Reacting to noise

The mother has just left the nest and when she flies out of the birdbox she causes some noise. This immediately triggers all the chicks to open their mouths again.

Chicks reacting to noise, 3 May 2014 6:32pm

The chicks have grown a lot since the last video and on the oldest ones you can see some black appearing on the wings and on their back: the very beginning of feathers! Also the noise the chicks make is getting louder.