Three Birds, One Stone

I'm somewhat stupefied at the moment. While mowing the yard today, I discovered three dead birds. All seemed of maybe adolescent size, they were too eaten up by ants to determine their health or what may have killed them. One was at the side of the trailer, another behind my car in the driveway and the last at the base of a tree. Now I take my dog out several times a day. They were not noticed there last evening. One Izzy may have got a hold of in the dark and fatally injured before I could get him to drop him, but he was actually on the ground to begin with, so maybe the bird was already sick or injured before hand. The other two I have no clue as to what may have happened. When I catch my neighbor returning home, I will ask if she has put any type of poison out they may could have gotten into, since all three are on the side that joins her property. If that doesn't work, I may call the Agricultural Extension Agency to see what they can do, if anything.