"Leguat's Giant" or géant, a hypothetical giant rail from the Mascarenes described as Leguatia gigantea, is based on his descriptions of flamingos (Phoenicopterus roseus), as Leguat was not familiar with their French name flamand or thought that it referred to other birds (it was in his time sometimes used for spoonbills, for example).
<bdi><a href="https://en.wikipedia.org/wiki/en:Frederick_William_Frohawk" class="extiw" title="w:en:Frederick William Frohawk"><span title="zoological artist and lepidopterist (1861-1946)">Frederick William Frohawk</span></a>
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Painting: 1905, Book: 1907
Extinct birds : an attempt to unite in one volume a short account of those birds which have become extinct in historical times : that is, within the last six or seven hundred years : to which are added a few which still exist, but are on the verge of extinction. By Lionel Walter Rothschild, 2nd Baron Rothschild (8 February 1868 – 27 August 1937). (<a rel="nofollow" class="external free" href="https://archive.org/details/extinctbirdsatte00roth">https://archive.org/details/extinctbirdsatte00roth</a>)