IDENTIFICATION

VOCALISATIONS

The territorial call is a rapid burst of up to 16 notes chuk-chuk-chuk-chuk-chuk-chuk lasting 2-4 seconds, repeated at short intervals, sometimes for minutes on end.

DISTRIBUTION & HABITAT PREFERENCE

The preferred breeding-season habitat is closed-canopy shrubland, often on low hills with permanent streams, and especially in the vicinity of a reservoir (Lewthwaite & Yu 2007, Lewthwaite & Fong in prep.). Forest is largely avoided. As a result it occurs locally in the New Territories (not in the Deep Bay area) and also on HK Island and Lantau. Favoured sites are Brides Pool Road, Lower Shing Mun, Mui Tsz Lam, Pak Sha O, Sha Lo Tung, Wu Kau Tang and Yung Shue O, all in the NT, and Shek Mun Kap on Lantau.

Outside the breeding season, Grey Nightjars are seen in widespread areas, including occasionally in the Deep Bay area, and also in Kowloon and on HK Island and offshore islands such as Po Toi, with migrants utilising habitats such as pine or bamboo stands, shrubland of various types, open grassy hills, airfields, urban parks and forest. There are also occasional observations in spring of birds on active migration over open sea.

OCCURRENCE

Grey Nightjar has been recorded in the period from 1 February to 23 December, with most records involving birds vocalising from 18 February to 9 July, and particularly March to May (Figure 1). From a low in February and early March, numbers rise to reach a peak between the second half of March and the end of May (72% of the total), then drop off in June and sink to a trough in July-August. A slight rebound involving birds visually detected occurs in October-November (24% of the total), indicating passage, after which there are just three further records in December. Highest counts of birds on territory are six at Brides Pool Road on 18 April 2020 and six at Mui Tsz Lam on 31 March 2021; all reports of migrants are of one or occasionally two birds apart from six over southern waters on 5 May 2007. Single birds seen at Lam Tsuen on 1 February  2008 and Tai Lam CP on 23 December 2019 are the earliest and latest on record.

A substantial increase in distribution is evident from a comparison of results from the two Nightbird Surveys, with singing birds detected at four sites in the first survey and at 22 sites in the second survey. Though this partly reflects the wider coverage of the second survey, a genuine increase is considered to have occurred as a result of maturation of habitat.

Passage migrants have been reported in spring between 16 March and 5 May, mainly at Ho Man Tin, Chek Lap Kok, Po Toi and occasionally over open sea. However, these comprise only 5%) of spring records. In autumn, passage migrants have been reported from 26 August to 10 December at wetland sites, urban parks, and small islands, which comprise over a third of the total (37%) in these months. The remaining 63% of individuals in autumn were at shrubland sites and there is little to indicate whether they were migrants from elsewhere or breeding birds lingering on territory.

The first records for HK were a specimen obtained at Stanley on an unknown date in 1860 or earlier (Swinhoe 1861, 1863) and a female flushed from a nest at Ma On Shan on 24 April 1938 (Herklots 1939). Most records from the 1950s to the mid 1980s were considered unproven due to confusion with Savanna Nightjar, with the exception of a number of dead or injured birds found in mid February, early April and from late September to late November in the 1970s and 1980s which were identified as Grey Nightjar based on biometrics and wing and tail pattern (Chalmers 1986, 1988). Also identifiable as Grey Nightjar based on biometrics provided by Chalmers (1998) is one captured at night among an exceptionally large gathering of 60 nightjars at Shek Kong Airfield on 6 July probably in 1957 (Walker 1957). Based on records in the 1990s, when a small summering population was found at Yung Shue O and there were occasional sightings elsewhere in spring and autumn, Carey et al. (2001) regarded Grey Nightjar as a scarce and very local summer visitor and a scarce passage migrant.

BREEDING

The only breeding observation involves a nest with two eggs found on 24 April 1938 at an altitude of about 200-250 metres asl on Ma On Shan (Herklots 1939). The female was accidentally flushed and gave a broken-wing display. A photograph of the nest and eggs is provided in an accompanying plate. The observer described the ‘nest’ as a patch of needles underneath a small pine-tree about 2-3 metres tall and noted that the eggs were “nicely marked with a lot of mauve and pearl-grey markings on quite a chalk-white colour”.

BEHAVIOUR, FORAGING & DIET

In the breeding season males frequently sing on the wing or from a perch at dusk, in early evening or at dawn. A tree stump about 8 metres tall in a stand of trees bordering open shrubland beside Brides Pool Road was regularly used by a male as a song-perch in March-May 2001 (Lewthwaite & Yu 2007). Autumn migrants are occasionally found roosting by day on branches in woodland, especially pines. One in autumn at Cloudy Hill was observed feeding on ants on a traffic-free road.

RANGE & SYSTEMATICS

Breeds from Pakistan east through the Himalayas to Burma, south to the Malayan Peninsula and across central, south and east China to southeast Siberia, Korea and Japan; winters in the Indian Sub-continent, southeast Asia, Sumatra, Borneo and the Philippines (Cleere & Nurney 1998, Cleere 1999). Formerly included as part of Jungle Nightjar C. indicus, but now treated as a separate polytypic species, with two subspecies recognised - hazarae breeding in the west of the range from Pakistan to W Yunnan and nominate jotaka in the east of the range including much of China.

In China, jotaka breeds southeast of a line from southeast Yunnan to Heilongjiang and occurs widely during both passage periods, but there are no confirmed winter records. Claims of birds in winter in the Delta and West River areas of Guangdong in the early 1900s (Kershaw 1904, Vaughan & Jones 1913) were queried by La Touche (1925-34) and Cheng (1987), and no specimens have been traced.

CONSERVATION STATUS

IUCN: Least Concern. Population trend stable.