Complete adult skull, I have put the lower jaw in place.
Top of the adult skull, no transparent parts.
Side view of juvenile skull, this one still needs cleaning.
Top of the juvenile skull, you can see the transparent sections in the skull.
You can see the transparent sections in the skull.
These are some of the Manx Shearwater skulls I found on Skomer Island in Wales. When I got home I had to clean them up by pulling off the feathers that were still left on and then putting them in hot water so I could clean up the skull.
If you look at the photos one of the skulls has thinner sections in it, I think this one is a juvenile bird and the skull hasn’t finished growing.