Open AccessExcess of unpaired males in one of the World's most endangered seabirds, the Chatham Island taiko Pterodroma magentae
Author(s) -
Lawrence Hayley A.,
Millar Craig D.,
Taylor Graeme A.,
Macdonald Linda D.,
Lambert David M.
Publication year - 2008
Publication title -
journal of avian biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.022
H-Index - 76
eISSN - 1600-048X
pISSN - 0908-8857
DOI - 10.1111/j.0908-8857.2008.04272.x
Subject(s) - biology , endangered species , allee effect , population , zoology , ecology , sex ratio , critically endangered , conservation biology , breeding pair , demography , sociology , habitat
The Chatham Island taiko Pterodroma magentae (tchaik) is one of the World's most endangered seabirds with a population size of between 120–150 individuals that includes only 8–15 breeding pairs. Molecular techniques were used to identify the sex of taiko, which is difficult to assign morphologically. Blood samples were obtained from almost the entire known living population and from some birds now thought to be dead. We report an approximately even sex ratio in taiko chicks and adults associated with breeding burrows, but a large male‐biased ratio in non‐breeding adult birds caught on the ground. This finding suggests that unpaired males may be having difficulty in attracting females to burrows and that this situation may be an example of the Allee effect, that reduced density of potential mates acts to decrease population productivity. Identification of the sex of taiko using a molecular technique has important implications for the conservation management of this critically endangered species, including the future transfer of taiko chicks to a predator‐excluded breeding site.