Black-headed Ibis Threskiornis melanocephalus 黑頭白鹮
Category I. Formerly a scarce winter visitor, but no records since 1999.
IDENTIFICATION
65-76 cm. Medium large wading bird with long and thickly-based decurved black bill, all-white plumage apart from restricted black on tips of primaries. Non-breeding adults largely lack grey scapulars of breeding plumage and neck plumes.
VOCALISATIONS
Usually silent away from breeding sites (Matheu et al. 2020).
DISTRIBUTION & HABITAT PREFERENCE
Apart from a bird that overwintered at Luk Keng from 21 November 1977 to mid-March 1978, and an adult at Kam Tin on 4 October 1995, all records were from the Deep Bay area.
OCCURRENCE
Black-headed Ibis was a scarce winter visitor that declined significantly in HK during the last quarter of the twentieth century. Typically, the number of records increased from August to peak during January, followed by a decline to a low during the second half of February. There was then an increase in records, presumably migrants, during March that reached a peak during the last week of the month and the first week of April. There were occasional records of over-summering birds. The highest counts were 25 on 6 January 1974 and 18 on 8 April 1973. Based on the peak count per winter period, the major decline occurred from the 1977/78 winter period, with the final record on 27 November 1999 (Figure 1).
Although it was not recorded by either Vaughan and Jones (1913) or Dove and Goodhart (1955), Macfarlane and Macdonald (1966) stated it was a scarce winter visitor between 28 October and 16 April, with one record on 9 August. Herklots (1953) recorded a flock of 16 over Stanley in mid May 1945; however, he was interned in a prisoner-of-war camp at the time, and there are no details to support this unusual record.
BEHAVIOUR, FORAGING & DIET
No observations.
RANGE & SYSTEMATICS
Monotypic. Breeds in parts of the Indian subcontinent, Cambodia, south Vietnam and Java, disperses in winter (Matheu et al. 2020). Although the latter indicates an east Asian population of fewer than 100 adults is thought to breed in Heilongjiang, China, Liu and Chen (2020) state that no birds have been seen for many years; this population is therefore likely extinct. There are occasional records in Yunnan, but these are likely to be from the Indochinese population.
CONSERVATION STATUS
IUCN: Near threatened. Population size 10,000 to 19,999 and decreasing due to hunting, disturbance and habitat loss.
Figure 1.
Dove, R. S. and H. J. Goodhart (1955). Field observations from the Colony of Hong Kong. Ibis 97: 311-340.
Herklots, G. A. C. (1953). Hong Kong Birds. South China Morning Post, Hong Kong.
Liu, Y. and Y. H. Chen (eds) (2020). The CNG Field Guide to the Birds of China (in Chinese). Hunan Science and Technology Publication House, Changsha.
Macfarlane, A. M. and A. D. Macdonald, revised by Caunter, J. R. L. and A. M. Macfarlane (1966). An Annotated Check-list of the Birds of Hong Kong. Hong Kong Bird Watching Society, Hong Kong.
Matheu, E., J. del Hoyo, E. F. J. Garcia, and P. F. D. Boesman (2020). Black-headed Ibis (Threskiornis melanocephalus), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.blhibi1.01
