It is the the amount, as in tonage, that has been introduced it is the size and shape of the pellets as well as the concentration of those pellet is certain areas. Lead toxicity killed a lot of waterfowl AND birds of prey that in turn consumed the dead or dieing birds. As to the amount, over that past 400 years or so the tonage would be quite high.
I would agree with you but there really isn't any proof in lead of itself is the cause of a demise of any bird or anything else for that matter. 400 years is not the time line we should even consider, between population growth of the 20th century, the introduction of chemicals in the 50's and a need to utilize modern farming seems to be more relevant than the previous 360 years.
What I mean is that if this was the case, the issue would have been at its greatest problem in the early and mid part of the 20th century where there were little control on what people did or used. Maybe it would have been a case where the amount of shot used would not have been great but the introduction of lead into the environment would have had an impact over the 40 something years before the advent of strict licensing and controls on hunters/screwing landowners and the environmentalist movement under TR.
In all honesty, any improvements made to the environment may very well be about other chemicals in the environment which now are strictly controlled or eliminated altogether - like some of the fertilizers and pest control chemicals.
AND after studying the effects of fallout in my university days, I have a strong opinion that a lot of what we saw in environmental damage from the 50's through the 70's was not caused by anything but the fallout of above ground nuke testing done from 1946 to 1962 where about 100 detonations done in Nevada alone and about 300 tests done world wide by the United States. In addition to these above ground surface detonations, there were some atmospheric test detonations taking place that actually would have caused more of an issue because of the distance and manner they detonated the warheads. THIS does not include the Soviets, French and Brits test detonations.
The fallout, which I won't get into details, has affected everyone of us regardless what the science community has said because a lot of them have yet to be funded by private entities hence maybe their funding is tied to what they say?
But I digress ...
For example, DDT is one issue that seems to be more of a victim than a real issue for us. Without DDT, human life has been at a higher risk and even at the peak usage of it, it seems that we haven't had our environment destroy as many have predicted. Carson's book were not all based on credible science and even when it was, there was a twisting of facts to fit an agenda. DDT has not left our ecosystem, it is still present in many areas of the great lakes, as is a large number of Chemicals (for example in the Saginaw bay where Dow dumped a lot of nasty stuff), but the last I heard we have still a lot of bird, too many geese and really too many rodents on hooves running around with a growing population, even though the presence of DDT still being out there.
I can't help but wonder where people's priorities are, I mean isn't eradicating things like Mosquito carried malaria or other pathogens that are carried by insects a hell of a lot more important than say duck populations for hunters?
I think animals evolve to their enviorment, chemicals are no different than changes in weather or what ever you can think of and even though many will scream at this or that being a great idea to stop using this or that to save the environment, not one of them can come up with any specific reasoning behind why one species is suffering or what makes another die off.
