Introduction
The close geographic relationship between South America and Antarctica (only 1000 km apart) and prevailing north-west winds south of the Patagonian coast allow some bird species to reach the Antarctic Peninsula (AP) (e.g. Montalti et al. Reference Montalti, Orgeira and Di Martino1999). The AP has been experiencing rapid regional warming and sea ice retreat over the past few decades (Šťastná Reference Šťastná2010) which has already been reflected in the breeding distribution and abundance of three local Pygoscelis penguin species (Lynch et al. Reference Lynch, Naveen, Trathan and Fagan2012). Yet warming of the AP area is likely to also influence vagrant birds that might benefit from reduced sea ice and increased ice-free land (Korczak-Abshire et al. Reference Korczak-Abshire, Angiel and Wierzbicki2011).
Although the north-west AP is a relatively well surveyed area, documentation of bird populations south-east of the AP is surprisingly infrequent (e.g. Montalti & Soave Reference Montalti and Soave2002). James Ross Island (JRI) (64°10′S, 57°45′W) is a large island (2500 km2) situated 20 km south-east of the AP. The north-west part of the island is one of the largest ice-free areas in the AP region. Prior to the establishment of the Czech J.G. Mendel research station on the northern part of the island in 2005–06, there had been no systematic survey of birds. Here we report on the observations of two bird species, the white-rumped sandpiper (Calidris fuscicollis (Vieillot)) and the brown-hooded gull (Larus maculipennis Lichtenstein), on JRI (Fig. 1).
Map of the north part of the Antarctic Peninsula (AP) with marked locations (filled arrows) of: (1) new records of the white-rumped sandpiper and brown-hooded gull at JRI, (2) the occurrence of the white-rumped sandpiper at the South Shetland Islands, (3) the probable occurrence of the white-rumped sandpiper at the Palmer area, and (4) the southernmost record of any sandpiper species, the pectoral sandpiper, at Rothera Point. Open arrows show the location of major bird survey areas along the AP where sandpipers have not been reported: (5) Esperanza Bay (Coria & Montalti Reference Coria and Montalti1993), (6) Cierva Point (Quintana et al. Reference Quintana, Cirelli and Orgeira2000), and (7) Seymour Island (Montalti & Soave Reference Montalti and Soave2002).
Observations
We conducted a survey of bird distribution on the ice-free area of the Ulu Peninsula, JRI, during three summers (January and February 2007/08, 2008/09, 2010/11).
A pair of white-rumped sandpipers was seen on 3–8 January 2009. The birds rested and foraged at two coastal lakes on Cape Lachman (63°47′46′′S, 57°48′24′′W, 9–15 m a.s.l.). The areas of lakes were 1.5 and 3 ha, a mean depth of 0.2 m (max 0.4 m). Both lakes have well developed littoral algae and a thick layer of fine sediments. The birds probably fed on the abundant crustaceans Branchinecta gaini Daday (Anostraca) and Boeckella poppei Mrázek (Calanoida) (Nedbalová et al. Reference Nedbalová, Nývlt, Kopáček, Šobr and Elster2012). The birds were observed with a 20–60X telescope and photographed.
A single brown-hooded gull, an adult bird in breeding plumage, was seen at midday of 8 January 2011, flying along the coast between Cape Lachman and St Martha Cove (63°49′20′′S, 57°48′38′′W). The bird was observed for about ten minutes with 10X binoculars, together with Antarctic terns (Sterna vittata Gmelin) and kelp gulls (Larus dominicanus Lichtenstein), which facilitated its identification through a direct comparison of sizes in flight.
Discussion
The white-rumped sandpiper breeds in the Nearctic tundra and winters in South America up to Tierra del Fuego (Del Hoyo et al. Reference Del Hoyo, Elliot and Sargatal1996). It is reported as a common visitor to the Falkland Islands, rare on South Georgia, and an accidental visitor to the South Shetland (Couve & Vidal Reference Couve and Vidal2003) and South Orkney (Coria et al. Reference Coria, Montalti, Rombola, Santos, Garcia Betoño and Juares2011) islands. Yet, multiple records of up to 25 birds and increased frequencies of its occurrence over the last 30 years from the King George, Ardley and Nelson islands suggest that white-rumped sandpiper is currently a regular visitor to the South Shetland Islands (Korczak-Abshire et al. Reference Korczak-Abshire, Angiel and Wierzbicki2011 and references therein; Lumpe & Weidinger Reference Lumpe and Weidinger2000, Peter et al. Reference Peter, Buesser, Mustafa and Pfeiffer2008). However, to our knowledge, there has been no firmly documented observation of this species from the AP or coastal Antarctica as yet. Surprisingly, the southernmost record (Rothera Point, 67°34′S, 68°08′W, Milius Reference Milius2000) of any sandpiper species was ascribed to the pectoral sandpiper (Calidris melanotos Vieillot), a species which has never been reported even from the South Shetland Islands. The only other published record of a sandpiper-like bird (a likely candidate was the white-rumped sandpiper) south of the South Shetland Islands is from Palmer Archipelago, west AP (64°46′S, 64°03′W, Parmelee Reference Parmelee1992; Fig. 1). Our present observation is thus the southernmost proven record of this species and the first one from the east AP.
The breeding range of the brown-hooded gull extends south up to Tierra del Fuego and the Falkland Islands (Del Hoyo et al. Reference Del Hoyo, Elliot and Sargatal1996). The species is an accidental visitor to South Georgia (Couve & Vidal Reference Couve and Vidal2003, Shirihai Reference Shirihai2008), but until now, there has been no published observation from more southerly locations, including the well surveyed South Shetland Islands (e.g. Peter et al. Reference Peter, Buesser, Mustafa and Pfeiffer2008). Our observation is the southernmost record of this species, extending its range more than 1550 km south-west of South Georgia.
Although the climatic conditions of the east coast of the AP are generally harsher than on the west coast (Moriss & Vaughan Reference Moriss and Vaughan2003), the Ulu Peninsula of JRI is extensively deglaciated with a number of shallow lakes (Nedbalová et al. Reference Nedbalová, Nývlt, Kopáček, Šobr and Elster2012) and adjacent to ice-free sea. Moreover, JRI lies in the precipitation shadow of the AP, which reduces seasonal changes in snow cover and also partly buffers the wind circulation (Láska et al. Reference Láska, Barták, Hájek, Prošek and Bohuslavová2011). Thus the ice-free areas on JRI might offer a temporary refuge for vagrant birds after having crossed the Southern Ocean and the AP mountains. Given continued environmental change, the number of bird species visiting this area and frequency of their occurrence are likely to increase, as has already been seen in the more clement north-west coast of the AP.
Acknowledgements
This study was supported by the Czech Geological Survey, the Ministry of Education (MSM 6198959212), and Ministry of Environment (VaV SP II 1a9/23/07) of the Czech Republic. The work in Antarctica was conducted under permission from the Ministry of Environment of the Czech Republic. Our thanks to the members of the J.G. Mendel station, to David Harderkopf for English corrections and to the reviewer.
