Belgian federal museums contain very important zoological collections, many of tropical origin. Type specimens have a permanently important status for taxonomic research. Less well known is that aspects of the biology of certain rare species (often never studied in nature) can be deduced from the study of the “old” specimens (including the non-types). Those series must therefore be retained. This is shown on the basis of African birds from the Royal Museum for Central Africa. Traditional methods are used: morphology, moult study and historical range and altitudinal analysis. The importance of such information when defining protected areas and designating new research zones is demonstrated with the African Albertine Rift. ... : Paper presented at the meeting of the Section of Natural and Medical Sciences held on 24 April 2018. Text received on 23 July 2018 and submitted to peer review. Final version, approved by the reviewers, received on 4 October 2018. ...