I learned about lead shot in 1968, from a warden at Sauvie Island, outside of Portland. He talked about picking up hundreds of 'greenies', ducks dead or dying with their butts stained green from the undigested vegetation dribbling out the back because lead shot in their gizzards prevented digestion. A vast amount of research since then showed that ingested lead kills birds; free-flying condors in California are trapped annually and put through a chelation process, broadly similar to dialysis, to remove lead from their blood. They pick it up from gut piles or ground squirrels shot with .22's.
I have no idea if birds saved from lead poisoning outnumber crippling losses due to steel, but there is absolutely no question that lead shot in ponds kills waterfowl. Not all science which inconveniences us is a hoax or evil conspiracy - seen any mercury thermometer recently? If you want to disprove the science, start swallowing lead #8's and see how you feel in a year or two.
