Organochlorine residues, eggshell thinning and hatching success in British sparrowhawks.

Abstract

SPARROWHAWKS (Accipiter nisus) in Britain have laid thin-shelled eggs throughout the period of DDT usage1, and in several predatory species in North America an inverse correlation has been shown between shell thickness and DDE levels in eggs, both in natural and in experimental situations2–4. It has been claimed that eggshell thinning is associated with reduced hatching success, and that both effects could be implicated in a sequence leading to population decline. We have examined these relationships up to hatching stage in the sparrowhawk in Dumfriesshire, southern Scotland, where it still breeds in good numbers. During 1971–73 full details were obtained from 325 nests, and eggs from 130 clutches were collected for analysis.