Introduction
:
Swainson’s Thrush is a medium sized (15-18cm) thrush which prefers to breed in dense shrub growth associated with spruce-fir forests. The "russet-backed" race prefers mixed forests and deciduous riparian woodlands of the coastal region from British Columbia, to northern California. These Pacific populations winter in mature tropical and secondary forests of Central America, whereas the "olive-backed" race that breeds in the Boreal and Rockies winters in S. America.
Models of Monitoring Avian Productivity and Survival (MAPS) demographic data and high-resolution land cover data showed that Swainson’s Thrush prefers large intact forest patches with low perimeter to area ratios.
On a regional scale productivity (reproductive effort) is higher at lower altitudes with more open canopy cover.
STAPI = productivity of Swainson's Thrush at each MAPS monitoring station calculated as the ratio of the total number of individual (i.e. uniquely banded) hatch year individuals to
adult individuals
1.06432-(0.000119 * "gtopo30") - ( "pnr_lat_grid"* 0.013561) - (0.00219 * "nlcd01cc2k") - (0.000285 * "strmnet5k")
Definitions of these parameters and how they were derived can be found in
www.birdpop.org/downloaddocuments/PNW_Landscape_Analysis.pdf
U.S. Department of the Interior
|
U.S. Geological Survey
