Scherer and Petry • SEASONAL VARIATION IN SHOREBIRD ABUNDANCE 
47 
area as either a wintering site or stopover point for 
the part of the population that winters in areas 
further south, such as Tietra del Fuego (Harrington 
et al. 1986. Morrison et al. 200), Piersma 2007). 
Nine species had a regular frequency of 
occurrence over the 2-vear period, whereas other 
species occurred occasionally and in low abun¬ 
dance (Rufous-chested Plover. Hudsonian God- 
wit. .Semipalmated Sandpiper, and Buff-breasted 
Sandpiper). The Rufous-chested Plover is an 
austral winter visitor from Patagonia, where it 
breeds (Belton 2000). This species occurs in low 
abundance on the beaches of southern Brazil 
lLara-Resende and Leeuwenberg 1087, Vooren 
and Chiaradia 1990, Belton 2000) and Argentina 
iBIanco et al, 2006). Hudsonian Godwits occur 
throughout the year in Lagoa do Peixc with 
highest abundance in November during its 
migration south (up to 1.300 individuals) and in 
March prior to migration north (Lara-Resende and 
Leeuwenberg 1987). Up to 3.000 individuals have 
been recorded at the site (Harrington et al. 1986. 
Morrison and Ross 1989). This species is highly 
sensitive to disturbed environments (Parker et al. 
19 %) and is rarely seen on beaches with people 
and vehicles. The Semipalmated Sandpiper occurs 
with low frequency and abundance in southern 
Brazil (Lara-Resende and Leeuwenberg 1987, 
Vooren and Chiaradia 1990. Costa and Sander 
- (|| )8), but is frequent and abundant on beaches of 
northern and northeastern Brazil, where it winters 
Morrison and Ross 1989, Azevedo-Junior et al. 
20Ulb, Telino-Junior et al. 2003, Barbieri 2007). 
The Buff-breasted Sandpiper is considered 
endangered (BirdLife International 201 i) and 
0CCUrs in wet grassland areas and grazed 
pasturelands near lagoons (Lara-Resende and 
Leeuwenberg 1987. Lanctol et al. 2002). This 
s pecies generally migrates through the interior 
the continent, using the central Amazon/ 
Pantanal wetland route, where it follows large 
rivers and wetlands until reaching Paraguay and 
Argentina (Antas 1984). This explains the low 
frequency and abundance on the beaches 
between Balneario Pinhal and Mosturdas. where 
11 recorded on only two occasions (Nov 
2007 and Oct 2008). 
The resident Southern Lapwing, which is 
Cn demic to South America, was among the species 
*rith regular frequency of occurrence and was 
observed on all counts. This species is common in 
grassland areas of Rio Grande do Sul. where it 
breeds, and Belton (2000) considered its occur¬ 
rence on the shore as rare. It is observed with 
greater frequency foraging on the beach near 
sandbars with drainage of waters from lakes 
between April and July: lower numbers are 
observed between October and December when 
this species is in its breeding season (Belton 2000). 
The American Golden Plover had a lesser 
frequency of occurrence and lower abundance 
than the Grey Plover with greatest abundance 
occurring between November and March, as 
previously reported for wintering areas in south¬ 
ern Brazil (Lara-Resende and Leeuwenberg 1987, 
Vooren and Chiaradia 1990). This species is 
found mostly on beaches within the proximity of 
Lagoa do Peixe (Morrison and Ross 1989) where 
they encounter habitat with less direct influence 
from humans and vehicles along the beach. The 
Grey Plover had low frequency and abundance 
along the beach throughout the year (Lara- 
Resende and Leeuwenberg 1987, Vooren and 
Chiaradia 1990). 
The frequency of the Semipalmated Plover was 
uneven with greater abundance in February and 
March 2008, and April and May 2009. However, 
this species has been observed in low abundance 
in southern Brazil (Lara-Resende and Leeuwen¬ 
berg 1987, Vooren and Chiaradia 1990). It is more 
abundant on beaches of northeastern Brazil, where 
most of the population winters (Rodrigues 2000, 
Telino-Junior et al. 2003, Barbieri 2007. Barbieri 
and Hvenegaard 2008). The resident Collared 
Plover, which breeds among the dunes along the 
Brazilian coast, occurs throughout the year. Little 
is known about this species. Its greatest abun¬ 
dance on the beaches between Balneario Pinhal 
and Mostardas was between March and August. 
This was during the breeding season, which 
extends from November to January, when the 
species is frequently found foraging near dunes 
where it breeds, as well as throughout (he non¬ 
breeding season in the austral winter (Lara- 
Resende and Leeuwenberg 1987, Belton 2000). 
Juveniles were observed foraging in (he wash 
zone and drainage sandbars of lakes in every 
month of the year, but with a considerable 
increase beginning in March and greater abun¬ 
dance in the subsequent months. 
Whimbrel occurred in low frequency and 
abundance. This species needs conserved envi¬ 
ronments due to high sensitivity to environmental 
disturbances (Parker et al. 1996), The largest 
flocks occur in the northern and northeastern 
regions of Brazil , and northern portion of South 
