I was gonna try to make these myself, but for whatever reason, I can't paste stickers on Swoop's upper body.
So here are some ideas:
Parakeet, blue jay, cardinal, pigeon, and any type of other bird that may look cool or cute. I also think any other type of bird Pokemon may be cool, to, like Starly, Articuno, Moltres, Zapdos, etc.

Let me know if you want to make or have made any of these already!