A note about aviculture practices: the mandarin ducks are in deed likely from
escapees. Many people keep their captive exotic and/or native ducks in covered
pens. The birds are full winged and capable of flight, often doing so in the
large enclosures.
I am currently aware of some swans that are not pinioned, and are
hybrids being kept in open ponds, their wings are clipped. If they are not
clipped yearly these birds will be able to fly.

Martha Jordan