By Neil Foley, Education Coordinator and Ecologist
Sunrises on Nantucket are worth the effort every time, even for a night owl like myself. Before most of the island wakes for the day and the rotaries jam with the traffic, it’s a spectacular feeling to face the fog banks and listen to a chorus of songbirds belting out their best into a misty morning. This summer in particular, I have embraced the opportunity to pull on my muckboots and explore the sounds (and smells) of our island’s salt marsh habitats to survey for elusive and cryptic marsh birds.
For the past 4 years, NCF has participated in auditory and visual point count surveys for marsh birds as part of the Saltmarsh Habitat & Avian Research Program (S.H.A.R.P.), an ongoing collaboration between universities, government agencies, and non-profits to survey and investigate marsh bird populations from Virginia to Maine. Salt marshes serve important purposes as buffers against coastal erosion, filters for landscape and agricultural runoff, storage of atmospheric carbon, as well as breeding habitat for fish, shellfish, and other wildlife. By monitoring the breeding success and distribution of marsh bird populations, the SHARP program hopes to keep an eye on the over health of these important habitats on the Atlantic Coast.
Surveys consist of 5 minutes of passive monitoring, listening and looking for any species using the marsh or surrounding edge, followed by seven minutes of active call-and-response where several rail and bittern calls are played on a bluetooth speaker to try and get one of those species to call back. Detections and activities of each individual bird is documented and the presence of Species of Greatest Conservation Need (SGCN), like Rails, Saltmarsh & Seaside Sparrows, American Bitterns, Willets, and American Black Ducks are noted.
On Nantucket we have 17 survey points in marshes across the island. These points all have varying degrees of isolation from human activity, an important consideration as salt marshes are often squeezed between rising sea levels and expansion of human development. Remote points in the middle of Eel Point have less human generated noise and larger swaths of undisturbed habitat, while the town-adjacent marshes of The Creeks are bordered by residences, closer to human-generated noise, and often subjected to harmful runoff from lawns and gardens.
The great news is that Saltmarsh Sparrows on Nantucket have been detected in strong numbers across the island! Saltmarsh Sparrows nest in ares of the marsh that only flood twice a month at the New and Full moon tides. They rely on salt marsh grasses around the edges of salt marshes remaining intact and stable with consistent tidal flooding. Increased frequency of extreme high tides and habitat loss across their breeding range have contributed to a steady population decline in this species region-wide. In 2016, researchers from UConn and UMaine found healthy and robust breeding populations of this imperiled species, particularly in Polpis Harbor, Eel Point, and Coskata. I am happy to report that these numbers have held steady and I have been able to detect breeding pairs of Saltmarsh Sparrows in these marshes, as well as The Creeks and Folger’s Marsh at the Nantucket Field Station! Other SGCN species detected include an extremely abundant (and noisy) population of Willets, regular sightings of American Black Ducks, Egrets, Black-crowned Nightherons, and a few vocal Virginia Rails who have called back to my bluetooth speaker.
SHARP surveys will continue into July, even as I am swarmed by clouds of mosquitoes. It’s good to know that some species in decline on the mainland are doing surprisingly well on Nantucket thanks to our continued protection of salt marsh habitat. Nantucket has over 1,600 acres of salt marsh and NCF alone owns and protects 1,200 acres of salt marsh that we will continue to promote, study, and appreciate for generations to come. Take a trip to the Nantucket Field Station and keep a watchful eye along the edges of the marsh and you could see one of these beautiful, but threatened salt marsh songbirds.