A simple homemade baffle can prevent fire ants from attaching bluebirds in their nest boxes. That was the conclusion of a study conducted in South Carolina from 2000-2006. In the study, 15% of unprotected bluebird houses were attacked by fire ants, resulting in the deaths of nestling bluebirds. However, none of the nest boxes with baffles were attacked.
To make a baffle for a nest box, choose a 1 liter soda bottle with a smooth surface and a vertical slope. Bottles with any type of texturing are not effective. Cut the bottle, place it upside down on the pole, then use electrician`s tape to seal the gaps between the bottle and the pole. All gaps must be closed because fire ants can squeeze through what seems the tiniest of openings.
For more information about imported fire ants in wildlife areas, see Fire Ant Project Fact Sheet, Managing Red Imported Fire Ants in Wildlife Areas.
Find more information about fire ants in eXtension's Imported Fire Ant Resource Area.