Expert: Roger Lederer - 7/21/2008

Question
I have a nest in a tree outside my livingroom.  This past spring I watched as 4 robin eggs hatched, developed and left the nest.  I have checked the nest to see if another bird would use it.  On 13 July I saw one white egg in the nest; no sign of a mother nesting on it for the past week.  Today (21 July) I discovered another egg, still no sign of a mature bird to sit on the nest.  I have even checked at night.  What type of bird lays small white eggs and uses an existing nest and how long can the eggs sit without incubation before they are no longer viable?

Answer
There are lots of birds that lay small white eggs and might use another bird's nest, so I can't tell you what it might be. Also you didn't tell me where your live, so I can't even guess. The eggs can sit for a month at least without being incubated unless the weather is very hot or cold.