Windowsill Mourning Doves

(Chesapeake, Virginia)

Mourning Doves are nesting on my windowsill beside the front door. The windowsill is lined with pinecones in order to deter the cat from jumping up and tearing the window screen ... which, by the way, has solved that problem.

But, because the doves have nested for nearly three weeks, I'm concerned that the eggs have fallen inbetween the pinecones and the doves are really only sitting on the pinecones.

Would the doves realize they are NOT sitting on eggs? Will they continue to nest idefinitely? Or, will their instinct tell them it's been a really long time and there should be babies by now?

Either of the mates is constantly sitting on the nest so I have not been able to see what is actually going on inside the nest.