Status of the Endangered Yellow Chat Epthianura crocea tunneyi on the western South Alligator River floodplain, Kakadu National Park

Abstract

The current status of the Endangered Yellow Chat Alligator Rivers subspecies Epthianura crocea tunneyi is poorly known. A survey of Kakadu National Park floodplains, Northern Territory, in 2004 identified the western floodplain of the South Alligator River as a key population area. To provide preliminary information on the status of the subspecies in Kakadu National Park, this floodplain was intensively surveyed over a 4-day period in September 2014 and compared with the 2004 survey, which was undertaken at a similar time of year (late dry season: October–November). Despite covering considerable areas of floodplain habitat over nearly 40 hours of surveying, Yellow Chats were recorded in only one area in 2014; 27 Yellow Chats from nine observations were recorded over 2 days, with a minimum number of 17 individual birds (16 adult and 1 juvenile) observed. This compared with a total of 65 Yellow Chats from 2 days of surveying in 2004, clustered around five areas of the western floodplain of the South Alligator River. Habitat in 2014 comprised predominantly dry floodplain lagoon, consistent with previous surveys. Feral animals (in particular Feral Pigs Sus scrofa ) were regularly observed throughout the surveys, as was significant feral-animal damage to wet floodplain areas. Although these results suggest a possible decline on the western South Alligator River floodplain over a 10-year period, a comprehensive survey is required of all floodplains within the subspecies’ range to assess overall population status. This could inform the establishment of annual monitoring sites in order to evaluate long-term population trends, essential data for management of threatened species.