PARENT SESSION
Poster Session 28: Avian Ecology
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
The facilitation of wintering mixed-species flock movement by Eastern Tufted Titmice (Baeolophus bicolor).
Contreras, Thomas*,1, Sieving, Kathryn1, 1 University of Florida, Gainesville, FL, USA
ABSTRACT- The role of positive interactions between heterospecifics (also referred to as facilitation) may be underestimated in determining the movement behavior and the resulting connectivity of landscapes for terrestrial vertebrates. For species that form mixed-species groups, the movement of individuals in the group is often influenced by the presence of a species that assumes a group leadership role (nuclear species). For forest passerines in north-central Florida, the Eastern Tufted Titmouse may act as a nuclear species and influence the movement of wintering mixed-species flocks in the region by reducing the actual/perceived predation risk for the group. If titmice are facilitators of flock movement within or between forest patches, we predicted that the movement distance and direction of Eastern Tufted Titmice was more highly correlated with overall flock movement direction and distance than any other flock species. In addition, the movement direction of non-titmouse flock members would be highly correlated with the initial movement of titmice. If titmice facilitate flock movement across forest boundaries, then other species would be more likely to cross forest boundaries in response to titmouse movement. To test these predictions, we observed the overall movement direction/rate of mixed-species flocks that contained titmice, as well as the movement of individual flock participants. Our results suggest that titmice do influence overall flock movement direction over short distances (<50-m) but titmice may have less influence on relatively long distance flock movements (>50-m) as well as the individual foraging movements of other flock participants. Our results would also suggest that titmice may exert a greater influence on overall flock movements across habitat boundaries. We speculate that titmice may influence the degree of landscape connectivity for other wintering forest bird species in north-central Florida.
Key words: facilitation, heterospecific attraction, mixed-species flocks, movement