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 Grassland Birds
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Background
The Grassland Conservation Program at the Center for Biological Conservation, initiated in 1993, is a regional effort to preserve grassland habitats that provide breeding and feeding sites for a wide variety of birds, plants, and butterflies. Program staff are working with private landowners, universities and airports, and state and federal agencies to promote effective conservation practices for these grassland sites. Staff scientists also study grassland birds to document reproductive success and habitat selection as part of a national network of grassland ecologists. Program funds are used to carry out, in partnership with a variety of state and federal agencies, a regional inventory and evaluation of threatened grassland areas and to create management plans for their preservation. The Grassland Conservation Program is a proactive effort that seeks to anticipate wildlife extirpations and the prohibitive costs they entail.
The information presented on this site concerning the conservation of birds on small, large, and agricultural grassland areas was originally presented in printed booklets prepared in 1997 by Andrea Jones and Peter Vickery of the Grassland Conservation Program, Center for Biological Conservation, Massachusetts Audubon Society, Lincoln, Massachusetts, in collaboration with Silvio O. Conte National Fish and Wildlife Refuge and the USFWS North American Waterfowl Management Program. Additional financial support was provided by Sweet Water Trust, Weeden Foundation, Wharton Trust and World Wildlife Fund (to request any of these booklets, click on the image to the right).
The purpose of this information is to help communities, agencies, and individuals manage grassland to protect bird species. The following information is included: history of grassland birds in the Northeast and detailed descriptions of six species of grassland birds (see "Introduction"); management options including mowing, grazing, and prescribed burning; grassland restoration; and options to protect grassland bird habitat. Tables included on this site provide detailed information on the following: breeding biology and management options for six species of grassland birds, native grasses recommended for restoration projects, nurseries providing native grass seeds, and agencies specializing in agricultural land management issues.
Information is available on three types of grasslands, described below:
- Small Grasslands: grasslands between 10 to 75 acres, including conservation lands (hayfields and meadows), corporate headquarters, recreation fields, and small capped landfills.
- Large Grasslands: grasslands of more than 75 contiguous acres, including conservation lands (may be a mixture of pastures, meadows, and hayfields), airports, and capped landfills.
- Agricultural Grasslands: grasslands on active farms including hayfields, crop fields, and pastures.
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History of Grassland Birds in the Northeast
Historically, most of the Northeast was forested. Natural, permanent grasslands were uncommon, except for scattered openings that existed along river floodplains, wetlands, beaver meadows, salt marshes, and coastal sandplain grasslands and heathlands. Other forested areas opened periodically due to fires set by lightning strikes, and burning and clearing by Native Americans. With European colonization, forests were cleared to make room for growing agricultural demands.
By the 1800s, grasslands were widespread in the Northeast, as land was cleared for pastures and hayfields, and grassland birds undoubtedly benefited from this expanded habitat. Historically, the large grasslands in the Northeast provided habitat for many grassland birds, particularly the grasshopper sparrow, savannah sparrow, vesper sparrow, upland sandpiper, eastern meadowlark, and bobolink.
In the early 20th century, changes in agricultural technology, movement of farms to the west, and an increase in human population in the Northeast caused a decline in the quantity and quality of grasslands for wildlife. Populations of grassland birds adapted to agricultural landscapes are now diminishing as farmlands are left idle, revert to forests, or are replaced by housing and business developments. Coastal grasslands are threatened by fire suppression and fragmentation due to development.
Old hayfields that were traditionally harvested late in the season provided ideal breeding habitat for birds. Today, remaining hayfields are mowed earlier and more frequently in the summer, or are planted in large monoculture crop fields.
The disappearance of the heath hen represents one of the most dramatic changes in grassland bird populations in the Northeast. Formerly abundant as a bird breeding in coastal sandplain grasslands and heathlands throughout the Northeast and along the Connecticut River valley, it became extinct in 1932 due to habitat loss. More recently, Breeding Bird Surveys (BBS) conducted by the Biological Resource Division of USGS and volunteers throughout the United States have shown alarming declines in the number of grassland birds nationwide. For instance, bobolinks have declined by 38 percent and grasshopper sparrows by 69 percent in the past 25 years. Within New England and New York, at least 9 species of grassland birds are now recognized as regionally threatened or endangered in at least five states. Conservation of grassland habitats and changes in management practices can maintain good quality habitat for these rare birds.
Because farmland has become fragmented, most remaining grasslands have become smaller and isolated and are no longer suitable for many species requiring large tracts of grassland. Bobolinks, eastern meadowlarks, and savannah sparrows are reliant on the remaining hayfields and pastures for their survival.
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1997 - 2000 Regional Grassland Bird Survey
During the 1997 - 2000 field seasons, Massachusetts Audubon Society coordinated a regional survey of breeding grassland birds in New England and New York. This project, funded by a matching grant from the National Fish and Wildlife Foundation and multiple other matching foundations, was complimented by grassland bird survey work already in progress in each state. This project would not have been successful without the cooperation of numerous individuals and agencies throughout the region, and we are thankful to all involved.
We censused 1,130 sites for eight species of grassland birds across New England and New York. These sites included hayfields, fallow fields, pastures, airports, and military bases from northern Maine to western New York. Efforts focused on areas that were historically recorded as grassland bird breeding areas. This project was aided by the cooperation of numerous state and federal agencies, conservation organizations, ornithologists, and birding enthusiasts. The contacts made during the course of this project enhanced communication and improved the coordination of many regional and local grassland bird conservation actions.
The Natural Resource Conservation Service was integral in helping us select sites by providing access to aerial photographs of each county within each state. We considered sites suitable if they were clear of trees and shrubs, were greater than approximately 5 ha (12 acres), and were dominated by grasses and forbs. Each site was surveyed using 100 m radius point counts. Bird abundances were then summarized across the region and within each state. All site coordinates were recorded and generated into a Geographic Information System (GIS) coverage.
Of the eight species surveyed, Savannah Sparrows were the most common, occurring on 75% of all sites in the region. Bobolinks and Red-winged Blackbirds were the next most frequently encountered species, occurring on 73% of the sites. Eastern Meadowlarks were detected on 45% of all sites. Vesper Sparrows, Grasshopper Sparrows, Upland Sandpipers, and Henslow's Sparrows occurred on <20% of all sites surveyed.
To print maps of each species distribution and abundance in New England and New York, click on the species name below.
A complete copy of this report can be obtained by clicking here to download a PDF file of the final report, or contacting: conservation@massaudubon.org.
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Massachusetts Audubon Society and Agriculture
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| Photo by Andrea Jones |
Massachusetts Audubon has consistently supported agriculture as a land use that is necessary for the production of food for human consumption. The Society recognizes that farms provide habitat for wildlife, and has supported federal and state laws and programs aimed at maintaining land in agricultural production and avoiding conversion of farmland to development. Massachusetts Audubon acknowledges the valid role of agriculture within the state's economy, its historic place as land use consistent with maintaining rural character, and its value in maintaining open space.
The information here and in the booklets is aimed at providing recommendations and options for managing open space for wildlife when appropriate, and are not intended to influence changes in agricultural production.
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2001 New England Salt Marsh Bird Survey
Salt marshes are unique coastal habitats that provide an important exchange in nutrients between marine and freshwater ecosystems. Salt marshes are critical nursery grounds for many commercially valuable fisheries. Worldwide coastal fisheries are significantly correlated with salt marsh area. Coastal marshes buffer shorelines from flooding and storm damage by intercepting runoff, limiting storm-induced erosion and enhancing water quality. Salt mashes also support highly diverse wildlife populations and provide valuable breeding and migratory stop-over habitat for numerous species of shorebirds, waterfowl, colonial waterbirds, and song birds.
Although the ecological services and biological diversity of salt marshes are well documented, these ecosystems have been altered, degraded, and lost throughout the coastal United States. Human population density is highest in coastal habitats, putting severe pressure on coastal ecosystems to maintain ecological integrity and ecosystem functions. Most salt marshes in the Northeast have been altered to some degree by agriculture, mosquito control, and development. In Connecticut, 50% of the salt marshes have been lost due to extensive urban development in coastal areas.
Due to the difficulty in accessing salt marsh habitats, the distribution and abundance of salt marsh breeding birds in New England is not well understood. Therefore, it is important to develop habitat specific surveys that can compliment the widely used Breeding Bird Survey to fill the gaps in our understanding of the basic properties of breeding bird populations. In recent years, multiple avian conservation ranking schemes (Partners in Flight, National Audubon Society) have indicated that salt marsh breeding birds are species of high conservation priority in the Northeast, due mainly to the lack of information about the distribution, abundance, and breeding ecology of these wetland dependent birds.
Herein we report the results of a regional survey of breeding salt marsh birds coordinated across all New England states. These data were collected using methods developed in Maine and have been incorporated into a regional database for all New England states. The primary objectives of this survey were to:
- Establish fixed radius points within salt marsh habitat to sample breeding birds from southern Connecticut to the Lubec, Maine;
- Determine if salt marsh bird communities responded to different vegetation comminutes, especially invasive Phragmites,
- Determine the landscape level influences on salt marsh bird communities, and;
- Build partnerships with federal, state, non-governmental organizations, and land managers to increase the exchange of information regarding salt marsh breeding bird communities.
A final report can be downloaded in PDF format or can be received by contacting: conservation@massaudubon.org.
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