In a response to a query, Where are all the dead pigeons? 20-May-1988, Janice-Mary Cunningham of Dallas wrote:
"I thought you might want to know that there is indeed a pigeon graveyard in Dallas. I have had the opportunity, if not the pleasure, of touring the old American Beauty flour mill on South Ervay Street. After having been abandoned for 15 years, the building now houses the remains of several hundred pigeons, in every stage of decay from recently deceased to crumbling skeletons.
As an interesting aside, the vast majority died flat on their backs with their wings spread and their little feet in the air."
I don’t know if Uncle Cec ever got his NRF grant to study the reason why all the stiffs were in this position–an unnatural one, BTW–there’s two possibilities: poison &/or predators.
Poison first: a pigeon normally rests on its belly, and a sick pigeon does a lot of resting. Granaries and mills often spread poison to kill rats, and some fungicides that used to be applied to grain had a mercury base; if the pigeon ingests any, particularly the latter, the resulting convulsions could flip it onto its back.
Predators: the location of the ‘pigeon graveyard’ might more accurately be termed the ‘Pigeon Deli Counter’. Many raptors (birds of prey), particularly those which chase down and catch other birds–the exemplars of this method are the falcons–have a preferred location to which they carry their prey to pluck off the feathers and start chowing down. Since the meatiest part of the bird are the big flight-muscles on either side of the breast-bone, a raptor will preferentially turn the prey onto its back to get at them. After a while, such a ‘butcher’s block’ location may come to resemble the scene described above by Janice-Mary.
So why don’t people see more of these butcher’s-blocks? Well, in nature, a larger predator may come along and jack the smaller one’s prey, and sometimes toss down the smaller predator as well, so the usual feeding locations tend to be hard to see from the highway.