According to wildlife biologists, calf crops for elk are also within the range of variability over the past 25 years or so. Survivability of elk calves waxes and wanes for a variety of reasons. Some influences are predator related, some habitat and weather related, some are disease related. Of course, trends in moose populations are also affected by some of these same variables. Some local moose populations, relatively recent arrivals to Wyoming in fact, may indeed be stabilizing or even slightly trending down.
Many factors contribute to big game survival rates.
Studies indicate that herbivory by large populations of elk on aspen and willow communities, coupled with historic lack of a needed wildfire regime, probably plays a part in lower moose numbers and depresses other wildlife species populations like songbirds and beaver as well. The same thing likely happens here in Jackson Hole. Diseases affect elk populations. Our elk in western Wyoming are probably sicker than any elk herds outside a research facility or game farm in North America. Our elk are susceptible to these and more.