The Wilson Journal of Ornithology 124(4):688-697, 2012 
WINTER SONGS REVEAL GEOGRAPHIC ORIGIN OF THREE 
MIGRATORY SEEDEATERS (SPOROPHILA SPP.) IN SOUTHERN 
NEOTROPICAL GRASSLANDS 
JUAN IGNACIO ARETA 1 
ABS TRACT.—The winter distribution of neotropical seedeaters (Sporophila spp.) known as capuchinos is pooriv 
known. 1 here are cl.ff.cult.es to understanding their migration patterns: fieldwork is lacking in their wintering areas, their 
eclipse plumages often make it difncul. to identify species, different spcc.es share habitats during winter, and there is little 
or no genetic dtfferent.at.on of several forms. Vocalizations display a geographic signature ,i.c„ diagnostic acoustic 
matures that arc found in a limited area during the breeding period) and can he useful as indicators of a specific geographic 
ongm ot » wmitaing bird I prevent data that: III dcmiinvlialcs Thai iKin-breedinj male Dark-lhroalcd Sealcalcr is 
ruficolhs). Rufnus-rumpad Seedeater (.V. hyiwchroma), and Tawny-he!lied Seedeater IS. h\poxunlha) in iMnlerine areas ran 
be assigned to a particular distant breeding populwion based on vocalisations: (2) evaluate the potential conlribinion of 
m er tuiTo u'V" “f *- *«* "'feato* btovenienls: and (31 use vocal,aanons 10 uflml 
Cerado 1 V n,fic "" ls fmm Hmre «°» regiolecl wen: iKoried in 
r , *•**""• ™ C ' Bwil f the Beni savannas close to Trinidad. Bolivia. 5. 
E«m R oIT. J, r "rf' wm Vila Bcl '' <*» Sann'ssima Trindude. and S. hypoxaMm from 
loZn „ , r , " ,r” T ‘ OSe 10 ’***•«■ Li "“"» hrmli "e «l non-breeding areuv .hrough song-types is 
7.TZfyZI. “**' “" J “ Prom ” tt —" f — "">■ '""distance Vs-*&- 
Stem-gleaner specialists are birds that feet 
upon seeds still borne on the stalks of natura 
grasses. Many of these species engage in short tc 
long-distance seasonal migrations in response t< 
temporal fluctuations in their food supply (Rem- 
sen and Hunn 1979. Silva 1999). One group of 
stem-gleaner specialists is the capuchinos, a 
distinctive subgroup of the genus Sporophila. 
This group is presently composed of 11 species: 
Dark-throated Seedeater (S. ruftcollis ), Rufous- 
rumped Seedeater (S. hypochroma ), Chestnut 
Seedeater ( S. cinnamomea). Marsh Seedeater (.S'. 
palustris), Tawny-bellied Seedeater (S. hypax- 
antha), Black-and-tawny Seedeater [S. nigrorufa ), 
Copper Seedeater (S. houvreuif), Pearly-bellied 
Seedeater (5. pileata ), Ruddy-breasted Seedeater 
(S. minuta). Chestnut-bellied Seedeater (5. casta- 
neiventris ). and Black-bellied Seedeater (S. me- 
lanogaster) (Sick 1997; Lijtmaer el al. 2004- 
Areta 2008. 2010; Machado and Silveira 2011). * 
Capuchinos are conspicuous members of di¬ 
verse neotropical grassland communities during 
the breeding season. Some species are known to 
m.gratefrom then breeding areas in winter, but 
remarkably little is known about their distribution 
migration ecology, and wintering areas (Ridgely 
and Tudor 1989, Chesser 1994). 
. p CICy J TP — CC)NICET ’ Ma,eri y EspafSa, 3105, Diamati 
te, Entre Rios. Argent.na; e-mail: esporofiIa@yahoo.com.ai 
Many species of capuchinos gather in mixed- 
specics (locks during migration to and from 
breeding areas. These seasonal movements were 
outlined by Silva (1999), who proposed that after 
breeding in the grasslands of central Bolivia, 
northern Argentina, Uruguay, eastern Paraguay, 
and southeast Brazil they migrate to their main 
wintering area; the Cerrado region. S. ruftcollis, S. 
hypochroma. and .S’, hypoxantha at the local scale 
were found mostly in spring in Concepcion, 
Bolivia, and were considered transient long¬ 
distance migrants (Davis 1993). Similarly. S. 
ruftcollis was (ound to be a complete migrant, 5. 
hypochroma suggested to be a medium-distance 
migrant, and S. hypoxantha to be a short-distance 
migrant during the winter in the San Joaquin area. 
Bolivia (Mitchell 1997). Wintering records of 5. 
cinnamomea and S. palustris suggest they do not 
venture into central Bolivia and western Mato 
Grosso (Ridgely and Tudor 1989). but gather in 
large (locks with other species including S. 
hypoxantha . S. melanogaster. S. ruftcollis. S. 
bouvreuil. S. castaneiventris, S caentlescens. S. 
nigricollis , and S. alhogularis during mid Sep¬ 
tember in Minas Gerais, Brazil (Sick 1997). S. 
ruftcollis, S. hypochroma. S. cinnamomea. and 5. 
palustris are encountered only in migratory 
passage in eastern Formosa. Argentina to and 
• orn more southern breeding areas in eastern 
Argentina, Uruguay, and southeastern Brazil 
(Ridgely and Tudor 1989. Di Giacomo 2005). 
