Which of the following is an endangered species that general pest control operators in Oklahoma might encounter?

The Interior Least Tern is recognized as an endangered species and is therefore subject to specific protections and conservation measures. General pest control operators working in Oklahoma may encounter this bird, particularly in habitats along rivers and large lakes where it typically nests. The regulations surrounding endangered species often require pest control operators to be mindful of their presence and to take precautions to avoid harming them or disrupting their habitats.

This awareness is crucial because the Interior Least Tern's population has significantly declined due to habitat loss and other environmental pressures. In contrast, the other species listed—such as the Indigo Bunting, American Robin, and Common Sparrow—are not classified as endangered and are more common in the region. Thus, the correct focus for a pest control operator involves understanding and ensuring compliance with environmental laws related to protected species like the Interior Least Tern.