Testing Testing

I have a theory about why the blue tits come to the bird box long before they start nesting.

I think they are doing practice runs. They sit in the tree, then swoop straight down to the mouth of the box, over and over again.They then dip their heads in and out of the box as if feeding their young. 

This probably explains why they are so good at it when the big moment comes. They move at lightning speed and are accurate every time. They need to be, it is a matter of life or death getting the food into the babies in time for their big day.