Dear Tim,
I don't think it does depend on how one defines art if you compare like to like.
Is a bird photograph worth more, less, or the same as a similar painting for example? In some ways, the painting is easier, lighting can be controlled, the subject can be dead (yet the painting of a living bird), there are no leaves in the way etc. while the photographer has used their skill to ensure they are in the correct position at the correct time to ensure correct lighting, they have had to stalk/hunt the bird and wait for the perfect subject position and framing, etc. I would say there is an art to making the bird photograph, but of course that doesn't mean the end result is art - but then neither is the painting 🙂
I feel the same way about bird and wildlife photography.