What animal is this skull from?

Answer

Dear Esther,

this leg is not a skull, but the synsacrum and pelvic bone of a bird, most likely a pigeon, although there is no size indication.

The synsacrum consists of fused lumbar and sacral vertebrae, and is also fused with the pelvis itself. The spine is in the midline, we look at the back of the animal, the body and head connect towards the top of the image. Towards the bottom only the coccyx fits in the midline.

The pelvis of birds, in contrast to the pelvis of mammals, is not closed towards the belly (so in photo on the side of the shelf), it remains wide open.

The two fine bones that protrude backwards are the pubic bones, but better known in birds as the leg bones, because the egg that is laid passes between these bones. In females, especially in laying, they are wide open.

You will notice that a joint socket is present on the sides of this bone (not in the photo). The head of the femur fits in that bowl, so that the walking legs connect to this skeletal part.