The earliest record from Hong Kong is a specimen taken in an unknown year between 1887 and 1903.
Vaughan & Jones (1913) reported a pair which roamed between Hong Kong and Macao over a 4-year period in early 1990s and nested on an island miles from Macao. Herklots (1953) gave the first account of Hong Kong population at 2-3 pairs, whilst Carey et al. (2002) summarized the records and put the HK population at 10 pairs.