Putting six-inch nails on
rooftops is bad enough, but some
pest control companies are advising
business associations to use
Avitrol for
pigeon control. They claim that it's only a
disorienting agent, not a
poison, but there is documentation of swarms of pigeons going into
convulsions after
ingesting it and of Avitrol killing pigeons by first inducing
seizures and then
cardiac arrest. There does not appear to be much being done to
prevent its use.
Also recommended are changing the angle of sills, installing mesh guards and nylon netting to prevent birds from landing, or removing their nests in the hope of relocating them. But surviving pigeons often fall victim to other wildlife such as hawks.
Not so long ago, people would look up at the sky and laugh over birds shitting on their heads. I think we should go back to that.