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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123. No. 2. June 2011 
the town of Oventeni, where syntopic with 
Yellow-browed Sparrow (A. aurifrons). one of 
the most common birds in this area. We obtained 
photographs and audio recordings of several 
individuals. Birds sang regularly early and late 
in the day, at which time they could at times be 
observed at length as they perched in an exposed 
location. Widespread in grasslands in more open 
parts of South America, the nearest known 
populations of Grassland Sparrow to the Gran 
Pajonal are at Pampas del Heath and in cleared 
lands around Puerto Maldonado, 600 km south¬ 
east (Graham et al. 1980; B. P. Walker, unpubl. 
data). Our records constitute the first for Ucayali 
and Ihc first from isolated patches of savanna in 
the eastern Andes. 
Plumbeous Seedeater (Sporophila plumbed ).— 
This species was uncommon in short graminac¬ 
eous savanna at Monte Tabor and fairly common 
in pasture and recently burned savanna at 
Oventeni. We obtained two male specimens as 
well as photographs and audio recordings. The 
birds were generally observed in small groups 
containing both male and female-plumage individ¬ 
uals, but occasionally alone or in flocks of up to 10 
individuals. 1 hey olten associated in Oventeni with 
large groups of primarily Blue-black Grassquil 
(Volatinia jucarina ) in grassy or recently burned 
areas. Plumbeous Seedeater has a similar global 
distribution to Grassland Sparrow, and in Peru is 
know n only from the Pampas del Heath (Graham et 
al. 1980). This species may be a non-breeding 
visitor to the Gran Pajonal from breeding areas 
further south; neither male collected was in 
breeding condition (testes < 1 X I mm). 
Black-billed Seed Finch (Oryzoborus atriros- 
tris ).—A male singing from a marsh of tall reeds 
bordering dry savanna in Oventeni throughout the 
day on 19 September 2008 was photographed and 
recorded. We did not detect this bird despite 
coverage of this area prior to 19 September, but its 
near-continuous song and strong response to audio 
playback appeared to be territorial behavior. It is 
possible this bird’s arrival was related to the 
appearance of large roosting aggregations of 
Black-and-w'hite and Yellow-bellied (Sporophila 
nigricollis) seedcaters in this marsh beginning 
about 17 September. Rare and patchily distributed 
in eastern Peru, most records of Black-billed 
Seed-Finch come from near the base of the Andes. 
The only previous record from Ucayali was along 
the Abujao River well to the east (LSUMNS 
specimens). 
DISCUSSION 
Biogeography .—In addition to the 462 bird 
species we recorded, 57 species are known from 
above 900 m only in the northern Cerros del Sira 
(J. S. Weske and J. W. Terborgh, unpubl. data: 
Mee et al. 2002), bringing the regional species 
total to 519. These totals are preliminary and there 
are few equivalent surveys for comparison, but it 
is clear the Gran Pajonal and southern Cermsdel 
Sira support high levels of avian diversity. 
The majority of the birds we found in the 
pajonales are widespread in disturbed areas 
anthropogenic or otherwise, in lowland Amazonia 
or the lower slopes of the Andes. Other species are 
restricted to regions with better-developed neo¬ 
tropical savannas (e.g., the Venezuelan llanos or 
Bolivian pampas) but occur patchily in isolated 
dry valleys of the eastern Andes (Chapman 1921, 
Robbins et al. 1999, Aleixo and Poletto 2002). 
This list includes Tataupa Tinamou (Crypiurellus 
tataupa ), Russet-crowned Crake. Spot-tailed 
Nightjar. Cinereous-breasted Spinetail. Rust) 
backed Antwren. Yellow-bellied Eiaenia (Elaenia 
flavogaster). Black-faced Tanager (Sclihtoclilti- 
mys melanopis), and Wedge-tailed Grass Finch. 
Plumbeous Seedeater and Grassland Sparrow are 
unique as they are widespread in neotropical 
savannas elsewhere, but were not previously 
known from isolated savannas in the eastern 
Andes (Graham et al. 1980). It is not obvious 
whether the above species have maintained 
relictual populations in this region or whether 
colonization has occurred more recently. Resolv¬ 
ing this question may provide insight into origins 
of the pajonales. 
The majority of the avifauna of humid montane 
habitats represents a subset of that found in these 
habitats on the eastern slopes of the Andes that are 
closest to the Cerros del Sira in the departments of 
Jum'n. Pasco, and Huanuco (SchuJenberg et al 
1984; pers. obs.). Some species detected, howe'¬ 
er, occur on multiple isolated Andean ridges, bin 
not on the principal cordillera of the Andes. 01 
these. Subtropical Pygmy Owl (Glaucidim P« r 
keri). Koepcke’s Hermit (Phaeilwmis koepekeae). 
Rufous-webbed Brilliant ( Heliodo.xa brunickii). 
Rough-legged Tyrannulet ( Phyllotnyias bunnels- 
teri). Sooty-headed/Yungas Tyrannulet, Buff- 
throated Tody-Tyrant ( Hemitriccus rufigtdarb). 
Brazilian Laniisoma ( Laniisoma elegans). Sharp- 
hill. and Gray-tailed Piha (Snowomis subalaris) 
were recorded. Two other species of isolated 
