Why do some birds, like the Flamingo, for instance, sometimes stand on one leg? They do it to conserve heat and energy. A bird’s leg receives more blood per heartbeat than its major muscle. The blood keeps the flamingo warm. The flamingos have very long legs, which means they would lose a lot of heat through them. What do we do when we feel cold? We tuck our hands in our woollens to stay warm, right? That’s exactly what the flamingos do! They tuck in their legs to feel snug.