A survey of the breeding seabirds and migratory shorebirds of the Houtman Abrolhos, Western Australia

A complete survey of the numbers and breeding stages of seabirds, resident and migratory shorebirds and raptors at the Houtman Abrolhos Islands, central west coast, Western Australia, was undertaken. One hundred and ninety two (192) islands, islets and rocks were surveyed over 21 days in December 2006.\n\nSeabird nesting habitat was mapped in its entirety for those islands considered as significant breeding areas (i.e. Pelsaert Island, Leo Island) and estimates of both breeding and roosting seabirds were made for each island. Notes on the stage of breeding were also taken, and where applicable, eggs were measured and weighed for some species to\nobtain breeding dates. Monitoring transects were established on West Wallabi and Pelsaert Islands to monitor longer term changes in the nesting density of the Wedge-tailed Shearwater Ardenna pacifica, Lesser Noddy Anous tenuirostris melanops, Common (Brown) Noddy Anous stolidus and Sooty Tern Onychoprion fuscata. The Lesser Noddy transects\nhad been previously established by Fuller and Burbidge (1992), and were used again for comparative purposes.\n\nWe recorded 14 species of seabirds, 16 species of migratory shorebirds, three resident shorebirds and two raptors during this survey. Of these, 14 species of seabirds, three resident shorebirds and the two raptors were breeding. These breeding populations are considered significant in a regional and national context. Of the 192 islands surveyed, 148 (77%) had breeding seabirds.

本研究对澳大利亚中西部西海岸豪特曼阿尔布罗洛斯群岛（Houtman Abrolhos Islands）的海鸟、留居型与迁徙型滨鸟以及猛禽的种群数量及繁殖阶段开展了全面调查。本次调查于2006年12月实施，历时21天，共覆盖192座岛屿、小岛及岩礁。

针对被认定为重要繁殖区域的岛屿（即佩尔塞特岛Pelsaert Island、利奥岛Leo Island），我们对其海鸟筑巢生境进行了全范围测绘，并对每座岛屿的繁殖与停歇海鸟种群数量开展估算。同时记录了繁殖阶段相关信息，在适用条件下，还对部分物种的鸟卵进行了测量与称重，以推算繁殖日期。我们在西瓦拉比岛（West Wallabi Island）与佩尔塞特岛设立了监测样线，用以长期监测楔尾剪水鹱（Wedge-tailed Shearwater, Ardenna pacifica）、小玄燕鸥（Lesser Noddy, Anous tenuirostris melanops）、普通（褐）玄燕鸥（Common (Brown) Noddy, Anous stolidus）以及乌燕鸥（Sooty Tern, Onychoprion fuscata）的筑巢密度变化。小玄燕鸥的监测样线此前由Fuller与Burbidge（1992）设立，本次调查再次沿用该样线以进行对比分析。

本次调查共记录海鸟14种、迁徙型滨鸟16种、留居型滨鸟3种以及猛禽2种。其中，14种海鸟、3种留居型滨鸟与2种猛禽均存在繁殖行为。从区域与国家层面来看，这些繁殖种群均具有重要生态意义。在本次调查覆盖的192座岛屿中，有148座（占比77%）存在繁殖海鸟种群。