2018-07-05 / Nature

Salt Marsh Sparrows in Trouble

By Charles Avenengo


Piping plover adult and chick at Sachuest Beach. (NTW stock photo) Piping plover adult and chick at Sachuest Beach. (NTW stock photo) The long days currently filled with sunshine mark the height of nesting season.

According to biologist Jennifer White of the U.S Fish and Wildlife Service, a pair of piping plovers have successfully reared four chicks on the Sachuest Point Wildlife Refuge side of the beach. This comes as good news, because if you haven’t heard about the local recovery efforts for the piping plover, well, you haven’t been in Rhode Island.

While the piping plover has received ample headlines, another species at the refuge is receiving a lot of attention. The salt marsh sparrow is also leading a precarious existence. In recent years, the sparrows have suffered massive population losses and are edging dangerously toward extinction.

The sparrows are having difficulty because salt marshes are in trouble. In addition to getting battered by seaward storms, salt marshes are also being assaulted by developers. They are prime real estate and in the past half century, the Ocean State has lost at least 15 percent of its marshland to development. Additionally, the sea is rising.

Because of these encroachments, salt marshes along the entire Atlantic Seaboard are at risk of being lost forever. Historically, when the ocean rises, marshlands have been able to expand landwards, but now, with the additional development boxing them in, they have nowhere to retreat. The U.S Fish and Wildlife Service at Sachuest Point is trying to help the sparrows.

The salt marsh sparrow is categorized as a salt marsh obligate species, a term that indicates that they spend their entire life-cycle in a salt marsh. Therefore, they are entirely dependent on the fortunes of the salt marsh.

When Hurricane Sandy struck in October 2012 with winds that exceeded 115 mph, it resulted in nearly $70 billion in property damage, the fourth costliest storm in U.S. history. While Newport County was largely spared, the South Coast was clobbered, specifically Misquamiquit Beach in Westerly, which was leveled.

Likewise, salt marshes were battered by the storm. With the post-storm federal relief funds, a small part of the funding was designated to strengthen vulnerable salt marsh habitats, including the Sachuest Point salt marsh. According to White, the general idea of the funding restoration has been to create a “thin-layered deposition,” which is an effort to essentially raise the marsh by spreading sand over low areas and dredging other areas. This endeavor directly accounts for the visible changes visitors to the Sachuest salt marsh have noticed in recent years.

The restoration has been conducted with the salt marsh sparrow in mind. Visually, the sparrow is typically nondescript, highlighted only by distinctive ochre-colored eyebrows and a moustache. It is also renowned for its shyness, and one must utilize extreme patience to catch even a brief glimpse of one.

For these sparrows, even a slight increase in water level would be disastrous. They nest low on the marsh grasses and have a limited window for rearing their young of precisely 24 days between the ultra high spring tides of early summer full moons.

In order to accomplish this, females have a gestation period of five days. They then have 12 days of incubation when the female tends to the nesting duties herself because the males move on and seek out other mates after breeding. After hatching, the chicks have about 10 days to fledge and get themselves above the high-tide mark. This doesn’t leave much margin for error. With a hurricane storm surge, forget it.

A redeeming feature in the event of nest failure is that a pair will nest again. Also, salt marshes are one of the most productive ecosystems on earth. The sparrows don’t have to look far for food.

Nevertheless, scientists have predicted these birds could vanish entirely within a few decades. The sparrow is classified as “vulnerable” on the Red List of Threatened Species and there are efforts to upgrade this designation to “endangered.”

In 1982, I helped conduct a survey to search for a second type of Rhode Island salt marsh obligate sparrow species called the seaside sparrow. Along with ornithologist Steve Reinhart of Barrington, we scoured the Gooseneck Cove salt marsh along Ocean Drive for seaside sparrows, which look like the salt marsh sparrow. Although they weren’t expected to be found in Newport, every salt marsh in the state had to be investigated for their presence.

Instead, what we found was a half-dozen nesting pairs of salt marsh sparrows. We were actually disappointed that they were salt marsh sparrows instead of seaside sparrows. By now, those salt marsh sparrows have long since vanished. The last holdout on Aquidneck Island is now at the Sachuest Point salt marsh.

Let’s hope the work at the marsh pays off.

Noteworthy Birds Nesting on Aquidneck Island

Osprey
Cooper’s hawk
Red-tailed hawk
Virginia rail
Killdeer
Piping plover
Common tern
Barn owl
Great horned owl
Screech owl
Chimney swift
Ruby-throated hummingbird
Belted kingfisher
Willow flycatcher
Great crested flycatcher
Bank swallow
Marsh wren
Veery
Black-and-white warbler
American redstart
Scarlet tanager
Rose-breasted grosbeak
Salt marsh sparrow
Bobolink

Naturalist Charles Avenengo has been chasing Aquidneck Island wildlife for more than 40 years.

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