Please send me any other links you find really useful.
http://www.mandaras.info/ The most important link for anyone working or interested in the cultures of the northern Mandara mountains is Gerhard Müller-Kosack's Mandara Mountains home page which offers a wide range of information including a review of the literature, a bibliography, notes on individual ethnic groups and on current research and much more.
http://www.nigerianfield.org/ The Nigerian Field Society is an organisation devoted to the study of all aspects of culture and environmental sciences in Nigeria, embracing interests in the fauna and flora, history, archaeology and geology, legends and customs, arts and crafts, sports and pastimes.
The Society is actively engaged in promoting conservation and preservation at scientific and popular levels, and in encouraging tourism in Nigeria. It publishes a journal twice a year. 'The Nigerian Field' has appeared regularly since 1931 and contains articles on the above topics covering all of West Africa. The Society has fulfilled a useful need over the past 70 years in bringing to wider notice aspects of life and culture in Nigeria, and in capturing records for posterity.