Meadowlands Bird Inventory Project:
A Year Round Study Of Distribution And Population Densities
By Ken Witkowski
The New Jersey Audubon Society (NJAS) has a long history of advocacy and research in the Meadowlands. During the Meadowlands Special Area Management Plan (SAMP) process, NJAS sat on the Citizen Advisory Committee. Richard Kane, former Vice-president of Conservation, has been conducting surveys and reporting on the Meadowlands avifauna since 1975. Much of this work has been published in Records of New Jersey Birds. In 1994-95, Kane headed up a team of NJAS research staff that conducted the first year-long inventory of the Meadowlands (Kane and Githens 1997). Much of what is currently known about seasonal occurrences of avian species in the District is based on this work.
Most people, even life-long area residents, are pleasantly surprised to learn of the diversity of habitats in the district which include tidal brackish wetlands, fresh water wetlands, a couple of upland forest remnants and some successional habitats of shrub/scrub. One of the prime benefits of this diversity of habitats is a corresponding diversity of avian species. While the most widespread use of the district for birds is as a migratory stopover location, it also provides over wintering habitat for numerous species of waterfowl and raptors. There are impressive numbers of Green-winged Teal, Ruddy Duck, Mallard, Black Duck and Gadwall to name just a few. The wintering population of Red-tailed Hawks and Northern Harriers is very evident. Rough-legged Hawk is also a frequent winter visitor although usually in small numbers. Migratory shorebirds numbers can be quite impressive in the spring and fall with many thousands of sandpipers present at times. No less important are the breeding birds. The Meadowlands is host to many common nesting species such as Marsh Wren, Swamp Sparrow, Red-winged Black Bird, Willow Flycatcher and Common Yellowthroat. More significantly, there are a number of state “threatened “ or “endangered” species such as Yellow-crowned Night Heron, Black-crowned Night Heron, Pied-billed Grebe and Northern Harrier nesting here as well.
In 2004, NJAS initiated a new field project funded by the New Jersey Meadowlands Commission to quantify information on birds of the district. Year round surveys are being conducted at many of the sites visited by Kane and Githens. Additionally, a number of old land fills and restoration sites are being surveyed. The specific objectives are to determine the abundance and distribution of avian species occurring throughout the annual cycle in the various habitats of the District, and to investigate habitat, landscape and disturbance characteristics that underlie avian abundance and distribution patterns. The sites being sampled give us a good representation of the habitats one expects to find in the Meadowlands and several sites from each category in the NJMC Meadowlands Environmental Sites Investigation Compilation (MESIC) report. Some of these are existing restoration, mitigation or preservation sites along with candidate restoration sites, waterbodies and other wetlands and potential remediation sites.
At each site we used Geographic Information System (GIS) data and the most current land use/land cover data available. Next, randomly placed survey points at least 250 meters apart to avoid duplicate counting were generated. The coordinates were then entered into a Global Positioning System (GPS) so that the exact locations could be revisited throughout the survey period. Site access was greatly facilitated by the staff at the New Jersey Meadowlands Commission and Hackensack Riverkeeper.
The actual field work began in September 2004. Ten minute surveys are being conducted at the designated points and all birds seen or heard are recorded by distance, habitat and compass direction. Distance sampling protocol provides a means to estimate detection probabilities and can help generate better estimates of breeding density. In addition, habitat and disturbance characteristics will be made at each point. Many survey points are reached on foot, however, a substantial number are accessible by boat only and in order to reach these points, a kayak is used. Hackensack Riverkeeper also provides access to survey points along the Hackensack River and the Sawmill Creek Wildlife Management Area. A New Jersey Audubon volunteer has also helped out with water access at times. The site visits take approximately 10 days to complete before beginning a new cycle.
This information will be used to generate models that explain the relative importance of various habitat, landscape and disturbance characteristics in determining avian site occupancy. This will also determine which sites are supporting the greatest number and diversity of birds and will allow us to infer which habitat, landscape and disturbance characteristics are important for the viability of breeding, migrating and wintering populations of birds in the Meadowlands District. Finally, this information will give the New Jersey Meadowlands Commission a scientific basis for making sound management, restoration and acquisition decisions. Surveys will be conducted through the summer of 2006 at which point the final report will follow.
Ken Witkowski is a Research Associate with the New Jersey Audubon Society.
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