Summary. Much has been published on the five subspecies of the Nubian Nightjar Caprimulgus nubicus, which range from southern Israel through western Arabia and north-east Africa south to Kenya, with an outlying population on Socotra (Yemen). Recent field observations, tape-recordings and photographs of the latter population, described as C. n. jonesi in the late-19th century on the basis of a single specimen, have permitted a reanalysis of the taxonomic status of this form. Because of overlap in features used to distinguish jonesi with those of C. n. torridus, from adjacent north-east Africa, I propose that jonesi be henceforth regarded as a junior synonym of torridus. Geographical variation within the other forms of C. nubicus is also generally rather weakly expressed, with several differences in opinion as to how taxa might be diagnosed having been suggested in the previous literature. The problems of assigning subspecific limits within this species is compounded by a lack of specimen material in the world's museums of at least two of these forms, taruensis (from southern Somalia and Kenya) and nominate nubicus (Sudan and extreme south-east Egypt). No differences in vocalisations between the five taxa are known and the movements of at least two, which are poorly understood, may mean that some taxa overlap to a greater or lesser extent. I suggest that most described variation in the Nubian Nightjar might be considered as (sometimes highly localised) responses to climatic and soil conditions, and, subject to future research, therefore of little use in determining significant evolutionary divergence and hence unworthy of taxonomic recognition. Despite the relative lack of specimen material, I support previous suggestions in the literature that taruensis is a junior synonym of torridus, and recommend that further work be carried out to determine whether tamaricis is definitely distinct from nubicus and whether torridus is safely distinguishable from tamaricis. In these and similar nocturnal taxa, vocalisations must assume a prominent role in taxonomic studies.