Sharp-tailed Sandpiper Calidris acuminata 尖尾濱鷸
Category I. Passage migrant, common in spring but scarce in autumn. Has become less common in spring.
IDENTIFICATION
Apr. 2014, Michelle and Peter Wong. Adult, breeding plumage.
17-22 cm. Medium in size, female slightly smaller. Warm brown upperparts with dark cap and contrasting pale supercilium, rather dense mottling on breast that thins out on lower chest and upper belly (not a sharp division as on Pectoral Sandpiper), neat white orbital ring, yellowish to brownish legs and paler base to blackish bill.
Juvenile has bright buff chest, buff flanks and chestnut and whitish fringes on upperparts.
Aug. 2022, Sarawak, Malaysia. Dave Bakewell. Adult, non-breeding plumage.
In non-breeding plumage dull and greyish with dense spotting on the chest and a slightly more obvious boundary between the white belly and upper chest.
VOCALISATIONS
A mono- or multi-syllabic ‘chreep’ or ‘chirireep’.
DISTRIBUTION & HABITAT PREFERENCE
Occurs on intertidal mudflats of Deep Bay and adjacent areas such as Mai Po NR and commercial fish ponds, but more than many other shorebird species passing through HK it occurs in freshwater wetland habitat such as marsh and wet agricultural areas. It has occurred away from the Deep Bay area at such places as Long Valley, the airport at Chek Lap Kok, the disused runway of the former airport at Kai Tak, Shuen Wan, Pui O, Wang Tong and Shui Hau on Lantau and islands such as Peng Chau, Tung Ping Chau and Po Toi.
OCCURRENCE
Sharp-tailed Sandpiper is primarily a spring passage migrant from the last week of March to the first week of June (Figure 1), with extreme dates of 22 March 1998 and 10 June 2018. Main spring passage occurs during the first three weeks of May, peaking in the second week; numbers after the third week are very low. From 1998 to 2020 peak spring counts were generally below 100, but in five years ranged from 170 to 300 (the highest count in HK 10 May 2004).
Autumn passage is weak and mainly in August and September, with the earliest on 17 July 2016 and the latest on 2 December 1994. The highest count in autumn is 31 on the 15 September 2005, though most records are of three birds or fewer. Juveniles have been recorded from 20 August to 26 October and during 9-24 November; adults have generally been noted earlier, from 29 July to 1 October.
Sharp-tailed Sandpiper was first recorded in HK in April 1953 (Dove and Goodhart 1955). Macfarlane and Macdonald (1966) reported up to 16 birds from 7 April to 1 June and ‘odd birds’ from 15 August to 12 October.
Three birds bearing Australian leg-flags were noted up to spring 1998: two birds from Victoria on 16 and one from northwest Australia on 20 April.
BEHAVIOUR, FORAGING & DIET
Unobtrusive, often occurring singly or in small scattered groups. Often forages among vegetation, but no information on diet here.
RANGE & SYSTEMATICS
Monotypic. Breeds northeast Siberia along the coast of the East Siberian Sea between the Lena and Kolyma River deltas, and winters in Australasia and Papua New Guinea (Van Gils et al. 2020). In China it is a passage migrant mainly through the eastern half of the country and along the south coast (Liu and Chen 2020).
CONSERVATION STATUS
IUCN: VULNERABLE. Population decreasing by approximately 45% over three generations due to habitat degradation, pollution and climate change.
Figure 1.
Dove, R. S. and H. J. Goodhart (1955). Field observations from the Colony of Hong Kong. Ibis 97: 311-340.
Liu, Y. and Y. H. Chen (eds) (2020). The CNG Field Guide to the Birds of China (in Chinese). Hunan Science and Technology Publication House, Changsha.
Macfarlane, A. M. and Macdonald, A. D., revised by Caunter, J. R. L. and Macfarlane, A. M. 1966. An Annotated Check-list of the Birds of Hong Kong. Hong Kong Bird Watching Society, Hong Kong.
Van Gils, J., P. Wiersma, and G. M. Kirwan (2020). Sharp-tailed Sandpiper (Calidris acuminata), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.shtsan.01
