Migration
Because of
their large size and food requirements, and because mountainous
habitat forces many herding animals to wander during the summer
and fall in search of food, elk often migrate when severe cold
or snow depths make it difficult for them to survive and find
food. The migration is usually from high cold or snow covered
regions, where the elk cannot find food; to lower, warmer
elevations with less snow depth and more easily found food.
Different elk herds may prefer different elevation depending on
snow depth and forage availability. In Wyoming wintering elk are
often found at 6000-7000 feet, while in Idaho they may be at
2000-3000 feet. In the Pete King area of Idaho bulls were found
at 2859 feet and cows with calves at 2770 feet. In the Sun River
area of Idaho elk were found at 5200 feet in December, 5105 feet
in January, 5250 feet in February and 5095 feet in March.
Spring
Elk often use
lower areas as winter feeding grounds. But, with the advance of
spring and new growth, the animals begin a slow migration back
to summer ranges, and the cows usually calve along the way. In
north Yellowstone the spring migration occurs as early as April
while seventy-five miles south, in north Jackson Hole, it may
occur in May. Roosevelt Elk on Afognak Island, Alaska migrate
during May and June. The timing of the migration may vary yearly
by several weeks from year to year, and from herd to another
herd in different locations.
The distance
herds migrate, and the speed of the migration also varies, from
one to as many as eighty miles, and from one day to a week.
Different sexes and age classes also show differences in
migration. Bulls generally migrate first in the spring, because
they don't need to provide extra nutrition for the calves like
the cows do. Bulls and some cows can usually be found following
the receding snow line to higher elevations. The bulls often
arrive at their summer range several weeks before the cows.
Calving
The gestation
period of elk has been reported to range from 247 to 265 days,
with an average of approximately 255 days. Cows usually halt
their spring migration for calving from mid-May to mid-June,
depending on their geographical location. Elk in northern
regions have a calving season of 20-45 days, while Tule elk in
California have a calving season of more than 50 days. Calving
areas are often between open brushy areas that offer food and
coniferous forests that offer concealment and escape. The actual
calving site is usually a low depression on a gentle slope;
southern slopes are often preferred. Water within a quarter mile
is often a key factor in choosing a calving site. Some calving
areas are traditional and are used every year. Individual cows
remain away from the herd 10-20 days before resuming their
migration from mid-July to June. The yearling calves are usually
forced away from their mothers at this time, but they often stay
in the vicinity of the herd. The young bulls are seldom
tolerated, and they may not migrate as far as the older animals.
They often wander in search of new range during their first 3
years.
Summer
During the
summer cows and calves rely heavily on grass and sedges which
make up 50-60 percent of their forage at this time. Browse and
forbes each make up another 20 percent of their diet. Calves
rely more heavily on succulent forage than the cows. In their
search for forage the cow/calf herds frequent open meadows with
nearby shade and cover, and spend up to 85 percent of their time
feeding and resting with very little travel.
The older
bulls do not usually associate with the cows during the summer.
Because they look different with their racks, which makes them
susceptible to predation, their strategy is to stay away from
the cows and calves. They need to renew the fat reserves they
used up over the winter and gain enough fat to get them through
the upcoming rut. They also need enough minerals to grow their
rapidly developing racks. To supply these needs the bulls seek
out areas with high quality foods. Because of the need to avoid
predation, and with the need to find high quality foods (which
are often limited) the bulls may travel extensively over large
home ranges of up to 40 square miles.
Antler Growth
Yearling bull
elk may start growing racks as early as late May. They often
grow a rack with one long point on each side. This point, which
is actually the main beam of the rack, may reach fifteen inches
or more in length. An occasional yearling will grow a 2x2 rack,
and I have seen yearlings with racks having three to five points
per side. The racks of yearlings often have tines of differing
lengths or numbers of tines on each side. Some hunters refer to
bulls with these uneven racks as "raghorns." When a bull elk
grows only one point they are referred to as spike bulls, and
people often refer to any one-year-old bull as a "spike."
Two-year-old bulls often start antler growth in late April or
early May, and continue for 105-125 days, with the velvet being
shed from middle to late August. They often grow 4x4 or 5x5
racks. They usually cast their antlers from mid to late April.
Bulls over
the age of three to four years old may shed their antlers and
begin growing new racks from mide March to early April, and
continue growing their racks for 130-150 days, shedding velvet
as early as the first week of August. Up to fifty percent of
these bulls may have five points per side while the rest may
have six or more points per side. In one study, bulls over the
age of four all had five points or more per side. The antler
growth of three year old and older bulls may take up 150+ days.
I sold a pair of 6x7 shed antlers from a 5-year old bull on
April 6th one year; the antlers had dropped off the
week before.
Up until the
age of seven most of the nutrients taken in by the bulls are
used for muscle and bone growth. By age seven the bulls have
usually reached full body size, which is when some of the
nutrients can be diverted to antler growth. This is when the
greatest growth in antler mass and length normally occurs; and
is known as the "seven year antler spurt." Because of this
antler spurt bulls between the ages of 9 and 12 can be expected
to grow the largest racks. After the rut the prime age bulls
usually leave the cow and calf herds to seek high quality forage
to get them through the winter. If these prime age bulls rejoin
the cow herds they may retain their antlers 10-20 days longer
than normal due to renewed sexual interest.
This article
is an excerpt from the Elk Addict's Manual ($14.95+ $5.00 s&h),
by T.R. Michels.
T.R. Michels
is a nationally recognized game animal behaviorist and
researcher, outdoor writer/speaker and author. His books include
The Complete Whitetail Addict's Manual, Turkey Addicts
Manual, Duck & Goose Addict's Manual, and Elk
Addict's Manual. For more information contact T.R. Michels,
Trinity Mountain Outdoors, 612-310-5585,
TRMichels@yahoo.com or
www.TRMichels.com.
