Cara Giaimo on Edward Lear as “a Teenage Parrot-Painting Prodigy” from Atlas Obscura.
And Matthew Bevis’s long review of Jenny Uglow’s Mr Lear for the London Review of Books, vol. 39, no. 24 (only available to subscribers, unfortunately).
I have also found out that many of John Gould’s books on birds are available at Archive.org.