Category Archives: Sitka black-tailed deer

Sitka black-tailed deer biology and behavior on Kodiak Island

Sitka Black-Tailed Deer (Odocoileus hemionus sitkensis)

DSC_0434

Twenty-five Sitka black-tailed deer were introduced to the north end of Kodiak Island in three transplants from 1924 to 1934, and another nine deer were introduced in 1934. The deer population has since spread to most areas of the Kodiak archipelago, and despite the limited gene pool from the original small herd, the population appears to be healthy. The size of the deer population fluctuates from year to year, depending on the harshness of the winter, but biologists estimate there are approximately 70,000 deer on the archipelago.

Sitka black-tailed deer are smaller, stockier, and have a shorter face than Columbia black-tails. An average adult doe weighs 80 lbs., while an average buck weighs 120 lbs. Much larger bucks weighing as much as 200 lbs. have been reported. The summer coat of a Sitka black-tail is light reddish brown, while the winter coloration is dark brownish gray. The antlers are fairly small compared to other species of deer and typically have three or four points on either side, including the eye guards. A very large buck might have five points on each side, including the eye guards.dsc_0043

During the summer, Sitka black-tailed deer feed on herbaceous vegetation and the leaves of shrubs. During the winter when there’s snow on the ground, their diet is restricted to woody browse, which is not an adequate diet to sustain the deer over a long period. During the spring on Kodiak, deer range from sea level to approximately 1500 ft., where they forage new plant growth as the snow line recedes. Deer continue to disperse into the higher altitudes as the snow melts, and they can be found anywhere from sea level to 3000 ft. in the summer. After the first frosts in mid to late September, the forage plants die, and the deer move out of the high elevations.

The breeding season, or rut, begins in mid-October and runs through November, and once again, the deer can be found from sea level to 1500 ft. Depending on snow accumulation, Sitka black-tails usually descend below 1000 ft. in the winter. During periods of heavy snow, many deer congregate on the beach or in heavily timbered areas at low elevations. Deer are good swimmers, and at any time of the year, Sitka black-tailed deer can be seen swimming across the long, narrow bays on Kodiak Island.

dsc_0030-2Does begin breeding when they are two and continue to produce fawns until they are ten to twelve years old. Does as old as fifteen normally don’t produce any offspring. Does between the ages of five and ten are in their prime and usually produce two fawns a year. Mating season on Kodiak occurs between mid-October and late November. The gestation period is six to seven months, so fawns are born from late May through June. Twins are the most common, although many young does only produce a single fawn, and triplets do sometimes occur.

Sitka black-tails have an average lifespan of ten years, and the mortality rate for fawns is between 45% and 70%. Severe winters are the number one threat deer face on Kodiak Island. During mild winters with moderate temperatures and little snow accumulation, the deer population increases, but a harsh winter can cause a dramatic population decrease. In contrast, limited, dispersed hunting pressure seems to have little effect on deer numbers in most areas.dsc_0023

Deer are often seen in the town of Kodiak, and in more remote areas of the island where they rarely see humans, it is not unusual to have a deer walk right up to you. Bears sometimes kill deer weakened by a harsh winter, but in the summer, you often see Kodiak bears and Sitka black-tailed deer standing within a few feet of each other on a stream bank. With so much other food readily available, bears do not seem interested in chasing and attacking deer, and the deer do not seem to consider the bears a threat. Nearly ninety years after Sitka black-tailed deer were first introduced to Kodiak Island the population has endured and appears to be healthy.

 

Mammals Introduced to Kodiak Island

Man has introduced every mammal species on Kodiak Island other than the six endemic species (Kodiak bear, red fox, river otter, short-tailed weasel, little brown bat, and tundra vole). We humans have a sketchy history of introducing mammals into ecosystems where they did not evolve. Sometimes these introductions are harmless, but often, they are not. Ecosystems are complicated, and it is impossible for us to fully understand how the plants and animals in a particular habitat have worked together to survive over thousands of years. When we introduce mammals not native to that environment, we change the balance.

It is tricky to introduce a mammal into a habitat where it did not evolve. For example, if an island has birds that nest on the ground and man introduces an egg-eating or chick-eating predator to this habitat, the predator will soon wipe out the ground-nesting birds. Of course, most introductions do not cause such an obvious impact, but the harm is often subtle and occurs slowly over time.

New Zealanders have waged an all-out war on introduced mammals in their country. New Zealand has lost 42% of its terrestrial birds since humans settled the country 700 years ago. Many of these birds were flightless and provided easy prey for introduced mammals such as rats, stoats (weasels), and dogs. New Zealanders are trying very hard to save the few species of flightless birds they have left, including kiwis and penguins, but at this point, it is an uphill battle.

While the mammal introductions to Kodiak Island have not had the disastrous consequences of those in New Zealand, introduced mammals have had an impact on the habitat here. Beavers have altered some watersheds on the island. Their dams can divert rivers and block salmon-spawning streams. In areas where beavers are native, their activity may be beneficial to other wildlife, but in an ecosystem where beavers did not originally exist, they can have a negative effect on riparian habitat. If beavers construct a dam on a small salmon stream, they can destroy the salmon-spawning grounds in that stream.DSC_53

Mountain goats on Kodiak are over-grazing their alpine habitat, and these impacts are now being studied. Sitka black-tailed deer have nearly decimated high-bush cranberries, a species that was abundant before deer were introduced to Kodiak. Other introduced mammals have also impacted the endemic flora and fauna of the island, but most mammals were introduced in the first half of the twentieth century, and those species that survived their initial introduction, are now thriving and are considered part of the complex ecosystem of the Kodiak Island Archipelago.

Over the next few weeks, I will write about several of the introduced wild mammal species on Kodiak Island. These include Sitka black-tailed deer, mountain goats, Roosevelt elk on Afognak Island, reindeer, beavers, and snowshoe hare. I will discuss how the species are doing and how their introductions have impacted the island.

I would love to hear your comments and opinions about mammal introductions. Are they good, bad, or a little of both?

 

 

Spring

Bald Eagle in Flight

According to the calendar it is spring, but in Alaska, we won’t see much evidence of spring for another six weeks. The days are getting longer, and when the sun shines, I can feel some warmth in its rays, but it easily could snow six inches tomorrow, and no one would be surprised if the temperature dropped into the low twenties or even the teens.

After an abnormally warm winter this year, I don’t mind waiting until late May for wildflowers and leaves, but before the first forget-me-not blooms, other signs of spring will be evident. Bald eagle pairs will soar, circle, dive, and even cartwheel during their mating rituals; schools of herring will arrive to lay and fertilize eggs; and baleen whales, seals, and sea lions will follow the tasty herring into the bays. I dream about sitting on our dock on a sunny day, watching whales and other sea mammals chase and feed on herring. Some years the show is spectacular, and other years, the herring run is insignificant, and the whales are absent. The red foxes are also active in the spring, and their haunting mating screams often awaken me. By early June, we should start seeing does and their newborn fawns. By then, the eagle pairs will be tending their nests as their eggs hatch and the chicks depend on them for a nearly constant supply of food.

I am busy this time of year getting the camp ready and the meals cooked for the spike camps for our spring hunting season. I also have a trip planned to visit my family in Kansas in mid-May, so I can watch two of my nephews graduate from high school. Meanwhile, my novel, Murder Over Kodiak, is being re-released by a small publishing company in Anchorage, so I’m preparing for another round of promotion, and that is hard work. The first thing I’m planning to do is to host a “virtual” book-release party on Facebook. I’ll write more about this next week. For now, I’m trying to learn everything I can about hosting a virtual party. It’s overwhelming, and I hope I’m not in over my head! I admit that I have an uncomfortable relationship with social media.DSC_0168

Between my day job, promoting my novel, keeping up with my blog and my mystery newsletter, working on my next novel and my other writing projects, and getting ready for a trip to visit my family, my spring will be busy. No matter how rushed I am, though, if the sun is shining, and the wind is calm, you can find me sitting on our dock, craning my neck to watch eagles circle and soar, and inhaling the sweet, salty scent of the low tide while scanning the beach for foxes eating clams and mussels. I’ll also be glancing hopefully at the ocean for roiling schools of herring, and listening for the powerful exhalations of large fin and humpback whales. Spring is my favorite time of year, and I am never too busy to enjoy it. I’ll let you know what I see.

Fin Whale near Kodiak Island

Tell me about your spring. I want to hear about the beautiful tulips, daffodils and other flowers already blooming in most places, or if you live in New Zealand or anywhere else in the southern hemisphere, how is your autumn?

If you haven’t already done so, sign up for my mystery newsletter. I am working on my next edition. Also, I apologize to anyone who has recently tried to order my novel Murder Over Kodiak. As I mentioned above, it is currently being re-released, and it will be available again soon with a bright, new, shiny cover. I’ll give you a sneak preview next week and tell you about my mixed emotions going from an indie author/publisher to working with a publishing house.

 

Reproduction for Deer, Foxes, and Goats

 

DSC_0434

Spring is an active time for Sitka black-tailed deer, red fox, and mountain goats on Kodiak, especially once the weather warms, the snow on the mountains begins to melt, and the vegetation starts to grow again.  All three species give birth in the spring, and while we rarely see nannies with their kids, we will soon start seeing does and fawns, and in a couple of months we’ll see young fox kits as they begin to play outside their dens.

DSC_1328 (2)

Sitka black-tailed deer bucks begin growing a new set of antlers in the spring, and I’ve seen several with little nubs beginning to grow.  During the spring and summer, the antlers receive a rich supply of blood and are covered by a fine membrane called “velvet”.  At this time, the antlers are very fragile and are vulnerable to cuts and bruises.  By August, antler growth slows, and they begin to harden, and a few weeks later, antler growth stops, blood flow to the antlers ceases, and the velvet dries up and falls off.

Doe_Fawn1

Mating season on Kodiak for Sitka black-tailed deer occurs from mid-October to late November.  The gestation period is six to seven months, so fawns are born from late May through June.  Does begin breeding when they are two and continue to produce fawns until they are ten to twelve years old.  Does between the ages of five and ten are in their prime and usually produce two fawns a year.

DSC_1915_01

Newborn fawns weigh between 6.0 and 8.8 lbs. (2.7 to 4.0 kg), and for the first two weeks, a fawn produces no scent, allowing the doe to leave the fawn hidden and safe from predators, while she browses for food to rebuild her energy reserves after giving birth.

DSC_0168

Red foxes breed in February and March on Kodiak.  Right after mating, the female makes one or more dens, and the extra dens are used if the original is disturbed.  The den is a hole in the ground that measures approximately 15 by 20 ft. (4.57m x6.1m) and may have several entrances.  Inside the den, the female constructs a grass-lined nest where the babies are born.  The litter is born after a gestation period of 51 to 54 days, and an average litter consists of four kits; although, litters as large as ten are not uncommon.  Kits weigh 4 ounces (113 grams) at birth.  They have fur but are blind, deaf, and toothless.  A kit cannot regulate its body temperature when it is born, and the mother must remain with it all times for the first two to three weeks.  During this time, the father or adult females bring food to the mother.  If the mother dies before the kits are old enough to care for themselves, the father will take over as the primary provider.  The kits’ eyes open eight to ten days after birth, and they leave the den for the first time about a month later.  Kits begin hunting on their own when they are three months old.

DSC_53

Breeding season for mountain goats occurs between late October and early December on Kodiak.  Mountain goats seem to avoid mating with relatives, and billies may travel long distances to find suitable mates.  Males breed with several females, but nannies breed with only one male.  Nannies do not give birth until they are at least four years old, and billies between the ages of five and ten do most of the breeding.  Nannies give birth in late May after a gestation period of 180 days, and they normally have only one kid, but sometimes produce twins.  Twinning is more common when goat populations spread into a new habitat with an abundant food supply, and as the goat population on Kodiak has increased and expanded its range, biologists have noticed more twinning than is normal.  Nannies seek out an isolated area to give birth but then form nursery groups with other nannies and kids.  The kid remains with its mother at least until the next breeding season and may stay with her for several years.

It is always a thrill to see the young of any species of wildlife.  Babies are shy but curious as they learn about their surroundings, and often they are unaware of potential dangers.  It is important to remember not to approach any wildlife, but especially mothers and their young, too closely.  If the mother runs one way and the baby the other, they may never reunite, and the baby is not yet equipped with the knowledge and skills to survive on his own.

Check out these pages for more information on Sitka black-tailed deer, Red foxes, and mountain goats.