The Whiskered Tern (Chlidonias hybrida) occurs widely across the world in Africa, Europe, Asia and Australia. It is rare in Germany and only breeds in Mecklenburg-Western Pomerania and Saxony-Anhalt. Evidence of breeding was also recently reported in Brandenburg. In other parts of the world, however, this Chlidonia tern is the most common of the genus.
Even in the breeding plumage, Chlidonia terns are not always easy to distinguish from one another or from some of the smaller Sterna terns. This is all the more true if the breeding plumage has not yet developed or the species has moulted into non-breeding plumage. I find the Chlidonia terns to be particularly tricky in non-breeding plumage, especially in the first calendar year, when they have lost their conspicuous young plumage, the plumage is a mixture of molten (light) and old (dark) feathers and the contrasting drawing of the magnificent dress is far from being developed.
I have therefore tried to get as much information as possible for the best possible identification of the species of young Chlidonia terns.
Many identification guidesbooks emphasize the differences in physique. The best book is definitely still the (English) Helm Identification Guides “Terns” by Klaus Malling Olsen from December 1994. It is now sold as an antiquarian bookshop at a significantly higher price than it was then in the store and has Continue reading ID immature Chlidonia’s terns