Western Kenya, like the coast, hosts a large number of species found nowhere else in Kenya. The rich bird faunas of this region are mainly associated with the Lake Victoria Basin and the Guinea-Congo Forests biomes, both of which only barely extend into Kenya. A few species of the Sudan-Guinea Savanna biome of northern Africa, e.g. Abyssinian Ground Hornbill (Bucorvus abyssinicus) and Piapiac (Ptilostomus afer), also occur in this region.
The western region comprises of Trans Nzoia, Elgeyo-Marakwet, Uasin Gishu, Kakamega, Bungoma, Busia, Nandi, Kericho, Kisumu, Vihiga, Siaya, Homa Bay, Nyamira, Bomet, Kisii and Migori counties. Notable features of this region include Lake Victoria, Yala Swamp, Mt Elgon, the Cherangani Hills, Kerio Valley, Nandi Hills, Gwassi Hills, Kakamega Forest and the South-western Mau Forest.
The first two regions we looked at, central Kenya and the coast, are quite densely covered on the Kenya Bird Map. Now, however, we are getting into the much sparser-covered parts of the country. Western Kenya is the third-best covered region of the country, but it is quite considerably less-densely covered than central and coastal Kenya. The gaps in this region are vast, and although atlassers have done a fairly good job in this area so far, there is still a lot of ground to cover before bird distributions in this area can start clearly being represented.
The best-covered part of the western region is undoubtedly the area around Lake Victoria. A large block of mapped pentads extends almost unbroken from Port Bunyala east to Yala town and south to Kamuga and Asembo (including the entire Yala Swamp). This block crosses the lake and continues south to Homa Bay, northern Ruma National Park and Magunga. The entire Mfangano island and the western half of Rusinga Island are also covered by this block. A gap about 4 pentads wide then separates this block from a narrow strip of covered pentads on the eastern shore of the lake stretching from the Sondu and Nyando River mouths north through Dunga Beach and Kisumu town to the Vihiga/Nandi counties boundary. Note, though, that almost all pentads in this area are yellow (1 card) or orange (2-3 cards). This means they still need several more full protocol submissions for a proper picture of bird distributions in the area to start showing itself. Several of these pentads have also been covered as a result of organized Kenya Bird Map expeditions and they need more bird mapping attention from local resident birders of their own accord.
There is also a small block of atlassed pentads covering the Kakamega and South Nandi forests, although the central part of Kakamega Forest and eastern Nandi Forest are untouched. The North Nandi Forest (only visible in satellite view – you can see it on the coverage map) is however almost completely untouched. Six pentads around Eldoret are atlassed, as well as a few around Iten (also covering Rimoi Game Reserve, Kaptagat Forest and Tambach Museum). The area from Burnt Forest and Kamwosor northeast through Kimwarer to the Elgeyo-Marakwet/Baringo counties border also has some coverage. The pentads in this area are also mostly yellow and orange, although several in the Kakamega-Nandi forests area have a good number of submitted cards (green, purple, blue and red pentads).
One other block of atlassed pentads worth mention is the area from Kapcherop Forest to Kitale and north-west along the Trans-Nzoia/West Pokot counties border to the border with Uganda.
The gaps in this area are extensive and rather obvious just from looking at the coverage map. I will, however, point out a couple of notable ones in areas of high interest and importance for biodiversity. One major one is the South-western Mau Forest in Bomet County (and extending into Narok, although that county isn’t covered in this article). This forest of very high national importance as a major catchment area for the Mara River and from an ornithological point of view it must also host a very interesting assemblage of forest specialist species. Yet we have practically no records from this forest on the bird map! Documenting what birds are there now, especially with the rapid rate of development and habitat change happening in Kenya at the moment, is of utmost importance. Anyone up for the challenge?
The Kakamega and Nandi forests, although they have several well-atlassed pentads, have some glaring gaps worth mention. These are 4-6 key pentads covering large sections of the Kakamega, North Nandi and South Nandi forests. See map below. The forest patches in the Tinderet-Timboroa area also have several untouched pentads that could produce interesting bird records.
East of Kapcherop Forest, a vast swathe of the Cherangani Hills, with a mosaic of large intact forest patches and deforested areas, remains unmapped.
Finally, and perhaps a bit surprisingly, Mount Elgon is almost completely unmapped! See below.
Western Kenya is undoubtedly one of the most species-rich parts of Kenya. With all the changes going on in Kenya at present, it’s very important that Kenya Bird Map atlassers put a strong effort into documenting the birds of western Kenya so that we can monitor how they are responding to these changes and identify appropriate conservation measures needed to ensure this area’s rich biodiversity is conserved.
To all those who have been recording and submitting bird observations from western, well done and do keep it up! Any other birders who live in or regularly visit western Kenya, please join us in this crucial bird conservation effort!