IDENTIFICATION

VOCALISATIONS

A vocal species, particularly near the nest or when in groups. The typical calls are a slightly rolling ‘chrrrt’ and variations of this according to context.

A call only uttered in flight is a mellow ‘proo’, which can be heard in this recording along with a typical double-note call uttered while perched.

DISTRIBUTION & HABITAT PREFERENCE

White-shouldered Starling favours open-country habitat with trees, buildings and overhead wires available for perching. It tolerates the presence of humans and is often associated with artificial and built-up areas (e.g. villages or sheds), but it generally avoids wooded and mountainous areas.

The largest population is in the northwest New Territories, especially in the area of commercial fish ponds in the Deep Bay area, including Mai Po, Lok Ma Chau, San Tin, Ma Tso Lung, Nam Sang Wai and Hoo Hok Wai. It is also common in the agricultural area at Long Valley. It is less common outside the northwest New Territories, but numbers have been increasing at Stanley, Pui O, Pak Nai, Shek Kong and Tai Mei Tuk in recent years. It is also regularly seen on migration on Po Toi where up to 55 birds have been reported since 1999.

The breeding bird surveys of 1993-96 and 2016-19 indicated no significant difference in the percentage of occupied 1km squares (3.7% and 3.8%, respectively); however, there was a significant change in the distribution. Thus, there was a reduction from 20 to six occupied squares in the area south and east of Sha Tin (including the islands of Lamma, Cheung Chau and HK), while on Lantau and the Sokos a decline from nine to one occupied square occurred. This was offset by an increase in the number of 1km squares in the Deep Bay hinterland and Kam Tin area, and the former area in particular now constitutes the species’ stronghold as a breeding bird.

OCCURRENCE

White-shouldered Starling occurs year-round (Figure 1). In spring it is most numerous in the first three weeks of April, after when it appears breeding birds dominate. Main autumn passage occurs from the last week of August to the middle of October, probably peaking in the second half of September (the highest mean aggregate count occurs in the first week of the month due to an exceptional roost count in one year). Numbers are generally low in winter, with less than 20 individuals reported per week across the entire territory.

Colour-ringing as part of the monitoring for birds breeding at the MTRC managed wetlands at Lok Ma Chau and West Rail indicates that breeding and wintering populations are essentially discrete; thus, it is unlikely that any birds are resident in HK.

The majority of sightings concern small flocks of up to a hundred, rarely over 200 birds. An exceptionally high count of 950 birds was recorded at Mai Po on 2 September 2014, with the next highest being 300 at the atypical location of Lai Chi Wo on 22 March 2016.

Vaughan and Jones (1913) considered it a common breeding species, while Herklots (1953) stated that it was abundant both on HK Island and in the New Territories.

BREEDING

Nest sites are largely dependent upon human artefacts, usually in holes in old buildings, crevices in village houses but also in street lamp standards and, since 2008, in nest boxes. Occasional nests have been found in tree holes, but all of these have been in gardens, golf courses or around fishponds.

Breeding birds are loosely colonial. Pairs have been seen investigating potential nest sites as early as February, though nesting behaviour generally occurs from late March to late July. Juveniles are mostly seen from mid-June to late August.

The breeding population was estimated at less than 50 pairs by Carey et al. (2001). However, the installation of nest-boxes with an entry hole of 40mm in diameter has proved highly effective at increasing the breeding population at the MTRC Ecological Enhancement Areas of Lok Ma Chau and West Rail, and the first of these sites now supports the bulk of the breeding population in HK. The trees present on site are relatively young with few natural fissures or voids, and the nest-boxes filled this gap.

In 2011 at least 137 broods were raised from which a minimum of 544 chicks fledged; nest box occupancy levels were 100% at Lok Ma Chau and 81% at West Rail. This was the highest number recorded, but since then in most years over 80 and 20 breeding pairs have been recorded at the two sites, respectively.

In 2011, the largest single brood was seven chicks (and one egg). Up to three broods were produced in a breeding season with the mean number of chicks being 4.43 (S.D. +/- 0.86) in the first brood and 3.47 (S.D. +/- 1.14) in the second. Second broods were recorded in 86% of the nest boxes at Lok Ma Chau and 60% of the nest boxes at West Rail. Egg laying occurred from 19^th May to 11^th July.

BEHAVIOUR, FORAGING & DIET

Gregarious and rather arboreal, typically roosting or foraging with other starlings. A roosting flock of 950 birds is the largest count in HK. Omnivorous, it has been recorded feeding on the fruit of Lantana camara and Ficus benjamina, in a flowering Eucalyptus tree and on caterpillars.

RANGE & SYSTEMATICS

Monotypic. Breeds in south China and north Vietnam, and winters south to peninsular Thailand and Indochina, but is scarce in the Malay Peninsula and Singapore (Craig and Feare 2020). In China it breeds in the coastal provinces of the south from Yunnan to Fujian and patchily as far north as the Yangtze; it is present all year in Taiwan, Hainan and coastal areas of Guangxi and Guangdong (Liu and Chen 2020).

CONSERVATION STATUS

IUCN: Least Concern. Population trend stable.