Design tip. If a sound repeats in your game, record some variations or at least vary tone and pitch. Listen to this 

Papo and Yo’s howls, grunts, steps and chirps are straight out of Panama

Real Talk with Klei Entertainment’s Matthew Marteinsson

The secret audio in BioShock Infinite sure is creepy

GRID 2: Principal Audio Designer speaks to GamesRadar

Have a peek at Jordi’s AngryBots demo 

Tutorial: Basic bird systems in UDK (Spanish)