Partnership for Harrier Habitat Preservation (PHHP)
Background
The northern harrier, formerly known as marsh hawk, is a slim, long-legged raptor that can be readily observed hunting in Nantucket's open spaces. These birds range from 16 to 24 inches in length, and can have a wingspan of up to 46 inches from tip to tip. The long, narrow wings are characteristically held in a V-shaped position as the bird courses low over its hunting territory. Male harriers are pale bluish-gray on the head and back, white on the breast, and have black wing tips. The females, which are slightly larger, are chocolate brown on the head and back, and have pale, streaked breast feathers. Both sexes have a conspicuous white rump patch, dark bills, and long orange-yellow legs. Their round, owl-like faces contain keen eyes and ears that enable them to accurately locate their prey species, including the meadow vole (a mouse-like creature that inhabits open grassy areas), small songbirds, and cottontail rabbits.
Northern harriers were quite common in Massachusetts until the early 1900's, inhabiting shrub swamps, grasslands, shrublands, abandoned fields, and coastal and inland marshes across the state. However, their population numbers have experienced dramatic region-wide declines during the last fifty years, which are attributed to habitat destruction due to development, alteration and filling of wetlands, and reforestation of former agricultural landscapes. The harrier is now listed as a "Threatened" species under the Commonwealth's Endangered Species Act. Breeding populations in Massachusetts are limited to Cape Cod, Nantucket, Martha's Vineyard, and other off-shore islands.
Currently, it is estimated that there are 35-55 breeding pairs of northern harriers on Nantucket. The island is an important breeding site for several reasons. Unlike most birds of prey, harriers nest on the ground, and their eggs and chicks are very susceptible to predation by ground predators such as raccoons, fox, coyote, skunk, and opossum. None of these predators occur on Nantucket, although dogs and domestic and feral cats can disturb nesting adults and prey on eggs and nestlings if they are allowed to roam freely through nesting areas.
Harriers require extensive acres of undisturbed habitat to nest and raise their young. Nantucket is fortunate in that over one third of the island has been protected by various conservation interests, including the Foundation. Many of these protected lands contain sandplain grasslands and coastal heathlands. These areas are characterized by low shrubs and groundcover plants interspersed with grasses that provide ideal habitat for meadow voles, which harriers can locate with relative ease.
Nantucket's grasslands and heathlands were created by the practice of grazing large numbers of sheep over extensive common lands through the 1800's. Grazing kept the vegetation low, promoting the growth of grasses and other heathland plants (many of which are quite rare) while discouraging the growth of taller shrubs and trees. However, since the decline and eventual end of grazing, Nantucket's grasslands and heathlands have gradually become encroached upon by tall shrubs and trees such as scrub oak, northern arrowwood, choke cherry, and pitch pine. Because of this process of vegetative succession, many of these areas are slowly becoming unsuitable habitat for many of the rare and endangered species that are associated with them.
The Partnership for Harrier Habitat Preservation
In 1996, the Nantucket Conservation Foundation and the Massachusetts Audubon Society began a cooperative vegetation management program with the Nantucket Golf Club. The goal of this innovative, long-term effort is to improve rare species habitat on properties owned by the Foundation and the Massachusetts Audubon Society on Nantucket using a variety of management techniques, including hydro-axing, brush-cutting, mechanical vegetation removal, and prescribed burning.
The construction and operation of the Nantucket Golf Club on property formerly owned by the Henry Coffin Family in Siasconset significantly altered known habitat of several endangered species, including the northern harrier and two species of rare plants: bushy rockrose and St. Andrew's cross. To comply with the Massachusetts Endangered Species Act, the Nantucket Golf Club reached a precedent-setting agreement with the Natural Heritage and Endangered Species Program of the Massachusetts Division of Fisheries and Wildlife. As a result, it has agreed to fund the long-term improvement and maintenance of rare species habitat elsewhere on Nantucket in order to mitigate for the alteration of habitat that occurred on the golf course property.
The purpose of this agreement is to expand upon established vegetation management efforts aimed at maintaining and restoring sandplain grasslands and coastal heathlands. Active land management practices such as prescribed burning and brush-cutting have proven to be effective in maintaining these vegetation communities and providing habitat for their associated wildlife. The University of Massachusetts, the Massachusetts Audubon Society, and the Foundation have been utilizing these management techniques on Foundation and Audubon property on Nantucket since 1983.
The Nantucket Golf Club created a tax-exempt, nonprofit organization called the Partnership for Harrier Habitat Preservation, Inc. (PHHP). This group is administering and implementing a cooperative research and land management program that is aimed at achieving a long-term benefit to Nantucket's population of northern harriers. The PHHP consists of a four member Board of Directors, including two representatives from the Nantucket Golf Club, one representative from the Foundation, and one representative from the Massachusetts Audubon Society. The Massachusetts Natural Heritage and Endangered Species Program participate via an advisory position. The Board of Directors guides research and land management efforts, with the Club providing funding for these activities.
Because of this agreement, habitat restoration efforts are occurring on approximately 1,110 acres of open land for a period of 50 years. These sites were selected because they are contiguous to or in close proximity to areas that already provide good quality habitat for harriers, and they are part of larger, contiguous parcels of protected open space. The Massachusetts Audubon Society agreed to allow 110 acres of its property, located just northeast of the golf course, to be managed as part of this program. The remaining 1,000 acres of managed habitat occur on Foundation-owned property.
These sites are located on the northern side of the Milestone Road within the Foundation's vast Middle Moors property holdings, property owned by the Massachusetts Audubon Society in the Eastern Moors, and Foundation-owned property in the southwestern corner of the island at Ram Pasture. Before the project began, they contained a mixture of habitats that were at various stages of being overgrown with taller shrubs. Areas that contained dense stands of tall shrubs and trees are being managed through a combination of mechanical tree removal, hydro-axing, York raking, brush-cutting, and prescribed burning. Sites with patches of grassland and low shrubs are being managed through prescribed burning and brush-cutting, conducted during the non-breeding season (August through early March). Several of the targeted management parcels had already been burned at least once before the project began by the Nantucket Heathlands Partnership, an existing coalition of island conservation interests that have been involved in the effort to manage Nantucket's unique vegetation communities since 1993.
This cooperative management program is producing positive benefits for all parties involved. The Nantucket Golf Club has been able to proceed with the construction of its golf course, and is gaining some valuable hands-on experience in propagating endangered plants at a scale that will benefit others who are involved in similar restoration efforts. Additionally, it is receiving positive public relations benefits from its sponsorship and participation in the PHHP.
Massachusetts Natural Heritage and Endangered Species Program is excited about this cooperative initiative that will result in a net benefit to a state-listed species, and sees it as a model for resolving conflicts between rare species protection and development projects.
Finally, the Foundation and the Massachusetts Audubon Society have been able to continue and expand upon over twenty years of research and management. All of the sites that are part of this new program had already been targeted for future vegetation management by the Nantucket Heathlands Partnership, but, until now, those efforts were not able to move forward because of lack of manpower and funding. The Partnership for Harrier Habitat Preservation is providing the resources necessary to accomplish many of the Foundation's established land management goals that would otherwise have been unachievable.