IDENTIFICATION

VOCALISATIONS

The distinctive song is given throughout the year is a simple phrase usually of 4-6 identical notes, though there may be as few as three or as many as nine. There may or may not be an introductory note, and the pace varies between birds.

The most distinctive call is a double-note, the first higher in pitch than the second.

The alarm call is a high-pitched chatter.

DISTRIBUTION & HABITAT PREFERENCE

Rufous-capped Babbler is a common resident of forest and more mature closed-canopy shrubland at all elevations, where it favours areas with dense vegetation such as bamboo thickets and tangles in the lower canopy.

First recorded in Tai Po Kau on 29 June 1985, it was not recorded again until 13 December 1991 at Shing Mun. It was regularly recorded at Shing Mun from 1993 with up to five singing males noted there in the 1990s. Also in the 1990s were the first observations at other sites on the Tai Mo Shan massif, while the first records from HK Island occurred in 1994 and in the northeast New Territories in 1998 (Carey et al. 2001). In the 1993-96 breeding atlas survey it was recorded in just four adjacent 1km squares (0.3%) in the central New Territories.

By the time of the 2001-05 winter atlas survey, Rufous-capped Babbler was well established and was recorded in 53 1km squares (4.4%); it was widespread in the central and northeast New Territories, though there were just single individuals recorded from two squares on HK Island and Lantau. Subsequently, its spread continued, and perhaps accelerated, such that in the 2016-19 atlas surveys it was recorded in 20.8% of squares in the breeding season and 23.3% of squares in winter.

Rufous-capped Babbler is now found throughout most of the central, east and northeast New Territories. It remains largely absent from the northwest New Territories and, whilst there have been a few further records from both HK Island and Lantau, it does not yet appear to be firmly established on either of these; there are also no verified records from the smaller islands.

OCCURRENCE

As evinced by its failure to become established on HK Island and Lantau, so far at least, Rufous-capped Babbler appears to have limited ability to disperse across water or areas of unsuitable anthropogenic habitat. Conversely, however, its rapid spread where such barriers are absent, as in much of the New Territories, indicates that it can be rather mobile. A record from Ho Man Tin in September 2017 suggests that urban areas may not constitute an insurmountable obstacle for this species.

This mobility is of interest and relevance to the origin and status of Rufous-capped Babbler in HK. When first recorded, it was considered that the pattern of occurrence, centred on the Tai Mo Shan massif, was inconsistent with it having colonised from Guangdong; hence, Rufous-capped Babbler was placed on the HK List in the equivalent of the current Category IIA (i.e., a southeast China breeding species, the established population of which is considered to derive from captive stock, but which probably occurred in HK prior to anthropogenic habitat changes).

However, the range of Rufous-capped Babbler in HK now extends to the boundary with Guangdong at several points, for example Sha Tau Kok and Robin’s Nest, whilst there are many recent eBird records from south Guangdong, notably from Wutongshan National Forest Park (which is only about 3km from Robin’s Nest) (eBird 2023). It seems highly likely, therefore, that the HK population of Rufous-capped Babbler is now continuous with that of Guangdong and that dispersing individuals may cross the boundary in either direction.

BREEDING

Breeding commences in March, with copulation observed in late March and nest-building in mid-April. Dependent fledged juveniles have been seen from 24 April to 15 August suggesting that there may be two, or perhaps three, broods in a season. The nest and eggs do not appear to have been described in HK.

BEHAVIOUR, FORAGING & DIET

Within its range, Rufous-capped Babbler is often one of the commonest species in forest and shrubland where it is a core species in small-bird flocks, together with other babblers, especially Blue-winged Minla, Silver-eared Mesia and Huet’s Fulvetta and, in winter, Phylloscopus warblers. It largely utilises the understorey, often moving through the thickest tangles of vegetation where it appears to particularly favour aggregations of dead leaves, only emerging briefly to inspect an observer, whilst keeping in touch with other flock members by means of churring contact calls.

Rufous-capped Babbler is probably an insectivore-frugivore, though its diet does not appear to have been studied in HK, other than an incidental observation of one feeding on fruit of Dichroa febrifuga, a common forest understorey shrub. It is often observed creeping through thick vegetation and exploring tangles and leaves, presumably searching for invertebrates.

RANGE & SYSTEMATICS

The range extends from eastern Nepal, northeast India and Myanmar south to northern Thailand, Laos and Vietnam. In China it is widespread in the southern and eastern provinces north to Shaanxi, Henan and Jiangsu and it is present on both Hainan and Taiwan (Collar and Robson 2020, eBird 2023).

There are six subspecies: C. r. davidi, which occurs throughout central and south China and northern Indochina is presumed to be the taxon present in HK.

CONSERVATION STATUS

IUCN: Least Concern. Population trend decreasing.