This particular mummified kestrel was fed a whole mouse and parts of a small sparrow. It is speculated that the bird died due to suffocation.
Previously, it was thought to be dead or injured birds that were captured and then force fed. However, due to the volume of bird mummies found, it seems that these birds were bred for this specific purpose.
The ancient Egyptians thought of birds as spiritual creatures. This kestrel was most likely bred to be killed, mummified, and given as a gift to the sun god Re.
The mummification of a bird was quite a lengthy process. Initially, most birds were gutted and then dried. This one, however, was not gutted. This gives information about what the bird ate (i.e. the force feeding) before death. After drying, it was dipped in a molten resin, wrapped up in cloth and placed at the site.
Osborne, H. (2015). Ancient Egyptians bred and force-fed kestrels as religious offerings to the gods. Retrieved November 7, 2017, from http://www.ibtimes.co.uk/ancient-egyptians-bred-force-fed-kestrels-religious-offerings-gods-1518362
Powell, E. A. (2014). Messengers to the Gods. Retrieved November 7, 2017, from https://www.archaeology.org/issues/124-1403/features/1724-egypt-animal-mummies-brooklyn-museum