One of the backyard Muscovy females (not sure which one) started laying eggs in a nest under my front window and returned religiously for 10 straight days, laying one egg a day. The nest was a little odd in that it had no feathers to soften it, it was just an indentation in the sand with leaves and twigs to line it. She rearranged the eggs each day, sometimes covering them with the leaves and sometimes just leaving them all out in the open.
On day 11, I was expecting yet another egg but instead I found that one egg was broken open on the edge of the nest. It was not eaten, just broken so I thought she was just clumsy when rearranging the eggs. She left the broken one in the nest. And there were no new eggs. So now there were just 9 unbroken ones but the nest did not look any more disturbed than the usual daily rearrangement, other than the broken egg. I took the broken one away and cleaned off a few of the eggs that got sticky from it.
Later that day there was a random egg dropped in the backyard.
It is now day 14 and it has been 3 days and no new eggs have appeared in the nest nor has it been touched at all. I found another random egg dropped in the backyard yesterday.
I put the 2 random backyard eggs in the nest just in case it was the mom's and she was confused or reluctant to use the nest for some reason.
So is the nest abandoned after 3 days of inactivity? Or should I wait longer to see if she will return? Does it make sense to try to incubate these eggs if she does not return, and how long is it safe to wait?
This is a photo from Day 10 where everything looked good.
This is one from Day 11 - note broken egg at top left and some eggs covered..