Mass. Gen. Laws ch. 111 § 174A
In order to preserve the purity and prevent the pollution of the waters of any reservoir, pond, and stream used for domestic water supply, by the watershed system of the division of watershed management of the metropolitan district commission, or by a town, water supply or fire and water district, public institution or water company, said division, the public board or commission, or the governing board in case of a water company, having control of such waters may authorize one or more of its employees, so far as permissible under federal law, to take such reasonable means and use such appliances and weapons as, in the judgment of such public board or commission, or governing board, as the case may be, will prevent the defilement of said waters by gulls or terns, any provision of chapter one hundred and thirty-one to the contrary notwithstanding. Every such division, public board or commission and governing board shall keep an accurate account of all birds killed by its employees under authority of this section and submit such account to the director of the division of fisheries and wildlife of the department of fish and game at such times and covering such periods as he may prescribe.
Mass. Gen. Laws ch. 111, § 174A