Abstract
During about thirty-five years of field work in bird ecology in eastern and central North America, I have examined in the field or collected and analyzed about 20,000 nests of 169 species of birds. This list represents nearly a third (31.3%) of the 533 species listed by Pough for the entire region of eastern and central North America from southern Texas to central Greenland. All of my studies have been confined within the region between the latitude of 30º and 50º north and between the 100th meridian and the Atlantic Ocean. The largest amount of my field work and study has been done in five counties of southeastern Michigan and three counties of southwestern Ontario where 25,379 nesting records have been established for 143 species of birds by about fifty field observers of the Detroit Audobon Bird Survey in the last 12 years.
