Shorebird monitoring and management at Cape Hatteras National Seashore: 2018 annual report

Doshkov, Paul; Losch, Konrad; Thompson, William; Wright, Jocelyn; Ziegler, Tracy

Cape Hatteras National Seashore (Seashore), located on the Outer Banks of North Carolina from Nags Head, NC, to Ocracoke Inlet, contains many ecologically important habitats such as marshes, tidal flats, and riparian areas that support a variety of shorebirds, including threatened species and species of special concern. Piping plovers (Charadrius melodus), American oystercatchers (Haematopus palliatus), colonial waterbirds, and Wilson’s plovers (Charadrius wilsonia) are monitored and managed at the Seashore to promote successful reproduction and to protect their habitat. Shorebird monitoring and management is conducted in compliance with the Cape Hatteras National Seashore Off-Road Vehicle Management Plan, as amended by the Review and Adjustment of Wildlife Protection Buffers Environmental Assessment (NPS 2010a, 2010b, 2015a, 2015b). Piping Plovers: In 2018, there were three pairs of piping plovers and three nests identified. The first nest was found on April 25, 2018 and the last active brood was documented as fledged on July 7, 2018. All three nests hatched and produced a total of 11 chicks. Three chicks successfully fledged from two broods, resulting in a fledge rate of 1.0 chicks/breeding pair; the highest rate since 2010. Chick loss was attributed to predation by ghost crab or unknown reasons. Since 1997, fledge rates have ranged from 0.0 to 2.0 chicks/pair at the Seashore. The mean fledge rate from 1997 to 2018 is 0.67 chicks/pair. American Oystercatchers: Twenty-five pairs of American oystercatchers nested at the Seashore in 2018. A total of 40 nests were identified, which includes re-nests from failed nest attempts. The first nest was found on April 17, 2018 and the last chick was fledged on August 21, 2018. Eighteen of the 40 nests hatched and produced a total of 34 chicks. Twelve pairs of American oystercatchers were successful in fledging 20 chicks, which is 0.8 fledged chicks/pair; this is the highest fledge rate since 2011. Since 2001, fledge rates have ranged from 0.08 to 1.3 chicks/pair at the Seashore with a mean fledge rate of 0.61 chicks/pair from 2012 to 2018. Colonial Waterbirds: Fifteen colonies were identified at the Seashore in 2018: nine on Hatteras Island, one on Green Island, and five on Ocracoke Island. Least terns nested in fourteen of the colonies. Four colonies hosted multiple species. Observations from peak nest surveys produced a total of 475 least tern nests with 15 chicks, 72 common tern nests with 12 chicks, 50 gull-billed tern nests in two colonies on Oracoke Island with 10 chicks, 368 black skimmer nests with 116 chicks. Productivity in colonial waterbird colonies is very difficult to determine. Of the 15 documented colonies, colonial waterbird fledges or juveniles were observed in 12 of them, but it is undetermined if these fledges were from the monitored colonies or passing through from other areas. Twelve colonies contained least tern fledges while black skimmer fledges were observed on Cape Point and Ocracoke’s South Point, totaling about 300 fledges. Wilson’s Plover: In 2018, no Wilson’s plover nesting activity was documented at the Seashore. Human Disturbance: Throughout the 2018 season, resource management staff documented 429 pedestrian, 21 off-road vehicle (ORV), and 52 dog, boat or horse intrusions in protected areas including all prenesting areas and wildlife protection buffers. These numbers are conservative since sites are not monitored continuously, weather erases tracks, and staff does not disturb incubating pairs or young in order to document disturbance. It is important to note that most of the resource protection areas contained multiple bird species, including oystercatchers, colonial waterbirds, and piping plovers. Most human violations in resource protection areas were not witnessed, but were documented based on vehicle, pedestrian, or dog tracks left in the sand. Pedestrian entry most often required visitors to lift or stoop under the string that connected........