Palearctic Waders in Western Australia C
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Palearctic waders in Western Australia C. D. T. Minton and R. J. Chandler ABSTRACT Together with Hong Kong (Brit. Birds 86: 231-242), the northern shores of Western Australia provide an irresistible magnet for shorebird enthusiasts, with huge numbers of species such as Great Knot Calidris tenuirostris and Little Curlew Numenius minutus which are scarce on a World scale yet have occurred as vagrants to Western Europe. This paper, which briefly summarises the status of all wader species in NW Australia, is illustrated by photographs obtained on a special trip to the area. The northern part of Western Australia (hereafter NW Australia) was 'discov ered' as an important area for waders in 1981, in the Royal Australasian Ornithologists' Union's Wader Census Programme. During this census, the whole of the 8,000-km coastline of northern Australia was covered by an aerial survey, with extensive follow-up on the ground to determine flock compositions. The greatest surprises of the survey were not only the absolute numbers of Palearctic waders (about 1.5 million), but also the fact that the area held many flocks of thousands of Great Knots*. This species was previously thought to be rare, with numbers possibly totalling only 5,000 worldwide. It is now known that during the Northern Hemisphere winter there are typically 320,000 Great Knots in Australia, with 180,000 of them in NW Australia. Many other species of Palearctic wader spend the non-breeding season in NW Australia; indeed, all the species occurring in the largest numbers are from the Palearctic. After Great Knot (plate 77), the most numerous are Bar-tailed Godwit *Scientific names are given in table 1. [Brit. Birds 89: 177-184, April 1996] © British Birds Ltd 1996 177 178 Minton & Chandler: Palearctic waders in Western Australia of the race bourn (plate 83), Red Knot, Greater Sand Plover (plate 81), Little Curlew, Red-necked Stint (plate 84), Oriental Pratincole, Curlew Sandpiper, Oriental Plover, Red-capped Plover, Terek Sandpiper (plate 82), and Grey-tailed Tattler (plate 80). These are the 12 most numerous species, each occurring in numbers in excess of 10,000, of which only the Red-capped Plover is an Australian species. The numbers of the different wader species involved are sum marised in table 1. Table 1. Minimum estimates of wader numbers in northern Western Australia. Non- Palearctic species (Australian endemics) are shown in square brackets. Data from Watkins (1993). Species (in order of importance) Numbers 1 Great Knot Calidris tenuirostris 180,000 2 Bar-tailed Godwit Limosa iapponica 100,000 3 Red Knot Calidris canutus 90,000 4 Greater Sand Plover Charadrius ieschenaultii 60,000 5 = Little Curlew Numenius minutus 50,000 5 = Red-necked Stint Calidris ruficollis 50,000 7 Oriental Pratincole Glareola maldivarum 35,000 8 Curlew Sandpiper Calidris ferwginea 30,000 9 Oriental Plover Charadrius veredus 20,000 10 [Red-capped Plover Charadrius ruficapillus] 15,000 11 Terek Sandpiper Xenus cinereus 12,000 12 Grey-tailed Tattler Heteroscelus brevipes 11,000 13 Black-tailed Godwit Limosa limosa 8,000 14 Broad-billed Sandpiper Limicola falcinelius 6,000 15 Greenshank Tringa nebularia 5,000 16 = Grey Plover Pluvialis squatarola 3,000 16 = Ruddy Turnstone Armaria interpres 3,000 18 = Sharp-tailed Sandpiper Calidris acuminata 2,000 18 = [Red-necked Avocet Recurvirostra novaeholiandiae] 2,000 18 = Lesser Sand Plover Charadrius mongolus 2,000 18 = SanderlingCa//c«sa/te 2,000 22 = Far Eastern Curlew Numenius madagascariensis 1,500 22 = Whimbrel Numenius phaeopus 1,500 24 [Pied Oystercateher Haemaiopus longirostris] 550 25 Marsh Sandpiper Tringa stagnatilis 500 26 Pacific Golden Plover Pluvialis fulva 250 TOTAL 690,300 Other Palearctic species occur in smaller numbers, including Broad-billed Sandpiper (plate 78), Sharp-tailed Sandpiper, Lesser Sand Plover (plate 79), Far Eastern Curlew, Pacific Golden Plover, Long-toed Stint Calidris subminuta, and Asian Dowitcher Limnodromus semipalmatus (Chandler 1995). The first four species occur in thousands, the remainder in lesser numbers. Altogether, 50 species of wader—almost one-quarter of the World's species—have been record ed in NW Australia. The main wader locations in NW Australia are Broome/Roebuck Plains, 80 Mile Beach and Port Hedland Saltworks, and these sites have been visited by 16 wader-study expeditions since 1981. Some of the expeditions were large Plates 77-84. Waders in Western Australia in March/April 1995 (R. J. Chandler). All are in adult summer plumage. The inclusion of these plates in colour has been subsidised by financial support from Carl Zeiss, sponsor of the British Birds Rarities Committee. 77. Great Knot Calidris tenuirostris, March 1995 (/?. J. Chandler) 78. Broad-billed Sandpiper LimicoJa falcinellus sibirica, April 1995 (R. J. Chandler) 79. Male Lesser Sand Plover Charadrius mongolus, April 1995 (R. J. Chandler) 80. Grey-tailed Tattler Heteroscelus brevipes, March 1995 (R. J. Chandler) 81. Male Greater Sand Plover Charadrius leschenaultii, March 1995 (R. J. Chandler) 82. Terek Sandpiper Xenus cinereus, March 1995 (R. J. Chandler) 83. Male Bar-tailed Godwit Limosa lapponica baueri, March 1995 (R. J. Chandler) 84. Red-necked Stint Calidris ruficollis, April 1995 (R. J. Chandler) British Birds, vol. 89, no. 4, April 1996 183 (25 people for two months), some small (five people for one week). These have included, at aE three main locations: 1. Ground and aerial surveys (additional to the now-standard summer and win ter monitoring counts of specified areas). 2. Ringing (cannon-netting and mist-netting), with a total of around 45,000 waders caught to date. 3. Migration-watching, using meteorological radar initially, and more recently by observing the departures on northward migration in March/April. Totals of 20,000-30,000 waders have been seen to depart each year from Broome alone. 4. Photographic studies. Ringing and other studies Ringing recoveries show that, on northward migration, the Chinese coast is a key stopover site for almost every species of wader. The Shanghai area (Yangtse estuary and its adjacent shores) is especially important, with virtually all the Great Knots, Bar-tailed Godwits and Red Knots using that area. Weight gains of 50-80% are made by aE species before departure. There is much direct and indirect evidence that all but the smallest species fly non-stop direct from NW Australia to the Chinese coast, a distance of 5,500 km and a flight of three days' duration. On southward migration, the birds are more spread out than on northward migration, and Korea and Japan are important stopover sites. Curlew Sandpipers do a loop migration, with southbound recoveries mostly occurring well to the west of the northward route, with one recovery as far west as southern India. The annual pattern Waders are present in good numbers throughout the year in NW Australia, with totals still in the thousands even during the Northern Hemisphere summer. This is because the one-year-olds of almost aE species do not migrate north until their second year, or not until their third, fourth, or even fifth year in the case of the larger waders. There is also a tendency for the resident Australian waders to flock during the Australian winter ('dry season' in northern Australia). For the wader enthusiast, perhaps the best time to visit is in March/April, when most waders are in breeding plumage prior to their northward departure. Some species, however, for example Far Eastern Curlew and Oriental Plover, mostly depart in early March, and the majority of several other species do so before the end of March, particularly Little Curlew and Oriental Pratincole. Wader numbers buEd up again from late August to October, as they return from the north, though arrivals start with Far Eastern Curlews in early August. At this time, many adults are still in breeding plumage; indeed, Grey Plovers, which are unlike most of the other species in migrating north while stiE in non- breeding plumage, are seen in Australia in breeding plumage only at this time. The photographs The photographs (plates 77-84) show Palearctic waders in NW Australia during March/April. At this time, most individuals that are due to migrate to the Palearctic 184 Minton & Chandler: Palearctic waders in Western Australia have largely acquired breeding plumage, while there are also immatures in non- breeding plumage that will remain in Australia. Those species that use the coastal mudflats are most easily photographed at high-tide roosts, where a number of the accompanying photographs were taken. At the highest spring tides some species may use the rocks or low cliffs around Roebuck Bay, but at neap tides all species roost at the head of the beach. They range up the shore depending mainly on size of species: Far Eastern Curlews and Bar-tailed Godwits in or at the water's edge; Great and Red Knots just at the edge of the water, where Red-necked Stints, Ruddy Turnstones and Sanderlings often continue to feed amongst them, while Greater Sand Plovers are likely to congre gate in single-species groups well up the beach. The inland, freshwater wader species have to be photographed using wait-and- see techniques from a hide set up in favoured feeding areas. Those photographed in this manner included Broad-biUed Sandpiper and Lesser Sand Plover. References CHANDLER, R. J. 1995. PhotoSpot: 36. Asian Dowitcher. Brit, Birds 88: 362-364, plates 99 & 100. LANE, B. A. 1987. Shorebirds in Australia. Melbourne. WATKJNS, D. 1993. National Plan for Shorebird Conservation in Australia. Report to WWFA by AWSG. Dr C. D. T. Minton, 165 Dalgetty Road, Beaumaris, VIC 3193, Australia Dr R. J Chandler, 2 Rusland Avenue, Orpington, Kent BR6 8AU Appendix 1. Habitats Roebuck Bay, Broome, is a 25-km diameter bay just to the east of Broome, with vast tidal mud flats.