An Ornithologist, probably Mr. Thomson Ramsay Richard Reinagle (1775-1862)

The picture has something of this: people, furniture, seat, woman, indoors, sit, wear, book bindings, room, facial expression, portrait, spirituality, reclining, light.
Perhaps it’s a painting of a man sitting at a desk with a book in front of him and a bunch of feathers on the table.