Abstract
We conducted an experiment on nestling tree swallows (Tachycineta bicolor) to examine predictions from signalling models for the evolution of conspicuous begging behaviour. Specifically, we examined the relationship between (1) nestling begging intensity and hunger, (2) begging intensity and parental provisioning and (3) begging intensity and nestmate condition. Forty broods of 9-day-old nestlings were removed from their nests for 1 h and assigned to one of the following three treatments: (1) all nestlings in the brood deprived of food (n = 13), (2) all nestlings in the brood fed (n = 11) or (3) half the nestlings in the brood deprived and half fed (n = 16). Videotapes before and after the treatments showed that begging intensity increased in broods in which all of the nestlings had been deprived and decreased in broods in which all of the nestlings had been fed. Deprived nestlings in the half-and-half treatment did not change their begging intensity in response to treatment, while fed nestlings in this treatment group showed a decrease in begging intensity. Parent tree swallows increased their feeding rate to deprived broods and decreased their rate to fed broods. Within broods, parents decreased their feeding rate to fed nestlings, but showed no significant change in feeding to deprived nestlings. Our results suggest that begging intensity is influenced by hunger and that parents appear to respond to variation in begging intensity. The begging of nestmates also appears to influence begging independently of need. These results are consistent with predictions derived from signalling models of begging.
| Original language | English |
|---|---|
| Pages (from-to) | 431-436 |
| Number of pages | 6 |
| Journal | Behavioral Ecology and Sociobiology |
| Volume | 42 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - Jun 1998 |
Bibliographical note
Funding Information:Acknowledgements We thank David Hussell, John Reynolds, Danny Weary, Nat Wheelwright, Hal Whitehead and an anonymous reviewer for reading the manuscript and the Behavioural Ecology group at the University of Nottingham for discussion. All provided many helpful comments. We also thank Sherman Boates for access to the field sites and the Brown, Eaton, Hines, and Coldwell families for allowing us to use their land. We especially thank Susan Leech and Satya Ramen for help in the field. This work is supported by grants to M.L.L. from the Natural Sciences and Engineering Research Council of Canada.
ASJC Scopus Subject Areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology