Food shortage. Cull the older and least fit individuals, and the younger ones can stay healthy through the shortage and then reproduce more readily after it is

Food shortage. Cull the older and least fit individuals, and the younger ones can stay healthy through the shortage and then reproduce more readily after it is over. Overpopulation. If the species is too successful, it may overgraze its environment and cause its food species to crash, leading to mass starvation of both the subject species and any other species that eat the same things, or anything the subject species begins to eat because its preferred food is scarce. This is the usual reason why deer herd management issues extra doe tags for a hunting season.