EGG AND CHICK FATES DURING TIDAL FLOODING OF SALTMARSH SHARP-TAILED SPARROW NESTS

We determined nest attendance patterns of Saltmarsh Sharp-tailed Sparrows (Ammodramus caudacutus) in Connecticut using temperature data-loggers. In this species, only females incubate and feed the young. Females maintained a stable thermal environment in their nests during incubation by modifying their attendance behavior in relation to ambient temperature; during cooler conditions, females made shorter, but more frequent, trips away from their nests to feed. Once eggs hatched, average nest temperature increased significantly. The data-loggers also recorded information on rare and unpredictable events, such as nest flooding, depredation, and fledging. Eggs and nestlings apparently tolerated nest inundation for periods averaging more than 90 min. Nestlings fledged from their nests soon after sunset on the flooding tide. Detailed insight into nest attendance behavior and the circumstances surrounding rare events such as flooding are especially important for this species of high conservation concern in which tidal inundation is the major cause of breeding failure.