A case in point is my jaunt to Waggoner’s Gap hawkwatch this past Sunday. From the top of Waggoner’s Gap, I can see Roundtop Mtn., my own mountain, directly to the south, with the Cumberland Valley stretched out between us. Roundtop and Waggoner’s are also of a similar height, and without doing anything like an official survey, the basic tree and shrub species and the relative abundance of each certainly appears to be very much the same.
And yet, here sits a black swallowtail butterfly on a rock that was not far from my feet. Now I would never claim there are no black swallowtails on Roundtop. But I have seen precious few of them amongst the numerous pipevine, tiger and spicebush swallowtails that flitted through my summer landscape. And I’ve seen none while I’ve had a camera in my hand.
Roundtop has plenty of clover, thistles and milkweed, the species’ preferred food, which is also the preferred food of the aforementioned pipevine, tiger and pipevine swallowtails. So why are they on Waggoner’s and not so much on Roundtop? I wish I knew the precise answer to that one. Instead, I will give an imprecise answer. Something is just probably different several miles to the north on a mountain that isn’t very much different than Roundtop. But those few miles do make a difference. And when we’re thinking about preserving species diversity, we would do well to remember that one eastern forest habitat is not the same as its neighbor.