Deuteronomy 14:16

The little owl, and the great owl, and the swan,

The verse belongs to the list in Deuteronomy 14:3-20 of unclean birds and beasts that were excluded and forbidden for food.
The prohibition was not an exercise of arbitrary authority but was given to prevent impurity and to preserve the life and health of the people.
Its health purpose was to keep the blood pure through simple, healthful food so that the powers of mind and body could be retained, pointing the people to the animals least objectionable for food.
These dietary restrictions were later distorted by excessive human rules, such as requiring water to be strained to avoid the smallest insect.