Eagles and Lead

Eaton Rapids was in the news because some local luminary claimed that nearly all of the eagles he had examined had been poisoned by lead.

A quick search on his name reveals that he is in his VERY early 20s and is not a veterinary doctor nor is he credited with a Ph.D.

Furthermore, he works at a wildlife rehabilitation facility where sick animals are brought for "therapy" with the intention of reintroducing them to the wild. One might suppose that the animals brought to the facility are not representative of the larger population.

Zooming back a little bit, it appears that many environmentalists want to enact California's restrictions on lead-based ammunition to all 57 states. They point to studies involving hundreds of raptors showing high levels of lead. The facts that they choose to present make a compelling case for the elimination of lead.

But what are they not telling us?

The study implies that many of the raptors that were assayed as having high lead levels were collected in California where lead ammo has been prohibited since 2013. If the raptors from California had significantly lower lead levels then the article would have trumpeted that information from the treetops.

And yet they still want to prohibit lead-based ammo...even though its on-the-ground effectiveness is still more theoretical than proven.

When non-toxic shot for waterfowl was first proposed, the "science" claimed that ducks and geese had functional gizzards. That organ processes food by grinding grains and hard foods with grit. The scientists of the day claimed that waterfowl picked up lead "shot" when collecting grit and the shot would be ground to very fine powder in the gizzard.

Lead is a relatively inert metal. It has been used to line coffins, for instance. It was only by increasing the surface area by two orders of magnitude, via grinding, that enough toxic Pb ions could be leached from the material consumed by the waterfowl to pose a health risk.

Raptors do not eat grain. They do not have functional gizzards. The shot (and bullet fragments) are not reduced in size through the digestive system. So where does the lead come from?

Furthermore, if lead in animal corpses is such a risk, why does it not seem to impact crows and buzzards? Or, for that matter, possums and coyotes. We don't seem to have a crisis in the population of any of those critters.

Just to add to the confusion, maybe mammals trap toxic metals in their livers and maybe large raptors preferentially eat the livers of carrion. Looking back at Greek mythology, Prometheus's punishment for giving humanity fire was to be bound to a rock and to have his liver eaten by an eagle.

Those Greeks were not stupid. They did not pull "...eagle eating his liver..." out of their nethermost.