NCRS - The Changing Midwest Assessment

Data Source: USGS North American Breeding Bird Survey

In 1970, the average number of wood thrushes detected along survey routes ranged from 0 to 50, which means that a birder with advanced skills could reasonably expect to see around 50 wood thrushes in about 2.5 hours of bird watching along routes in prime habitat.

The Regional estimate of relative abundance (see the map on this slide) ranged from 0 to 9. In other words, an individual who spent 2.5 hours bird watching at random points in southern Illinois or Indiana could reasonably expect to see around 9 wood thrushes.