What if you have MORE than 7 bluebird eggs in one nest? The odds are:
- Two clutches of eggs have been laid in the one box. One set may be old and won’t hatch, while the other might hatch.
- If some of the eggs are buried under nesting material, they are from an earlier clutch, or a clutch laid by another bird that has lost/abandoned the nest site.
- You have sister wives – more than one female laying eggs in the box. Both may incubate the eggs, and may be paired with the same male.
- You may have an egg dumper. This is when another female that does not have her own nest lays eggs in a nest started/being used by another of the same species.
- Note that CHICKADEES and WOOD DUCKS lay a LOT of eggs in a clutch.
What to do?
- Wait and see what hatches. Next time you check the nestbox look to see if the black spots on the egg shells are fly specks. If you see black dots on eggs shells, they may be from Carrion Flies that can smell the rotten eggs and will be crawling around on them leaving their black watery feces on the eggs.
References and More Information:
– Human Footprint, PBS