Philantomba monticola (Thunberg, 1789)

Don E. Wilson & Russell A. Mittermeier, 2011, Bovidae, Handbook of the Mammals of the World – Volume 2 Hoofed Mammals, Barcelona: Lynx Edicions, pp. 444-779 : 716

240.

Cape Blue Duiker

Philantomba monticola

French: Céphalophe bleu / German: Kap-Blauducker / Spanish: Duiker azul de El Cabo

Taxonomy. Capra monticola Thunberg, 1789 ,

Cape Colony.

P. monticola was formerly a parent taxon that included all blue duikers (all members of the genus Philantomba east of the Cross River, Nigeria) as subspecies. The present taxonomy has divided this group into ten distinct species, and the Cape Blue Duikeris now restricted to the southern coast of South Africa. Monotypic.

Distribution. S South Africa (from the city of George, Western Cape, E through Eastern Cape).

Descriptive notes. Few body measurements specific to the Cape Blue Duiker (as defined here) are available, but head-body c. 60 cm, tail ¢. 8 cm; weight c¢.4-5 kg. Skull size 1s similar to the Zimbabwe Blue Duiker ( P. bicolor ), and body size likely follows. In color, the Cape Blue Duiker is rather paler than the Zimbabwe Blue Duiker; the overall color is a pale gray or fawn. The rump is not particularly dark, and the haunches have only a slight reddish tinge; there is very little difference in color between these two areas (cf. the Zimbabwe Blue Duiker). The underparts are whitish. All four legs are bright rufous in color. The tail is only slightly darker than the dorsum. The face is colored similarly to the body; although the cheeks and underside of the jaw are paler. Simple, spiked horns may be present in both sexes; they are longer than in the Zimbabwe Blue Duiker, averaging 4-7 cm in males. Dental formula is 10/3, C0/1, P 3/3, M 3/3 (x2) = 32.

Habitat. Evergreen forests and scrub, a habitat type now limited to fragmented forest patches along the southern Cape. The dominanttree species in areas inhabited by the Cape Blue Duiker in coastal South Africa is Trichocladus crinitus. Most foraging occurs in open forest glades, where vegetative ground coveris typically less than 10%. Denser cover is important for refuge, especially from aerial predators such as the crowned hawk-eagle (Stephanoaetus coronatus ). Population densities are 14-28 ind/km?; this is significantly lower than the adjacent population of the Zimbabwe Blue Duiker in Kwa-Zulu-Natal, a discrepancy attributed to lower habitat quality (rather than to predation or competition).

Food and Feeding. Folivorous, opportunistically frugivorous. Although most forest duikers rely on fruit, this is a highly variable and often limited food resource in South Africa. Fallen leaves and fruit are consumed from the ground. The Cape Blue Duiker is highly selective and appears to use scent in order to select the highest quality foods available. Stomach contents from a single individual indicate a strong preference for the leaves from Canthium obovatum; leaves from Canthium mundianum, Cassine papillosa, Apodytes dimidiata, Olea capensis macrocarpa, and Olinia ventosa were also present in small (but not trace) quantities. Fruit from C. mundianum, seed pods from Dietes iridioides, and traces of fungi were also identified.

Breeding. There is no specific information available for this species from the wild. Reproduction in captivity in South Africa occurs year-round, with a distinct peak in births from September to November (over 50% of 49 recorded births). Other aspects of reproduction are likely similar to those of the Zimbabwe Blue Duiker.

Activity patterns. Active throughout the day: transect counts show no significant difference in activity between morning, midday, and afternoon. No data are available on night-time activity.

Movements, Home range and Social organization. Most field observations are of solitary individuals (73%), although pairs and groups of up to five individuals are sometimes seen. Sightings of groups are most frequent between October and February; these are most likely juveniles accompanying a parent. The Cape Blue Duiker uses regular pathways within forested habitats, including “game trails” created and used by larger species. The alarm call is a shrill whistle.

Status and Conservation. CITES Appendix II. Classified as Least Concern on The [UCN Red List (combined with the other nine blue duiker species within the P. monticola complex). Habitat destruction has dramatically affected the Cape Blue Duiker, and the fragmented nature of the remaining forest pockets may lead to issues with long-term population viability. Viable populationsstill exist in several protected areas. Low populations have in the past been attributed to a rise in Caracal (Caracal caracal) numbers, although it now appears that habitat quality plays a significant role in determining population size.

Bibliography. Crawford (1984), Grubb & Groves (2001), Hanekom (2001), Hanekom & Wilson (1991), IUCN/ SSC Antelope Specialist Group (2008as), Vernon (2001), Von Ketelhodt (1973).

Figures

233. Western Blue Duiker (Philantomba congica), 234. Bioko Blue Duiker (Philantomba melanorhea), 235. Eastern Blue Duiker (Philantomba aequatorialis), 236. Mountain Blue Duiker (Philantomba lugens), 237. Simpson’s Blue Duiker (Philantomba simpsoni), 238. Malawi Blue Duiker (Philantomba hecki), 239. Zimbabwe Blue Duiker (Philantomba bicolor), 240. Cape Blue Duiker (Philantomba monticola), 241. Angolan Blue Duiker (Philantomba anchietae), 242. Zambian Blue Duiker (Philantomba defries)

Distribution. S South Africa (from the city of George, Western Cape, E through Eastern Cape).