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

overall diet (36% of total prey occurrences) and was present in 69% of all faecal samples, whereas
diurnal rats Arvicanthis blicki, Lophuromys melanonyx and Otomys typus (respective mean weight
126 g, 94 g and 100 g) together accounted for 59% of occurrences and appeared in 78% of the
samples. These four species together accounted for 86% of prey occurrences and no significant
differences were found for these main four prey items between months or between dry and wet
seasons (Sillero-Zubiri and Gottelli 1995a).
Direct observations indicated a higher incidence of large prey (hare, rock hyrax Procavia
capensis capillosa, birds, lambs, and antelopes) than suggested by scat analysis. Of all feeding
instances observed, 69% were grass rats while giant molerat kills accounted for 22% of all successful
attempts. Giant molerats formed the bulk of the prey by weight (40%), while diurnal rats were second
(23%), although taken more often. Carrion, hares, hyraxes, and birds contributed the remaining
36.5% of the total prey weight, of which 12% was scavenged from livestock carcasses.
The diet was broadly similar at the three sites (Web Valley, Sanetti and Tullu Deemtu), with
giant molerat as the single most important food item. In areas where this species is absent or rare it is
often replaced by the common molerat Tachyoryctes splendens. For instance in the Bale Mountain’s
Gaysay Valley, common molerats constituted 32 % of all animals eaten (Malcolm 1997), and in
Menz, central Ethiopia, 31% of occurrences - 17% by volume - in the wolf diet (Ashenafi 2001).
Analysis of faeces from wolf populations across the Ethiopian highlands confirmed this dietary
specialization, amply dominated by diurnal rodents even where molerats were absent or rare and
livestock abundant (Marino et al. 2010).
Foraging behaviour
During 946 hours of focal observation away from dens, wolves spent 43% of their time foraging
(Sillero-Zubiri and Gottelli 1995a). They foraged solitarily throughout the day, travelling widely at a
walk or trot, covering large areas of their home range. Peaks of foraging activity were synchronised
with the activity of diurnal rodents above the ground. The wolves used various hunting strategies:
molerats were commonly stalked, while zigzag and hole-checks were aimed at grass rats. Although
foraging wolves were mostly observed alone, their daily hunting ranges overlapped considerably.
Of 35 occasions in which more than one wolf was present during kills involving rats, only 23%
were within 10 m. In the remaining observations, wolves shared the same foraging area, but did not
appear to interfere with each others’ foraging attempts or prey captures. Occasionally small packs
hunted hares, antelope calves, and sheep. In 12 of 20 attempts to catch hares, two to four wolves
hunted simultaneously. In the northern grasslands wolves have been observed in packs of three to
four animals hunting reedbuck Redunca redunca (n = 3) and a mountain nyala calf Tragelaphus
buxtoni (Sillero-Zubiri pers. obs.).
Rodents and Ethiopian wolf distribution
The role of the Afroalpine rodent community in limiting the distribution of Ethiopian wolves was
studied by looking at the relationship between wolf abundance and the species composition, relative
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