Blue Duiker

Philantomba monticola

General Description

Scientific Name: Philantomba monticola

Subspecies: 12 subspecies

Northern Subspecies:

P. m. aequatorialis: Nile Blue Duiker
P. m. congicus: Congo Blue Duiker
P. m. lugens: Tanzanian Blue Duiker
P. m. melanorheus: Guinea Blue Duiker
P. m. musculoides: Ugandan Blue Duiker
P. m. sundevalli: Coastal Blue Duiker

Southern Subspecies

P. m. anchietae: Angolan Blue Duiker
P. m. bicolor: Limpopo Blue Duiker
P. m. defriesi: Muchinga Blue Duiker
P. m. hecki: Luangwa Blue Duiker
P. m. monticola: Cape Blue Duiker
P. m. simpsoni: Kasai Blue Duiker

Status: Least Concern (decreasing)

Total Population: around 7,000,000

Population in Surveyed Areas: 0

Description: Though females are usually slightly larger than males, both usually weigh between 3.5-9 kg each and 32–41 cm at the shoulder, making them the smallest of the duiker species, and the second smallest antelope species (after the Royal Antelope). Their horns are also very small, usually only up to 5-7.6cm long.

Despite their name, there is a great range of variation of coat colour, depending on the subspecies. The grey-legged northern subspecies show a grey to brown coloration, with a posterior stripe that marks a transition from the rump to the buttocks. P. m. congicus has a bright grey to black back, with dull grey flanks; a dark brown stripe marks the shift from the black rump to the lighter buttocks. P. m. sundevalli is similar, though the difference between the flanks and the rump is less notable. P. m. aequatorialis is paler and browner than P. m. congicus with a less sharp transition. The stripe is fainter and the back darker in P. m. musculoides. P. m. lugens can be told apart from its darker coloration; the flanks and the dorsal parts are dark grey to brown, the underside grey and a black rump. The diminutive P. m. melanorheus stands apart as well, with black dorsal parts, pinkish grey sides, and long thick fur.

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Ecology: Blue duiker are exclusively browsers and highly selective concentrate feeders of fresh fruit, berries, flowers, broad-leafed forbs and fresh leaf litter on the forest floor. In western Africa the diet has been recorded to comprise 92% of fruit. Dried and old vegetative matter is totally avoided. A high nutrient content food supply is critical essential for duikers to grow, making them vulnerable to changes in forest structure. Blue duiker live in close correlation to the presence of fruit eating birds and primates especially yellow-billed pigeons, parrots and the Somango and vervet monkey. The birds and monkeys provide lots of fresh fruit and leaf litter from the tree canopy above. Because of their tendency to eat large amounts of fruit, they're very important disperser of seeds in the forests they

Duiker are strictly territorial. A ram and ewe form a mating pair and establish together a permanent territory which they mark and defend together. Marking is by means of excretions from preorbital glands that are smeared onto twigs and vegetation, and from inter-digital glands between the hoofs that are left on the footpaths. Territories are small, 0,4-0,8ha, and incorporate the major of the home range. Intruders from neighbouring territories are not tolerated. Neighboring territories does not overlap. Fixed permanent latrines are used

repeatedly.

Blue Duiker are commonly preyed upon by a number of carnivores, such as Leopards, Caracals, Servals, Large Birds of Prey, and Pythons. Other predators may take them opportunistically.

Behavior: Blue duiker are predominantly day-active especially in morning before 09h00 and late afternoon after 16h00. In mid-day they lie down ruminating in the hide in the shade of thicket. When finding a fresh spoor on the forest floor the hunter may take position for a long wait; the chance is good that either the same animal or its mate might appear in due time. A second person may be send around in a circle 30-50 m often flashing the animal. When pursued on foot a blue duiker dashes from thicket to thicket, seldom revealing itself in any open. Snorts and a high pitched “miaau” can be heard when a blue duiker becomes excited.

Diet: Herbivore - Browse, Grasses & Fruits

Male Size: 4 Kgs

Female Size: 4.7 Kgs

Trophy Size: 4.45 cm

Generation Length: 4.5 years

Reproductive Season: Year Round

Time of Activity: Diurnal

Reproduction: Blue duiker keep mostly in pairs or as an adult ewe and her youngster. Partners are highly attached and stick together for many years, mostly until one dies, before taking another mate. During daily roaming the mates keep in close vicinity of a few meters and when resting lay up beside each other. Bodily contact between mates are frequent. Solitary animals are mostly sub-adults that has left their parents in search for a mate of their own. Mating occur all year round and lambs are thus born at any time of the year. A single lamb of 350-400 gram is born every 9 months, after a gestation of 7 months. The lamb is hidden for 10-14 days and weans after 3-4 months. Shortly before the birth of the next lamb the previous lamb is driven away by the mother to seek its own path. The lamb then becomes a solitary nomad until it reaches social maturity at around 13 months.

Conservation Analysis

Map of Blue Duiker Range

Current & Historic range: The blue duiker is restricted to the abundance of suitable habitat. Its distribution is patchy between the tropical rain forests of central and western Africa, and in Nigeria, Sudan, Uganda, Kenya, Tanzania, Zaïre, Congo, Gabon, Angola and the central areas of Mozambique. In South Africa it is restricted to a narrow stretch coastal thicket and mountain forest from along the south-eastern shore from the Umfolozi River mouth in KwaZulu-Natal to the George region.

Though much of the historic range and habitat of the Blue Duiker has been fragmented by human development, they have expanded into mosaics of suitable habitat outside of their regular range. This is usually agricultural plantations where fruits, nuts, and leaf cover are abundant.

Current & Historic Populations:. the historic population number of blue duiker is largely unknown, though it is likely to be significantly large than current numbers. Due to the degree of habitat fragmentation, increased poaching rates, and predation by free ranging feral dogs, many populations are at low numbers, or fragmented across pockets of suitable habitat. That being said, they are still abundant in the majority of their range, and inside protected areas, they populations are stable or increasing.

Blue duiker show considerable tolerance for high hunting pressure, with Duiker meat making up a considerable portion of the African bushmeat trade. Their relatively fast reproductive rate, as well as their small territory size and tendency to hide in thick vegetation likely contributes to this. Current population estimates by the IUCN place Blue Duiker populations at around 7 million across sub-Saharan Africa, though this is likely an underestimate. Due to the reclusive nature of this species, it can be difficult to accurately monitor populations over large areas. Non-traditional population monitoring techniques, such as Camera Trapping or Spoor counts could achieve better results.

Threats to Species Survival: the greatest threats to the long term survival of wild blue duiker, especially in their more restricted range in Southern Africa, is habitat fragmentation, and poaching. Due to the tendency of duikers to inhabit areas with high annual rainfall and fertile soils, much of the habitat fragmentation stems from the spread of agriculture, especially plantations and crop fields, as well as development for human settlements. Some of these plantations can provide ample habitat for duiker, but they also expose them to increased rates of poaching (due to easier access for hunters and their dogs). Features of human development, particularly roads, also split duiker habitat into smaller areas, and often lead to increased mortality due to car accidents.

The bushmeat trade in Eastern and Central Africa has over the last 50 years, expanded greatly, and is completely unregulated. So even though Blue Duikers have a fest reproductive rate, the rate of harvest often greatly exceeds the population growth rate, leading to the decimation of populations close to human settlements. Protection and regulation of the harvest of blue duikers needs in these areas to be implemented to ensure long term species survival.

Inside of protected areas, such as national parks or game reserves, blue duiker populations are flourishing. Particularly in South Africa, their importance as a game animal means landowners protect populations from excessive hunting, and sometimes may even enhance the habitat to make it more conducive to forest dwelling duikers. These protected areas are very important for the specie's survival over the long term.

Recommended Conservation Actions:

Increased protection from development and poaching in populations close to human settlements, as well as further economic incentives to not overharvest a particular species.
Greatly increased regulation in the Bush Meat industry, including a ban on the sale of blue duiker meat in many parts of their range. This should be done whilst allowing for local subsistence harvests, and regulated tourism hunting.
Increase surveying capabilities of most of it's populations, especially outside of protected areas, where much about the statusof this species is unknown.

Economic & Cultural Analysis

Ecotourism Value: Moderate

Hunting Value: High

Meat Value: High

Average Trophy Value: $1,830 USD

Meat Yield per Animal: 1.9-4 kg

Economic Value/Impacts: by some estimates, blue duiker are one of the most valuable wild ungulate species in all of Africa, largely due to their prevalence in the bush meat trade, large population, and extensive range. Their small size makes it relatively accessible to most people to hunt, with hunters pursuing the species with guns, bows, dogs, snares, and other traps. Though many of these practices are highly unsustainable, it should be noted just how important this species is to the people of Central and Eastern Africa, from a consumption perspective.

Blue Duiker are also considerably valuable to the Trophy Hunting industry, being one of the most sought after, and one of the hardest to hunt, of the Tiny 10 antelope species of Southern Africa. Many hunters dedicate 2-4 days for a Blue Duiker hunt, waiting in a blind for extended periods of time for a mature male to present themselves.

Cultural Value: Blue duiker have likely been hunted by humans and our ancestors for millions of years, due to their small size, lack of defenses, and palatability. Their meat is said to be similar in taste to other antelope species, being very low in fat compared to domestic meats.