Yes, that is a real bird, the Blue-footed Booby, only living on the Galapagos Islands.Here's the original painting.
Original
The sources.
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That's a big snake you've got there.Original source: Winding the Skein by Lord Frederic Leighton<a href="http://www.billwang.net/bbs/oldattach/2007/01/03/billwang_5322457-Leighton_Winding_the_Skein2-embed.jpg"/a>
Original by Rubens, and the pig source.