IDENTIFICATION

VOCALISATIONS

Uttered both when perched and in flight is a short, modulated, high-pitched rattle.

Also gives an upslurred, nasal ‘dweee’, similar to Common Rosefinch. The song is a medley of chattering, rattling and higher-pitched ‘tyoo-tyoo…’ and drawn out nasal ‘zweer’ notes.

DISTRIBUTION AND HABITAT PREFERENCE

Occurs in a variety of lowland open-country habitats, including village edge areas and other anthropogenic habitats. Most summer records during 1958-1980 were from Mid-Levels and western and southern HK Island, the less densely-developed parts of the Kowloon peninsula (especially Ho Man Tin and Kowloon Tong) and towns in the New Territories, in particular around Tolo Harbour, Tuen Mun and in the northwest. Notably, however, they did not include the earlier stronghold of Nathan Road referred to by Herklots.

The Tolo Harbour area was previously a stronghold of the species, and breeding season records in the Sha Tin area continued for some years. However, although nest-building was observed in 1992 and breeding was successful in 1995, there have been no similar records in the area since 2004. The only other reports of confirmed or probable breeding since 1999 were at Siu Lam in 2009, Tsing Yi in 2011 and Tuen Mun in 2012, 2014 and 2016.

OCCURRENCE

Vaughan and Jones (1913) described Grey-capped Greenfinch as an irregular winter visitor to HK Island and Kowloon. Subsequently, Herklots (1953) described it as resident, occurring in winter on HK Island and in flocks in the New Territories at such sites as Lam Tsuen and Ping Shan. Walker (1958), among other records, reported a party of about 150 birds at Ping Shan on 11 October, which he considered were probably migrants.

Whilst the pattern of records subsequently did not suggest large-scale immigration into HK in winter, with no defined peak during the winter months, it seems likely that some flocks outside the breeding season were not made up of local breeding birds. For example, it seems probable that 48 birds on Cheung Chau on 17 April 1978 were migrants and flocks of 80 at Pok Fu Lam on 20 January 1973 and 100 in Victoria Park on 10 November 1980 seem unlikely to refer to a population resident on Hong Kong Island. However, the largest flocks recorded, 150 at Fanling Golf Course on 17 September 1979 and 200 there on 26 August 1977, were both in early autumn and suggest post-breeding aggregations of resident birds.

The population of Grey-capped Greenfinches in HK undoubtedly crashed after 1980 and has shown no recovery since. This decline affected the number of sites where it was present and counts at all times of year (supporting the view that immigrants form a small proportion of the winter population). Although the number of sites at which the species is recorded has increased since 2010, at many of these only one or two reports were made indicating chance encounters likely a result of increased observer activity.

Figure 1 illustrates the pattern of occurrence from 1999 to 2020 and indicates that numbers are highest from the third week of October to the first week of March, while lowest numbers occur from the last week of May to the final week of September, with a small number of breeding records responsible for slightly higher numbers in June and July. The highest counts since 1999 are 70 at Plover Cove Dam on 3 March 2020 and 40 at Lai Chi Wo on 19 December 2014.

Grey-capped Greenfinch has only been recorded on Po Toi several times from 25 March to 22 April and in autumn on 3 September and 9 November indicating that the number of migrants passing through is low. Other sites where it appears migrants (rather than winter visitors or breeding birds) occur are Cheung Chau, Lok Ma Chau MTRC Ecological Enhancement Area and Fan Lau and Yi O (both on Lantau), at which the spread of dates is 25 March to 10 May and 4 October to 18 November.

The full reasons for this species’ sudden decline are not known. Its breeding season habitat in HK always appears to have been low density suburban areas, and it is perhaps significant that the Nathan Road area, which Herklots (1953) described as a principal site, had already been abandoned by the time the HKBWS began collecting records in 1958. Thus, as with several other species that formerly bred on the Kowloon peninsula and on western HK Island, these areas were abandoned as development intensified. Less clear is why new low-density residential areas such as those in Sai Kung and the central and northwestern New Territories have not been colonised.

Whilst winter flocks formerly ranged through agricultural land, there is no evidence that this species was a specialist feeder in rice paddies; indeed, Vaughan and Jones (1913) noted that it was particularly attracted to ‘fir seeds’, presumably those of Chinese Red Pine Pinus massoniana. This species has also declined catastrophically due to the exotic pinewood nematode Bursaphelenchus xylophilus, but since this was not identified in HK until 1982 (Dudgeon and Corlett 1994) the dates do not quite match. In any case, it is hard to believe that such a widespread species of anthropogenic habitats as the Grey-capped Greenfinch is dependent upon a single food source, and it is difficult to envisage why this, or indeed any other single factor, might have led a sudden decline throughout HK.

BREEDING

The first reference to breeding in HK was by Pereira and Herklots (1934) who reported that ‘many birds have returned to their favourite nesting-places - the Banyan Trees (Ficus microcarpa) of Nathan Road, Kowloon’, suggesting this was a regular event in the 1930s. These authors and Pereira (1935) also reported nesting nearby in Kowloon. It appears, therefore, that it arrived as a breeding species between 1912 and 1929.

HKBWS records during 1958-1980 showed that it was a rather localised resident, primarily in and around settlements. Nest-building was observed from 28 March to 13 April, and newly-fledged young noted from 21 April to 30 May. These dates accord closely with those recorded by Vaughan and Jones (1913) but differ from those of Pereira and Herklots (1934) and Pereira (1935) who reported finding nests with eggs in Kowloon between 9 January and 14 May.

Since 1999 the very few breeding records have comprised dependent juveniles, which have been seen from 12 May to 3 July.

BEHAVIOUR, FORAGING & DIET

Feeding has been noted on the seeds of Chinese Arborvitae Platycladus orientalis, Queen Crape Myrtle Lagerstroemia speciosa, Horsetail Tree Casuarina equisetifolia and Vitex negundo.

RANGE & SYSTEMATICS

Summer visitor from Kamchatka southwest to Sakhalin and Hokkaido, resident in the rest of Japan, Ussuriland, the Korean Peninsula and northeast China south to cover all lowland and non-desert mainland areas of the country, as well as coastal Vietnam (Clement 2020, Liu and Chen 2020).

Four subspecies are recognised, of which the nominate breeds from central and east China south to central Vietnam, including HK. The remaining three occur in northeast Asia, with ussuriensis breeding Ussuriland, the Korean Peninsula and northeast China, kawarahiba in Kamchatka, Sakhalin Kuril Islands and northeast Hokkaido and minor in the south of the Korean Peninsula and from Hokkaido to south Japan.

CONSERVATION STATUS

IUCN: Least Concern. Population trend stable.