Does can give birth to from one to three fawns, uncommonly four, and, this is hearsay, but five are said to have been born to a single doe. Usually the does have two fawns. In keeping with their flexibility as survivors, whitetails have a "strategy" for good years and bad years. In the poorest years a doe might not breed at all; in a bad year she will have a single, and in a normal year she will usually produce twins. If, in a good year she used her energy surplus to just make a bigger fawn, she would probably have trouble giving birth to it. If, in a bad year she tried to grow twins, the twins would be malnourished in the uterus, the pregnant doe would be starved and weakened so she would be more likely to be taken down by predators, or to get sick. If the doe and her fawns somehow made it to a successful birth, the doe would not be able to produce enough milk for the normal growth of her two fawns, and the fawns' odds of survival in those dangerous first days of life would be worse than normal...and normal is very high risk.
Sometime before delivering her new fawns, the mother doe will drive off last year's male offspring. Male deer have no inhibitions about trying to breed their own mother. She will however tolerate her female offspring, and whitetail often form maternal family groups. The actual birth can take minutes to hours. It is touching and almost painful to watch new fawns, struggling to manage their long, stick like legs, some of them collapsing repeatedly, resting between efforts. At this stage right after birth, the fawn does not know that it is a deer, and might follow, anyone. The mother doe, in these first "getting to know you" days, has to sometimes claim back a fawn that goes to another doe, ready to follow her as its mother. Sometimes a fawn that tries to call another doe "mom" will be bluntly run off. Sometimes a doe will obligingly accept another's fawn that wants to nurse.
The mother cleans, inspects, and then leads her fawns from the birthing area to hide them while she returns to eat the placenta. She does this to remove the scent of blood, so they will all remain as invisible to predators as possible. The placenta is most likely a source of quality nourishment as well for the doe that must now go on to produce the rich deer milk.
The hiding fawns are helped by their lack of body scent for the first few days. When in a few hours the fawns are more oriented, they will hide with a vengeance. If they sense any movement at all they might drop to their bellies like a trained soldier; sometimes they just collapse like a pile of sticks and will not move from even the most awkward position. If they are old enough to be curled up in the typical "cute fawn" position, they will hold as still as the earth, keeping their heads up and alert or tucked down if that was their posture when they spotted trouble. Some might bolt at a thing's approach, but others, usually those who are only hours to a few days old, will hold tight even as a mowing machine comes down on top of them.
An amazing example of the resourcefulness of a fawn was displayed when I had to retrieve twin fawns whose mother had died from mastitis. I found one twin, but couldn't find the other. I walked the pen, which had foot high grass, over and over. I checked the fence closely to see if he could have escaped. Nothing. Finally, in my continued search, I caught something out of the corner of my eye. It was the three day old fawn carefully slipping along the fence. He had been moving from spot to spot to elude me, so that I was always looking where he wasn't!
Does and fawns do not instantly bond. The bond gradually builds by suckling and mutual grooming. The doe stimulates and consumes the urine and feces of the fawn, again to eliminate scent, and again probably as a source of nourishment. A doe will sometimes protect her fawn if the predator is small, but more often she will not. Many fawns are lost to predators and does often must stoically move on without the fawns they produced, this breeding season a loss. The mother-fawn bond can also be broken in cases of starvation in which a doe will drive her own fawn away from a food source. That is nature's strict law for the species: the fittest come first. A doe can make more fawns, but she must be fed, alive and healthy to do it.
Fawns
Fawns
I take that life if I can, with regret as well as joy, and with the sure knowledge that nature’s ways of fang and claw or exposure and starvation are a far crueler fate than I bestow. – Fred Bear