Levaillant’s Pie-Grièche Rouge A Plastron Blanc, the White Shrike with the Red Breastplate, is one of several enigmatic species of birds that were described in the early 1800s based on stuffed specimens that were actually just fakes composed by some business-minded taxidermist from the parts of several other birds, a practise that was quite common in former times.
The more unusual such a specimen the higher probably was its price ….
Here is a part of the description, which mentions the supposed origin of this ‘species’ as having been the islands of the South Seas, which actually could be anywhere …:
“Cette belle espèce appartient, à ce qu’on m’a assuré, aux îles de la mer du Sud. De quatre individus que j’ai vus, deux avoient la barre de l’aîle blanche au lieu d’être rouge; celles-ci seroient- elles des femelles? C’est ce que j’ignore, n’ ayant euà leur égard aucun renseignement quelconque, et n’ayant vu que les peaux rembourrées de ces oiseaux.“
“This beautiful species belongs, as I have been assured, to the islands of the South Sea. Of the four individuals I saw, two had the bar of the wing white instead of being red; would these be females? This is what I do not know, having had no information whatsoever about them, and having only seen the padded skins of these birds.“
However, the fake was uncovered 60 years later.:
“Note. – The Lanius mystaceus, Lath. Ind. Orn. Suppl. p. xix; Levaill. Ois. d’Afr. t. 65 (Laniarius mystaceus, G. R. Gray, Gen. of B. i. p. 299), has been stated by Levaillant to be from an isle in the South Seas. It is, however, a made-up bird, being composed of a portion of the Lanius ferrugineus, Gm., with the feathers on the belly and tail from a species of red Psittacus, while the breast and vent are those from a species of Malaconotus.” 
The Lanius ferrugineus, Gm., mentioned here, is the Southern Boubou (Laniarius ferrugineus (J. F. Gmelin)) a bird without red feathers, so I personally think that the original body was ‘borrowed’ from another species, possibly from the Crimson-breasted Gonolek (Laniarius atrococcineus (Burchell)), which then got decorated with the red tail feathers of another bird, which might well have been some species of parrot.
 François Le Vaillant: Histoire naturelle des oiseaux d’Afrique. Paris, chez J. J. Fuchs, libraire, Rue des Mathurins, Hôtel de Cluny: de l’imprimerie de Perroneau, Rue des Grands Augustins 1799
 George Robert Gray: Catalogue of the birds of the tropical islands of the Pacific Ocean in the collection of the British Museum. London: printed by order of the Trustees 1859