I think it is safe to say that one of the most well-known and often seen wildlife species is the white-tailed deer. One of the joys of summer is seeing mothers with their small speckled fawns. Typically, we see them once they start moving with their mother, which is right about now for most of the population. My goal in writing about fawns is to clear up two misconceptions: 1) the number of apparently orphaned fawns, and 2) the fawn predation by coyotes.
Fawns are born April through July, with the majority born in June. Most first-year does have one fawn, but twins or even triplets can occur for older females. White-tailed deer fawns are born precocial, which simply means they are born at an advanced state of maturity, being fully furred with open eyes and the ability to stand and take a few shaky steps just hours after birth. Nonetheless, they cannot keep up with their mother while she feeds nor can they outrun predators.
Consequently, for their first few weeks of life their best defensive mechanism is to lie perfectly still and remain hidden while their mothers go off to feed. Mother deer must leave to feed because lactation is extremely energetically demanding, even more so than pregnancy. While mothers feed, fawns are typically left in areas with tall grass or bushes, but occasionally they are left in more open areas. They instinctively lay quiet and still and this instinct is so strong that on one occasion I was in the field when someone accidentally stepped on a fawn. The fawn was unharmed because at the last second it let out a bleat of fear that nearly scared the pants off of my fellow field biologist!
It may seem that white-tailed deer are not good mothers because they leave their helpless young alone. However, they do not go far. The mothers are actually quite protective of their fawns and will often try to distract predators. I worked on a project in Missouri where we searched for and radio-collared (with small break-away collars) white-tailed deer fawns. I recall walking up to a fawn that remained perfectly motionless, until I picked it up, at which point it screamed bloody murder and mother came running. She stayed and kept trying to approach her fawn. She circled and snorted at us until we completed our tasks and left. Mothers can be so persistent that one person in our group was assigned to keep the mothers off of us.
My point is that a fawn alone in a field or in the woods is likely not orphaned or abandoned, and the worst thing you can do for it is to try to “rescue” it. There is an exceptionally good chance that mother is nearby and will return at feeding time.
Regarding coyotes, they do not kill a significant number of adult deer, but they will consume fawns when possible. This is especially true during the first few weeks of a fawn's life when it is unable to travel with its mother. Unfortunately (or fortunately for the coyote), most fawns are born when coyote pups are being weaned and coyotes must hunt more than usual to feed their pups. However, nature has its way of balancing the scales. By birthing most of their fawns in a narrow time window, white-tailed deer ensure a high overall survival of fawns by filling the woods with more fawns than the predators could possibly consume. In ecology, this is a common behavior in ungulates, and it is known as “predator swamping.” Predators will eliminate some deer, of course, but the overwhelming majority will survive until they are able to fend for themselves.
There is no indication that coyote predation or predation in general has any limiting effect on the white-tailed deer population in Ohio. Thus, the predation of fawns by coyotes is likely what is known as compensatory mortality. This means that if they were not killed by predation, a similar number of deer would die from other sources of mortality, such as starvation when the population has surpassed its habitat’s carrying capacity. However, before succumbing to starvation, an over populated herd will decimate ecosystems and do far more damage to other species than coyotes ever could. Nature is the great equalizer. Given a chance, the evolution of increased predation is countered by the evolution of prey defense mechanisms. It seems it is only when we perturb the system that things go wrong.
They are many who villainize coyotes because they are believed to predate an excessive number of white-tailed deer fawns. So, I will close with one of my favorite passages from Aldo Leopold, the father of wildlife biology. Although there are no wolves in Ohio, I think the sentiment still holds.
“We reached the old wolf in time to watch a fierce green fire dying in her eyes. I realized then, and have known ever since, that there was something new to me in those eyes - something known only to her and to the mountain. I was young then, and full of trigger-itch; I thought that because fewer wolves meant more deer, that no wolves would mean hunters' paradise. But after seeing the green fire die, I sensed that neither the wolf nor the mountain agreed with such a view.…I now suspect that just as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear of its deer. And perhaps with better cause, for while a buck pulled down by wolves can be replaced in two or three years, a range pulled down by too many deer may fail of replacement in as many decades.”
- Aldo Leopold, A Sand County Almanac and Sketches Here and There, Thinking Like a Mountain.
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