The Wilson Journal of Ornithology 124(l):40-50. 2012 
SEASONAL VARIATION IN SHOREBIRD ABUNDANCE 
IN THE STATE OF RIO GRANDE DO SUL, SOUTHERN BRAZIL 
ANGELO L. SCHERER 1 - 2 AND MARIA V. PETRY' 
ABSTRACT —We describe the frequency of occurrence and seasonal variations of shorebirds (Charadriidae and 
Scolopacidae) along a 120-km transect of beach between Balnefirio Pinhal and Mostardas north of Lagoa do Peixe 
National Park. Rio Grande do Sul State over a 2-vear period (Oct 2007 to Sep 2009). A total of 96.889 shorebirds was 
recorded. The greatest abundance occurred between October and April and the lowest occurred between May and 
September. The most abundant of the 17 species recorded were Sanderlings (Calidris alba). White-rumped Sandpipers tC 
fuscicollis ). and Red Knots (C. camttus). The least abundant were Senupalmated Sandpipers (C. pusilta). Rufous-chested 
Ploxers (Charadrius mode slits), and Hudsonian Godwits (Li most/ haemastiea). Fourteen species were migrants from the 
Northern Hemisphere, one was a migrant from the Southern Hemisphere, and two were residents. Nine species were 
recorded regularly, two were recorded sporadically, and six were recorded occasionally. Six Nearctic species were 
recorded in June and July most likely indicating the presence of non-breeding immatures. The beaches of Rio Grande do 
Sul are important migration stopover and wintering sites for many shorebirds in southern Brazil and should be a focu> of 
conservation efforts, especially given the increasing development pressure that threatens these areas. Received 10 
February 2011. Accepted 25 October 2011. 
Brazil is visited by thousands of birds that 
migrate seasonally from the Northern lo Southern 
Hemisphere and vice-versa (Morrison and Ross 
1989, Chesser 1994). Those that come from the 
north prior to the boreal winter (Antas 1994) 
arrive in Brazil seeking wintering sites rich in 
food resources (Telino-Junior et al. 2003). Shore- 
birds from the Northern Hemisphere occur in 
Brazil during the austral summer and those from 
the Southern Hemisphere occur in the country 
during the austral winter. Immature individuals of 
certain shorebirds occur throughout nearly the 
entire year, as they are not yet capable of breeding 
and return to breeding areas only when they are 
sufficiently mature to begin nesting (Sick 1979. 
Azevedo-Junior and Larrazabal 1994. Azevedo- 
Junior et al. 2001a. b). 
The sites at which shorebirds stop during 
migrations are of considerable importance for 
conservation. Lagoa do Peixe National Park and 
nearby beaches on the coast of the State of Rio 
Grande do Sul in southern Brazil attract large 
concentrations of migratory shorebirds (Lara- 
Resende and Leeuwenberg 1987. Morrison and 
Ross 1989. Vooren and Chiaradia 1990. Belton 
2000). The availability of food resources at these 
sites oilers the birds the opportunity to gain body 
Graduate Program in Biology. Laboratory of Ormtl 
ogy and Marine Animals. Center for Health Scienc 
Va ' 1 ' d ° Ri,> dos Si ™ s - Avenida Unisin 
. ‘ °‘ ^ 0 '-2-°00. P. o. Box 275. Room 2D223E. 5 
Leopoldo. Rio Grande do Sul, Brazil 
Corresponding author; e-mail: alscherer@pop.com.bi 
mass and acquire adequate energy for molting 
and return to breeding areas (Azevedo Junior 
et al. 2001a, b; Baker et al. 2004, Fedrizzi et al. 
2004). 
Shorebird populations fluctuate during (he 
breeding and wintering periods in number of 
individuals and migratory species using the 
beaches of southern Brazil (Lara-Resende and 
Leeuwenberg 1987, Barbieri et al. 2003. Telino- 
Junior et al. 2003. Barbieri and Mendon^a 2005) 
The greatest abundance occurs from September to 
April along the Brazilian shoreline with slight 
temporal variations (Barbieri 2007. Barbieri and 
Hvenegaard 2008. Barbieri and Paes 2008). In 
southern Brazil. Lara-Resende and Leeuwenberg 
119X7) found the highest abundance of shorebirds 
from November to April in Lagoa do Peixe 
National Park (Ramsar site) (31 21’ S; 05 1 03’ 
W). I he beaches from Balneario Pinhal to 
Mostardas. which are north of this conservation 
unit, offer adequate stopover, feeding, and resting 
sites for migratory shorebirds and are important 
locations for their conservation (A. L. Scherer, 
pers. obs.). 
The coast of Rio Grande do Sul is considered a 
key area for shorebird conserv ation in the Western 
Hemisphere (Serrano 2008). Our objectives were 
to: (I) record the occurrence and seasonal 
variations ot shorebirds (Charadriidae and Scolo¬ 
pacidae) along a 120-km transect of beach north 
of Lagoa do Peixe National Park, and (2) 
document the frequency of occurrence of species 
of shorebirds over a 2-year period. 
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