Saltmarsh sparrow needs tide to turn in its favor if it is to survive

Saltmarsh sparrows inhabit a narrow band where the tide turns and are the only songbird restricted to the tidal salt marshes of the Atlantic. (Neil Pearson)

Chesapeake marshes in the winter have a special charm. An extraordinary range of warm brown, ocher and russet tones lend the grasses a hypnotic quality. At this time of the year, I tend to focus my attention on the Chesapeake’s bountiful waterfowl. But the marsh grasses are always there, adding a backdrop of ineffable beauty to any visit.

We were in the Blackwater National Wildlife Refuge in Dorchester County, MD. Our attention turned from the snow geese to the simpler pleasure of scanning the marsh for songbirds.

The LBBs — little brown birds in birding lexicon — are always there, camouflaged among the scrub and grasses. There were song sparrows, wrens, Savannah sparrows and lots of white-throated sparrows.

My focus turned to another sparrow, comically stretched between two reeds, with tiny feet firmly grasping the separate stalks.

While this bird had a white throat patch, it also had a bright orange eyebrow and similarly colored malar (moustache) region forming a triangle on each side of the head.

The bird’s body and flight feathers were typical of sparrows, a mix of blacks, browns and whites. It had a streaked buffy breast band and heavily streaked sides. I was watching a saltmarsh sparrow (Ammospiza caudacata).

Saltmarsh sparrows are closely related to Nelson’s sparrow. Until recently, the two species were considered one, called sharp-tailed sparrows. The new name is perfect. These sparrows inhabit a narrow band where the tide turns and are the only songbird restricted to the tidal salt marshes of the Atlantic.

During the winter, saltmarsh sparrows can be found from the lower Chesapeake to Florida and across the upper Gulf Coast.

In early spring, they head north where they breed from the mouth of the Chesapeake all the way up to Maine.

Saltmarsh sparrows tend to occur in discontinuous pockets, largely because their favored habitat is so fragmented.

While its range is extremely restricted, saltmarsh sparrow mating habits are nothing short of promiscuous. Females typically lay about four eggs per nest… and they average 2.5 different fathers per brood!

The wide-ranging males play a minor role in reproduction. It is the female who constructs the nest, broods the eggs and feeds the young.

Nests are a simple open cup of grass built near the edge of the tide line. Spring high tides, especially around full moons, often inundate these nests. Females will quickly build new nests, which may face the same fate a month later.

Nestlings are fed a diet exclusively of arthropods (invertebrates such as adult and larval insects, tiny crustaceans, and spiders) plucked from tidal flats or while clinging to marsh grasses. After seeds set in late summer, saltmarsh sparrows add them to their diets. They favor cordgrass and spartina.

With their narrow habitat niche and frequent nest failures, saltmarsh sparrows are in steep decline. The population crashed 75 percent between 1998–2012. With a 9 percent decline annually, the species may be extinct in another 30 years without intervention.

The U.S. Fish and Wildlife Service is conducting a study to determine if the bird should be protected under the Endangered Species Act. A threatened or endangered listing can be a lifesaver: Just witness the rebound of the bald eagle. The act can be used to help save critical habitat as well as prioritize limited federal conservation dollars.

The habitat squeeze is especially acute in the Chesapeake region. For centuries, the land around the Bay has been sinking, as Ice Age geologic forces continue to be felt. Until recently, the subsidence has been mitigated by the natural addition of peat from dying vegetation in the wetlands. But climate change, sea level rise and increased storm severity are interrupting this cycle of renewal. As more and more humans develop property right up to the marsh’s edge, the wetlands are unable to retreat naturally to higher ground.

Luckily for the saltmarsh sparrow, conservationists aren’t waiting for an endangered species listing to take action. Audubon Maryland-DC is leading a host of government, nongovernmental organizations and private sector partners in a habitat restoration project just a few miles from where I stood.

The Audubon Society’s Chesapeake chapter owns a 700-acre sanctuary nestled inside Maryland’s Fishing Bay wetlands complex just south of Blackwater. The parcel has a natural depression that is now flooding, turning the area into an ever-expanding open water pond. Critical habitat for the saltmarsh sparrow — and similarly imperiled swamp sparrow — is disappearing.

Even as I watched the saltmarsh sparrow at Blackwater, the coalition was busy altering the hydrology of the nearby site to let the pooled water flow away into adjacent tidal creeks. The Audubon-led partnership hopes to demonstrate one way to preserve essential habitat in the face of climate-driven sea level rise.

Conservationists around the country are investigating a wide array of management interventions to save our marshes and the birds that rely on them. This project is among the most innovative.

I continued to watch the saltmarsh sparrow precariously balance between two reeds. All I could think was: hang on! And hope for the help that is on the way.

Mike Burke, a Bay Journal columnist, is an amateur naturalist based in Maryland, having retired from a career that toggled between Capitol Hill and the U.S. Environmental Protection Agency.

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