IDENTIFICATION

VOCALISATIONS

Vocal. The typical call in flight is a thin high-pitched ‘tswee-weet’, the first syllable higher in pitch than the second. Thinner and slightly higher-pitched than Scarlet Minivet whose equivalent call terminates more abruptly.

Occasionally a rapid ‘srisisee’ but heard less frequently.

A short ‘pit’ call is sometimes given when perched or, more often, in flight.

DISTRIBUTION & HABITAT PREFERENCE

Occurs almost exclusively in closed-canopy woodland at all elevations. The expansion of woodland habitat has allowed this species to increase its range in both breeding and non-breeding seasons. However, it remains rare on offshore islands, even Lantau which has a substantial area of mature woodland.

The breeding range increased from 0.6% to 3.5% of 1km squares as measured by the breeding bird surveys of 1993-96 and 2016-19. Previously restricted to the central New Territories, it now occurs in the Country Park areas of Lion Rock, Kam Shan, Tai Lam, Pat Sin Leng, Plover Cove and Sai Kung West.

Between the winter atlas of 2001-05 and 2016-19 the percentage of 1km squares in which it was recorded increased from 2.5% to 7.2%. In the former survey it was largely restricted to the Tai Mo Shan massif and was rare in the northeast New Territories and Sai Kung. Subsequently, it became more numerous in the latter areas and spread to the Kowloon and Ma On Shan ranges of hills, with isolated records on HK and Lantau Islands.

OCCURRENCE

Grey-chinned Minivet was first recorded in 1957 (Walker 1958), January 1960 and February 1966, but not again until 3 January 1976 at Tai Po Kau. Up to seven birds were then reported there throughout the winter and the first summer record occurred on 13 June 1981. Evidence of possible breeding was first noted in 1984, and this was confirmed in 1987 (see below).

In December 1988 a flock of 40 birds at Kap Lung was the first seen away from Tai Po Kau. Range expansion continued in the 1990s, with at least 100 birds at Tai Po Kau on 14 November 1992, 60 at Kap Lung on 15 September 1996 and small numbers elsewhere at Kowloon Hills catchwater, Ho Chung and Kadoorie Farm and Botanical Garden.

This process continued after 1999. It is now regularly recorded at sites at which it was previously absent, such as Wu Kau Tang (since 2007), Hok Tau (2009), Fung Yuen (2010), Lai Chi Wo (2013) and Pak Sha O (2013). This range expansion reflects the continuing increase in forest cover in the New Territories. The largest flocks occur at Tai Po Kau, Kap Lung, Ng Tung Chai, Shing Mun: 120 birds were seen at Tai Po Kau on 27 June 2018, and 80 were at Kap Lung on 26 August 2001 and Ng Tung Chai on 16 October 2006.

Grey-chinned Minivet is regarded as resident and sedentary within its range (Cheng 1987; Kirwan et al. 2021). However, a clear seasonal pattern is evident from 1999 to 2020 (Figure 1). To some extent this may be due to the formation of flocks in the non-breeding season, but it appears that some birds move south or to lower altitudes for the winter. In recent years apparent migrants have occurred, exclusively in April: on 14 April 2011, 26 April 2018, 7 April 2020 and 14 April 2020 on Po Toi and on 6 April 2018 on Cheung Chau. In addition, at Pak Sha O regular observations from 2013, when it was first recorded, to 2021 indicated numbers peaked from mid-September to the end of the year followed by a decline to August, during the first half of which month there were no records.

BREEDING

The first breeding evidence was of two adults and five juveniles at Tai Po Kau on 18 June 1984; subsequently, a nest found on 31 March 1987 remained in use until 2 May. Breeding has become more frequent in recent years, with nest-building activities at Tai Po Kau, Ng Tung Chai, Kap Lung and Uk Tau (from March to May), and juveniles observed at Tai Po Kau, Hok Tau and KFBG from May to August.

BEHAVIOUR, FORAGING & DIET

Often with Scarlet Minivet in foraging flocks in winter. Few data on diet, though a faecal sample collected on 26 August 2015 contained mainly invertebrates (Yu et al. 2016).

SYSTEMATICS & RANGE

Widespread from the Himalayas east to south China and south through Indochina and Malay Peninsula to Sumatra and Borneo. Of the eight subspecies, only one, P. s. griseogularis, occurs in southeast China (including HK), northern Vietnam, northeast Laos, and on Hainan and Taiwan (Kirwan et al. 2021).

CONSERVATION STATUS

IUCN: Least Concern. Population trend stable.