In the month of May, the 55-acre nature sanctuary that is the Four Mills Nature Reserve is getting some much needed attention. Scientists with the Morris Arboretum pored over the lush of plants found in our floodplain forest. Wissahickon Valley Watershed Association staff is conducting a breeding bird survey to determine how many species of nesting birds call this area home. Stewardship planted hundreds of understory native shrubs, trees and flowers to increase the diversity of species that is part of this ecosystem.
For an urban nature preserve, surrounded by suburbia, industry and congested roads, the fragmentation of the forest cuts off this forest patch from other similar natural areas. Since its original preservation in 1957 what species of animal and plants have survived till the present? But, first let’s talk about the backdrop, conservation in the 60’s was one of benign neglect; let the natural order of things proceed unfettered by the human hand. So by 2013, what have we inherited?
According to the botanists of the Morris Arboretum, there are more species of exotic plants than native ones in the preserve. Siebold Viburnum, an understory shrub is the dominant viburnum in the forest in places. Lesser Celandine, a flowering wildflower from Europe has thoroughly dominated the forest floor with their aggressive tentacles and rapid rhizome generation. Norway Maple is the most common tree sapling in the understory poised to threaten the Sugar Maples that are found here.
The vernal ponds, stagnant pools and rivulets of the Wissahickon Creek hold few amphibians. For long stretches the water remains silent when a hiker passes by. Even backswimmers, a common insect that literally floats of the water, is strangely missing. Has anyone seen a turtle basking in the sun lately? Is their decline climate related? Is the water quality that poor? Or have the amphibian species slowly died out due to some other unknown cause?
Interestingly enough, two raptor species attempted to nest at the Four Mills Nature Reserve. A pair of Red Shouldered Hawks carved a territory and built a nest. A female Red Shouldered Hawk appeared to be incubating on the nest in mid-April but suddenly the pair abandoned the nest. Replacing the hawks was a pair of Common Crows. They too disappeared after a week or two. A pair of Screech Owls apparently were nesting near the Barn itself. Local birders were monitoring the pair for a while every evening by listening to their dueling calls. Then they too seemed to disappear. Did they try to nest and suffer some calamity? We don’t know.
Overall, the breeding bird survey tallied 43 species, a high number for a small nature preserve. Among the birds that migrate to and from South America, we had some good representation. Scarlet Tanager, a striking red bird with black wings, counted three singing males. Wood Thrush, a cousin of the Robin also tallied four singing males. Red Eyed Vireo had ten singing males which could mean that their population at the preserve is over 20 birds! Colorful little birds called warblers had a small smattering; there were 3 Redstarts, 1 Yellow Warbler, and Common Yellowthroats. There is a pair of Common Yellowthroats greeting all walkers by at the entrance of the Rotary Trail!
Most mammals are hard to find. But raccoons have been rock stars! A family of raccoons have been found in the hollow of a dead tree right between the two bridges along the Wissahickon Creek. They have put on quite a show for many weeks. In fact, a domestic squabble compelled the mother raccoon to chase away a baby. Found at the foot of the nesting tree, volunteers and staff of the WVWA rescued the youngster and transferred it to a local wildlife rescue center. There is yet another family of raccoons in the cavity of a sycamore tree not far from the Rotary Trail.
This year, the staff of the WVWA, hired scientists and volunteers are taking critical view of the nature of the Four Mills Nature Reserve. We are asking Mother Nature, how are you doing? We hope to get a better understanding by the end of the year. Stay tuned!