''Nauclerus'' was a genus of birds of prey, containing the African and American swallow-tailed kites. Though similar, the two species are not closely related, belonging to separate subfamilies

Elaninae An elanine kite is any of several small, lightly-built raptors with long, pointed wings. Some authorities list the group as a formal subfamily, Elaninae. As a subfamily there are six species in three genera with two of these genera being monoty ...

and

Perninae The raptor subfamily Perninae includes a number of medium-sized broad-winged species. These are birds of warmer climates, although the ''Pernis'' species (European honey buzzard and crested honey buzzard) have a more extensive range. Several of ...

. The term is preserved in the modern French common names "élanion naucler" and "naucler à queue fourchue".

Taxonomy

The name ''Nauclerus'' was published by Nicholas Aylward Vigors in 1825, and used by other authors in the 19th century. Vigors' original description contained both the

swallow-tailed kite The swallow-tailed kite (''Elanoides forficatus'') is a pernine raptor which breeds from the southeastern United States to eastern Peru and northern Argentina. It is the only species in the genus ''Elanoides''. Most North and Central American b ...

(''N. furcatus'', also called the Carolina kite or forked-tail hawk) and the then-recently discovered

scissor-tailed kite The scissor-tailed kite (''Chelictinia riocourii''), also known as African swallow-tailed kite or fork-tailed kite, is a bird of prey in the monotypic genus ''Chelictinia'' in the family Accipitridae. It is widespread in the northern tropics of A ...

(Riocour's kite, ''N. Riocourii''), separating them from the ''Elanus'' of Savigny. In contrast, Vieillot had earlier published the genus ''Elanoïdes'' in 1818, containing ''E. furcatus'' and ''E. (f.) yetapa''. ''Falco riocourii'' was not known until a few years later: illustrated in 1821 for a work by Temminck, and described in 1822 by Vieillot. In 1823, Vieillot grouped all of the known elanine kites in ''Elanoïdes'': ''E. furcatus'' (''forficatus''), ''E. leucurus'', ''E. yetapa'', ''E. cæsius'' (''cæruleus''), and ''E. riocourii''. Lesson split the scissor-tailed kite into a separate genus as ''Chelictinia Riocourii'' in 1843, leaving ''N. furcatus'' as a junior synonym of ''Elanoïdes furcatus'' Vieillot, 1818. An alternative approach is to consider ''N. riocourii'' the type species of ''Nauclerus'', giving ''Nauclerus'' Vieillot 1825 precedence over ''Chelictinia'' Lesson 1843. The effect would be to keep ''riocourii'' in ''Nauclerus'', and move ''furcatus'' to ''Elanoides''.For example, Sharpe in ''Catalogue of Birds in the British Museum'' lists ''E. furcatus'' as the type of Vieillot's ''Elanoides'' and ''N. riocouri'' as the type of Vigors' ''Nauclerus''. Sections "56. Elanoides" and "57. Nauclerus" in Vol. 1 pp. 317–31

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Description

Both species have deeply forked tails with slender bodies and long, pointed wings. The scales on their lower legs are reticulated, and the nails of their talons are not rounded underneath. They spend much time on the wing, taking insects, amphibians and small reptiles from tree branches, and insects from the air. In ''C. riocourii'', the second primary flight feather is the longest. It is the smaller of the two, with light grey plumage and black patches under the bends of its wings. ''E. forficatus'' has the third feather longest; it is notably larger; and its coloration is strikingly pied, being charcoal above and white below.

Notes

References

{{Taxonbar, from=Q48995924 Accipitridae Bird genera Obsolete bird taxa