Coastal Habitats

New Hampshire’s coastline may be small, but it contains three habitats found nowhere else in the state: salt marsh, dunes, and coastal islands. Each supports a relatively small number of breeding species. Salt marsh, the most extensive of the three, occurs on the coast and inland along Great Bay, its tributary rivers, and upstream along the Salmon Falls River. It is home to three species of sparrows restricted to salt marshes. The state’s tiny remnant dune system is at Hampton and Seabrook beaches. This is the only place in New Hampshire where endangered Piping Plovers and Least Terns nest. Offshore islands, particularly the Isles of Shoals, are the primary nesting sites in the state for gulls, terns, and other marine birds.

The entire global population of Saltmarsh Sparrows occurs from southern Maine to Chesapeake Bay, and it is threatened by habitat loss and sea level rise everywhere it occurs. Photo credit: Kyle Wilmarth

Beach-nesting Least Terns are vulnerable to predation and excessive human disturbance. Photo credit: Len Medlock

Willets nest in salt marsh and forage on coastal mudflats. Photo credit: Scott Heron

Species of Greatest Conservation Need

Salt Marsh

American Black Duck

Willet

Common Tern

Purple Martin

Marsh Wren

Nelson’s Sparrow

Saltmarsh Sparrow

Beach and Dune

Piping Plover

Least Tern

Coastal Islands

Roseate Tern

Common Tern

Arctic Tern

Coastal habitats are also important for several SGCNs that do not breed in New Hampshire. See Birds and Migration in Winter for more detail.

Other Representative Species

Common Eider

Herring Gull

Double-crested Cormorant

Osprey

Current Trends

Across these three habitats, roughly half of coastal nesting birds are increasing or stable. The majority of these are the recipients of targeted conservation efforts over the last few decades (e.g., Piping Plover, Common Tern). Declining populations include Tree Swallow and Purple Martin, both aerial insectivores, and the salt marsh specialists Nelson’s and Saltmarsh Sparrows.

Primary Threats

New Hampshire’s dunes and salt marshes have suffered significant loss to buildings, parking lots, roads, and lawns over the years. One estimate is that 12% of the marsh in the Hampton-Seabrook Estuary has been lost since the 1930s, and dunes occupy only 16% of their former extent. Where habitat has not been destroyed, centuries of salt marsh alteration, through ditching, filling, and dam and road construction have degraded habitat quality. Studies in Hampton found that Saltmarsh Sparrows occupy only a tiny portion of available salt marsh, preferring the unaltered areas.

Beach goers and their dogs don’t mix well with dune-nesting birds. Interference with incubating birds and the feeding of young causes fewer young birds to survive. Birds of less accessible salt marshes and islands are generally less susceptible to this kind of stress.

Increased predation by feral cats is a threat to dune-nesting birds, as are skunks, foxes, and other small animals. Predation, especially by gulls, is also an issue for island bird populations.

This threat to coastal birds, especially fish-eating birds such as terns, relates to potential impacts from unsustainable fishing practices, climate change, pollution, or a combination of factors.

Rising sea level from climate change threatens all the coastal habitats, and the potential for habitat to shift inland is limited by existing development. See the section on climate change for more information.

An important threat to Great Bay is excessive nutrient run-off from municipal wastewater treatment facilities. Oil spills from shipping or pipelines also pose a risk to fragile coastal ecosystems, and plastic waste is present on both land and sea.

Conservation Actions

To ensure the continued presence of salt marsh birds in the state, efforts should focus on restoring degraded salt marshes and protecting those that are still intact. At the same time, we need to determine which areas of salt marsh are most likely to remain viable in the wake of projected rises in sea level induced by climate change and also identify and protect adjacent uplands that may become salt marsh with sea level rise. For dune-nesting species, key conservation actions include public education and restricted use areas to minimize human-bird interactions. Without the restricted use areas in Hampton and Seabrook, the state’s population of plovers would disappear within a couple of years. Continued human intervention to discourage predators and maintain nesting habitat also will be needed to maintain the tern colony at the Isles of Shoals.

Data Needs

Although more trend information on salt marsh birds is needed, actions should be taken now to protect what little remaining habitat exists. More information on threats to island nesting populations is needed to identify the best protective actions.

Breeding Habitats

Many threats faced by birds are tied to the habitats where they breed. Explore the habitats and learn more about each one’s characteristics, population trends, threats, and conservation actions.

Coastal Habitats