Bird species having specialized nesting substrates could suffer reduced reproductive success in habitats modified by human activities where optimal nest sites may be in short supply. We examined nest sites of Florida Scrub-Jays (Aphelocoma coerulescens) in intact, natural oak scrub and in scrub islands embedded in a suburban matrix. Despite differences in vegetation structure between natural and suburban scrubs, scrub-jays used scrub oaks (Quercus spp.) as substrate for >80% of all nests in both habitats. Because of fire suppression, vegetation in suburban scrubs tended to be taller than in natural scrubs; however, in both habitats jays appeared to prefer shrubs slightly taller than those available. In both habitats, nest height increased with nest shrub height, but the relationship was stronger in suburbs. In suburbs, the height of nests relative to nest shrub height remained constant, whereas in natural scrub, nest height declined relative to nest shrub height. In both habitats, nests built near the top of shrubs were associated with the presence of Smilax spp., a perennial vine that provides dense foliage near the crown of oak shrubs. However, 68% of all nests in suburbs were associated with Smilax, whereas in natural scrub 9% of nest sites had Smilax. Few nest site characteristics, including habitat, were associated with nest failure, but nests built in oak shrubs were more successful than nests built in other vegetation. Suburban nests built near the top of relatively tall shrubs appeared to be more vulnerable to wind damage.