Bromethalin is poisoning the parrots of Telegraph Hill.

Bromethalin, a common rat poison, is the agent responsible for a neurological disease that has sickened or killed birds from a popular flock of naturalized parrots that reside primarily in the Telegraph Hill area in north San Francisco, according to a new study led by the University of Georgia Infectious Diseases Laboratory and funded by Mickaboo Companion Bird Rescue.