How to Estimate the Stage of a Nest

When we find a duck nest we candle the eggs to determine the stage of incubation. It is easy to candle, as ducks put little pigment in the shell.

Candling means we look at the developing duckling inside the egg. This technique is decades old.

The photo below shows what you see when looking through the tube. The trick to candling is to make sure the light you see is coming through the egg, not leaking in at the edges of the tube.

 

Unfortunately, this is my best picture and the embryo is on the other side. 

Frank