Photo Share: Should you remove unhatched eggs from a nest?

Hi Sarah,

First baby bluebird

We wanted to share these pictures with you. Our two houses are both occupied with Bluebirds & Black Capped Chickadees. We got that little feeder at your store and its perfect. We take the mealworms out twice a day to feed them.

I read you can train them to come, so I whistle when I go out at breakfast and after supper. She comes out of her nest box as soon as she hears me whistle. He is always nearby as soon as the mealworms are down. It’s so amazing to see!

Tonight we went out a third time to get you the picture on the feeder. She didn’t come out of her box. We are wondering about the bluebird eggs though. The first one hatched on the 8th. Shouldn’t the others have hatched by now? I read usually within 24 hours latest 72 hours. I will check again tomorrow at the dinner feeding.

Do you know if they will remove the other two eggs if they are not fertile? The Chickadee is harder to look at she is always on the nest we have been surprised twice by her so we are leery to keep checking. If you have any input or suggestions on these eggs, please let us know.

I have more pictures I’ll send another time I never have enough hours out in the summer:) Holly

Thank you for the photos!

One of the best resources I’ve found for information on bluebirds is http://www.sialis.org

Their advice about removing unhatched eggs is the following:

NEVER REMOVE UNHATCHED EGGS FROM A NEST UNLESS YOU ARE ABSOLUTELY 150% SURE THE NEST IS ABANDONED, OR ALL OTHER EGGS HATCHED OVER THREE DAYS EARLIER.

In Eastern bluebird nests, about 17% of eggs do not hatch. Sometimes you don't know an egg didn't hatch because the parent removes it.

Reasons can include the following:

Two baby black caps

• Not enough time has passed.
• Most birds lay one egg a day. They don't start incubating the eggs until they lay the last egg. This helps ensure the eggs all hatch together. So just because you don't see adults around doesn't mean the nest is abandoned.
• Depending on when incubation begins, eggs in the same nest can hatch a day or several days apart.
• It could be a new egg from a previous nest
• The eggs were not fertile (because one or both of the parents was infertile.) Note: when bluebirds realize the eggs are not viable, they may build a new nest on top of the other eggs, remove them, or bury them in the original nest material and lay more eggs. The parents may have a series of unsuccessful broods where no eggs hatch (unless one or more eggs were fertilized by a different male due to an extra-pair mating.)
• The eggs got too hot or too cold.
• Pesticide/chemical exposure?
• Defective embryo (e.g., malformed due to temperatures, etc.)
• The eggs were addled (possibly rolled around too briskly when the female was startled, or suffered other trauma).
• The eggshell broke
• The egg belonged to a different species (e.g., a cowbird egg.)