hmmmm
http://www.etsy.com/listing/87968553/bird-photograph-crow-silouhette-in-aYour item is missing the tags 'bird photograph', 'bird photography', 'crow photograph' or similar terms. The idea is to try and guess the most common short phrase people will be searching for an include it. I would also suggest that most people can't tell the difference between a raven and a crow, and more people will be searching using the term raven. If you're going for a spooky theme, then raven will be much more popular than crow, and associated search terms would include thing like Edgar Allan Poe (who wrote The Raven, a classic thriller poem).
I guess what you need to do is think more like a buyer and imagine who would be buying your prints at an art show. Black and white photos of birds in classic horror poems sell well to goths. I'm not sure about the rest of your pieces though.