Head bobbing?

[OllyGreen]

My parrot has recently learned to talk. He can say 'Elo' and 'What you doin?' haha, it's so cute. When I talk to him, he starts doing these cute little twitters and then he starts bobbing his head. I'm interesting in what that means when they do that? I hope he's happy

[sanjays mummi]

Sanjay bobs his head excitedly when he knows I am approaching with a tasty morsel, it's a sign of happy anticipation.

[Skyes_crew]

Skye bobs her head in anticipation of bed time at night. It's really cute