Is it permissible to purchase one of the types of birds whose lineage branched from two birds stolen approximately one hundred years ago?

It is forbidden to buy birds or other items from someone if it is known that they are stolen or not owned by the seller. However, mere suspicion does not make the purchase forbidden. If a person is certain that the item is stolen or usurped, or that the seller does not lawfully own it and is not an agent for it, then it is forbidden for him to buy it.