Patterns of Wood Duck Nest Temperatures during Egg-Laying and Incubation

We studied the thermal environment of Wood Duck (Aix sponsa) nests in southeastern British Columbia. Mean daily nest temperatures (TN) were correlated with maximum daily air temperatures. TN increased as the egg-laying period advanced among both successful and unsuccessful nests, although TN was lower among unsuccessful nests. Hens began spending nights on nests when there were as few as four eggs in clutches. TN and the precision of nest thermoregulation increased among successful nests as the incubation period advanced, although there was a great deal of variation between days and nests. Length of the incubation period was not correlated with clutch size, nor with mean overall nest temperature during incubation, but was correlated with the variance of TN's during incubation.