How do you beat the sandbird level?

Look on the bird. There are small cubes sticking out of the wings and body.You have to be right next to one when the bird turns sideways so you don't fall off.

First, slide down the hill and jump at the end to reach the hole.
Then, when you are on the sandbird take it slowly, and when it turns sideways go just underneath it's wings, there are 7 coins on the bird and one at the top of the tower. Time your jump off the sandbird's wing to reack the tower.

Gelato Beach - Episode 4: The Sand Bird is Born
Once you slide into the hole in the Shine Tower, you are dropped on the first cloud, onto the Sand Bird's back.
Factor in wind drag when jumping.

Grab 1ST and 2ND Red Coins on back and neck of Sand Bird.
Grab 2 Red Coins on each wing of bird.
Hang off the edge of the sand block near where it's "right foot" would be. When it turns, you'll drop onto it's side. Hover/walk back onto it's back when it rights itself again.
Get 7TH Red Coin at end of it's tail.
When you can see the top of the central tower, jump off left wing and hover to 8TH Red Coin.

Can't tell you when it turns itself on successive circuits around tower though, as it changes it's flip pattern.