Thursday, June 4, 2020

Bucks, does and fawns: All about deer

Editor’s note: This is part one of a two-part series.

Following Bergman’s Rule, white tails in colder climates will be larger on average than deer in warmer climates, as larger deer in colder climates are more likely to survive cold winters, thus surviving to breed and pass along their genes for superior size. Adirondack bucks average about 200 lbs, with mature females at about 160 lbs.

While deer flourish in widely varying habitat, ideal habitat tends to be woodlands, river valleys, forest edge, swamp, meadow and farmlands. The Adirondacks, with its rough mountainous terrain, is not good habitat, and most of the hunters who hunt in the Adirondacks are here as much for the beauty and splendor of an Adirondack autumn, and would more likely find more deer in their back yards or local forest, than they will up here. 

Deer are mainly browsers, feeding on leaves, shoots, woody stems, shrubs, bushes or fruits. They also consume large quantities of forbs, mainly broad leaved, flowering plants, which are not grasses, sedges or rushes. Some grasses are grazed, along with some lichens and mosses. But deer are also opportunistic and will eat bird’s eggs, and even nestlings. Food proportions change season to season, based on availability, and while there is no season in which browse is not their main source of food, the highest percentage of browse is consumed in the winter, while the highest percentage of forbs are consumed in Spring and Summer. Special circumstances like nursing does, rutting bucks, etc. require higher quantities of food. Mature deer eat about five to seven pound of vegetation a day.

Bucks spend a great deal of nutrition growing those impressive antlers, which begin to sprout in April, and are quite sensitive, as they are covered in a fuzzy skin called “velvet”, which contains nerves to keep the buck aware of physical obstacles in the immediate surrounding of the growing and vulnerable antlers, and blood vessels to feed oxygen to the antlers, which consist of cartilage, and two types of bone. The cells of interior “spongy” bones enable the inflow of nutrition and growth regulating hormones, and the hardened bones which make up the exterior of the antler, and whose gradual thickening will serve as the main weapons in the jousting and pushing of the rut. 

As the antlers reach full size in August, the velvet covering the hardened antlers dies and dries, and is sloughed off by bushes, tree branches and gravity. Like boxers in training camp, the bucks begin to spar with each other in preparation for the rut. As with bull moose, large, experienced bucks will spar playfully with youngsters preparing for their first rut. As they approach the November rut, buck necks thicken, preparing for the impact of serious fighting. The number and size of the tines on the antlers not only attract deer trophy hunters, but also signal the bucks readiness for the rut, and their desirability as mating partners to does.

Mating habits

White tail mating season in the Adirondacks peaks in early November. Does go into estrus during this period, but are only receptive for about 24 hours at a time. What triggers estrus is not entirely clear, but most research cites a “photoperiod” meaning length of daylight, which would explain why estrus periods vary from climate to climate, with latitude the most important factor in providing the photoperiod.

Does leave hormonal clues, mainly melatonin, announcing their condition as they move around, and aroused bucks follow these scents, often sparring with other bucks, for the right to mate with does, when the does are receptive, or to stay near the does, waiting for them to come into heat. Bucks become so focused on mating, that they will forgo eating. The rut naturally weakens them, and local predators like wolves and cougars will exploit that vulnerability. Does who are not impregnated during the main rut, may enter a second estrus period in early December, which may lead to a second rut. Like moose, bucks will drop their antlers after the rut season is completely over, in the Adirondacks usually around New Years. 

Bucks who have successfully mated with does, may hang around the doe until her estrus cycle has ended, to discourage other bucks from mating with her. This type of behavior, protecting male semen, is found in a wide range of animals, even down to the insect world, where male damsel flies actually have a scoop appendage to “scrape” out the semen of other males who mate with their intended after they do. 

While I’m generally very skeptical about any explanation that smacks of teleology, the belief that nature has a purpose which manifests itself above and beyond the actions of individuals within a species, often used as a proof of a creator or intelligence which guides what happens in nature, this is indeed a fascinating observation.  

I’ve always scoffed at the notion that the buck mounts the receptive doe in order to insure the continuation of his genes, rather than just his compulsion to have sex because it is pleasurable, but here is one argument in favor, in as much as the intricacies of intercourse from “foreplay” to consummation do in fact lead to the continuance of your genes in the gene pool. And it doesn’t always work, as it is not uncommon for two sibling fawns to have different fathers. 

The same thing happens in bear litters. Bear sows may mate with a third boar, even as two other boars are battling to determine mating rights to their unfaithful sow. Someone should tell bucks and boars that fighting over the right to mate with their intended, may be less productive than just running around and mating with as many as you can! 

This is the most productive time of year for the deer hunters, but it is also unfortunately the most likely season for car accidents, as aroused bucks are even less careful near roads than they normally would be, and encounter unwary drivers who may be focused on the upcoming holiday seasons.

While a doe can mate at only seven months old, most bucks and does generally mate for the first time during their second year. The doe’s gestation period is about six and a half months Mature does commonly give birth to a litter of two fawns, while first year mothers usually have a single fawn. Mom will encourage a newborn fawn to stand and nurse within 20 minutes of birth, and will lead it to tall brush or grass, where it should be safe from predators, while Mom forages to generate a milk supply for the fawn.

Deer fawns, as well as moose and elk calves, have less odor than one would expect, because predators, over thousands of years of predation on them, inadvertently weed out the “stinkier” prey, leaving the surviving fawns and calves to survive and breed, passing along the genes for less odor. This makes the doe’s strategy of hiding her fawn in tall grass and brush a sensible solution, as they are not as likely to be smelled by patrolling predators, unless they are stepped on by the predator. Folks encounter fawns who are lying down, call us at the Wildlife Refuge to report there is something wrong with the fawn, because it makes no attempt to escape. We respond that the fawn is just doing its job, and you should clear out, as you may be noticed by mom, and the last thing we want is for her to abandon her fawn.

Fawns suckle mom for the first three months, will lose their spots in the Fall, and will stay with Mom, usually through the first Winter, until they go out on their own the following Spring. Deer molt their coats twice a year, having tawnier, deeper tone coats in the Spring, and grayer, duller coats as camouflage for the Winter. 

Photos by Joe Kostoss, “Eye in the Park,” courtesy of the Adirondack Wildlife Refuge

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Steve Hall

Steve and Wendy Hall run the Adirondack Wildlife Refuge and Rehab Center in Wilmington. They've been rehabbing and releasing wild animals for over 45 years, specialize in predators, keep wolves as the cornerstone of their educational program, and have lived in the Adirondacks for the past 20 years. The Adirondack Wildlife Refuge became a non-profit about 10 years ago.

Visit www.AdirondackWildlife.org to learn more.




One Response

  1. Chris says:

    Terrific article. Thanks for the education!

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