On Aug. 3, 2001, Ogawa and Kanamori left Mpanda, passed Katuma village, turned left at Kapanga (6°19'S, 30°37'E) out of Mpanda-Mwese road, and visited Kasunga village (6°21'S, 30°29'E). We walked a total of 30.8km (rounded-trip) at Mgange Hill (6°23' S, 30°32'E) (1,753km) and Kalole Hill (6°22'S, 30°30'E) on Aug. 4 and 5.

"Makomayo" as used here refers to the region near a series of peaks (Makoma, Sitebi Makomayo, Mwelu and Kalumangile) located about 25km NNE of Katuma village. All exceed 1,950m elevation (above the tree line) (Fig.1). The slope northward is gentle, but the mountains fall steeply in other directions where they are deeply cut by valleys containing permanent water and riverine forest; ridges are covered with short grasses, herbs, some Protea and at exposed locations, bare rocky earth. This network of highaltitude riverine forest is spread over an area of roughly 100km². Below tree line, the surrounding forest is miombo woodland broadly similar to that of Wansisi, with large stands of Uapaca in places. Moore and Kamenya camped at the Lufilisi River about 12km north of Sitebi Makomayo Hill from July 23-26, searching for chimpanzees near 6°07'S, 30°39'E and 5°58'S, 30°42'E.

Results
1. Wansisi:
We did not encounter chimpanzees, but found 78 beds and 17 feces of chimpanzees on the slopes and the ridges in the woodland of Mgange and Kalole Hills. We found few traces of chimpanzees in the bamboo thickets and the woodland in the plains.

Feces of chimpanzees contained seeds of Ficus sp., Grewia mollis, Azanza garkeana, Pterocarpus tinctorius, and Pseudospondias microcarpa, leaves of Monocotyledoneae, and fragments of adult ants (Formicidae). We also found 3 wadges of bamboo shoots.

Bed groups, in which nests of the same age were located in the same place, averaged 5.2 beds (range: 2-9, n=15). Fresh nest leaves indicated that two recent sleeping parties were composed of 5 and 8 individuals. Although there were few evergreen forests on the hills, some deciduous trees had leaves in this period. Chimpanzees made beds on such deciduous trees of Brachystegia bussei, B. boehmii, Julbernardia paniculata, and Isoberlinia angolensis. We saw claw-marks of a carnivore like a leopard (Panthera pardus) on the trunk of a nest tree, and diarrhea feces of the chimpanzee were under that bed.

The population density was roughly estimated at 0.06 individuals/km² based on 20 beds within 70m of each side of our 19.2km walking route on the hills, assuming a bed disappears in 180 days and 70% of beds in the range are found (after Kano¹). This indicates that about 30 chimpanzees inhabit the 500km² area.

During the survey, we heard vocalizations of yellow baboons (Papio cynocephalus) and a bushbuck (Tragelaphus scriptus), and saw traces from elephant (Loxodonta africana), zebra (Equus burchellii), and bushpig (Potamochoerus porcus).

2. Makomayo:
No evidence of chimpanzees was encountered. Although there were a few farms visible in the valley bottoms, they were not easily reachable and no local interviews were conducted. The topography was excellent for hearing sounds, and the combination of no bed sightings or chimpanzee vocalizations is a strong indication that none were present in the high part of the hills at least. Although there were large areas of evergreen forest, there were few fruit and no flowering Saba was visible from lookout points above the valleys.

A number of other primates were encountered. Most notably, there were red colobus (Colobus badius) even in a small (c. 1km²) evergreen pocket at about 1,900m (to reach other forest would require crossing at least 500m of short grass and exposed rocky soil). This group had at least 2 adult males; and over 25 individuals were observed, none with ventral infants. Yellow baboons and blue monkeys (Cercopithecus mitis) were seen and heard daily. No galagos (Galago spp.) called at night, and one glimpsed monkey at lower altitude may have been a redtail (Cercopithecus ascanius). There were indirect signs of elephant (possibly years old), zebra, bushpig, hyena (Crocuta crocuta), leopard, and civet (Viverra civetta), and several duiker (unidentified) were glimpsed.


Discussion
In the 1960's, Kano¹ estimated that 40-80 chimpanzees over 3-4 years of age in 1 or 2 unit group(s) inhabited the 500km² of the Wansisi area. Our survey showed that chimpanzees still inhabit the northwestern part of this area. Local Bende people said that chimpanzees are also present in the eastern part. However, the population density in this area was low: 0.12 individuals/km² estimated by Kano¹ and 0.06 in this study. In addition, the chimpanzee population in the Wansisi area seems isolated from other populations¹ in Mahale National Park, Kakungu, Karobwa, and Ntakata². These findings indicate that a limited number of chimpanzees inhabit the isolated Wansisi area. We heard that poachers killed at least one chimpanzee in this area in June 2003. The population of chimpanzees in the Wansisi area may face extinction by poaching and commercial logging. Kano did not visit the Makomayo area because the nearest villagers stated there were no chimpanzees there, and this visit was entirely consistent with that report. This is mildly surprising, given the surrounding miombo and extensive evergreen forest. The most likely explanation is that the composition of these high altitude forests is deficient in chimpanzee food plants (or, that it is simply too cold -- morning temperatures were around 10°C).


Acknowledgements
Ogawa and Kanamori thank T. Kano, G. Idani, H. Y. Kayumbo, J. Itani, T. Nishida, T. Nemoto, E. T. Massawe, and their local assistants for guidance. This study was permitted by COSTECH and TAWIRI and financially supported by a Grand-in-Aid for Scientific Research of MEXT (#09041160). Moore and Kamenya thank Emmanuel Mtiti, Frank Mbago, Yahya Abeid and Steve Smith, and gratefully acknowledge the logistical assistance of Charles Stafford and Anglo American Mining, as well as permission from COSTECH. Their survey was supported by National Geographic Television; thanks to David Hamlin and the crew.


References

1. Kano T 1972. Distribution and adaptation of the chimpanzee on the eastern shore of lake Tanganyika. Kyoto University African Studies 7:37-129
2. Zamma K, Inoue E, Mwami M, Haluna B, Athumani S, Huseni S 2004. On the chimpanzees of Kakungu, Karobwa and Ntakata. Pan Africa News 11: 8-10.