Lock them in for 2 days, with food and
water, of
course. They'll bond with the space and should come back to roost at night.
Additionally, is there any way you can block them from roosting underneath? If you could put a temporary
fence around the base of your egg mobile, they will get frustrated trying to get under there.
"The rule of no realm is mine. But all worthy things that are in peril as the world now stands, these are my care. And for my part, I shall not wholly fail in my task if anything that passes through this night can still grow fairer or bear fruit and flower again in days to come. For I too am a steward. Did you not know?" Gandolf