For making this bookmark, I've used origami paper.
It might be a little thin, but it works!

Fold a + sign.

You have to cut 1 square.
It doesn't really matter which one you choose.
Just make sure you'll end up with this figure.

fold the bottom two squares,
like this! ^^

Now cut off the triangles you've folded.
You'll still have one square,
and 2 triangles at the bottom.

now fold one triangle and put some glue on the top of your triangle.

Now fold the other triangle and make sure the glue will attach both triangles.

yeah! bookmark :)

Now use your own imagination ^^
for Hedwig, I've attached another triangle ( a yellow one) for the eyes.
on top of that one, I've attached a white triangle. ( Before I glued it one the yellow one, I cut a pair of eyes)
Now use a fine liner and draw Hedwig's head.
at the end, I've just glued a beak and wing on the triangle.

Good luck! ^^