeders with helpers produce more young than do lone pairs. Cooperative breeding and associated life-history traits have been the focus of our long-term study of a marked population since 1969. Most data reported here are derived from this study. Many aspects of life history and demography, briefly summarized here, are described in detail in Woolfenden and Fitzpatrick ( Woolfenden and Fitzpatrick 1984 ).
Our main study site, Archbold Biological Station, is an ecological research institute located 13 kilometers south of Lake Placid in Highlands County, at the southern end of the Lake Wales Ridge in south-central Florida. This 2,000-hectare preserve, predominantly oak scrub, supports about 100 Florida Scrub-Jay families. Other data reported here are from studies in suburban habitats by Reed Bowman (Highlands County) and Jon Thaxton (Sarasota County), and in Atlantic coastal scrub by David Breininger and coworkers (Brevard County).