The Wilson Journal of Ornithology 124 ( 3):487 496 , 2012 
ECOLOGY AND HABITAT SELECTION OF THE MAGELLANIC 
PLOVER ( PLUV1ANELLUS SOCIALIS)’. A LITTLE-KNOWN 
PATAGONIAN SHOREBIRD 
CARMEN LISHMAN 1: ' AND ERICA NOL 1 
ABSTRACT.—We studied the ecology and habitat selection ol the Magellanic Plover (Pluvianellus socialis) in southern 
Patagonia during two austral summers. We searched for the presence ol this rare species along the shores of 33 privately- 
owned lakes and portions of Lago Argentino across 12,000 knr of steppe habitat in Santa Cruz Province, southern 
Argentina anti compared characteristics of occupied and unoccupied lakes. Aeolian lunette size was a significant predictor 
of occupancy. Most lakes had only a single pair of breeding birds, although one had 14 pairs. No lake feature successfully 
predicted number ol breeding pairs per lake. Territories were on cobbled beaches on the side of the lake with Aeolian 
lunettes, and at sites significantly closer to small streams and further from vegetation than random sites. Nest sites within 
territories had significantly less clay than unused sites. Clutch size was small 1 1 2) while hatching success was moderate 
1 70 %). Future studies of this species should focus on adult and juvenile survival, and the development of a demographic 
model that assesses the long-term stability of the population. Received 12 February 2011. Accepted 21 March 2012. 
Northern tundra and wetland habitats support 
diverse and. at times, dense populations of breeding 
shorebirds (Melinite et al. 2007). Studies of areiie- 
breeding shorebirds largely inform our understand¬ 
ing of shorebird biology (Colwell 2010). However, 
shorebirds also breed throughout tlte world wherev¬ 
er suitable habitats exist (e.g.. prairies, steppes, 
agricultural fields, river beds, beaches). Many ol the 
species that breed outside of arctic habitats occur al 
low densities and are. partially as a consequence, 
poorly studied (e.g., Madagascar Plover \Chara- 
tlrius thoracicus\\ Long et al. 2008). Habitats of 
these species are also often inaccessible (e.g.. 
Diademed Plover | Phegornis itiitchellii | which 
breeds at altitudes >3,000 m in inaccessible habitats 
of the central Andean cordillera: Johnson 1964). 
Few of the 15 species of South American breeding 
shorebirds have been studied in any detail (Piersma 
et al. 1997, St. Clair et al. 2010). 
The Magellanic Plover (Pluvianellus socialis) 
is a rare shorebird that breeds on the shores ol 
lakes and rivers of Patagonia in southern South 
America (Jehl 1975. BirdLife International 2012). 
It is listed as near threatened on the IUCN Red 
List (BirdLife International 2012). Population 
estimates suggest fewer than 1,000 individuals 
(Jehl 1975) with a more recent value of 'fewer 
than 10.000’ (BirdLife International 2012). Few 
systematic evaluations of this species' breeding 
Department of Biology, Trent University, Peterborough. 
ON KVJ 7B8. Canada. 
Current address: 1336 Queen Street. Halifax, NS B3J 
2H5. Canada. 
'Corresponding author; e-mail: 
carmen.lishman@gmail.com 
success or habitat use have been conducted either 
al landscape or local scales (Jehl 1975: Piersma 
et al. 1997; lmbertj 2003: Ferrari et al. 2003, 
2008). 
We report results of a regional survey of the 
Magellanic Plover in southern Patagonia. Argen¬ 
tina, including a habitat selection study at three 
scales. We assessed characteristics of this species’ 
habitat within Santa Cruz Province, Argentina at 
the scale of lakes, territories, and nest sites. Out- 
goal was to provide specific habitat information in 
the center of the species’ geographic range to 
assist in more accurately assessing global popu¬ 
lation si/.e. We also compared habitat character¬ 
istics between successful and unsuccessful nests, 
and provide an estimate of detection probability 
for this species on lakes searched on multiple 
occasions. 
METHODS 
Field Procedures.—We studied Magellanic 
Plovers during two consecutive breeding seasons 
in austral spring and summer from August 2006 
to March 2007 (hereafter 2006) and during the 
summer. December 2007 (hereafter 2007) in 
southern Santa Cruz Province. Argentina (48 lo 
52 S). The semi-arid Patagonian steppe region 
is characterized by a cold (average 7.2 C). dry 
(<200 nun annual rainfall) climate with strong 
(average 35 ktn/hr. gusting to 150 km/hr. Ferrari 
et al. 2003) persistent westerly winds (Soriano 
1983). The flat grassland landscape supports 
many endorheic lakes (i.e., lakes within basins 
that do not drain to the ocean, hereafter ’lakes’) 
that vary in salinity, size, and geomorphologic 
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