I have questions about the synchronicity of screech owl hatching.  We have been watching a brood of screech owls -- numbers one and two fledged FOUR days ago, within an hour of each other.  Number three has remained in the box, but its behavior indicates it is finally ready to go.  (Lots of bobbing and leaning out.)  
I had assumed that the gap in development was caused by the eggs being laid on different days and incubated as soon as the first is laid-- as occurs with most birds of prey.    (Most passerines incubate after all eggs are laid.)
  In fact,  the Bent Life History book states that there may be a gap of several days between eggs being laid.    The Birder's Handbook contradicts this, saying that screech owls hatch synchronously.  
Can't seem to find any other references on line (free).  Anyone out there able to set me straight?  
sue hamilton, calvert