Wetlands Functions and Values
Many people believe that wetland habitats, such as marshes, bogs, and swamps, are of little value simply because they cannot be developed for human profit. In reality, wetlands are of critical importance to many animals, including ducks, herons, turtles, frogs, beavers, deer, dragonflies, butterflies, and fish. Dozens of species would disappear completely from Massachusetts if it were not for the wetland habitats that dot the state. These animals depend on wet places for food, shelter, migration rest stops, breeding sites, and travel corridors.
Birds are some of the most conspicuous wetland inhabitants. Migrant waterfowl are attracted to wetlands and water bodies, to feed and rest in ice-free open water in spring, or the leaf-studded shallows of autumn. The first migrants of spring appear as early as the first weeks of March, when lively buffleheads and dapper ring-necked ducks dot the still-chilly waters of late winter. These are followed shortly by vividly colored wood ducks and tiny green-winged teal. Warblers fill the wetlands with song and color on their way to more northerly breeding grounds. In October, open water habitats may lure transient scaup and mergansers, while pintails and black ducks will seek out the protective cover provided by vegetation in freshwater marshes.
During the warm weather of summer, freshwater marshes serve as host to a wide variety of breeding birds. From flamboyant red-winged blackbirds to modestly-cald marsh wrens and swamp sparrows, wetlands provide exciting and challenging opportunities for the bog-trotting birdwatcher. Certain species are notably elusive, however, not only because of they prefer heavily vegetated habitat, but because of their preference for vocalizing only at night or very early in the morning. Indeed, visiting a freshwater marsh at dawn can sometimes produce bitterns, rails, and moorhens that would scarcely be noticed at any other time.
Wetlands provide an abundance of food for many different wetland species. Food sources include fish, frogs, and invertebrates such as midges and flies, as well as submerged pondweeds and cattail tubers. Great blue and green herons stalk the shallows for fish and tadpoles, while ospreys and kingfishers dive on fish from the air. And with autumn comes the bountiful production of seeds, nuts, and berries. Wild rice and the seeds of many other grassy plants sustain migrant soras, blackbirds, and sparrows. These and other wetland "crops" fuel southbound migrant birds and provide food that year-round resident animals need to survive the oncoming winter. Not only birds, but deer, beaver, squirrels, and other mammals will take advantage of nature's bounty.
One of the marshland's most distinctive inhabitants is the northern harrier (formerly called marsh hawk), whose striking white rump and habit of coursing low over cattails in search of small rodents makes it easy to spot. Sadly, however, like many of our wetland species, the harrier is now fast declining as a breeding bird in Massachusetts. The harrier needs marshes surrounded by large expanses of open, undeveloped habitat in order to breed. Loss and fragmentation of wetland habitat, along with development of adjoining uplands, contribute to the decline of the harrier and other species.
At least half a dozen of the Commonwealth's most seriously declining birds are wetland species that are listed by the Massachusetts Natural Heritage and Endangered Species Program as either endangered or threatened. This underscores the importance of maintaining the health and integrity of the state's remaining wetland habitat. Because so many birds and other animals depend on wetlands for food, shelter, and breeding sites, wildlife habitat is one of the eight wetland functions protected under the Massachusetts Wetlands Protection Act. This law is administered by local conservation commissions, but responsibility for protecting these vital habitats rests with all of us.
For more information about how you can get involved in the protection of wetlands and wildlife habitat, contact the Haverhill Conservation Department or the Massachusetts Audubon Society at 781-259-9500.