IDENTIFICATION

VOCALISATIONS

In territorial defence gives a drawn out, somewhat quavering, buzzing ‘kreee’.

In alarm it utters an inflected ‘sweet’ sometimes together with a rapid series of ‘tik’ notes.

DISTRIBUTION & HABITAT PREFERENCE

A regular winter visitor to rocky streams and water catchments. Favoured wintering sites in recent years have included Bride’s Pool/Chung Mei, the Lam Tsuen River and Tso Kung Tam at Tsuen Wan. Migrants are occasionally noted at unusual sites, e.g., one was noted on rocks on the beach at Tung O, Lamma Island on 25 December 2006, and a male was seen on a dry hillside at San Tau, Lantau on 28 October 2012.

OCCURRENCE

Locally uncommon with extreme dates of 21 October 2019 and 19 April 1961, though the latter is the sole April record and the latest this century is 16 March. Uncommon before the third week of November, after which numbers remain relatively stable until the third week of February (79% of records occur from December to February). There are few records between the last week of February and the third week of March (Figure 1).

Plumbeous Water Redstart is usually found singly or in pairs; rarely three may occur in the same general area. Total numbers each winter are rather variable. From 1999/2000 to 2019/20, there were two winters with no records. In other winters, there were usually single-digit total numbers but 11 occurred in winter 2009/10 and 13 in 2019/20. A count of 12 in 2017/18 includes three chicks (see below). A general increase in numbers recorded is likely due to increased observer activity.

Historically, it was regarded as a common winter visitor by Vaughan and Jones (1913), with occasionally a pair remaining to breed, though there is no evidence it bred in HK. It was first listed for HK by Herklots (1934). Subsequently Herklots (1953, 1967), noted it as an occasional winter visitor.

BREEDING

A pair bred at Tso Kung Tam in 2018. A male was first seen at the site on 24 November 2017, and a male and a female were recorded there on 5 January 2018. An adult and three chicks were seen on 10 March but were not reported subsequently.

There are at least two reports of males singing in the presence of accompanying females: at Wun Yiu on 3 February 2003 and at Chung Mei on 29 January 2004.

BEHAVIOUR, FORAGING & DIET

Frequently waves and spreads tail scissor-wise. Forages actively at the water’s edge or among rocks in the stream course and sometimes makes short aerial flights in pursuit of flying insects. Prey items identified include Crane Fly (Hexatoma sp.), Black-banded Gossamerwing Euphaea decorata and Red-base Jezebel Delias pasithoe. It has also been observed eating the fruit of Litsea rotundifolia var oblongifolia. A male on a dry hillside at San Tau Lantau on 28 October 2012 was seen feeding on berries that it gleaned from a shrub and ate on an exposed rock.

RANGE & SYSTEMATICS

Two subspecies are recognised, of which R. f. fuliginosus is largely resident from eastern Afghanistan east through the Himalayas to northeast and east China, south to south China, Indochina and northwest Thailand. There is altitudinal movement in winter, although some move longer distances to central and south Myanmar. In China it breeds above 1,000m south of a line from south and east Tibet north through Qinghai and Gansu to Inner Mongolia and Hebei (Collar and Christie 2020, Clement and Rose 2015). R. f. affinis is resident on Taiwan.

CONSERVATION STATUS

IUCN: Least Concern. Population trend stable.