Harvey et al. • AVIFAUNA OF THE GRAN PAJONAL AND SIRA 
291 
TABLE 1. Sampling effort in 2008 at 
Habitat codes are in the Appendix. 
primary study sites in the Gran Pajonal and southern Cerros del Sira, Peru. 
Habitats surveyed 
Dates surveyed 
Observer-hrs 
Nel-hrs 
Species detected 
Monte Tabor 
SpJFuF, 
6-11 Sep 
303 
92 
186 
Oventeni 
S P ,F„F|,M 
4-6, 12-15, 17-19 Sep 
307 
12 
193 
Menkoremon 
P,F e 
2, 4-6 Oct 
194 
0 
42 
Upper Shaani Valley 
Fro 
23 Sep-1 Oct, 3, 8-9 Oct 
474 
290 
107 
Upper Shinipo Valley 
F, 
1-6 Nov 
282 
83 
149 
and precipitation higher due to the deposition of 
rain by warm, moist winds from the east. At least 
short periods of heavy rainfall occurred on a 
nearly daily basis during our study, and prolonged 
downpours were common. Atalaya, at the eastern 
foot of the southern Sira, averages 2,950 mm of 
precipitation annually. 
Geology and Soils .—Soils in the region are 
largely derived from residual material from 
upland formations with some alluvial deposits. 
Most pajonales overlay calcareous shale bedrock 
with soils comprised of poorly draining red 
latosols or yellow podzolics (Scott 1978). The 
montane forests of the Sira ridge occur chiefly on 
lithosols derived from red Permian sandstones 
iChrostowski and Denevan 1970, Scott 1978), 
which are relatively poor in nutrients and support 
a ’h* 11 organic cap at higher elevations (ONERN 
1968). Patches of fine, white substrates of 
unknown composition occur sporadically in 
humid forest in the highlands (pers. obs.). Rain 
water in these locations often collects at the 
surface, suggesting low internal drainage. 
Vegetation —The Gran Pajonal plateau (800— 
'•300 m) is covered in humid evergreen forest 
interrupted by pajonales ; these are generally 
waller (<100 ha) and total 9.000-10,000 ha 
region-wide. 3% of the total area of the Gran 
Pajonal (Hvalkof 2006). The historical and 
n°ristic relationships between the pajonales of 
ihc Gran Pajonal and other neotropical savannas 
•md seasonally dry forest remain unclear (Linares- 
Pulomino 2006). Climatic and edaphic factors 
wny have contributed to their origins, but the 
Pajonales have been deliberately maintained 
through fire management by the indigenous 
Ashdninka population for centuries (Chrostowski 
and Denevan 1970; Scott 1977. 1978; Hvalkof 
'998. 2006). Several failed national cattle-raising 
efforts in the Gran Pajonal since the 18th century 
have augmented the extent of open areas and, in 
^ent years, settlers have increased deforestation 
for pastoral and agricultural uses (Hvalkof 2006). 
Forest is much more widespread regionally, but its 
characterization is complicated by the slow 
transition between tropical lowland evergreen 
forest in the valleys and montane evergreen forest 
on the ridges of the Cerros del Sira. The crests of 
the highest ridges of the Sira support elfin forest, 
semi-humid/humid montane scrub, and a habitat 
resembling paramo grassland, Additional impor¬ 
tant avian habitats scattered throughout the region 
include Chusquea bamboo, small marshes, and 
rivers and streams. Our habitat descriptions 
generally follow Stotz et al. (1996); however we 
follow Grubb (1974) in distinguishing between 
lower montane evergreen forest, which is domi¬ 
nated by trees with mesophyll leaf types and 
vascular epiphytes, and upper montane forest with 
more microphyllous trees and bryophytic epi¬ 
phytes. We also erect a separate category for the 
pajonales , although some may be within the 
broader category or semi-humid/humid montane 
scrubs. 
Study Sites .—The authors surveyed the Gran 
Pajonal and southern Cerros del Sira during 
38 days between 4 September and 17 November 
2008. focusing on pajonales and montane ever¬ 
green forest at five sites (Table I). 
Monte Tabor (10° 53' S, 74* II' W) is a 
sandstone cap at 1,350 m at the northern edge of 
Quitchungari Ridge with forested slopes and a 
175 ha pajonal at its crest (Scott 1978). The 
vegetation of the Monte Tabor pajonal is a short, 
windswept community of grasses dominated by 
Tricachne spp.. Aristida spp., and Vemonia spp. 
(Scott 1978) with occasional small islands of trees 
and shrubs, and sparse coverage in areas by 
bracken fern (heridium spp.). The pajonal 
boundary is characterized by an abrupt demarca¬ 
tion with surrounding forest. No agriculture or 
grazing currently occurs on the Monte Tabor 
pajonal. but local Asheninka villagers regularly 
bum it, and it was historically the site of a mission 
