When I cleaned the box last week, I took the opportunity to collect the non-viable egg “Gabuda” (Wiradjuri for ‘egg’. It appears to be unfertilsed based on the clarity of the contents.
The egg is being ‘candled’. This simply means holding a torch underneath the egg to see its contents. Peregrines’ eggs are blotchy, so interpretation is not as simple as with chicken’s eggs, but if fertilsed there would be dark patches and/or veins visible.
The egg will go to the Australian Museum. Last year’s would have gone to, except that it broke.