I lived quite near Bird Hills from 1964 to 1976 and visited there often during the 1970s. I mostly studied the trees and wildflowers while I was there. I never saw a deer in the park when I lived there. But other than that, I doubt the basic ecology of the area has changed that much since I left. In most of Bird Hills, the oldest trees can't be much more than 100 years old, as that's when the area was replanted after serving as cow pasture for quite some time. However, the beech grove at the Beechwood entrance (the one I always used) seemed to me to be older growth. The whole southern side of the area (now right next to the freeway) is botanically very interesting. You could find Trillium up there in a few places, and also some great wild lilies, but the deer may have changed that. Also, the Flowering Dogwoods were always a prominent part of the springtime forest up on the ridge. In the center part of the area, which is obviously all relatively new forest, I recall Tulip trees and Sassafras, along with the oaks and maples. Various unusual conifers were also part of the replanting. Closer to the river, I recall numerous Hawthorn and also some more open areas. The forest floor could get covered in the spring by Fawn Lilies and other special wildflowers. I recall the spring flower blooms as being quite breathtaking. It's great this has been preserved as a park. When I lived there it was one of the most diverse natural areas available to me.