How many common loons in Ontario are actually dying of lead poisoning?
To know that, you’d have be satisfied that we actually know how many loons there really are in this province, and also be satisfied that the small number of dead loons that are found every year (and having been turned in to authorities, are in a condition that allows a necropsy to be performed) represent a reasonable sample of mortality in the population overall. Nevertheless, the post-mortems performed on 134 adult loons carcasses recovered (outside of the botulism cases) in Ontario in the April–September period between 1989 and 2005 have produced death rates due to lead toxicosis in line with findings in similar U.S. studies. Necropsies conducted by the Canadian Cooperative Wildlife Health Centre (CCWHC) at the University of Guelph have determined that thirty-three of the recovered birds died of lead poisoning—the second highest cause of death after trauma (which includes collisions with boats, drowning in gill nets and gunshot wounds), at 43. That’s one in four recovered birds havin
