On the topic of deer predation in Pennsylvania, I wrote this to Jerry Feaser at the PGC:
On a discussion board the topic of whitetail predation came up, and someone made the point that the the PGC doesn't know how many deer are lost to predation from bears and coyotes. So, my questions are:
(1.) Does the PGC know how many whitetails are lost to bears, coyotes and other predators? (2.) How does the PGC know it? And, (3.) what is the breakdown, fawns to adults?
Secondarily, do we know how many deer are killed by collisions with cars, and how that compares to the numbers lost to predation?
Here is his reply:
Here is a link our deer page, which includes information on the fawn mortality study that we conducted, which documents predation: http://www.portal.state.pa.us/portal/server.pt/community/deer/11949
Under "Research Publications," look for "Survival rates, mortality causes, and habitats of Pennsylvania white-tailed deer fawns
As for road-killed deer, no one truly knows how many are hit and killed on the highways as there is no central reporting mechanism for such incidents. Insurance companies only know the number of claims that they process. PennDOT only knows how many deer carcasses they handle. We only know of the number claimed for consumption. For example: a motorist clips a deer with their car and does very little damage to their car. They don't want to pay the deductible, so they don't report it. The deer runs off and dies in the bushes, so there is nothing to remove from the road. How or who counts this?
He forwarded my questions to Dr. Chris Rosenberry, the deer section manager at the PGC, and back came this reply:
[size="1"]The Game Commission does not estimate the number and age of deer killed by various predators on an annual basis. However, we have conducted field studies to monitor survival and identify mortality causes over the last decade. From these studies and our ongoing monitoring of the deer populations, we also can monitor whether predators are preventing us from achieving our management objectives.[/size]
Rosenberry also added another place to look on the above link:
That's a short, and very interesting document. Here's the salient quote: "Deer management objectives are based on pre-hunt' deer population trends. The pre-hunt' population is the number of deer available at the beginning of the first hunting season. Across most of Pennsylvania, this is the population in late September or early October. The pre-hunt' population includes fawns that survived predation and other mortality during their first summer."
So, basing the antlerless allocation on the fall "pre-hunt" population means that fawn predation has already been taken into account. Obviously, this is not an exact science, since they don't have exact numbers and since the antlerless allocations are decided early. We're dealing with scientifically-based estimates here.
The earlier link is a longer paper, and part of a much larger study. I'll leave the reading of it to you, but clearly, this stuff is being studied and taken into account.