In March 1837, ornithologist John Gould announced that Darwin's rhea was a separate species from the previously described rhea (though their territories overlapped), that mockingbirds collected on the Galápagos Islands represented three separate species each unique to a particular island, and that several distinct birds from those islands were all classified as finches.
How many species of mockingbirds were found to be present on the Galapagos Islands?
three separate species