Which method is NOT effective for controlling bats in structures?

The method that is not effective for controlling bats in structures is poisoning. Bats are protected species in many places, so using poison against them can not only be ineffective but also illegal. Additionally, poisoning creates further complications: it can result in the bats dying in hard-to-reach areas, leading to a foul odor and potential secondary poisoning of other wildlife and pets that may consume the poisoned bats. Moreover, bats play crucial roles in ecosystems, such as pest control, and using poison disrupts their natural contributions.

In contrast, exclusion, trapping, and building them out are methods that focus on humane and effective removal. Exclusion involves sealing entry points to prevent bats from entering, trapping involves capturing them humanely for relocation, and building them out includes modifications to structures to make them less hospitable to bats. Each of these methods aims to address the issue while being considerate of the bats themselves and adhering to wildlife protection laws.