Organochlorine residues in New Zealand birds of prey

Pectoral muscle samples from 13 New Zealand falcons, 3 Australasian harriers, 7 little owls, 7 moreporks, one long-tailed cuckoo and one New Zealand pigeon were analysed for organochlorine pesticide and polychlorinated biphenyls. Five juvenile falcons had a mean level of 2.6 mg total DDT per kg wet weight, and six adult falcons had an equivalent value of 11.7 mg/kg. Total DDT levels in harrier muscles ranged from 2.0 to 64.9 mg/kg. Levels in other species were probably too low to have detectable biological effects. There was no correlation between falcon eggshell thinning and residues in two eggs and two chicks