William John Swainson FLS, FRS (8 October 1789 – 6 December 1855), was an English ornithologist, malacologist (study of molluscs) , conchologist, entomologist and artist. In 1816 he accompanied the explorer Henry Koster, who was a botanist, to Brazil. Henry Koster had travelled to Brazil once before and became famous for his book Travels in Brazil. There he met Dr Grigori Ivanovitch Langsdorff, also an explorer of Brazil, and Consul General of Russia. They did not spend a long time on shore because of a revolution, but Swainson returned to England in 1818 in his words "a bee loaded with honey", with a collection of over 20,000 insects, 1,200 species of plants, drawings of 120 species of fish, and about 760 bird skins.

Swainson kept a diary and one of the entries refers to the Lear’s macaw. It reads as follows:-

Left Canavieiras, near St Anna, saw macaws (scarlets and blue & golds) and also hyacinth. Serra of San Jose: I have reason to think the macaws I saw today were of a different species (of the hyacinthe macaw). A sertanejo who visited me says they are of an entirely rich bleu colour with a cast of green, the blue and yellow macaw (which I described to him very particularly) is called calinda and the red and bleu arara verdadero. This latter is not seen at present, its note is very different from the one I heard, beinga single prolonged note or more properly croak. The bleu arara, which is now found in the Tabulara’s comes regularly towards this time every year, sometimes in considerable flocks. In other years (as at present) they are seen in small numbers and are supposed to breed a long way in the Sartoon’s. (Standard answer to enquiries of any sort) 

In another entry in October 1817 he writes “ I found myself on the border of the Sartoon, or more correctly, just entered the dry cheerless tracts of table land, where nothing meets the eye, but stunted vegetation and dreary uniformity.” The website editor assumes he was referring to the sertão