Last year we did a craft similar to this but used pine cones.
I found this on the Hearts and Trees blog - the stars were aligned, cuz we had some stale bagels hanging around.
It was super easy - we used a mixture of lard and sunbutter to coat the bagel halves and then pressed them into birdseed (safe birdseed mind you). We strung them up with kitchen twine on some of the trees in our yard.
It was quick and surprisingly fun to do with little B. I have birdseed all over my dining room floor, but it's a small price to pay for getting our craft on.
I'm hoping a crazed racoon doesn't run away in the night with them!
Photo from About.com via Hearts and Trees