The Streby Lab
Actionable Science for Evolutionarily Rational Conservation and Management
It has long been known that songbird home ranges are often much larger than song territories. However, Anich et al. (2009) found that telemetry-delineated song territories in one population of Swainson's Warblers were larger than spot-mapped song territories in other populations, suggesting spot-mapping underrepresents territory size in that species. We used telemetry and spot-mapping to delineate song territories for individual Golden-winged Warblers and found that territories are much larger and include much more mature forest than spot-mapping suggests. These results were recently corroborated in other populations of Golden-winged Warblers with work by Frantz et al. (in press, Studies in Avian Biology). Spot-mapping probably remains an excellent low-cost tool for identifying core-use areas within song territories and assessing abundance of breeding males within an area. However, the assumption that spot-mapping accurately delineates song-territory boundaries, and therefore accurately identifies areas of territory use vs. non-use, is not valid.