Summary
The Cerulean Warbler (Dendroica cerulea) is currently the focus of considerable management interest; however, our ability to develop effective management strategies is hampered by a dearth of life history and basic behavioral data. Here, we present information on male-female interactions of Cerulean Warblers and parental nest attentiveness that is, to our knowledge, among the first such rigorously collected data for this species. Males feed females during nest building and on the nest during incubation; the relative infrequency of these events suggests that they play more of a role in pair-bond maintenance than they do in enhancing female energetics. Female incubation rhythms were not significantly influenced by temperature, time of day, or egg age. Compared with other Dendroica warblers, we observed relatively infrequent female departures during incubation, perhaps in response to a high risk of nest predation. As the nestlings aged, females spent less time brooding nestlings, presumably to allow for more frequent feeding; however, both males and females exhibited relatively low rates of food delivery compared with other Dendroica warblers. Despite the low rates of food delivery, feeding trips were more frequent at successful nests than unsuccessful nests. Our results suggest that Cerulean Warblers are tightly constrained by the competing pressures of predation risk and sufficient food provisioning for nestlings.