The western and central parts of Africa now have an excellent guide in the Birds of Western Africa by Borrow and Demey. It is a fantastic reference work and thoroughly recommended. It covers 23 countries south of the Sahara, from Mauritania in the northwest, to Chad and Central African Republic in the east, and Congo Brazzaville in the southeast, include the Cape Verde and Gulf of Guinea Islands. The paperback version is much more portable than the hard cover edition and it is ideal for the field, although there is less detail.
Birds of Africa south of the Sahara also covers the same countries except the Cape Verde Islands.
Helm Identification Guide. 147 plates depicting over 1280 species in 2800 individual figures. Covers Senegal, Gambia, Guinea Bissau, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Togo, Benin, Nigeria, Cameroon, Rio Muni, Gabon, Congo, Central African Republic, Chad, Niger, Burkina Faso, Mali, part of Mauritania and the islands of Sao Tome, Principe and Bioko (Fernando Po). All the species described are illustrated in colour apart from a few vagrants, which are depicted in black-and-white in the text. Distribution maps are provided for the majority of species (except vagrants). 832 pages.
Helm Field Guide. Utilises all the plates from the Helm ID Guide by the same authors, with a concise, authoritative text on facing pages, to create a guide covering all 1,304 species found in the region. The guide also contains an updated colour distribution map for each species and a number of new images have been painted just for this guide. Covers Senegal, Gambia, Guinea Bissau, Guinea, Sierra Leone, Liberia, Ivory Coast, Ghana, Togo, Benin, Nigeria, Cameroon, Rio Muni, Gabon, Congo, Central African Republic, Chad, Niger, Burkina Faso, Mali, part of Mauritania and the islands of Sao Tome, Principe and Bioko (Fernando Po). 512 pages.
Second edition, including 500 new images and 400 updated distribution maps. Unrivalled coverage of African birds in a single volume. 2129+ species covered with an additional 101 vagrants briefly described. Revised to reflect the latest changes in taxonomy. Species descriptions give precise identification features highlighting differences between similar species as well as briefly reporting habitat, status and call. Annotated illustrations portray distinctive plumages as well as diagnostic flight patterns and major geographic variants where applicable.
BOU checklist 4. Second edition 1994. Introductory chapters cover the history of Nigerian ornithology, geography, geology, climate and vegetation. Other chapters cover migration, breeding, and co-operative / parasitic breeding, and there are appendices of ringing recoveries, references, English and scientific names. The bulk of the book comprises the Systematic list, which includes every species reliably recorded in Nigeria. 306 pages.