A swarm is a clump of bees exposed to the elements , either hanging off a tree, bush, park bench, etc. or spread out on the ground. The bees have not constructed much, if any, honeycomb. Swarms are generally easy to capture. The earlier a swarm is reported, the better. Otherwise, the swarm may leave to inhabit somewhere where it's not wanted. In cold or wet weather, the swarm may perish or greatly diminish in numbers.