Proceedings of the Vertebrate Pest Conference
Assessment, understanding and management of blackbird-agriculture interactions in eastern Canada
- Author(s): Weatherhead, Patrick J.
- et al.
The major results of recent research on the problem of red-winged blackbird (Agelaius phoeniceus) damage to field corn (Zea mays) in eastern Canada are reviewed. In the area of damage assessment, an indirect approach relying on energetic considerations appears to provide a rapid and inexpensive means for generating reliable damage estimates. The identification of pronounced compositional changes in roost populations has provided a more accurate means for predicting the impact of any management technique relying on population reduction at roosts. Investigation of the interaction of blackbirds and insects revealed that prey species conform to general patterns of coloration, mobility and the type of substrate from which they are taken. Also, a detailed examination of European corn borer (Ostrinia nubilalis) populations near a blackbird roost indicated that there was a tangible benefit to agriculture derived from blackbird predation of corn borers. An evaluation of blackbird population reduction through both surfactant spraying of spring roosts and through the use of decoy traps indicated that neither represented a viable solution to the crop damage problem.