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The "Other" Sparrow on the Salt Marsh

Seaside Sparrow

In June and July of 1982, former Audubon board member Frank Golet, Peggy Stoll, and a small army of volunteers walked every salt marsh in Rhode Island, counting all of the Seaside Sparrows (Ammodramus maritimus) they could find. It was the first statewide census of these birds. They published their results in the Audubon Society of Rhode Island Report in May 1983. Below is an update to this study by Walter J. Berry of the U.S. Environmental Protection Agency

This spring the sparrows will come back to the marshes in Rhode Island (RI). Unlike Willets (Tringa semipalmata), which fly around and make a huge racket if you get near their nests on the marsh, Saltmarsh Sparrows (Ammodramus cauducatus) and Seaside Sparrows are much more discreet and spend most of their time skulking in vegetation.

Saltmarsh Sparrow versus Seaside Sparrow Identification Tips

Both sparrows breed exclusively on salt marshes and as their breeding habitat shrinks, the threat to both sparrows grows. The Saltmarsh Sparrow is getting more attention these days as its population levels are so low. It nests directly on the surface of the marsh, causing it to be at greater risk for loss due to flooding. In fact, the Saltmarsh Sparrow population is predicted to face global collapse within the next 50 years. Although the Seaside Sparrow builds nests in taller marsh vegetation and has a lower nest flooding risk, it is still vulnerable to habitat loss.

In 2007 and 2008 several of my EPA colleagues and I, along with a number of local birders (including two Audubon Society of RI staff), repeated Stoll and Golet’s Seaside Sparrow inventory, using their methods on twenty RI salt marshes. Since the Seaside Sparrow prefers large marshes, we searched all of the locations where sparrows were found in 1982, as well as the larger marshes where sparrows were not found in the earlier survey.

What did we find?

There were fewer Seaside Sparrows counted at 10 of the 12 marshes where Stoll and Golet had found sparrows in 1982, while sparrow abundance increased on three marshes, one of which had no sparrows detected in the earlier survey. Also, Seaside Sparrows were not found on the four smallest marshes where they had been counted before. The total abundance of Seaside Sparrows observed at our sites decreased from 98 in 1982 to 58 in 2007 (41% decrease from 1982) and 68 in 2008 (31% decrease from 1982).

What has happened since 2008?

The two marshes with the largest number of Seaside Sparrows in 2008 were Hundred Acre Cove in Barrington and Ninigret Pond in Charlestown. We revisited Hundred Acre Cove in 2013, and counted 21 Seaside Sparrows (there were 19 in 2008.) We have gone back to the Ninigret and Quonochontaug marshes in Charlestown every year since 2008. The numbers of Seaside Sparrows at Ninigret have held steady since 2008, and actually increased from 31 in 2008 to 35 in 2016. At Quonochontaug the story is not as good. It is the smallest of the marshes we surveyed that had Seaside Sparrows in 2008. Observed numbers there have gone down from 14 in 1982, to 7 in 2008, to zero in 2012. We have not found any Seaside Sparrows at Quonochontaug since 2012. This continues the trend of loss of Seaside Sparrows at smaller marshes. (In marked contrast, the numbers of Saltmarsh Sparrows observed at Quonochontaug has remained relatively constant.)

What is the future for the Seaside Sparrow in Rhode Island and beyond?

We estimate that the current population of Seaside Sparrows in Rhode Island might be 50 to 60 birds (assuming that the numbers at Hundred Acre Cove have remained relatively constant.) The Saltmarsh Habitat and Avian Research Program (SHARP), using a very different procedure from ours, estimated that there are only 24 Seaside Sparrows in Rhode Island. The Seaside Sparrow is currently classified in Rhode Island as a species of “Concern” just a step above “Threatened.” Given the population decline and the impending threat to salt marsh habitats by rising sea levels, it only seems reasonable that the classification be re-examined and that monitoring of the species be continued.

Let’s hope that efforts underway, like the thin layer application of dredged material currently being tested on several Rhode Island marshes, will help to slow the loss of salt marsh habitat. In the meantime, it cannot hurt if these little birds get some extra attention. Get out there and visit them (from a respectful distance) on a trail through a local salt marsh. And watch out for Willets.

Walter J. Berry
U.S. EPA, 27 Tarzwell Drive, Narragansett, Rhode Island, USA, 02882