Expert: Roger Lederer - 7/18/2008

Question
I found a nest in a tree in my yard about a week ago and there are two eggs
blue in color about an inch long with just a little spotting.  I haven't seen any
mom bird tending to the nest during the days.  I don't know for sure what
type of egg it is but i live in san diego and i'm assuming it's a songbird of
some sort.  I'm wondering if the eggs are something that will hatch or if the
nest has been abondoned??  I know that a robin will lay eggs even if she
hasn't mated and those eggs will never hatch and she should attend to the
nest if they are fertile eggs??  any input would be appreciated.

Answer
Wild bird females typically do not build nests or lay eggs without mating. Chickens and domestic birds of course do, but it is rare for wild birds to do so. She should attend to the nest, yes, but it is not unusual for a bird to abandon the nest, especially if it is the first time she has mated. Then again she might have been killed before she laid all the eggs. Can't tell you exactly what  happened.