DISAPPEARANCE AND RECOVERABILITY OF SONGBIRD CARCASSES IN FRUIT ORCHARDS

Authors

Mark E. Tobin, New York Cooperative Fish and Wildlife Research Unit
Richard A. Dolbeer, New York Cooperative Fish and Wildlife Research UnitFollow

Document Type

Article

Date of this Version

June 1990

Comments

J. Field Ornithol. Spring 1990. Permission to use.

Abstract

Songbird mortality due to agricultural pesticides is often assessed by searching treated areas for carcasses. However, carcass removal by scavengers and the failure of searchers to find carcasses that are present may bias mortality estimates. We conducted two studies in 1987 and 1988 in New York to evaluate such biases at the time of fruit maturation in cherry and apple orchards. In the first study, mean survival times for carcasses were 8.2 d in cherry and 10.4 d in apple orchards. In the second study, searchers located an average of 75% of carcasses placed in orchards. Our results suggest that careful searches co nducted within 2 d of application of pesticides in orchards should suffice for detecting significant songbird mortality. However, variable survival times among orchards demonstrate that studies to assess songbird mortality by searching for carcasses should also measure disappearance rates of carcasses.