From this book I discovered some interesting anecdotal information on the blue macaws

I recently acquired A.G. Butler's Foreign Birds for Cage and Aviary published in two volumes in 1909 in a second-hand bookshop and discovered some interesting anecdotal information on the blue macaws. These entries are reproduced here Hyacinthine Macaw, Lear's Macaw, Glaucous Macaw and Spix's Macaw as well as articles mentioned within them as source information including the reports on Glaucous Macaws and the acquisition of a Spix's Macaw in the Proceedings of the Scientific Meetings of the Zoological Society of London as well as items in the Avicultural Magazine. Of particular interest is the Reverend Astley's account of his Lear's Macaw with a fine plate by H.Goodchild. Also new on the website are the entries from Reichenow'sVogelbilder aus fernen Zonen published in 1883, which includes an illustration of a Glaucous macaw with a Hyacinthine Macaw.