The Summer Migration
by Thomas Gomersall
Summer is a slow season for birdwatching in Hong Kong. By this time, the same Mai Po ponds and gei wai that bustled with birds in the winter are now empty and silent, their former inhabitants having long since left for their northern breeding grounds. With most of the spring migrants having moved on too, it can seem like all there is for birdwatchers to do at this time of year is twiddle their thumbs and wait for autumn to come again.
However, there are a few seasonal specialities around at the moment to tide them over until then. Although they only make up a small proportion of all the bird species in Hong Kong, summer migrants nonetheless include some particularly charismatic and even challenging species to find. Also, unlike winter and spring migrants, many of them come to Hong Kong to breed, meaning that you may even spot a few juvenile birds if you’re lucky (Agriculture, Fisheries and Conservation Department, 2019).
So if you’re willing to brave the rain, humidity and mosquitos, here are seven summer migrants to get out and look for:
Chestnut-winged Cuckoo (Clamator coromandus): Many of Hong Kong’s cuckoos are summer migrants and with its brown wings, black back, dark yellow throat and cockatoo-like crest, the chestnut-winged cuckoo is probably the most eye-catching of them all. Like most cuckoos, it is a brood parasite that lays its eggs in the nests of other birds, with the greater necklaced laughingthrush being a preferred host species (Viney et al, 2005, p. 132). Though not a common bird, it is widespread in woodland habitats across Hong Kong, such as Plover Cove Country Park (Tipper, 2016, p. 77; Agriculture, Fisheries and Conservation Department, 2018).
Roseate Tern (Sterna dougallii): Another group of birds commonly seen here in the summer are the terns. Three species flock to the waters of Hong Kong to nest on its offshore islands: the roseate, bridled and black-naped tern (see Sai Kung Archipelago blog for more details on this species). Of these, the roseate tern is perhaps the most colourful with its orange-red beak and legs. It is also the least common species, occurring in smaller numbers in Hong Kong than the other two terns (Tipper, 2016, p. 69). However, it has a very wide global range — with individuals caught for leg ringing by the Hong Kong Bird Watching Society having first been ringed on the Great Barrier Reef (Allock, 2019) — and is not considered a threatened species (IUCN Red List, 2019). Sai Kung harbour and the waters off Tap Mun Island are good places to spot them (Allcock, 2019).
Bridled Tern (Onychoprion anaethetus): Instantly distinguishable from the roseate and black-naped tern by its dark brown wings and back, the bridled tern is a very common tern species in Hong Kong. It also differs from the other two species in its feeding habits. Whereas the roseate and black-naped tern feed by plunge-diving for fish, the bridled tern feeds by dipping its beak in the water as it flies, although it has been known to also dive from low heights (Tipper, 2016, p. 69). Large numbers breed on the islands of Mirs Bay, so the waters off Tap Mun Island are a good place to spot them. However, the ferry to Po Toi also passes islands that are good for them (Allcock, 2019).
Yellow Bittern (Ixobrychus sinensis): Although small numbers of this bird do spend the winter in Hong Kong, the vast majority of the ones that occur here come during the summer to breed. They are found mainly in Deep Bay where they spend most of their time nesting in reed beds and other dense vegetation. This combined with their small size and naturally secretive nature make them difficult to spot and they are most often seen when flying from one place to another (Tipper, 2016, p. 24). Adults have a dark black crown and flight feathers and uniformly yellow upperparts and buff underparts. Meanwhile immature birds have prominent brown and white streaking on their breasts (Tipper, 2016, p. 24; Viney et al, 2005, p. 44).
Slaty-legged Crake (Rallina eurizonoides): Unlike other crake species, which tend to be found in wetland habitats, the slaty-legged crake prefers woodlands and close canopied shrubland areas such as Tai Po Kau and has even been known to fly up into trees, (Tipper, 2016, p. 39; Viney et al, 2005, p. 84). However, it is no less secretive than most other crakes, preferring to stay hidden amongst the vegetation. The best way to tell if one is nearby is to listen out for its monotonous, two-note call that it regularly repeats at dusk or at night (Tipper, 2016, p. 39).
White-shouldered Starling (Sturnia sinensis): Visitors to Mai Po disappointed by the dearth of birds at this time of year may find some consolation in the presence of the charismatic white-shouldered starling, which in summer can be seen all over the northwestern New Territories (Tipper, 2016, p. 130). As well as places like Mai Po, they can sometimes be seen in urban areas as well. The abundant village houses in this part of Hong Kong are ideal for these birds, as they prefer to nest in the crevices of man-made structures. However, they will also occasionally nest in tree holes(Viney et al, 2005, p. 220).
Hainan Blue Flycatcher (Cyornis hainanus): This little bird is a widespread breeding visitor to Hong Kong’s woodlands. Like several flycatcher species, it is sexually dimorphic, with the male having a shiny blue head, breast, wings and tail feather and the female being brown with an orangey-buff chin and breast. It has a very similar appearance to the blue-and-white flycatcher, but can be distinguished from that species by its smaller size and the absence of a black throat and breast in the male (Tipper, 2016, p. 136). It is the preferred host species of the Hodgson’s hawk cuckoo (Allcock, 2019).
References
· Agriculture, Fisheries and Conservation Department, Plover Cove, [website], 2018, https://www.afcd.gov.hk/english/country/cou_vis/cou_vis_cou/cou_vis_cou_pc/cou_vis_cou_pc.html (Accessed: 3 June 2019).
· Agriculture, Fisheries and Conservation Department, Birds, [website], 2019, https://www.afcd.gov.hk/english/conservation/hkbiodiversity/speciesgroup/speciesgroup_birds.html (Accessed: 5 June 2019).
· Allcock, J., interviewed by Thomas Gomersall, 2019, WWF — Hong Kong Birdwatching Society.
· IUCN Red List, Roseate Tern, [website], 2019, https://www.iucnredlist.org/species/22694601/132260491 (Accessed: 9 July 2019).
· Tipper, R. 2016. A Naturalist’s Guide to the Birds of Hong Kong, John Beaufoy Publishing, United Kingdom. 24pp., 39pp., 69pp., 77pp., 130pp., 136pp.
· Viney, C., Phillipps, K. and C.Y. Lam. 2005. The Birds of Hong Kong and South China. Information Services Department, Hong Kong SAR Government, Hong Kong. 44pp., 84pp., 132pp., 220pp.
