Habitat preference of a vulnerable shorebird:
By Ana Guerra     Awards: Myers

My research focuses on bristle-thighed curlews (Numenius tahitiensis), a species of shorebird listed as "vulnerable" by the IUCN Red List. Shorebirds are a diverse group of birds that undertake some of the longest migrations known (Bar-tailed Godwits can fly up to 11,000 km nonstop!) and disperse across vast and inaccessible areas, making it difficult to study their numbers and ecology. Currently, nearly 50% of the world's well-studied shorebird populations are in decline due to human impacts; however, not much is known about what impacts are causing the population declines.

Palmyra Atoll, USA (a small atoll 1,000 mi south of Hawai'i) hosts several species of shorebird, including the largest aggregations of bristle-thighed curlews of any central Pacific Island. While there is some information on curlew habitat use during the breeding season in Alaska, detailed information on habitat use at their non-breeding sites on Pacific Islands is lacking.

My goal is to understand bristle-thighed curlew habitat use on the lagoon flats of Palmyra Atoll and shed light on how land alterations made to the atoll by the US Navy during World War II have affected the availability of the habitat preferred by the curlews. Palmyra is a unique environment where the effects of historical human impacts from WWII are still present. In the 1930s and 1940s, the US Navy modified the land around the Atoll by cutting a channel through the reef, nearly doubling the total land area of the islets, and restricting water flow to parts of the atoll's inner lagoon and flats by building roads and causeways between them. By observing curlew habitat use across a gradient of human impact on the lagoon flats, I aim to find out how these impacts increased or decreased curlew habitat.

This research will provide much-needed information on a shorebird species of critical conservation concern. Threats to tropical overwintering habitats are the primary reason for local declines of curlew populations; therefore, information on curlew habitat preference, habitat use, and the relative importance of these habitats will help with land management decision-making both at Palmyra Atoll and other curlew wintering grounds.