My cat used to protect our birds. The wings were clipped and our backyard was fenced off so we'd let them out during the day and they'd have a BLAST running all over the backyard chirping at each other from tree to tree, or playing in the sprinklers. And the cat would sit there the whole time, protecting our birds. If anything came close, the cat would chase it away. For years, she'd do this.
I got lucky one day though... I left the birds roam free in the living room (was cold out, and they were trained to poop in their cage) and I started to hear my cat making these strange noises so I came in to see what was up. Before I got there though I heard a LOUD thud, then all my birds started freaking out. A baby hawk crashed into the window and broke his neck on impact. Lesson learned.
I guess it's more "common" for a cat and bird to live in harmony (than a snake and mouse), but I've seen some strange creatures live in harmony like that.
I too saw on one of those "amazing animal" shows, a cow who took in an abandoned animals as her own. Nursed them as if they were her own babies. There was a dog, and I THINK a pig (I forget what the other animal was). They all slept together and everything. Not that these are natural emenies, but my point is it does happen.
I'd love to see the pic, newt. If you have somewhere to upload it to (or email it to me) I can shrink it and post it for you here.
Here's a pic of the Hawk. Turns out it was a Coopers Hawk and are very rare in my area. I had to get a license to keep it (and can never take it across the border), but I decided to have it stuffed anyway. Just a beautiful bird.
