Numerous studies have been conducted by Citizens United on the birds of the Maurice River region. These research efforts have taken place throughout the seasons investigating the breeding birds of the river and it's tributaries (principally the Manumuskin), winter bird populations, and the use of the area by migratory birds in spring and fall. Also, key parcels of land have been specifically surveyed for bird use, an important aspect of assessing the preservation potential and priority of undeveloped or threatened lands.
The principal ongoing project is an investigation of the status and trends in wintering raptors and waterfowl on the Maurice River. In year seventeen the study was extended to encompass the entire year. This study is one of very few true long-term systematic monitoring studies conducted in the Delaware Estuary. The study year July 2004- June 2005 marked the eighteenth annual survey.
Waterfowl Studies
Ducks and geese have been counted along the tidal portions of the Maurice River for the past thirteen winters, beginning in 1987-1988. Surveys have been conducted between November 22 and March 22 each season, on an average of once every ten days. In this way, the status and trends of waterfowl on the Maurice River can be assessed. In all, 32 species of waterfowl have been recorded on the Maurice River to date. Key species on the Maurice River and its tributaries include Snow Goose, American Black Duck, Mallard, and Northern Pintail.
• Snow Geese are found in the salt marshes on the lower river, with an average of 3,000 to 4,000 found each winter. The peak daily high count was 14,000 recorded early in 1990.
• Black Ducks are found in large numbers along the length of the river, with average counts between 1,000 and 3,000 each winter. Peaks have been as high as 8,000 birds for this species of special concern.
• Mallards and N. Pintails are found primarily on the brackish marshes of the upper river, with largest numbers usually recorded in late winter and early spring. These species are found in highest numbers in the wild rice marshes north of the Maurice River Causeway. Average numbers vary considerably due to the severity of the winter, but peaks of nearly 4,000 Mallards and 3,000 N. Pintails have been recorded.
Raptor Studies
Raptors (hawks and eagles) have been monitored concurrently with waterfowl for thirteen winter seasons, beginning in 1987-1988. Presently the study encompasses the entire year with the ability to extract the winter data for comparison purposes (click for available STUDIES). Raptor studies have yielded significant long-term data on the status and trends of birds of prey in the Maurice River region. Raptors are predators at the top of the food chain. Accordingly, raptor numbers are a good barometer of an area's environmental quality. The Maurice River system continues to support one of the largest wintering hawk and eagle concentrations known in New Jersey or the Delaware Estuary region. Fourteen species of raptors are recorded most winters.
• Turkey Vultures are the most numerous species found. Regional Turkey Vulture roosts support up to 300 birds each winter. Vultures are near the northern limit of their winter range in southern New Jersey.
• Red-tailed Hawks are the second most numerous species on the winter river. Average counts of 40-50 birds are achieved along the 14 mile stretch of river surveyed.
• Northern Harrier, formerly known as "Marsh Hawk," are another representative species of the vast marshes of the Maurice River. Counts of up to 30 N. Harriers are found each winter.
• The Bald Eagle is a hallmark species on the Maurice River and its tributaries. The numbers found here each winter are significant and generally the highest concentration in both New Jersey and in the entire Delaware Estuary region. Numbers have been growing over the thirteen years of study. Currently peak counts of up to 20 Bald Eagles are achieved each winter.
Photo: Clay C. Sutton
|
The following is from the report summarizing the first ten years of this ongoing study:
"Ten years of monitoring winter raptor and waterfowl numbers on the Maurice River have indeed confirmed and corroborated the first season's findings originally reported in Records of New Jersey Birds in 1988. The wintering populations of raptors are regionally significant, and the annual numbers of eagles are among the highest in the state (rivaled only by the upper Delaware River and the Mullica River complex). The wintering populations and early spring staging of waterfowl on the Maurice River and its tributaries are significant both in New Jersey and on the so-called "eastern flyway." Collectively, the Maurice River and its tributaries represent some of the most important waterfowl habitat in New Jersey.
"The extraordinary abundance of waterfowl and raptors together make the Maurice River one of New Jersey's most important natural areas, and every effort must be made to keep these habitats from being fragmented and degraded by those forms of change which have reduced the wildlife values of so many of the state's once important natural wetlands and upland buffers.
"The high species diversity and large numbers of winter raptors and waterfowl documented here make the Maurice River area exceptional in the Delaware Estuary and the mid-Atlantic region. The Maurice River and three of its tributaries (Manumuskin River, Menantico Creek and Muskee Creek) are now included in the U.S. National Park Service Wild and Scenic River Program. The diversity and abundance of wintering raptors and waterfowl, at minimum, confirms and affirms the designation and supports the need for increased and long-term open space protection for the remarkable Maurice River region."
Autumn Migration
Additional bird studies conducted along the Maurice River have looked at the migratory bird use of the lower river by fall migrants. Following is a summary from a study 
cofunded by the Citizens United and the New Jersey Audubon Society's Cape May Bird Observatory:
"A major autumn raptor flight has been discovered and documented flying west up the Delaware Bayshore. These are birds that are electing to fly around the Delaware Bay rather than cross the bay from Cape May to Cape Henlopen. A concentration of this flight occurs at East Point, near the mouth of the Maurice River, due to geography (birds following a wooded peninsula to the southwest) and a minor water crossing (Maurice River Cove). In 1989, 1,788 raptors were recorded in 43.25 hours over 10 days of observation. In 1990, 9,042 raptors were recorded at East Point in 308.5 hours of observation over a 60 day period. Flights were compared and contrasted to the famous Cape May hawk flights. The 9,042 raptors recorded by the East Point watch represent 34.6% of the 26,164 birds seen at Cape May during the same 60 day period. Except for Osprey, Merlin, and Peregrine, virtually all birds were moving west around Delaware Bay, giving us a picture of the importance of bayshore habitats to migratory raptors. The data clearly shows the major importance of the Delaware Estuary shoreline, both salt marshes and upland edges, to migratory raptors for roosting, resting and feeding. Prior to this study, virtually all knowledge of the return flight up the bay was anecdotal. From this quantitative study, the first ever done, we now have a clearer picture of the dynamics of coastal plain raptor migration through New Jersey and around the Delaware Bay."
All Maurice River ornithological studies have been directed and co-authored by Clay Sutton, either as an independent contractor or formerly as staff ornithologist of Herpetological Associates, Inc., Plant and Wildlife Consultants. Principal publications resulting (either wholly or in part) from the above studies (either funded or co-funded by CU) are as follows:
Niles, L. and C. Sutton. 1995. Migratory Raptors. Pages 433-440 in L. E. Dove and R. M. Nyman, Editors. Living Resources of the Delaware Estuary. Delaware Estuary Program, USEPA.
Sutton, C. and J. Dowdell. 1987. An Inventory and Habitat Assessment of the Birds of the Manumuskin River Drainage System and Portions of the Adjacent Maurice River, Cumberland County, N.J. Herpetological Associates, Inc.
Sutton, C. 1988. "Wintering Raptors and Waterfowl on the Maurice River." Records of New Jersey Birds, 14 (3): 42-51. New Jersey Audubon Society.
Sutton, C., J. Dowdell, et. al. 2000-2002. "Wintering Raptors and Waterfowl on the Maurice River." Yearly progress and summary reports prepared for Citizens United to Protect the Maurice River and its Tributaries. (Fifteen Individual Seasonal Reports.)
Sutton, C., C. Schultz, and P. Kerlinger. 1991. "Autumn Raptor Migration Along New Jersey's Delaware Bayshore -- A Hawk Migration Study at East Point, New Jersey." Hawk Migration Studies, 17 (1): 58-64. Hawk Migration Association of North America.
Sutton, C. and K. Williams. 1992. Comparative Raptor and Waterfowl Use of Specific Sections of the Maurice River. Report prepared for the Natural Lands Trust, Inc., by Herpetological Associates, Inc.
Sutton, C. and P. Kerlinger. 1997. "The Delaware Bayshore of New Jersey: A Raptor Migration and Wintering Site of Hemispheric Significance." The Journal of Raptor Research, 31 (1): 54-58. The Raptor Research Foundation.
