How long of a window should we expect for the fourth egg to hatch?
Could be happening right now or it could be tomorrow or the next day. After that the gap between the chicks' ages may start to work against the last one in terms of his/her development and ultimately their survival. We generally don't have problems like this, mostly all our chicks hatch out in about 24-30 hours. And it may be that that egg won't hatch, Princess and Trey used to lay four then get rid of one egg in the first week of incubation. We all assumed it was because they knew it wasn't viable. In 2007, they laid four eggs but one was half the size of its companions so we were sure it wasn't viable but Princess and Trey knew better and that chick did just fine in the end - and without any help from anyone but her family.
Not sure if I should post this here and if not sorry. It is related to the watching of the chick. Apparently there is a weather watch for Winnipeg for very high winds gusting to 90 km per hour. Not sure of the wind direction or how it will affect Princess, Ivy and the chicks.
Look forward to your updates as I can't watch at work.
Yup, wind warning for here in Winnipeg. Its blowing like crazy but there is tons of sunlight and blue sky and its dry. As for the peregrines, they are in a west-facing nestbox with three full sides, a covered section at the back of the box and a high front lip to the box that is blocking much of the wind. The birds may get muffed up in the box and have to "stick" their landings, but everyone in the box is in great shape, high, dry and protected from pretty much everything!