Shorebird monitoring and management at Cape Hatteras National Seashore: 2017 annual report

Doshkov,, Paul; Losch, Konrad; Thompson, William; Wright, Jocelyn; Rhodes, Amber

Cape Hatteras National Seashore (Seashore), located on the Outer Banks of North Carolina from Nags Head, NC to Oracoke 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 palliates), colonial waterbirds, and Wilson’s plovers (Charadrius wilsonia) are monitored and managed at the Seashore to promote successful repro-duction 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 Adjust-ment of Wildlife Protection Buffers Environmental Assessment (NPS 2010a, 2010b, 2015a, 2015b). Piping Plovers In 2017, there were six pairs of piping plovers and 12 nests identified; seven were re-nests from failed nest attempts. The first nest was found on April 16, 2017 and the last active nest was documented as failed on July 16, 2017. Reasons for nest loss were mostly unknown, but some loss occurred from ghost crab depredation, aban-donment, and overwash. Three nests hatched and produced a total of 10 chicks. Two chicks successfully fledged from one brood, resulting in a fledge rate of 0.33 chicks per breeding pair. Chick loss was attributed to ghost crab depredation, infanticide, or unknown reasons. Since 1997, fledge rates have ranged from zero to two chicks per pair at the Seashore. The mean fledge rate from 1997–2017 is 0.66 chicks per pair. American Oystercatchers Twenty-four pairs of American oystercatchers nested at the Seashore in 2017. A total of 53 nests were identified which includes re-nests from failed nest attempts. The first nest was found on April 10, 2017 and the last chick was fledged on August 18, 2017. Nine of the 53 nests hatched and produced a total of 15 chicks. Two pairs of American oystercatchers were each successful in fledging one chick which represents a 0.08 fledge rate per pair; the lowest fledge rate to date. Since 2001, fledge rates have ranged from 0.08 to 1.3 chicks per pair at the Seashore with a mean fledge rate per pair of 0.55 from 2011–2017. Colonial Waterbirds Sixteen colonies were identified at the Seashore in 2017: 10 on Hatteras Island, one on Bodie Island, one on Green Island, and four on Ocracoke Island. Two colonies hosted multiple species and least terns nested in the remaining 14 colonies. Observations from peak nest surveys produced a total of 189 least tern nests with 17 chicks, 90 common tern nests with 10 chicks, 14 gull-billed tern nests in one colony on Oracoke Island with 25 chicks, 214 black skimmer nests with 32 chicks, 149 white ibis nests with 78 chicks, and 11 tricolored heron nests with 17 chicks. Productivity in colonial waterbird colonies is very difficult to determine. Of the 16 documented colonies, colonial waterbird fledges or juveniles were observed in seven of them, but it is undetermined if these fledges were from the monitored colonies or passing through from other areas. Five colonies contained least tern fledges while black skimmer fledges were only observed on Ocracoke’s South Point. White ibis and tricolored heron fledges were observed on Green Island. Wilson’s Plover In 2017, one Wilson’s plover pair and two nests were identified. All nests were found on South Point, Ocracoke Island. The first nest was found on April 29, 2017 and the last chick was lost on June 29, 2017. One nest was abandoned on May 7, 2017 and the second nest hatched a maximum of three chicks; these plovers are evasive and difficult to observe so it can not be confirmed if all three eggs in this nest hatched. No chicks fledged. This is consistent with recent years of Wilson’s plover nesting at the Seashore. Nest losses have been attributed to aban-donment, predation, or overwash events, but the cause for chick mortality...

Shorebird monitoring and management at Cape Hatteras National Seashore: 2017 annual report

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