Three Rivers BCA Management Guidance Summary
Site Name: Three Rivers
State Ownership and Managing Agency: Department of Environmental Conservation
Location: Three Rivers Wildlife Management Area, Town of Lysander, Onondaga County.
Size of Area: 3,615 acres
DEC Region: 7
General Site Information: Three Rivers has a mixture of grassland, shrubland, wetlands and forested habitat. These habitats support a diversity of early successional grassland and shrubland bird species. Marsh and wetland habitats support nesting osprey and bald eagle.
Vision Statement: Maintain and enhance the grassland habitat present to ensure continued use by grassland birds. Maintain and enhance early successional habitats to prevent reversion of these areas to forests, and increase use of these habitats. Manage marsh habitats to benefit nesting eagles and ospreys and other wetland dependent species.
Key BCA Criteria: Diverse species concentration site; migratory species concentration site; individual species concentration site, and species at risk site (ECL §11-2001, 3.e, f, g, and h). Supports a variety of nesting grassland and early successional species. Also supports nesting bald eagle and osprey. Supports a wide diversity of songbirds during migration, including several species of thrush (wood, veery, hermit, gray-cheeked, Swainson's). Northern shrikes overwinter here most years. Species at risk include: Henslow's sparrow (may be extirpated), grasshopper sparrow, bald eagle, osprey, Cooper's hawk, vesper sparrow. Species of conservation concern, such as American woodcock and bobolink, are common.
Critical Habitat Types: Large contiguous areas of grassland; shrubland and early successional forest habitats; marsh and wetland habitat.
Operation and Management Considerations:
- Identify habitat management activities needed to maintain the site as a BCA.
Encroachment of shrubs and weeds (for example goldenrod) into grassland habitat has begun to limit grassland bird species use of these grasslands. The area is currently managed in part for field trial use (dog competition). Strips are mowed in fields leaving strips of higher cover that it is hoped will hold released pheasants for the field trials and for pheasant hunting. Current mowing rates are allowing much of the grassland to revert to old field habitat, with shrub and aggressive weeds allowed to gain control.
To enhance grassland bird use of the grasslands, the larger areas of grasslands (greater than 10 contiguous acres) need to be managed more intensively. These larger fields should be mowed at least once per year after July 15, and the entire field should be mowed each year until the shrubs and aggressive weeds are suppressed. Smaller fields (less than 10 acres) could continue to be managed on a rotational basis as old field habitat, and shrub encroachment could be allowed.
In the larger fields, once the shrub and aggressive weeds have been suppressed, then a rotational mowing cycle could be instituted. Mowing could then occur just frequently enough to keep the shrubs and weeds under control. Rotational mowing, where portions of the area are mowed every year, and other portions are left as standing grass, will maintain a good mixture of grassland habitats over time.
Shrubland habitats support brown thrasher, American woodcock, and a host of other shrubland birds. Portions of the shrubland should be brush-hogged periodically to prevent succession to forest. Strips or patches could be brush-hogged periodically to maintain a mix of shrub ages, and prevent trees from taking over the shrublands. Trees should be periodically removed to prevent the shrublands from beginning to revert into forest.
Forested areas, including drier swamp areas, could also be periodically disturbed to increase the amount of early successional habitat present. Patch cuts or strip cuts would provide structural diversity and enhance use of the area by early successional species. Care should be taken to not disturb areas near osprey and bald eagle nests during the periods the nests are occupied.
Aggressive management of invasive species, including at present water chestnut, European frog-bit, and purple loosestrife, is needed. Also there is a need to evaluate the effect of aerial pesticide application on purple loosestrife biological control beetles and work to reduce use of these if warranted.
- Identify seasonal sensitivities; adjust routine operations accordingly.
The timing of mowing is critical. Grassland bird species can begin nesting as early as February or March (horned lark) and may nest into September (sedge wren). The best period for mowing is late July through early October when dry conditions normally persist. Mowing during this period should result in minimal interference with nesting birds.
Management activities in areas surrounding eagle and osprey nests should not occur during the nesting season.
- Identify state activities or operations which may pose a threat to the critical habitat types identified above; recommend alternatives to existing and future operations which may pose threats to those habitats.
The greatest threat to these critical habitat types would be the lack of active management. Periodic mowing is required to maintain the larger contiguous grasslands. Otherwise, vegetative succession will result in the reversion of these areas to shrublands and then forest. Smaller fields (less than 10 acres) not surrounded by open grasslands could be allowed to revert to shrublands or maintained as old fields.
Portions of forest and shrub habitats will need periodic disturbance to maintain and enhance shrubland and early successional forest habitat. Small (5-10 acre) patch or strip cuts would be one way of accomplishing this.
- Identify any existing or potential use impacts; recommend new management strategies to address those impacts.
Parts of the area are presently used for dog training and field trial activities. More information is needed on whether or not these activities significantly affect nest success of grassland and other nesting birds.
Limited human disturbance has been allowed around the eagle nest site and that practice should continue.
Education, Outreach, and Research Considerations:
- Assess current access; recommend enhanced access, if feasible.
Public access is considered adequate.
- Determine education and outreach needs; recommend strategies and materials.
There is a need for an educational effort directed at grassland, shrubland, and early successional forest bird management. Grassland birds, as a whole, are declining throughout the Northeast as their habitats decline. Many shrubland and early successional forest birds are also declining. Kiosks and other educational materials should be developed and focus on the need to maintain grasslands and shrublands, and the diversity of associated bird species.
- Identify research needs; prioritize and recommend specific projects or studies.
Better data on the grassland and shrubland bird use of the area would be helpful. Surveys on the species present and relative abundance would increase our knowledge of avian use of the area.
There is a need to assess the impacts of allowing dog training and field trials during the nesting season (April 1 to July 15), particularly the effect on grassland bird nest success.
DEC Region 7 Wildlife Manager, 607-753-3095
Bull, John L. 1998. Bull's Birds of New York State. Comstock Publishing Associates, Ithaca, NY.
Jones, Andrea L. and Vickery, Peter D. Conserving Grassland Birds. Three volume set. USFWS and Massachusetts Audubon.
Mitchell, Laura R., et al. 2000. Ecology of Grassland Breeding Birds in the Northeastern US. Cornell University.
NYSDEC. 1997. Three Rivers WMA Biodiversity Report. NYSDEC, Albany, NY.
Sample, David W. and MJ Mossman. 1997. Managing Habitat For Grassland Birds. Dept of Natural Resources, Madison, WI.
Vickery, Peter D. and Peter W. Dunwiddie. 1997. Grasslands of Northeastern North America. Massachusetts Audubon.
Date Designated: 9/25/06
Date Prepared: 4/7/07