Effect of insecticides on bird populations

Abstract

Scope and Method of Study: This report has been undertaken as a comprehensive survey of scientific literature since 1945 that has dealt with the effects of insecticides on bird populations. Particular attention was given to the effects of large scale programs, including

(1) the Dutch elm programs in the East and Middle West,

(2) the Japanese beetle program in the Middle West, and

(3) the fire ant program in the South.

Findings and Conclusions: Dutch elm disease programs in the Middle West were found to decrease songbird populations 30 to 90 percent in the urban communities studied. Some study areas treated for the fire ant in the South sustained bird losses in excess of 80 percent. Japanese beetle control programs in the Middle West led to an 80 percent decrease in songbird populations in several localities. The author finds some circumstantial evidence that insecticides may be lowering the fertility of Woodcock, Bald Eagles, and possibly songbirds. The author is critical of the lack of field testing before the Japanese beetle and fire ant programs were implemented and further suggests that advance publicity preceding such programs has been lacking or inaccurate. It is suggested that values other than those immediate and economic deserve more consideration than they have received in the past. Alternatives to and modifications of some present spraying practices are suggested which will be less harmful to bird populations.