Vertebrate Pest Conference Proceedings collection


Date of this Version

March 1967


When corn is damaged by birds, kernels are eaten or "milked" and the affected ears are left with fewer intact kernels. The resulting damage, or loss, can be expressed in terms of the number, weight, volume, or value of the kernels that were removed or pecked. Assessment of loss thus frequently entails measuring, counting, or estimating from evidence of kernels lost. Estimates of loss resulting from the activity of birds should express the difference in value between a crop grown under the conditions that prevail and the value under the hypothetical condition of no adverse bird activity. To offset the effect of subsequent storm loss or failure to harvest a given crop, we found it expedient to assume that 96 percent of a standing crop one month prior to harvest will complete development, be harvested, and ultimately be utilized. The volume of destroyed corn further varies from the value of the eventual loss according to the response of the growing corn to bird damage: an animal nutritionist (George Haenlein, per comm.) indicated that in some corn varieties light damage to the tip of an ear early in the maturation will result in little or no reduction in the eventual total nutrient yield of the ear.