IDENTIFICATION

20–25 cm. Has slaty-grey crown and mantle, white forehead extending back over the eyes, black chin and black wings, broad white patch on greater coverts and small flash at base of primaries and white-tipped tertials and secondaries. Long graduated black tail with white bands and white tip. White rump. Bill black, legs pinkish. Sexes similar. Juvenile has grey-brown crown and mantle, dark scaling on the breast and lacks the white on the face.

VOCALISATIONS

A moderately high-pitched ‘tseep’ sometimes repeated approximately every second.

DISTRIBUTION & HABITAT PREFERENCE

Occurs on rocky forest streams. Most records have been from three sites: Tai Po Kau, Ng Tung Chai and Shing Mun.

OCCURRENCE

An adult at Tai Po Kau on 31 December 1977 and 1 January 1978 was the first record, followed by occasional records at the same site in seven years between 1979 and 1994. More frequently recorded from 1995 to 2005 (although no sightings in 2001 and 2002) with reports from four sites, mainly Tai Po Kau and Ng Tung Chai.

A pair was present all year at Ng Tung Chai from January 1995 and a juvenile was seen there from 23 May onwards. What was presumably the same pair remained at Ng Tung Chai throughout 1996 until at least September 1997. Single birds were recorded at Ng Tung Chai in 1998, 2003 and 2004 but no further evidence of breeding was reported. There was one record of a single bird at this site on 5 April 2005, but it has not occurred there since then.

At Tai Po Kau, a bird was seen in April 1995, and in 1998 an adult was reported on 27 June and a juvenile was present between 30 August and 22 December. Single birds continued to be reported at Tai Po Kau through 1999 until 1 March 2000, including a first-winter bird on 25 January 1999 – which was presumably the juvenile first reported on 30 August 1998. A single adult was reported from 4 September 2004 to 24 February 2005.

A juvenile was also seen at Shing Mun on 4 October 1998 and what was probably the same bird was seen again on 6 December 1998.

The species became very scarce between 2006 and 2016 with records in only five of the 11 years; all single birds seen on one day except for one at Tai Po Kau from during 1-3 May 2014.

From September 2017 to at least January 2022 up to two birds have been recorded at Shing Mun. Reports of what are assumed to be second calendar-year birds in December 2017, December 2018, January 2019 and August 2020 suggests that breeding occurs at this site.

BREEDING

Evidence of breeding is based upon the occurrence of juveniles as follows:

1995: one at Ng Tung Chai from 23 May onwards.

1997: one at Tai Po Kau on 27 June.

1998: one at Tai Po Kau from 30 August to 22 December; one at Shing Mun on 4 October.

In addition, courtship feeding was noted at Ng Tung Chai on 22 February 1997 and one of a pair was seen carrying food on 25 April. The presence of adults and occasional reports of first-year birds at Shing Mun from 2017 to 2022 also indicates that breeding occurs at this site. The lack of reports of nests is doubtless due to the inaccessibility of the rocky streams frequented by this species.

BEHAVIOUR, FORAGING & DIET

Walks and hops between stones in water. Often bobs tail up and down. Feeds mainly on aquatic insects found along rocky streams.

RANGE & SYSTEMATICS

Monotypic, occurring in the central and eastern Himalayas from northern India east to Myanmar, south-central and eastern China, Thailand, Indochina and Peninsular Malaysia. In China it breeds in southeast Tibet, Sichuan, Yunnan, Guizhou east to inland Fujian and south to inland Guangdong and Hainan. It is largely resident with some altitudinal movement in winter (Clement and Rose 2015, Collar 2020).

CONSERVATION STATUS

IUCN: Least Concern. Population trend stable.