A bald eagle grabs a fish from the Susquehanna River near the Conowingo Dam, Friday, Nov. 20, 2020. A bald eagle died in March along the Charles River after being poisoned by a toxic substance meant to kill vermin. (Julio Cortez/AP) Animal rights groups are pressing Massachusetts lawmakers to limit the use of highly toxic rat poison following the death of a bald eagle blamed on the poison. The bald eagle that died in March along the Charles River was poisoned after ingesting a toxic substance meant to kill vermin. State wildlife officials said the eagle succumbed to poisoning from a “second-generation anticoagulant rodenticide.” The second-generation anticoagulants prevent blood from clotting normally, resulting in a fatal hemorrhage. They are more toxic than first-generation poisons.