Taxonomy
Terns were previously considered a subfamily (Sterninae) of the gull family Laridae, but are now usually treated as a separate family Sternidae. Most terns were formerly treated as belonging to one large genus Sterna, with the other genera being small. In 1959, only the noddies and the Inca Tern were considered as separate genera. However analysis of DNA sequences supports the splitting of Sterna into several smaller genera.
A study of part of the cyt b gene sequence found a closer relationship between terns and the Thinocori, some species of aberrant waders. These results are in disagreement with other molecular and morphological studies, and are best interpreted to prove an extraordinary amount of molecular convergent evolution between the terns and these waders, or as retention of an ancient genotype.
The common English name for this group and the original genus name, Sterna, appear to be derived from the Old English "stearn"; a similar word was also used by the Frisians for tern. "Stearn" appears in the poem The Seafarer, written around 1000 AD.
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