Poison Killed the Babies Again

Over the course of many years I have seen baby birds nest in lot around the house every year the baby robins will suddenly die. The only thing that makes sense is some kind of poison is building up inside of them killing them. Why the adults are not dying and where they are getting it from makes absolutely no sense to me. I don't feel that bad but it happens year after year. Pesticides, rat poison and anything toxic to people is most likely toxic to birds. It gets onto my nerves that people can spray chemicals onto there lawns and the robins go and eat the worms full full of poison and the poison concentrates into something more toxic into the parent birds who feed it to their young who die from it. Think before you spray.