Organochlorine pesticide contamination in grassland-nesting passerines that breed in North America

Organochlorine pesticides and metabolites were measured in grassland-nesting passerines that breed in North America. We also examined testes of male birds for abnormalities that may have resulted from pesticide exposure. Forty-four of 99 individuals contained one or more organochlorine pesticides above the detection limit, representing nine of 10 species. The most prevalent compound detected was p,p′-DDE (minimum-maximum levels: 7.55–285.85 ng/g, carcass concentration). Insectivorous birds had significantly higher levels of p,p′-DDE than both omnivores and granivores. Birds that frequented moist grassland habitats had significantly higher levels of p,p′-DDE than those that frequented drier grassland habitats. No evidence of feminization was observed in any of the testes analyzed; however, other endpoint effects of contamination (e.g. hormone levels and immunological parameters) should be investigated in future studies.