President's Corner | Sharyn Magee
Washington Crossing Audubon Society volunteers have spent hours in the field conducting citizen science research, including monitoring bird populations, conducting biosurveys, mapping breeding birds, and banding birds at Hannah Suthers’ Featherbed Lane banding station. Special emphasis was placed on searching for threatened and endangered species and species of conservation concern in the Important Bird Areas (IBA’s) threatened by the proposed PennEast pipeline. It was gratifying to see that our efforts paid off when the United States Fish and Wildlife Service (USFWS) cited our research, especially the 2008 to 2016 breeding bird survey at Baldpate Mountain, in their critique of the PennEast draft Environmental Impact Statement (DEIS). USFWS recommended that the pipeline rerouted to avoid IBA’s where migrants are concentrated in any part of their life cycle. This does not stop PennEast but it does put another obstacle in the way.
WCAS has conducted monthly biosurveys at the D&R Greenway’s St. Michael’s Farm Preserve for the past seven years and monthly bird and plant surveys at the Mt. Rose Preserve For Friends of Hopewell Valley Open Space since September 2015. These surveys show which bird species are present on the preserves, which habitats they are utilizing, and for St. Michael’s, how the populations are changing over time. St. Michael’s has been especially important for the New Jersey threatened American Kestrel, both for breeding and migration. Participants in our September 17 field trip were treated to a spectacular display of at least ten Kestrels hunting in a field. This knowledge can be incorporated into management plans to help maintain or increase biodiversity in these preserves, an important consideration when overall biodiversity is decreasing at an unsustainable rate. We are fortunate to partner with land trusts that understand the importance of protecting our local biodiversity.
While our successes have been gratifying, much remain to be done. We are fortunate to have so much preserved land in central New Jersey but our preserved lands are under- surveyed , especially the smaller preserves. The Rock Hopper Trail Preserve off Route 518 has some of the highest quality understory in the Sourland Mountains (Blue & Red Trails) and a maze of creeks that look like prime Louisiana Waterthrush habitat (Yellow Tail) but remains largely unexplored. The small grassland preserves such as the Thompson Preserve and the Cider Mill Preserve are also under- birded. Our members can help by birding any of these preserves and recording the results in eBird. Our cumulative records add up to a powerful argument for conservation.—Sharyn Magee, President, WCAS
Baldpate Mountain is a very special place.
Surrounded by a biological desert, Baldpate Mountain is a hotspot of biodiversity. Baldpate is part of the Greater Sourland Mountain Ecosystem, a high area formed by erosion resistant diabase after the softer surrounding rocks eroded away. As a raised wetland with poor drainage, this ecosystem has resisted development, leaving the two largest contiguous forested areas in central New Jersey. Because of its steep slopes and history of deer hunting, Baldpate Mountain has retained the greatest expanse of healthy understory in the Greater Sourland Ecosystem. The Sourland Mountain has a greater area of contiguous forest, but Baldpate has a larger expanse of high quality understory with four areas of extensive understory dominated by native plants, primarily Spicebush. Because of the combination of contiguous forest, high quality understory, and its location as the meeting place of Southern and Northern species, Baldpate Mountain has the highest concentration of nesting Nearctic-neotropical birds in New Jersey and the largest number of species of breeding Nearctic-neotropical migrants in central New Jersey. The interior forest has breeding Hooded Warblers, Kentucky Warblers, and Worm-eating Warblers, Wood Thrush and Veery, all New Jersey species of conservation concern. The forest has a mosaic of habitats, with naturally occurring treefall gaps supporting a tangle of vegetation that supports a different group of species, including the American Redstart. Baldpate also supports edge breeding species, especially where there is a soft edge between the forest and the open areas, giving a total of thirteen breeding wood warblers, which makes Baldpate a birding mecca. The area attracts large numbers of species of migrating Nearctic-Neotropical migrants, as well. Several New Jersey threatened raptors, including Barred and Long-eared Owls and Redshouldered Hawks, use Baldpate for at least part of their life-cycle. Cooper’s Hawks, a New Jersey species of conservation concern, breed at Baldpate.
Baldpate Mountain was designated as an Important Bird Area due to all these factors. For an area to support this number of birds, it must support an intact ecosystem with other taxa, especially native plants and insects, having healthy populations and diversity. In addition to rare birds, Baldpate supports rare reptiles, including NJ species of special concern Eastern Box turtle and Northern Copperhead, and rare amphibians, including the Fowler’s Toad.
While Baldpate has an intact ecosystem, it is also highly stressed. Baldpate is at the lower size limit for an interior forest habitat and its shape is long and narrow, increasing its vulnerability to edge effect. Increased edge effect increases the number of invasive species, especially non-native plants, and the Brown-headed Cowbird, a nest parasite. Any reduction in size of Baldpate would have serious consequences, both by threatening native plants and increasing the incidence of Brownheaded Cowbird nest predation. Nest predators, such as the Eastern Chipmunk, which have higher concentrations on the edges and in disturbed areas, would thrive. The proposed PennEast pipeline runs along the north slope of the mountain and would change one of the high quality interior forest habitats into edge habitat and bring the edge closer to the other areas of high quality habitat, seriously degrading an already stressed ecosystem.
We are going to walk along the powerline and then into the woods, initially through edge habitat and then through high quality habitat to show you what is at stake. Thank you for your interest in Baldpate. (Notes from the April 17 Baldpate Mountain, PennEast Guided Walk can be found on the WCAS website.)
Confirmed breeding pairs of Kentucky Warblers at Baldpate Mountain went from ten in 2011 to three in 2012, the year the Eastern Chipmunk population exploded on the north side of the mountain. Kentucky Warblers did not breed in previous strongholds along the Ridge Trail and the Northwest Red Trail in 2012 but still bred on the southern slope. That year a decrease in Red Fox sightings was observed on Baldpate and on adjacent properties. In the following two years, Barred Owls were heard by multiple observers during their breeding season on the north side of Baldpate, where they were attracted to an abundance of their favored prey. A Kentucky Warbler pair was confirmed breeding in 2015 on the periphery of an old territory. A decrease in foxes led to an explosion of their prey, Eastern Chipmunks, which led to a decrease in a ground-nesting bird, Kentucky Warbler – a classic trophic cascade. Eventually, the proliferation of chipmunks attracted a second predator, the Barred Owl. Keep enough pieces and the web of life is resilient. Checks and balances maintain a healthy biodiversity.
Keeping all the pieces is the key to successful conservation. In nature everything is connected to everything else. The more we ensure connections between species, the more resilient the ecosystem. In the example above, two of the species are in trouble. The New Jersey threatened Barred Owl requires a large expanse of wooded habitat. Breeding territories can be as large as two square miles. The ground-nesting Kentucky Warbler, an Audubon Watch List species and New Jersey species of conservation concern, is an interior forest-breeding species, requiring well vegetated understory and ground layers within the interior forest. Kentucky Warblers need a specialized habitat within a specialized habitat to successfully breed. Both species are highly sensitive to forest disturbance.
Baldpate Mountain’s strength is its native plants, a healthy assortment of native canopy trees, four large areas of high quality Spicebush understory, and areas with native groundcover. Baldpate is not pristine, but where the native plants are dominant, native wildlife thrives. Baldpate’s weakness is its size and shape. Its area is at the lower limit for a viable interior forest ecosystem, and the long, narrow shape enhances the edge effect, making the Baldpate ecosystem highly vulnerable to habitat loss, fragmentation and degradation. This is why the proposed PennEast pipeline will have a devastating effect on Baldpate’s biodiversity.
Baldpate is perhaps the most fragile of the Important Bird Areas and other preserved lands threatened by PennEast, but fragmentation and degradation of habitats will have a negative effect on biodiversity along the entire route. Pieces will be lost, connections will be broken, and resilience will be lost.