1The taking of possession also includes confinement, as in the case of bees, which  are wild by nature. For if they settle in my tree they are no more mine, before I  shut them into a hive, than are birds who make their nest there, and therefore if  another hives them he will be their owner. A swarm that flies out of my hive is  taken to be mine so long as it remains in my sight and its pursuit is not impossible,  otherwise it becomes the property of the taker. But if another takes it he does not  make the swarm his if he knows it belongs to another; indeed he commits a theft  unless he has the intention of restoring them.2 All these rules are true, but sometimes  and in some places other rules hold good by custom.
Of tame beasts and birds.
 3What has been said applies to animals which always remain wild. But if wild  animals are tamed and customarily go and come back, or fly away and return,  as deer, peafowl and pigeons, another rule is applicable, [namely], that they are  taken to be ours so long as they have the intention of returning, for if they cease  to have that intention they cease to be ours. They are taken no longer to have the  intention of returning when they lose the habit of returning. The same is true of  wild hens and wild geese that have become tame. With regard to domestic animals  a third rule is applicable, that though they fly out of my view they remain my hens  and geese, no matter where they are, and he who takes them with the intention of  keeping them commits a theft. This sort of occupation is also applicable to those  captured from the enemy, as where free men are made our slaves; [if] they escape  from our potestas they recover their original status. Occupation of this kind also  applies to things common to all, as the sea and the seashore,4 and to precious stones,  gems and other such things found on the shore. So too it applies to islands arising in  the sea and other such things and to those left derelict,5 unless there is a custom to  the contrary because of the privilege of the fisc.6
[Dominion] is acquired by accession according to the jus gentium.  7By the jus gentium the dominion of things is acquired through accession, discernible  or imperceptible, whether effected by growth or conjunction. The young born of  animals