Prompt
Generate a realistic portrait of John Cassin, an American biologist and ornithologist, in a 19th-century style. Depict him outdoors, surrounded by lush greenery and perched birds, wearing attire typical of the era, such as a top hat and a long coat, with a thoughtful expression, and holding a pair of binoculars or a book related to ornithology. Incorporate subtle hints of his contributions to the field, such as a sketchbook or illustrations of birds in the background. The color palette should be earthy and natural, reflecting his connection to nature and the bird species he studied.