MICROHABITAT FACTORS INFLUENCING PREDATION AND SUCCESS OF SUBURBAN BLUE JAY CYANOCITTA-CRISTATA NESTS

We examined how microhabitat features surrounding nest-sites influence probability of nest predation by testing unique predictions generated from the ''distance to human activity, the ''habitat complexity, and the ''multiple nest-site'' hypotheses. During spring and summer 1990, we quantified nine features of nest-sites and 11 features of 0.1 ha ne st-patches surrounding 42 nests of suburban Blue Jays Cyanocitta crist ata in Fayetteville, Arkansas, to determine differences associated wit h depredated and successful nests. Overall nesting success was 52% and mean daily survival rate of nests was 0.983 (+/- 0.004 SE). Twenty-fo ur nests fledged at least one young, and 18 failed as a result of nest predation. Features of the nest-site, including nest height, size of the nest tree, and nest concealment, were not related to nest predatio n, although distance from a nest to the nearest building was inversely related to duration of nest survival. The latter relationship suggest s human activity may decrease nest predation in suburban areas. Densit y of vegetation surrounding nests did not influence nest fate, thus pr oviding no support for the habitat complexity hypothesis. Instead, fai led nests occurred in patches containing fewer trees of the same speci es, size class and vine cover as the nest tree. Because this pattern w as not an effect of size or species of either the nest tree or neighbo ring trees, nor an effect of vines in the nest tree or neighboring tre es, it provides support for the multiple nest-site hypothesis.