It’s not short for bowling (although it can be expressed like that too), it’s the infinitive form of the verb, to bowl. “Have you seen the birds fly?”

You could also read it as a vowel.

(in bowling) to roll a ball along a smooth surface during a game of bowls or bowling

(in Cricket) to throw a ball towards a batsman (= the player who hits the ball) using a vertical circular movement of the arm while running:

https://dictionary.cambridge.org/dictionary/english/bowl