Grey background indicates the days covered by camera footage.
Broad paler bars indicate that the respective species occupied the cavity, i.e. Small narrow, darker bars indicate visits. Each row represents one of twelve cavities with cockatoo interest.
breeding seasons, November 2016–April 2019, in the forested areas of central and western Sumba. The research team also relied on physical inspections of the nest cavities and observations from the ground.į I G U R E 4 : Visitors and occupants of nesting cavities monitored by camera-traps over three.
These interactions were captured using camera traps (Figure 3), and took place over one to as many as four breeding seasons for a total of 266 monitored cavity-seasons. To answer these questions, a recent study by an international collaboration of scientists from Manchester Metropolitan University, BirdLife International, Burung Indonesia and Bogor Agricultural University ( ref), documented interactions between citron-crested cockatoos and their nest competitors as well as all potential nest predators at 95 nest cavities. Why? Was their productivity always low? Or is the effect of having a diminishing number of suitable nest cavities more severe than expected? Despite this protective measure decades ago, the Critically Endangered citron-crested cockatoo population has not recovered. In recognition of growing threats to its endemic cockatoos from trapping, Sumba finally made it illegal in 1992 to trap them. Sumba’s human residents have one of Indonesia’s lowest per capita incomes so they are primarily subsistence farmers, keeping large numbers of livestock, as well as growing maize, rice, cassava and other crops, which served as the impetus for clearing of most of the original pristine forest.į I G U R E 2 : Traditional Sumbanese houses near Bondokodi, West Sumba. The western side of the island is more fertile and more heavily populated than the east. Originally, most of the island was covered in deciduous monsoon forest while its south-facing slopes, which remain moist during the dry season, were evergreen rainforest. Sumba’s landscape is mostly comprised of low limestone hills that experience a dry season from May to November and a rainy season from December to April. It is thought to be a 20 million year old fragment of the Australian continental crust that strayed north from the mainland (Figure 1), thereby isolating its unique biota. But a growing number of its unique bird species are threatened by human activities. For this reason, Sumba is recognized as an important center of endemism and biodiversity in the region. Seven bird species, including the citron-crested cockatoo, are found only on Sumba and on a few nearby islands, but nowhere else in the world. This island is home to a number of mammals but it is especially rich in avifauna, with nearly 200 bird species known to live there. The citron-crested cockatoo is endemic to the eastern Indonesian island of Sumba.
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