For a children's story, you need a simpler narrative. You've got an upward and a downward story flow, when it should only be a downward flow for stories for youth under 4. You should begin with the four birds together, and the Puffin challenging the others to contests they aren't good at, but it is average, because it wouldn't be "fair" to compete in something they're obviously the best at. Then it lords it over them and laughs at them. They talk it out and realize the Puffin is purposefully keeping them from showing off their real talents, and compete in their dominant trait. Puffin flees the scene as all the birds in the flock praise the trio for being good at one thing.

Finish with pithy statement about how everyone is good at something, and shouldn't feel bad about what they worked hard to be good at.

An alternative ending would be that somehow a disaster happens to Huffy Puffin, and the trio need to use their strengths to solve the problem, and Puffin realizes its errors in trying to stop people from excelling.