Amagansett NWR Least Tern Chicks - 2015 - Photo Credit: Carolyn Comber, USFWS

Amagansett NWR Least Tern Fence - 2015 - Photo Credit: Timothy E. Simmons, Jr., USFWS

Amagansett NWR Least Tern Fence Skirt - 2015 - Photo Credit: Timothy E. Simmons, Jr., USFWS

In 2015, the Long Island National Wildlife Refuge Complex (LINWRC) installed the first known colonial tern fence in New York State at its Amagansett National Wildlife Refuge. The Amagansett NWR consists of 36 acres, and is located in the town of East Hampton, New York. The refuge provides ¼ mile of shoreline nesting and foraging habitat, as well as a unique double dune ecosystem that hosts a variety of migratory birds, other wildlife, and rare plants.

The objective of the project was to improve nesting habitat for least terns (Sternula antillarum) at Amagansett NWR. Use of the removable fence was a new effort to reverse the downward population trend in nest success. The Atlantic coast population of least terns is threatened in New York State and both the interior population and California subspecies are federally endangered. Historically, the refuge has had low hatch and fledge rates dating back to 2009 due primarily to predation by mesopredators.  Three years prior to 2009 did result in fledglings with seven fledges in 2006, 24 fledges in 2007 and 40 fledges in 2008. The placement of the least tern fence was chosen based on historical shorebird nesting data. New York is the seventh known state in the country to incorporate the use of a colonial tern fence. New York State’s predecessors are Massachusetts, Maine, South Carolina, Indiana, Oklahoma, and California.

The removable least tern colonial fence is a defensive predator management tool designed to be integrated with techniques outlined in the U.S. Fish and Wildlife Service’s Piping Plover, Atlantic Coast Population: 1996 Revised Recovery Plan and Tern Management Handbook.  The tern fence is one part of a multi-faceted approach to mesopredator management used at Amagansett NWR which also includes the use of visual and audio pest deterrents. The tern fence was modeled after the design outlined in the Colony Site Management Techniques October 2000 publication written by Steven Kress from the Ithaca New York chapter of the National Audubon Society. Implementation of the fence and pest deterrents resulted in twenty-five fledglings on the refuge in 2015; numbers not seen since 2008. Data shows little to no least tern productivity from 2009 to 2014. A total of two least tern fledglings were observed in that time frame; both of which hatched in 2010.  Other shorebirds including the piping plover (Charadrius melodus) were also expected to benefit from the fence. Four out of four plover chicks fledged from the refuge during the 2015 season. The correlation between the success of the piping plovers and existence of the tern fence is inconclusive. However, refuge staff had observed piping plover adults and young inside the tern fence on several occasions.

The tern fence was approximately 800 feet in length by 75 feet in width, totaling 1,750 linear feet and protected 60,000 square feet of shorebird nesting habitat. Due to the size of the fence, it took about three days to get the majority of the fence installed. Most of this time was spent on initial setup tasks that only need to be done the first year of use. The fence was comprised of turkey wire mesh and was held in place by cable ties and metal posts. The bottom exterior of the fence had a skirt made of the same turkey wire mesh and was laid flat on the ground paralleling the fence extending out from the base; this was attached to the base of the fence. The top of the fence was electrified using a solar charger; visual and audio pest deterrents were also used around the exterior of the fence. The skirt and pest deterrents were used to keep out mesopredators. Social attractants including decoys and audio calls were used to encourage nesting inside the fence.

Refuge staff and volunteers monitored the shorebirds and fence conditions seven days per week noting things such as nest and chick counts, bird behaviors, and signs of predators. The staff and volunteers of the LINWRC are proud to report that not a single egg or chick was lost to predation at Amagansett NWR during the 2015 breeding season. Fourteen nesting pairs produced 25 fledglings for a colony productivity rate of 1.79. This is the first season since 2010 with successful production at the Amagansett NWR Colony. Based on the success of the project, the tern fence at Amagansett NWR will continue to be used in future breeding seasons.