Working for birds in Africa

The identification, taxonomy and distribution of the Mountain Nightjar / Fiery-necked Nightjar complex

p 86-97

Résumé: Deux groupes d'engoulevants afrotropicaux sont tellement étroitement liés qu'ensemble ils forment une superespèece. Ils partagent des caractéristiques extrêmement similaires du point de vue du plumage et des vocalisations et habitent des bois, des campagnes boisées et les lisières des forêts. Un groupe comprend l'engoulevant d'Abyssinie, Caprimulgus poliocephalus, des formes complexes de montagne qui vivent normalement au dessus de 1500 m. L'autre groupe consiste en l'Engoulevant musicien, Caprimulgus pectoralis, des formes complexes des plaines qui vivent normalement en dessous de 1500 m. L'opinion taxonomique est divisée quant au nombre d'espèces appartenant à chaque groupe, certains penchant pour une espèce de montagne et une de plaine, d'autres pour deux espèces de montagne et deux de plaines. La présente communication examine la morphologie, les vocalisations et la distribution de toutes les formes existant au sein des deux groupes et soutient l'avis que quatre espèces peuvent être reconnues. Un nouvel examen des deux races du sud de l'Engoulevant d'Abyssinie Caprimulgus poliocephalus est également effectué.
Abstract: Nightjars are generally nocturnal birds that spend the day roosting on or close to the ground, often in rather open situations. It is whilst roosting that they are most vulnerable and they rely almost exclusively on camouflage to remain undetected. Many species prefer to roost on or amongst leaf-litter and have evolved plumages which render individuals cryptic by day. This, together with their nocturnal behaviour, makes identifying many nightjar species in the field rather daunting. Geographical and individual variation, especially in colour, can further complicate the correct identification of similarly sized, variegated nightjars. As a result a set of consistent characters needs to be examined to ascertain a nightjar's identification. Characteristics which are, presumably, of importance to other nightjars are the vocalisations, especially the territorial song of the males, and the white markings on the wings and tail, which are used in a variety of displays. These may be by one sex to another during courtship and breeding, by one male to another during territorial establishment and defence, or by an adult to potential danger during the defence of its eggs or young. These markings are often only visible when the wings and tail are spread, usually whilst birds are in flight. Most nightjars also have white patches on the throat, but this characteristic can be quite variable and is not generally recognised as being of specific or subspecific importance. Two groups of closely related afrotropical nightjars share extremely similar plumage features and vocalisations, one group comprising the Mountain Nightjar complex, the other, their lowland counterparts, the Fiery-necked Nightjar complex. Together these groups constitute a superspecies, although taxonomic opinion is divided as to whether two (one montane, one lowland) or four (two montane, two lowland) species are involved. This paper briefly examines the morphology, vocalisations and distribution of all forms within the two groups and supports the view of several authorities e.g. Fry that four species may be recognised. A reappraisal of the two southerly races of the Mountain Nightjar is also given. Nigel Cleere

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