Also a common pattern in biological ecosystems. Great weather one year leads to lots of fresh grass around, so more rabbits than usual survive to adulthood. An

Also a common pattern in biological ecosystems. Great weather one year leads to lots of fresh grass around, so more rabbits than usual survive to adulthood. An abundance of rabbits leads to more foxes than usual surviving. But the next year the increased fox population over-hunts the rabbits, crashing their population, and the next winter the underfed fox population crashes in turn, allowing more rabbits to survive to adulthood... etc. etc.