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Babes In The Woods

Window-peeking on the sex lives of elk

By David Petersen

"Across most of the wapiti's range, calving season runs mid-May through mid-June, peaking around the first of June."

Here in the San Juan Mountains, as throughout most of their North American range, beginning in late May, beneath the cool shimmering shade of newly leafed aspens, elk calves are born by the thousands. Born: the luckiest of the lot, at least. Across most of the wapiti's range, calving season runs mid-May through mid-June, peaking around the first of June. A few months hence, with the onset of their first and therefore most dangerous winter, early-born calves enjoy a distinct survival advantage over late arrivals.
Foremost, they've had a few weeks longer to gain weight. Born at around thirty-five pounds, in their first six months elk calves will grow to around two hundred pounds, larger than most adult deer. Acquiring strength, foraging skills and social knowledge, all of which take time, also helps to assure survival through the months-long winter gauntlet of deep, delaying, calorie-gobbling snow, numbing cold, lurking predators and slow starvation. As many as half of a summer's crop of calves (and deer fawns) may perish before or during their first winter, if that winter is bad. Since late-born calves enter the cold months smaller and weaker, with fewer caloric reserves and less survival savvy, they are more likely than their slightly older and hardier peers to become winterkill.
The timing of an elk calf's birth is determined, naturally, by the timing of its mother's impregnation the previous fall. Count back 8.5 months from a given birth and there you have it, more or less. The timing of an elk cow's fertilization, in turn, is controlled primarily by the timing of her ovulation, which depends on adequate nutrition to function on schedule. But a cow's ranking in the herd hierarchy also counts for much, with prime experienced cows bullying to the front of the breeding quay. Bull-to-cow ratios and average sire age also figure in. In over-hunted and otherwise poorly managed herds, the bull-to-cow ratio is low, prompting social disharmony and delayed fertilizations. An unnatural preponderance of young bulls leads to inefficient and delayed breeding, stresses both sexes and can extend the rut as much as six weeks, leading to dangerously late births the following summer. In such unbalanced, unhealthy and altogether unnatural social and rutting situations, a higher percentage of cows fail to become fertilized the first time around and must wait three weeks for another ovulation and a second go. And sometimes even a third. The unfortunate calves born late to such unfortunate cows have significantly reduced odds of surviving to adulthood and may be permanently runted if they do.
It's no surprise that human activity is the root cause of most population, social and reproductive malfunctions in elk. While livestock overgrazing has hugely negative impacts on arid western wildlife habitat, logging is just as bad. Not only does logging destroy and disrupt the natural forest ecology upon which elk depend for food, water and cover, but the resulting new roads provide easier access to larger numbers of lazier, sloppier, less nature-connected "recreational users," resulting in yet more damage to fragile ecosystems, increased harassment of wildlife, littering and polluting of soil and water, a heyday for slob road "hunters" and poachers, and all of this further compounded by decreased wildlife hiding cover and the proliferation of non-native invasive plants - such as thistles, hound's tongue and knapweed - which eagerly displace indigenous wildlife forage.
My own backyard mountain is a textbook example of the lower montane ecosystem. Positioned as the middle ground between lower-lying wintering areas and higher subalpine summer range, it provides migrating elk with rich spring and fall habitat. This puts the herds in precisely the right place for calving season, just when and where all the best forage is attaining its nutritional prime. As an expectant cow's time approaches, she leaves the herd in search of good hiding cover with access to nearby food and water. Immediately after delivery - one calf per cow per year is the norm - the mother does what she can to eliminate predator-attracting odors by devouring the afterbirth and licking her infant clean. As soon as it can stand and wobble on sapling legs, the babe follows its mother to a fresh hiding spot, always in the shade, where its white-splotched-roan pelage melts it into the foliage.
Since elk calves (like deer fawns) aren't strong enough in their first days or weeks to escape predators by running, they've evolved a "hider strategy," of which camouflage is but a single element. Infant calves are also nearly odorless. In order to avoid attracting the attention of predators by their own visibility and odor, mothers nurse their calves in brief bouts, move them often and stand watch from a distance. Another critical strategy to the success of infant calf survival during the hider phase is the mother's skill, or lack thereof, in choosing good hiding cover, plus her courage and savvy in defending her young. In any event - whether tucked invisibly into the shade of a clump of brush and grass, or left foolishly exposed next to a fallen tree in the middle of a shaded forest opening - the essence of the hider strategy is catatonia. No matter how threateningly close a predator may approach, the infant remains instinctively still. With luck, the hungry hunter will overlook the immobile morsel and pass on by.
Alas, as survival strategies go, hiding and luck are imperfect. During the first week of June each spring for many years, Caroline and I camped and hiked in Yellowstone's then blissfully tourist-neglected Lamar Valley. Here the elk came by the hundreds to calve and here the big carnivores came to feast. The primary attractions for us were the grizzlies. Happily for the elk, calf hunting is a learned experience in bears and no way universal. While some grizzlies do nothing but hunt during calving time, most continue to graze bucolically on grass and wildflowers. As Caroline and I have observed, only mother bears who themselves are experienced calf hunters seem to teach their cubs to hunt for hiders. It's a family affair and while emotionally jolting to watch at first, this annual spectacle of violence, gore, ecological balance and biological continuation through termination has a beauty all its own, encapsulating the connective circle-dance of all life on Earth.
A local example of the imperfection of the hider strategy played out some years ago, just up the hill from our home on the flank of Missionary Ridge. At the time, the third member of our family was a black-and-gold retriever/setter mix of calm disposition. As we do with all of our dogs, we had trained Amigo not to chase the deer and elk that frequently appear on our walks, sometimes quite nearby. With easygoing Amigo, whom we adopted in his later years, the teaching had been easy. Yet things went weird one early summer evening when a sleek young cow stepped boldly from an oak thicket just ahead and into the open a few yards uphill - then stood stiff-legged and stared.
Given her behavior and the time of year, we knew immediately what was up - or rather, what was down and hiding. Taking our cue from the cow, C and I stopped in our tracks and focused on her, unaware that Amigo had slipped away and was nosing around in the brush from which the cow had come. While the old hound couldn't locate the hider he somehow seemed to know was cowered there, he must have been getting warm because suddenly the cow, being young and inexperienced, lost her cool and barked the doglike elk alarm call. Shocked and confused, the calf jumped up and wobbled toward its mom ? and right into the waiting arms of our old dog. Acting on some dim wolfish imperative, the normally gentle mutt body-slammed the calf, knocking it down. And there they posed, the calf outwardly calm (the silence of the lambs) while Amigo stood proudly astraddle his catch and grinned, tongue happily lolling.
While the cow stood paralyzed I sprinted up, grabbed Amigo by the scruff and jerked him off of the calf - at which happy turn the infant bull rose and hurried to his mother's side. Without looking back, the reunited pair walked - did not run but walked away - apparently little worse for the wear and, one must hope, a wee bit wiser in hiding strategy when trouble is at hand.
In this encounter it was the inexperienced mother, not the calf, who'd buckled under pressure and almost blown the game. Still, the fact that the hider strategy could fail to the extent of allowing a sick old pet (Amigo succumbed to lymphoma just a few days later) to make a virtual kill suggests that it fails with regularity in the face of a wild world teeming with skillful and ever-hungry predators. Our ancestral hunting/gathering forebears, wild predators themselves, knew where to be at ungulate birthing time and made the most of the short-lived bounty. It's almost as if evolution, in shaping such an imperfect defense, intended that a tithe of cervid young become protein for hungry carnivores - who, after all, have their own babes to feed. The savior of the calves is the "short-lived" part. On average, considering the normal time spread of annual births, predators have a window of only a few weeks during which to find and munch helpless hiders. By late June the surviving calves will have doubled in weight and are competent runners. Scattered cow/calf pairs now rejoin in protective maternal herds and the first harsh round of Darwinian culling is complete.

David Petersen, the author of Elkheart: A Personal Tribute to Wapiti and Their World and Heartsblood: Hunting, Spirituality, and Wildness in America, is the Colorado roadless coordinator for Trout Unlimited and state chair of Backcountry Hunters and Anglers.