I prefer catching these birds in flight without the nesting box, but I made an exception here due to the dynamic scene and interaction presented. Although I do not normally approach natural nests, the birds in this nesting box in a friend's yard are used to his comings and going.

This is a very late-in-the-evening situation, minutes before the sun set behind some trees, and my camera settings reflect this.

Canon 5D Mark III with the 500L f4 lens handheld @ 1/640, f4, ISO 800, +2 exposure compensation. Minimal crop for composition purposes, and a bit of dodging of the hungry nestling.

Cheers,

Mike