IDENTIFICATION

VOCALISATIONS

The song is a long, descending series of bubbling notes.

Other sounds include an explosive two-note ka-kup repeated several times and rising in volume.

Also short, strangled squeals.

DISTRIBUTION & HABITAT PREFERENCE

Asian Barred Owlet has been recorded from widespread lowland parts of the New Territories and occasionally also Kowloon, HK Island, Lantau and Lamma. It occurs in wooded areas on the edge of farmland or marshes, especially fung shui woods, occasionally mangroves and also deep in forest, typically at lower altitudes but locally up to about 500 metres asl. Favoured sites include Mai Po NR, the Lam Tsuen Valley, Shek Kong Catchwater and Tai Po Kau.

OCCURRENCE

Records are in all months of the year, both by day and by night. Most records are of one or two birds, and the highest count is six at Shing Mun on 11 May 2001, all vocalising at night. Since over 93% of individuals were detected through their vocalisations, the numbers detected reflect this. They are highest from January to May (peak in February), which coincides with the early stages of the breeding season, and then rapidly decline during the post-breeding period in June and July, which in combination with lower levels of observer activity at this time results in a summer trough. Thereafter, an increase in September and October is followed by a decline, with the second trough of the year reached in December. The reasons for the September-October increase are not known. One possibility is that juveniles are dispersing at this time, leading to increased vocal activity from adults whose territories they are passing through.

The first records were of up to three birds heard or seen in the Lam Tsuen Valley in the 1930s following the discovery of a nest there in the spring of 1931 (Hutson 1931, Herklots 1939, 1953). After a period from the late 1950s to the mid-1980s when it was scarce, an increase became apparent in the 1990s. Since then, a further increase has occurred. Higher levels of coverage and reporting are clearly a factor, but the spread and maturation of woodland is thought to have contributed.

BEHAVIOUR, FORAGING & DIET

Individuals at favoured sites such as Mai Po NR and Tai Po Kau are detected far more frequently by night than by day relative to levels of coverage, indicating that the species is mainly nocturnal both in forest and more open habitats in HK, whereas it is considered to be mainly diurnal elsewhere in the range (Konig & Weick 2008). Individuals seen in the daytime are usually in mid-canopy in a tree, or occasionally perched on top of a post, or in undulating flight between stands of trees. One individual at Shek Kong village in November 1992 regularly used an artificial nest-box as a day-time roost-site.

Poorly-concealed individuals may attract mobbing passerines, such as Red-whiskered Bulbul, Swinhoe’s White-eye, Crested Myna, Black-collared Starling and Oriental Magpie Robin. Prey items reported include small birds, reptiles, amphibians and fleshy insects such as cicadas; the only species identified are Swinhoe’s White-eye, Long-tailed Skink Mabuya longicaudata and Gunther’s Frog Rana guentheri.

BREEDING

Despite this being a widespread and common species throughout its range, few details have been published of its breeding behaviour in the literature beyond it being a tree-hole nester and normally laying four eggs. There are at least 19 records in Hong Kong of pairs nesting successfully in April or May and raising broods of up to five young. The first involved two eggs found in the hollow limb of a pollarded Water Banyan Cleistocalyx operculata in the Lam Tsuen Valley in the spring of 1931 (Hutson 1931, Herklots 1939).

Most nest-sites found since then are natural tree-holes 3-8 metres above the ground in the trunk or on a major limb of a native tree, especially Chinese Banyan Ficus microcarpa. One large Chinese Banyan at Kam Tin was used for nesting in at least five years during 2007-2012. Pairs have also been found nesting in artificial nest-boxes in Country Parks (Lock & Hui 2003) and at the edge of Deep Bay, while a pair nested successfully for two consecutive years in a disused kitchen on the top floor of a three-storey village house near Ho Sheung Heung (Holmes 2002).

Nesting records indicate adults at possible nest-sites from 11 April, fledglings in the immediate vicinity of the nest-site between 3 May and 3 June, and family parties up to 27 July. Photographs taken in nest-boxes and reproduced in Lock and Hui (2003) are unfortunately undated but show that the eggs are white and illustrate three stages in the development of the young inside the nest-box: (1) very small young nestlings covered in pure white down and with eyes closed, (2) larger greyer nestlings with feather sheathings showing through and the eyes fully open revealing yellow-orange irides, and (3) fledglings in juvenile plumage with the irides now yellow.

RANGE & SYSTEMATICS

Widely distributed from the Himalayas and northern India east through Burma to eastern China and south to Hainan and S Indochina, and resident throughout (Konig & Weick 2008). Polytypic, with eight subspecies recognised. G. c. whiteleyi occurs across widespread parts of central, eastern and southeast China, including HK.

CONSERVATION STATUS

IUCN: Least Concern. Population trend increasing.