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THE WILSON JOURNAL OF ORNITHOLOGY • Vol 124. No. 4. December 2012 
(Silva 1999). S. ruficollis overwintering in the 
Cerrado region arc, at least in part, from the 
southern and easternmost breeding areas in Entre 
Rios, Santa Fc. Buenos Aires. Paysandu, and/or 
Rio Grande do Sul. However, there is no evidence 
suggesting where birds wintering in Humaita 
breed. The wintering populations of S. ruficollis 
in the cerrado of central Bolivia are completely 
migratory (Davis 1993. Mitchell 1997). and the 
source of these populations remains unknown. 
The main wintering areas identified for S. 
hypochroma are the Cerrado region and central 
Brazil (Silva 1999). Populations from Corrientes 
(to which 1 add Santa F6) that Short (1969) 
attributed to S. hypochroma seem to overwinter in 
the Cerrado of eastern Brazil, but precise evidence 
of the source populations of birds in central Brazil 
is lacking. The western populations of S. hypo- 
chroma have been considered mid-distance north¬ 
ward austral migrants during winter (Mitchell 
1997). At least two populations with distinct vocal 
types are involved within S. hypochroma as 
currently delineated (JIA, unpubl. data). Further 
recordings of S. hypochroma should prove 
rewarding to elucidate both the systematics and 
the migration of this poorly known species. 
The Cerrado region is also considered an 
important wintering area for S. hypoxantha (Silva 
1999). Possible short- and long-distance migrant 
populations of 5. hypoxantha might coexist in the 
Cerrado during winter. This seems to be the case 
in the Trinidad grasslands where presumably 
resident or short-distance migrants from the 
lowland Bolivia regiolect co-occur together with 
long-distance migrants from the Entre Rios 
regiolect. The overall seasonal patterns of S 
ruficollis, S. hypochroma. and S. hypoxantha ii 
Concepcion (Bolivia; Davis 1993) were interpret 
ed as consistent with different migratory move 
ments; "long-distance temperate-tropical migra 
tion, intraregional migration, local wandering o 
several of these categories applied to the saim 
individuals or populations over several years' 
(Joseph 1996:190). My vocal data support the 
long-distance migration hypothesis for .S’ hypo¬ 
xantha in Trinidad, and for .S. hypochroma anc 
5. ruficollis in Vila Bela. Neither my data, no. 
previously published studies (Ridgely and Tudoi 
1989, Davis 1993, Pearce-Higgins 1996. Mitchell 
1997, Silva 1999) support Short’s (1973) claim 
that 5. hypoxantha (including .S', ruficollis and 5. 
palustns) and .S’, hypochroma are non-migratory at 
a wide scale. The general pattern suggests at least 
some populations of these species migrate long 
distances, but some resident local populations 
may remain at or close to their breeding areas in 
wintering flocks. 
The lack of geographic variation in vocalizations 
of S. cintuunomea and S. palustris (Areta 2008) 
suggest that, whereas voices can aid in identifica¬ 
tion of wintering males, they cannot be used to 
identify the origin of individuals of these species. 
The locally-breeding 5. nigronrfa and S. niela/w- 
gaster have little or no geographic variation in 
song-types (Areta 2010; Repcnning et al. 2010; JIA. 
unpubl. data). Geographic variation in vocalizations 
of populations of S. houvreuil and S. pileata could 
provide useful guidance to allocate wintering birds 
to a specific breeding area (Areta 2010; Machado 
and Silveira 2010; JIA. unpubl. data). 
Vocalizations have three advantages that make 
them promising tools to unravel the migration 
patterns of capuchinos. First, they can he detected, 
recorded, and identified from a fairly longdistance, 
partially overcoming the problems associated with 
surveying a large wintering area. Second, they do 
not vary seasonally for sexually mature males. 
Third, they are geographically structured for some 
species (Areta and Repenning 2011, Areta et al. 
2011). In contrast, plumage traits vary seasonally 
and seem lairly uniform over the geographic range 
of the species. Vocalizations may prove to be a 
uselul tool to uncover migration patterns of 
capuchinos. Future migration, biogeographic, eco¬ 
logical. evolutionary, and conservation studies of 
seedeaters will benefit enormously from this source 
of information. 
ACKNOWLEDGMENTS 
I am most grulelul to all who made possible my field" 
work outside Argentina: Sebastian Herzog and Bennett 
Hennessey in Bolivia, L. F. Silveira. Vitor Piacentim. Erika 
Machado. Marcelo Pena Padua. G. N. Maurfcto, C S. 
Fontana, and Marvin Repenning in Brazil, and Joaquin 
A Idaho in L ruguay. Heman Povedano. Leticia Haudemand, 
Violcta Gomez Serrano. Guadalupe Garriz, Joaquin Areia. 
Diego Isaldo, Enrique Carnba, Bemabe Lopez Lamb, Jorge 
Noriega, Roscndo Fragu. Marcio Repenning. Marcelo Pena 
Padua. L. F. Silveira, Vitor Piacentini. Erika Machado, and 
Ingrid Hol/mann are thanked for sharing fieldwork. 
Agradczeo muy especialmente a Luis Pagano por compartir 
el arcnal. la ciudad dc las mujeres de Zitairosa y los 
gavilanes bidbn. y a J. Noriega por su apoyo consume 
durante las csporofilcadas. Comments by K L. Cockle 
greatly improved a previous version of the manuscript. 
Fieldwork in Mato Grosso (Brazil) was possible (hanks to 
funding from the Frangoise Vuilleumier Fund (Neotropical 
Ornithological Society). 
