Wildlife Damage Management, Internet Center for

 

Date of this Version

February 1989

Abstract

In an attempt to reduce valley wide populations of grackles in the Rio Grande Valley of South Texas, PA-14 was sprayed over a staging area where as many as 10,000 birds were located. This attempt was unsuccessful and this method of population reduction was deemed not suitable for south Texas. Dog food bait was treated with DRC-1339 and presented to great-tailed grackles in several different situations in an attempt to control depredations to citrus by this bird. Bait presented in feedlots during winter (Nov-Feb) was readily taken by the birds, resulting in a significant reduction of numbers of birds visiting these sites, but with little apparent effect on the valley-wide population or damage to citrus. Baiting at pre-and post-roost staging sites was not effective, even when supplemented with decoys. Baiting at nest colony sites early in the breeding season (Apr-May), and at water sources during the post-breeding period (Jul-Aug) were effective in reducing damage locally.