Why does my Pigeon make this noise?

[Mitzi]

I just got my young Capuchine pigeon a few wks ago, he's coming along fine although he does still "bite and twist" on my hands at times. Anyway, when I move him to another spot, put him in his cage or when I stand and talk to him and touch him on his chest and tell him he's a good boy he does this cooing/grumbling noise. I always call it his "mad-coo". Is he mad though? It reminds me of an annoyed noise but it's his only noise. I wish I understood Pigeonese.