Full list of all 16 SkateBIRD achievements worth 1,320 gamerscore. It takes around 6-8 hours to unlock all of the achievements in the base game on Xbox One.
The base game contains 12 achievements worth 1,000 Gamerscore, and there is 1 DLC pack containing 4 achievements worth 320 Gamerscore.
You've become a skateboarding bird
Beat every mission, find every unlockable, then watch the credits
Reach the rooftop
Get into the boss's office, so you can trash it
Find the GIBSON
Escape the collapsing organization
Finish "decorating" for the party
Complete all the missions in Humble Bedginnings
Complete all the missions in Scared Of Heists
Complete all the missions in Big Business
Complete all the missions in The Forgotten Gibson
Complete all the missions in Bringing It Home
You've gone out into the world and touched some grass
You've proven you can be trusted in the Big Room, and maybe get to go out more often
You Made Seagull Happy
You Brought Him Back