In densely populated Hong Kong, where every square metre counts, even birds face an acute shortage of suitable nesting sites. Yellow-crested cockatoos (Cacatua sulphurea), listed as critically endangered, find an unexpected refuge here — about two hundred individuals, descendants of escaped or released pets, are successfully settling in urban parks and on school grounds.
Natural tree hollows, where these birds usually raise their chicks, have suffered greatly in recent years: severe storms and regular crown pruning have destroyed more than sixty percent of such shelters. Biologist Astrid Andersson of the University of Hong Kong calls the situation a "housing crisis" for the birds, which in urban conditions are deprived of their usual choices.
To help the birds, Andersson, together with arborist Harry Wong, launched the HK Cockatoo Watch project. Since March 2025, they have installed fifteen artificial nests — PVC boxes adapted to Hong Kong's humid climate and equipped with cameras for observation. Four of them are already occupied by cockatoo pairs, and in one of the nests a chick that had previously been found in a ventilation shaft has successfully fledged.
Schoolchildren actively participate in the project: they draw the birds, photograph them during breaks and learn to observe urban nature. Genetic studies show that the Hong Kong population retains high diversity, which makes it a potential reserve for restoring wild groups in Indonesia and Timor-Leste.
Harry Wong continues to refine the design of the boxes, lowering the internal temperature and improving conditions. This approach demonstrates how targeted human measures can turn urbanised spaces into viable habitats for rare species.
Protecting urban cockatoo populations helps preserve the species' genetic pool and reminds us of the possibility of harmonious coexistence between humans and wildlife.
