Birds became the world's master musicians in order to convey to potential mates, rivals and predators all the important things they have to say, from "Clear off!" to "Come on!" And their songs ...

Odin and Heimdall watch from the battlements of Asgard as the birds approach. Odin orders Heimdall to make a bonfire then, when Loki and Iduna tumble through the smoke, Heimdall fans the flames.

Springtime is the best time to hear bird song, as the breeding season is just ... Why playing out and exploring is good for our kids Steve Backshall, Helen Glover and child psychology expert ...