50 CFR §19.12

The prohibitions of the preceding section shall not apply to any person who:

(1) Is acting within the scope of his official duties as an employee or authorized agent of a State or the United States to administer or protect or aid in the administration or protection of land, water, wildlife, livestock, domesticated animals, human life or crops; or

(2) Is acting within the limitations of a permit referred to in § 19.21 or § 19.31 of this part.