Squirrel Killings

Long time lurker, first time poster here. Hi everyone.

I live on the north side of Prospect Place between Carlton and Flatbush. My neighbor brought to my attention that he's found 4 dead squirrels in his backyard (adjacent to mine) recently and I subsequently found 2 dead in my yard this morning.

Is someone poisoning them? Perhaps they are eating poison meant for rats? Since he mentioned it, I haven't seen one live squirrel in the backyards behind our buildings. Super quiet when it used to be squirrel grand central. (I'm talking about the yards between Prospect and St. Mark's Place between Carlton and Flatbush).

This is also I guess a warning to anyone who let's their pets out there that there may be some kind of poison in the yards. Anyone else notice alot of dead squirrels in the area?