| DatasetID | 227 |
|---|---|
| Name | A comparison of territorial behavior in the hummingbirds Archilochus alexandri and Calypte anna |
| Description | Changes in territorial behavior of blackchinned hummingbirds (Archilochus alexandri) in response to experimental changes in territory quality were investigated using artificial feeders and simultaneous, pair-wise observations of owners. Some of the responses of A. alexandri were similar to those documented by a previous study of the Anna's hummingbird (Calypte anna): A. alexandri defending rich territories spent more time on their territories, encountered a greater percentage of intruders, and chased more intruders than did A. alexandri defending poor territories. In contrast to C. anna, A. alexandri supplemented chases with energetically inexpensive threat vocalizations more extensively when territory quality was increased. This difference may be related to A. alexandri's more tenuous control of rich territories. When both species were observed on very poor territories, A. alexandri chased a greater percentage of intruders, consumed a greater proportion of available food, and obtained a greater net energy gain from their territories. When observed simultaneously on territories with ad lib food, both species defended highly exclusive territories but A. alexandri suffered higher intrusion pressure and spent more time and energy in defense. These interspecific differences in territorial behavior may facilitate sympatric coexistence of the two species through aggressive partitioning of flower patches according to productivity: the greater payoff received by C. anna on rich territories and A. alexandri on poor territories should favor a corresponding monopolization of rich areas by C. anna and poor areas by A. alexandri. Hastings Natural History Reservation was one of three sites studied: "Simultaneous comparisons of A. alexandri with C. anna on poor territories were made from 16 August through 31 August 1982 at Hastings Natural History Reserve of the University of California, Santa Lucia Mountains, Monterey County, California." |
| Physical Location | |
| Publisher/Owner | Ray Joseph Bransfield, USFWS, ray_bransfield@fws.gov, 805-644-1766 |
| Publication Date | |
| Permissions | Public |
| Source | Mark Stromberg NRS file |
| Contact | Mark Stromberg |
| Type | Biological Survey - Experimental |
| Subject | Animal |
| Geo. Extent | Hastings Reserve |
| URL | https://berkeley.box.com/s/i901oz9dpguplxzghp5iwu4mhdczysgf |
| NRS Registry? | yes |
| Format | |
| Timespan Start | 1982 |
| Timespan End | 1982 |
| Total Items | |
| Databased Items | 0 (as of 2012-08-28) |
| Comments | Ewald, P. W. and R. J. Bransfield (1987). "Territory Quality and Territorial Behavior in Two Sympatric Species of Hummingbirds." Behavioral Ecology & Sociobiology 20(4): 285-294. |
| Entered By | Jessica Rothery |
| Last Updated | 2015-12-27 13:38:10 |