Classified as Critically Endangered, the Ultramarine Lorikeet Vini ultramarina is one of the world’s most threatened lorikeet species. Endemic to the Marquesas Islands in French Polynesia, the species was formerly distributed over most islands in the archipelago, but is today found primarily on the island of Ua Huka, its range having contracted significantly in recent decades. Habitat alteration and loss, and over-exploitation of natural resources, are cited as impacting the Ultramarine Lorikeet, but the influence of introduced black rats Rattus rattus as predators has been implicated as the primary threat to the species. To assess population status and document aspects of the species biology, including habitat preferences and diet, we conducted the first systematic surveys of the species during two independent surveys spaced seven years apart (2002 and 2009). Population estimates of 2,011 ± 284 (in 2002) and 1,922 (in 2009) individuals on Ua Huka suggest the population was relatively healthy and stable between these periods. However, surveys and searches of other islands in the species’ contemporary range, where black rats occur, either failed to document the species or noted very few individuals. These findings highlight the critical importance of Ua Huka as a rat-free refuge and the value of our surveys as baseline estimates of the population status of the species. We discuss the conservation implications of our findings and propose recommendations to secure the species’ future survival.

Ultramarine Lorikeet Vini ultramarina被列为极度濒危物种，是世界上最受威胁的澳洲鹦鹉物种之一。该物种是法属波利尼西亚马克萨斯群岛的特有物种，以前分布在群岛的大多数岛屿上，但今天主要在乌胡卡岛上发现，近几十年来其范围已显着缩小。栖息地的改变和丧失以及自然资源的过度开发被认为是影响群青澳洲鹦鹉的原因，但引入的黑鼠Rattus rattus的影响因为捕食者被认为是对该物种的主要威胁。为了评估种群状况和记录物种生物学的各个方面，包括栖息地偏好和饮食，我们在间隔七年的两次独立调查（2002 年和 2009 年）期间对物种进行了首次系统调查。Ua Huka 的人口估计数为 2,011 ± 284（2002 年）和 1,922 人（2009 年），这表明这些时期之间的人口相对健康和稳定。然而，对该物种当代范围内的其他岛屿的调查和搜索，其中黑鼠出现，要么未能记录该物种，要么发现很少有个体。这些发现强调了 Ua Huka 作为无鼠避难所的重要性，以及我们的调查作为对该物种种群状况的基线估计的价值。