Walia Special Edition on the Bale Mountains (2011) - Zoologische ...

Table 3. Estimates of population density and abundance using DISTANCE.
Parameters Dec 06 –Jan 07 Aug 07
A=area occupied by Bale Monkey 108 km 2 149 km 2
L=total length sampled 89.6 km 79 km
Density (ind/km 2 ) 8.18 9.64 (SE=8.8)
Abundance 883 1437 (SE=1315)
Mean cluster size 11.4 (SE =2.26)
Mean cluster density 0.84 (SE =0.75)
Habitat and feeding preferences
Monkeys were observed between 2200 m and 3400 m, in bamboo and bamboo mixed forest. Within
these two habitats, there was no correlation between the number of animals found per group and
altitude (Spearman Rank Correlation). No animals were observed in the non-bamboo forest in the
dry season. Overall, 77% of the monkeys recorded were observed feeding on bamboo leaves, 9.1%
perching on Schefflera, 7.6% foraging on the ground, 6.1% perching on Hagenia and Dombeya
trees.
Although monkeys were most frequently observed feeding on young bamboo leaves,
additionally they were seen to forage on other parts of the bamboo, such as shoots, rhizomes, roots
and immature stem of the cane. According to local informants, Bale monkeys prefer to feed on the
regenerating roots and shoots over the leaves. Stems of immature bamboo that are fed on by the
monkeys seemed to either dry up or experience stunt and malformed growth. In fact, encountering
this type of bamboo was useful as a sign of the presence of the species. Monkeys were seen feeding
on other plant species, and local informants also listed several species that were commonly used as
food by the monkey (Table 4).
Table 4. Plants consumed by Bale monkey in the Harenna Forest, with note of part eaten and source
of information. Monkeys were also observed eating insects.
Species Parts eaten
Source of
information
Allophyllus abyssinicus fruit Local people
Anano (Vernacular name) stem Local people
Arundinaria alpine leaf, rhizome Direct observation
Galiniera coffeoides fruit Local people
Harira (Vernacular name ) stem Local people
Kalala (Vernacular name ) stem Local people
Polycias fulva fruit Local people
Rapanea melanocephalus fruit Local people
Rubus steudnerii fruit Local people
Schefflera abyssinica fruit Direct observation
Shefflera volkensi fruit, leaf Direct observation
Syzygium guineense fruit Local people
<strong>Walia</strong>-<strong>Special</strong> <strong>Edition</strong> on the Bale Mountains 85