Population Density, Vocal Behavior, and Recommended Survey Methods for Bicknell's Thrush
Rimmer CC, Atwood JL, McFarland KP, Nagy LR. 1996. Population Density, Vocal Behavior, and Recommended Survey Methods for Bicknell's Thrush. The Wilson Bulletin. 108(4):639-649
We studied territorial and vocal behavior of Bicicnelf s Thrushes (Catharus bicknelli) on Mt. Mansfield, Vermont, during June to September 1992 and in June 1993 to 1995. Birds sang and called consistently throughout the day during early–mid June Later in the season, songs were given infrequently, with vocalizations (mostly call notes) being concentrated at dawn and dusk Spot-mapping of vocalizing males yielded breeding density estimates of 36-52 pairs/40 ha in 1992, 50-59 pairs/40 ha in 1993, 55-65 pairs/40 ha in 1994, and 45-53 pairs/40 ha in 1995. Other less labor-intensive techniques, including fixedwidth point counts and fixed-width transects, generally resulted in lower density estimates. We recommend that future presence-absence surveys for Bicknell's Thrush in the northeastern United States be concentrated from 1-20 June. Surveys from late June through mid- September should be attempted onIV if observers are able to be on-site before dawn or after sunset. Received 26 Jan. 1996, accepted 8 May 1996
- Type
- Journal Article
- Authors
- Rimmer, Chirstopher; Atwood, Jonathan; McFarland, Kent; Nagy, Laura
- Units
- NETN
- Keywords
- Behavior, Bicknells thrush, Birds, dawn, dusk, Mapping, songs, teritory