BISMARCK, N.D. (AP) — A Texas oil company has agreed to plead guilty and pay a $1,000 fine for killing a duck during drilling operations in western North Dakota.Dallas-based Petro-Hunt LLC was charged under the Migratory Bird Treaty Act for the death of a northern shoveler found in one of the company's waste pits May 6. Under a plea agreement filed in federal court Friday, Petro-Hunt will pay the fine to the nonprofit National Fish and Wildlife Foundation.Two other oil companies charged with killing birds during drilling operations in North Dakota this year have pleaded guilty and have agreed to pay fines. Three companies have pleaded not guilty to the charges.