We examined the demographic consequences of road mortality in the cooperatively breeding Florida Scrub‐Jay (Aphelocoma coerulescens), a threatened species restricted to the oak scrub of peninsular Florida. Between May 1986 and July 1995 we monitored the survival and reproductive success of a color‐banded population of jays along a two‐lane highway at Archbold Biological Station. Annual mortality of breeding adults was 0.38 on road territories, significantly higher than the rate of 0.23 for breeders on nonroad territories. High mortality on road territories appeared to be a direct result of automobile traffic per se and not a consequence of road‐induced changes in habitat characteristics. Mortality was especially high for immigrants without previous experience living along the road: in their first two years as breeders on road territories, naive immigrants experienced annual mortality of 0.50 and 0.45. From year 3 onward, however, annual mortality dropped to 0.29, not significantly different from the rate for birds on nonroad territories. This experience‐dependent decline in road mortality could be caused either by surviving jays learning to avoid automobiles or by selective mortality operating through time (demographic heterogeneity). Proximity to the road had no effect on nesting success beyond its indirect effects on breeder experience and group size. Because the mortality of 30‐ to 90‐day‐old fledglings was significantly higher on road territories than on nonroad territories, however, breeder mortality greatly exceeded production of yearlings on road territories. Roadside territories therefore are sinks that can maintain populations of Florida Scrub‐Jays only via immigration. Because Florida Scrub‐Jays do not avoid roadside habitats and may even be attracted to them, road mortality presents a difficult challenge for the management and conservation of this threatened and declining species.

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We documented number of acorns eaten, cached, and retrieved by Florida Scrub Jays (Aphelocoma coerulescens coerulescens), through one full annual cycle and part of another, in an oak scrub habitat characterized by abundant and reliable annual acorn crops. Jays consumed acorns during all months, with highest consumption from September through February and lowest in June and July. From August through December, most acorns consumed by jays were picked directly from shrubs; during the remaining 7 mo, acorns were recovered from ground stores. Acorn caching occurred throughout the fall, peaking in September and October. Data pooled across sex and age classes suggest that individual jays, on average, each cached between 6500 and 8000 acorns during fall of 1974. Only about one—third of those acorns were recovered later. Intact acorns recovered by Scrub Jays during fall usually were reburied, but by summer most recovered acorns were consumed. Acorn crops in the study area exhibit moderate annual variation but no crop failures. Acorns are available in substantial numbers every year, permitting Florida Scrub Jay territories to serve without fail as year—round warehouses of stored acorns. Those stores provide resources to carry group members through seasons of low arthropod availability, and perhaps facilitate delayed dispersal by juveniles. Use of a habitat characterized by relatively large and dependable annual acorn crops that are evenly dispersed, coupled with caching behavior, may contribute to the maintenance of permanent territoriality and cooperative breeding in this population.