Meeting Abstract
Although there is extensive evidence that individuals can strategically adjust their investment into various activities such as parental care and self-maintenance, the cues that they use in making these strategic decisions are not well understood. Here we report an experiment with tree swallows, Tachycineta bicolor, asking whether parents adjust their feeding rates in response to increased demand from nestlings. We studied tree swallows at two locations: at Queens University Biological Station (QUBS), Canada and near Davidson, NC. These two populations differ in the current brood value with the QUBS population having higher current brood values because of lower return rates and the shortness of the breeding season for northern populations vs. southern populations. We used an automated RFID system that played back extra nestling begging calls every time the female but not the male entered the box. We asked 1) whether the females would adjust their feeding rate in response to increased demand 2) whether the males would respond to any changes in female behavior and 3) whether there would be population differences in female and male responses. We found that females in neither population showed significant differences in feeding rates with respect to playback. Similarly, males in NC population did not show any change in feeding rates in response to playback their mates were getting. Surprisingly however, males in QUBS showed a significant increase in feeding rates when their mates were getting playbacks than when they were not. We discuss these results in the context of how mates adjust their parental behavior based on cues from nestlings and from each other.
