Grassland-nesting birds, including Bobolinks, Eastern Meadowlarks and Savannah Sparrows, are among the most imperiled birds in the nation.
Between 1966 and 2012, these species experienced steeper, more consistent, and more widespread population declines than any other group of birds in North America, according to MassAudubon. While only a minority of song bird species nest on the ground, these birds, having migrated north, all nest in grassland, even in areas where trees and shrubs are available.
While there are many factors in the decline, including the loss of grassland properties to development, the greatest threat may come from farmers.
Nests and young chicks are destroyed by haying machinery, and those adults that do survive may not have enough time to lay more eggs before migrating south for the winter. “We at Mass Audubon are convinced that mowing for hay during the height of breeding season is now the leading threat to grassland-nesting birds in New England.”
Protecting these nesting sites does present a very difficult dilemma. Hay provides feed for livestock and is also a source of income, and hay cut at different times of the year varies in value. In general, hay with the highest protein content and the highest yield per acre comes at exactly the time grassland birds have begun nesting: mid and late June.
“(The) destruction of eggs and nestlings is heartbreaking. Bobolinks and Upland Sandpipers, for example, survive the myriad hazards of long-distance migration to locations as far away as Argentina, return to New England to invest a year’s worth of energy to reproduce in local fields, only to have all of their effort wasted under a sunny sky in June or early July when the fields are mown,” MassAudubon writes.
At the same time, New England Farmers often face severe financial pressures that force them to mow earlier and more frequently.
At Greenbelt, the fields at reservations where grassland birds nest are not cut for hay during the time when the birds breed and produce chicks who cannot fly or walk when they are first born. These properties include the Cox, Han Morris and John J. Donovan/Sagamore Hill Reservations.
Mass Audubon has adopted The Bobolink Project to protect grassland birds on working hayfields. It offers farmers economic assistance to delay their mowing schedules so that grassland nesting birds can complete their breeding cycles.