Crossbreeding threatens conservation of endangered milky storks

Date:  January 31, 2019

Source: National University of Singapore

A team of researchers from the National University of Singapore (NUS) has discovered that the conservation of Milky Storks (Mycteria cinerea), an endangered wading bird native to Southeast Asia, is threatened due to crossbreeding with their more widespread cousins, the Painted Storks (Mycteria leucocephala).

"Apart from habitat loss and fragmentation, extinction through hybridisation is one of the major threats to endangered species. Our study is the first to provide an estimation of the population genomic status of the endangered Milky Stork in Singapore, and the findings can contribute to the design of effective solutions for conservation management of the globally endangered species," said research lead Assistant Professor Frank Rheindt, who is from the Department of Biological Sciences at the NUS Faculty of Science.

The research, which was conducted in collaboration with Wildlife Reserves Singapore, was earlier published in the journal Biological Conservation.

When Milky Storks meet Painted Storks

The Milky Stork is an almost completely white plumaged stork species found in coastal mangroves, mudflats, and estuaries across Southeast Asia. It is currently considered endangered on the International Union for the Conservation of Nature Red List, with about 1,500 individuals left in the wild. About seven to 10 per cent of them are found in the region around Singapore and Johor, Malaysia, and it is believed that the majority of them are related to those which escaped from captivity.

Since the late 1980s, Milky Storks and their sister species, the Painted Storks, have been held together in captivity in Singapore and Malaysia. Being kept in the same enclosure has led to inadvertent crossbreeding or hybridisation between the two stork species. The Painted Stork is differentiated from the Milky Stork by the presence of a black pectoral band and a pink flush in the inner wing coverts and tertials. However, the hybridised storks display intermediacy in these traits.

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