Life is precarious for newborn elk calves. In their first six weeks, they’re vulnerable to predation from black and grizzly bears, mountain lions, wolves and coyotes, as well as the vagaries of spring weather. But it’s what happens before their birth that often decides their survival. Research shows that birth weight is the most important factor for elk calf survival, which is a reflection of how well nourished the mother was before and during pregnancy. Elk calves are born weighing anywhere from 20 to 44 pounds, with the average around 34 pounds. As birth weight decreases, so do a calf’s chances for survival. Lighter calves are at more risk from predation than taller, faster and stronger ones.
Even if a calf does make it through the first months, when its risk of being eaten is highest, underweight calves remain at a disadvantage. Elk weight at 6 months old is directly correlated to birth weight. And if calves are underweight going into their first winter, they are much less likely to live to see spring green-up.