When a colony swarms, the cluster leaves the hive and, in this model, drifts across a property boundary toward a tree on the neighbour's land. Whether the beekeeper still owns that swarm once it crosses the fence line is a classic property-law puzzle: bees are wild animals (ferae naturae), but a beekeeper keeps a qualified property in them while hived, and — under long-standing common-law principle — can retain ownership while in fresh, continuous pursuit of an escaped swarm. That right weakens with delay, and entering someone else's land to retrieve it without consent is a separate matter from ownership: it can be trespass.
This is a simplified, illustrative model for education, not legal advice. Real disputes turn on the specific facts, jurisdiction and case law — always seek professional guidance for an actual ownership or access dispute.
A 3D scenario of a swarm leaving its hive and crossing a property boundary, showing how pursuit, timing and a neighbour's permission decide who keeps ownership of the colony.
Ownership of a swarm follows pursuit and time, not just where it lands: catching it in flight or reclaiming it promptly with consent keeps it yours, while unclaimed delay can make it fair game for someone else.
Set the hive's distance to the boundary, your pursuit speed and the wind drift, then release the swarm. Toggle the neighbour's permission to see how crossing the fence to retrieve a settled swarm changes from trespass risk to lawful recovery.
Common law has long treated a beekeeper's claim over an escaped swarm as strongest while in fresh, continuous pursuit — a principle echoed in disputes over other roaming animals, from bees to livestock.