Just about every time I check on this nest there is an egg on the side. This morning there are two! The temperature here is 61 degrees F.
I wonder if more gravel or larger rocks in the box would help as the scrape seems to be down to the floor of the box.
The eggs are probably fine - and probably not the same egg each time. When I had a look just now, it looked like it has been raining and though I don't watch this site much, it seems like Mom is on the eggs and everyone is tucked up nice and safe. I'm willing to hazard a guess and say it is Dad who is having trouble keeping the kids under control - they are smaller and 4 eggs is alot of real estate to keep covered if you are a male. A bit of time uncovered - up to 1/2 hour if the temperatures are favourable doesn't seem to cause a problem in our experience here - Madame used to get off all the time and leave her eggs uncovered. Don't know the layout of the box, but it could be warmer in there than the ambient temperature recorded - sun shining on the box isn't really cooler, just shadier.
As for more gravel - lots of birds don't like deep gravel - its like walking in soft sand which is not what the peregrines are looking for - and more gravel doesn't a better scrape make. For the last 2 years, Smiley has sucked at making scrapes at the Radisson, he had good form but his scrapes did not. This year, he had a nice bowl shape impression about 1-2 inches deep and the right circumference and nice slope on the walls. Fits an adult peregrine just perfectly but holds the eggs safe from rolling around/away. As for bigger rocks - do you mean bigger gravel? If that is what you mean, then no, the size gravel they have there is perfect - bigger means harder to move and potentially more dangerous for fragile eggs - and has to be more uncomfortable for adults and chicks. The scrape also won't stay where it is right now, as the eggs are incubated and even a bit after the chicks hatch the scrape will migrate somewhat as the adults tuck in under the eggs/chicks and with changes in weather or whatever. Bigger gravel would be a problem for this.
Your last comment was about that the scrape seemed to be on the floor of the box - it is a different box design where there is a box up front for the adults and chicks to use but which operates like a barricade for the chicks when they are young. It also allows for the box to be bigger - often boxes have to be higher to give the birds access over a lip or retaining wall on a building - this design lets them get more room inside by dropping the inside floor. It also helps provide the birds with more shade which at some sites is more of an issue than at others and much much more protection from rain/snow. We have a design like this for the nestbox on the roof at McKenzie Seeds. The nestbox at West Wpg is a variation on the same theme with the bottom of the box being almost the height of a peregrine below the edge of the building. The low ledge we have around the edge of the box allows the chicks to get up and look around when they are old enough so they can get used to the higher winds in this area. If they were to go straight from the bottom of the box to the roof edge, we'd have more chicks fledging prematurely at this site. As it is, the chicks can now get up on that ledge after banding age and then they tend to go down the ramp onto the roof for a couple/three weeks then they start visiting the roof edge regularly and then they are off.
