Blue Noddy (Anous ceruleus)

Genetic data suggest that both species formerly placed in Procelsterna should be included in genus Anous#R. Closely related to A. albivitta, with which often considered conspecific, but significant differences in size and coloration (see below); the two are sometimes incorrectly treated as pale and dark morphs of a single species; some authors have claimed that races skottsbergii and imitatrix of A. albivitta belong to present species, but specimen evidence refutes this. Internal taxonomy confused at present, with much overlap of forms, e.g. birds from Society Is significantly darker than those from Tuamotu Is and may not be referable to same race; validity of races and their distributions require careful systematic revision based on known breeding specimens, but these are lacking from various parts of the species’ range. Five subspecies currently recognized.