Sorghum can be heavily damaged by birds in Botswana but as control measures are expensive bird-proof sorghums merit consideration. However, varietal resistance is difficult to evaluate because when many varieties are grown close together birds avoid unpalatable ones, thus giving a false estimate of resistance. This paper describes the performance of a supposedly resistant variety, Savannah 5, when grown in time isolation from other sorghums. Heavy grain losses resulted, mainly due to doves (Columbidae) and weavers (Ploceidae). Consequently it is suggested that all resistant cultivars be tested in isolation before final release to farmers.