The first description by a European ornithologist of a falconet from this group was published by George Edwards in 1750, as "the little black and orange colour'd Indian hawk". It was from a specimen that had been collected in Bengal and sent to the King's physician, Dr Mead.[2] In 1758 Carl Linnaeus used the illustration and description by Edwards to formally describe the species under the binomial nameFalco cærulescens[3][4] In 1760 the French naturalist Mathurin Jacques Brisson also used Edwards' publication to describe le Faucon de Bengale.[5][6] Although the white collar was not mentioned, the English ornithologist Richard Bowdler Sharpe believed that this was the same species that is now called the collared falconet.[5]
In 1824, Vigors proposed a new genus Ierax, writing "whoever has seen that beautiful species, the smallest of its race, F. cærulescens, Linn., now rendered familiar to us by the accurate and splendid illustrations of Dr. Horsfield, will at once acknowledge its separation from every other established genus of its family."[7]: 328 Later authors rendered the name Hierax.
Sharpe coined the name Microhierax in 1874, from the Greek μικρός ἱεραξ meaning "tiny hawk".[5] By this time, four species were known: M. cærulescens, M. fringillarius, M. melanoleucos, and M. erythrogenys. He lists Horsfield's specimen "Falco cærulescens" as being actually M. fringillarius, making the latter the type of the genus.
A fifth species, the white-fronted falconet M. latifrons, was described by Sharpe in 1879.[8][9]
^ abcSharpe, R. Bowdler (1874). "Microhierax". Volume I: Catalogue of the Accipitres or Diurnal Birds of Prey in the Collection of the British Museum. Catalogue of the Birds in the British Museum. Vol. 1. London: Trustees of the British Museum. pp. 366–369.
A. Pelletier (illustrator), C. [Charles Joseph] Hullmandel (lithographer) 1822. Illustration of Falco cærulescens from Java [later Microhierax fringillarius] BHL (Smithsonian)BHL(Singapore). Plate 35 in Horsfield, Thomas (1824). Zoological researches in Java, and the neighbouring islands. London: Kingsbury, Parbury, & Allen. doi:10.5962/bhl.title.44848.
Section Falco cærulescens, page 135 IABHL in Horsfield, Thomas (1822). "Systematic arrangement and description of birds from the island of Java. Read April 18, 1820". Transactions of the Linnean Society of London. 13: 135–200. "The drawing of Edwards was made from a bird sent from Bengal. The Javan specimens are somewhat smaller, and differently marked. They appear to form a distinct variety..."