Artificial nest boxes installed in Hong Kong for critically endangered cockatoos

On a humid September afternoon, conservationist Harry Wong climbed a candlenut tree at St. Louis School in downtown Hong Kong and installed a nest box for yellow-crested cockatoos, according to Mongabay. Two secondary school boys repeated "Spiderman … Tom Holland" to each other as they watched, the outlet reported. Wong used a harness and ropes to climb the tree and rappelled down after installing the box.

Wong works with Astrid Andersson, a biologist and postdoctoral researcher at the University of Hong Kong, on HK Cockatoo Watch, a project that seeks to protect the city's feral yellow-crested cockatoos. Andersson said the birds normally build nests in tree holes, which abound in Southeast Asian rainforests, but that "in the city, they do not have that luxurious choice available." She estimated that more than 60% of natural tree hollows in Hong Kong are gone, creating what she called "a housing crisis for these birds."

Andersson said many of the birds' 15 natural tree-nesting sites "have been removed by typhoons or government pruning." She said she was inspired by conservation work in countries such as Australia. The nest boxes are modeled after Australian prototypes but adapted to Hong Kong's humid climate, and each has an internal camera connected to a mobile signal so researchers can remotely monitor breeding behavior, according to Mongabay.

Since the project began in March 2025, 15 artificial nest boxes have been installed at different locations across Hong Kong Island, Mongabay reported. Andersson said the team started at the HKU campus because she is based there, then approached the Leisure and Cultural Services Department.

Yellow-crested cockatoos are considered critically endangered, with fewer than 2,000 individuals remaining in their native range in eastern Indonesia and Timor-Leste, according to Mongabay. Hong Kong is home to the largest wild population of the species outside those two countries, with roughly 200 cockatoos, or about 10% of the global wild population, which Mongabay says are believed to be descendants of released or escaped pets. The outlet reported the number is stable, citing the lack of natural predators and strict legal protection.

A DNA analysis by Andersson and her research team found that Hong Kong's feral cockatoos have unexpectedly high genetic diversity and may be key to saving the species from extinction in Indonesia, according to Mongabay. Wong, an arborist by training with six to seven years of experience in bee conservation, said he found it easy to move into cockatoo conservation after helping people relocate beehives or wasp nests safely in nature. "What I am doing is to find a way: How can we coexist with them?" he told Mongabay.