I guess Mon is not quite as stupid as I thought. Perhaps half as stupid?
A while ago, I put a fake egg in the left nest, mainly to distract Monta, who is very possessive.
For some reason though, this month they are both getting along very well and Monta doesn’t seem to mind Mon being in the nest. So the fake egg turned out not to be necessary this month.
Anyway, Mon laid another five eggs around the fake one. Then today, she kicked the fake egg out of the nest! I didn’t realize she recognized the difference! It is a slightly different shape though.