7 out of 8 swarms are expected to not survive their first winter unless captured and rehived by a beekeeper. A few beekeepers in rural or outlying areas feel feel to let their hives swarm each year, for at least 2 reasons. First, this means that their hive will requeen itself each year with a young robust queen. Second, those swarms are just "returning to nature," right? Wrong, it's basically a death sentence unless that swarm is rehived by a beekeeper.
For more about feral hives check out Tom Seeley, Professor Emeritus at Cornell University. He has been doing important research on feral colonies ever since he started studying the feral colonies of the Arnot Forest in the northeastern US back in the 1970s. He has published much research and a number of books about honey bees in the wild. One is “The Lives of Bees: The Untold Story of the Honey Bee in the Wild” (Princeton University Press, 2019), by Thomas Seeley.
Unfortunately, some have misunderstood Tom Seeley's work to mean that honey bees can simply return to nature and do fine without the diseases or pests of managed hives. His research finding are much more complex than that.