Thickness of the American woodcock eggshell, 1971

Eggs or empty shells of the American woodcockwere collected from 10 states in 1971and shell thickness (mean of clutch means) was compared with that of eggs collected from 16 states during the years 1859-1939. The 1971 shells (n = 91) from hatched eggs or those containing fully developed embryos were about i0 percent thinner (P