Tag Archives: Kodiak Wildlife

Mountain Goats (Oreamnos americanus)

Kodiak Wildlife, Mountain Goat, ,

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It is estimated that 100,000 mountain goats live in North America. They occupy steep mountain ranges from the Cascade and the Rocky Mountains to Southcentral Alaska. Mountain goats occur naturally in the Southeast Panhandle and north and west to Cook Inlet. In Southcentral Alaska, goats can be found in the Chugach and Wrangell Mountains. Mountain goats have been successfully introduced to Baranof Island and Kodiak Island.

From 1952 to 1953, eleven female and seven male goats were transplanted from the Kenai Peninsula to Hidden Basin near the head of Ugak Bay, approximately 30 miles from the town of Kodiak. After a few severe winters, it was uncertain whether any of the transplanted goats had survived, but a 1964 aerial survey counted 26 goats. By 1972, biologists estimated that 100 goats lived on the island. By 2004, the population was estimated at 1560 goats, and by 2013, it had increased to 2500 animals. Goats now occupy every suitable habitat on Kodiak, and biologists are concerned that there are too many goats for the habitat to sustain.

While steep mountain cliffs are barriers to most animals, they are the preferred habitat of goats. Forested valleys, on the other hand, tend to be barriers to goats, because goats live not only where they can find an adequate food supply but also where they can quickly and easily escape predators such as bears. The steep slopes where goats live are easy for them to maneuver but are inaccessible to predators.

Mountain goats are both grazers and browsers. They eat sedges, ferns, mosses, and lichens. They spend their summers in the high alpine meadows where they consume sedges, forbs, and shrubs. During the winter when there is less food available, goats eat whatever they can find, including blueberry, hemlock, and lichens. Recent research on Kodiak indicates that fern rhizomes are an important part of the goats’ diet in early summer before and during vegetative green-up, but as the summer progresses, goats switch from ferns to sedges and forbs. Goats particularly seem to favor feeding sites with abundant long-awned sedge.

Mountain goats live an average of twelve years but may live as long as eighteen years. They inhabit an extreme environment that harbors a number of threats. Some of the main causes of death for goats include malnutrition, bear and wolf predation (although on Kodiak, there are no wolves), avalanches, falling, and human hunters. The ability to survive the winter depends on the goat’s body condition in the fall and the winter food supply. Mortality spikes in October during the first snowfalls and biologists surmise this is probably due to avalanches and the risks of traveling between summer and winter ranges, possibly through bear habitat. There is an even larger spike in mortality in late winter when malnutrition becomes a greater threat. Mortality also tends to be higher after a hot summer, and this may be because the most nutritious forage occurs at the edges of snow patches. If it is cooler and the snow recedes more slowly, the period of early-growth sprouting lasts longer than it does when the temperatures are warmer, and all the snow melts at once. Warm summers also cause heat stress.

The goat population on Kodiak continues to grow, and mountain goats have dramatically expanded their range in recent years. Introduced species like mountain goats can have negative impacts on native plants and animals, and biologists are concerned that a high density of mountain goats could adversely impact alpine areas where the slopes are steep, and there is not much soil. There is very little vegetation in this habitat, and goats could easily over-graze the plants that are there. Not only could over-grazing be irreversibly detrimental to the habitat, but it could and probably would cause a crash in the goat population. Researchers are trying to determine how many goats the alpine habitat on Kodiak can support, or in scientific terms, they want to find the carrying capacity for mountain goats on Kodiak. Biologists are concerned that mountain goats may have already exceeded their carrying capacity on the island, and current ongoing research by the U.S. Fish and Wildlife Service and the Alaska Department of Fish and Game is focused on better understanding exactly what and how much a goat eats over the course of a year.

 

 

 

 

 

Sitka Black-Tailed Deer (Odocoileus hemionus sitkensis)

Kodiak Wildlife, Sitka black-tailed deer, , , ,

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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

Kodiak Wildlife, Mountain Goat, Sitka black-tailed deer, , , , , , , , ,

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?

 

 

End of Summer

Kodiak Wildlife, Living in the wilderness on Kodiak Island, , , , , ,

 

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Our summer wildlife-viewing and sport-fishing trips ended three days ago. It was time for them to end because summer is over here on Kodiak Island, and a fall storm broadsided us with our last group of bear viewers. They were good sports as we fought through the wind and rain to watch bears. The bears didn’t seem to mind the weather and put on a fantastic show, and while our guests loved watching sows chase salmon while their cubs played, we were all very wet by the end of the day. I love our September bear-watching trips, but I am tired of fighting boats in the wind, and I admit I am ready for a break. It is time to let my bruises heal and curl up with a blanket on a rainy, windy day instead of pulling on my foul-weather gear and heading out on a boat. dsc_0590b

We had a great season this year. No two days of our summer trips are ever the same, and every minute is as much of an adventure for us as it is for our guests. In July, we enjoyed great salmon fishing, and halibut fishing was good most of the summer. We saw bears in July, but they weren’t concentrated in any one place. As the summer progressed, the bear viewing steadily improved, and by September, we enjoyed phenomenal bear viewing every day. We watched several sets of sows and cubs this summer, and while our guests crouched behind fallen trees on a riverbank, they were thrilled by bears that fished only a few feet from them. They were so close; they could hear bones snap when a bear bit into a salmon.dsc_0204-2

We saw whales nearly every day of our summer season. Huge fin whales surfaced beside our boat, while humpbacks raised their flukes in the air. We saw killer whales a few times, and once, they swam over to us when we were in our 19-foot whaler, jumping beside the boat and playing in our wake. We saw dozens of sea otters and countless bald eagles every day, and we watched Sitka black-tailed deer prance along the beach while red foxes dug for clams.dsc_0287-2

On the sport-fishing front, our guests caught 17 halibut over 40 lbs. (that’s what it takes to make the Munsey’s Bear Camp halibut club) and many more halibut between 20 and 40 lbs. The largest halibut of the summer weighed 128 lbs. We enjoyed great pink salmon fishing in July, but we had a poor silver salmon run.

Michael Acela and his 128-lb. halibut
Michael Acela and his 128-lb. halibut

As always, we had guests from around the world, and we shared many laughs on ouradventures with them. Summer always seems to fly by too quickly. Sure, by mid-September I’m tired, but come next June, I’ll be excited for our summer season to begin again.

Visit our Munsey’s Bear Camp website for more information about our summer trips. If you haven’t signed up for my free Mystery Newsletter yet, head over to my home page and do that now. My newsletters chronicle true crime stories from Alaska.

Gordy Sexton with his 87-lb. halibut
Gordy Sexton with his 87-lb. halibut

Steller Sea Lion, Part 2

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This week I’ll tell you a little about Steller sea lion reproductive behavior and biology.

Steller sea lions use both haul-outs and rookeries.  Rookeries are breeding colonies where sea lions mate, and females give birth; and haul-outs are areas where sea lions rest.   Rookeries are used during the mating and pupping season by adults and pups.  Haul-outs are sites used by some non-breeding adults and sub-adults throughout the year and by adults during times other than the breeding season.

Female Steller sea lions reach sexual maturity between the ages of three and six, and most breed every year.  Males are sexually mature between the ages of three and seven, but they are not physically mature and large and strong enough to hold territories until they are nine to ten years old.  Male Stellers are very territorial, and holding and defending a territory is physically exhausting.  Not only must they sometimes engage in fierce, often bloody, fighting with other bulls, but a male often goes without eating for one to two months while he stays on the rookery to defend his territory.  Because of these exhaustive physical demands, males hold territories for an average of only two years, which means they only have a few mating seasons.  It is probable that most males never breed, but the largest, strongest, most successful bulls are those that hold territories, and they mate with many females, passing on their genes to the next generation.

Bulls come ashore at rookeries in mid-May, and they use vocal and visual displays to establish territories, sometimes fighting with other males.  Bulls defending a territory will remain on the rookery until mid-July without eating or drinking.  Females arrive soon after the males and give birth to a single pup within three days of their arrival.  Females remain with their pups for five to thirteen days before leaving the rookery every one to three days to feed, and feeding trips generally last less than 24 hours.  Pups usually nurse for one year, but unlike other pinnipeds for which weaning is predictable, Steller pups may continue to nurse for up to three years.  Mothers use smell and vocalizations to create a bond with a newborn pup.

Approximately two weeks after giving birth, a female Steller will mate again.  Like many other animals, Steller sea lions exhibit delayed implantation.  While a female breeds in June, the fertilized egg does not implant on the uterine wall until October, making the gestation period, from implantation until birth, approximately seven to eight months.    Pups are able to swim and crawl soon after they are born.  They are approximately 3.3 ft. (1 m) in length and weigh between 35 and 50 lbs. (16-22.5 kg). 

 Next week’s post will cover some surprising new research about Steller sea lions and a possible predator that may be at least partially responsible for the decrease in Steller populations in the North Pacific.

Once again, if you like mysteries and true crime, sign up for my Mystery Newsletter on my home page.

 

 

Steller Sea Lion

Kodiak Wildlife, Steller Sea Lion, , , , ,

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Steller sea lions are impressive animals, and you wouldn’t want to run into one in a dark alley, or even on a fishing dock.  A large bull can way over a ton, and they have a have nasty attitudes to go along with all that blubber.  For all you Star Wars fans, I’ve always imagined that Jabba the Hutt was created with a Steller sea lion in mind.  For this post and the next two, I will write about Steller Sea lions, their biology, distribution, social structure, and some amazing new research pinpointing a surprising possible predator of Stellers.

The Steller or Northern sea lion (Eumetopias jubatus) is a member of the order Pinnipedia, which includes harbor seals and walruses, and it is the largest species in the family Otariidae, the “eared seals”.  This family also includes the California sea lion and the Northern fur seal. Otariids, unlike phocids (the “true seals”), have external ear flaps, an elongate neck, long fore flippers used for propulsion, and hind flippers that can rotate, allowing sea lions to use all four limbs for movement on land.  They are called sea “lions”, because adult males have thick necks with long fur on the neck, resembling a lion’s mane.  Steller sea lions were named after German physician Georg Steller, who was the naturalist on the 1741 Russian expedition led by Vitus Bering.

Steller sea lions are found from southern California, along the coastline of the Pacific rim to northern Japan, but most of the breeding rookeries are located from the Gulf of Alaska to the Aleutian Islands.

Steller sea lions exhibit marked sexual dimorphism.  Males, on the average, are 1.3 times longer than females, but they weigh 2.5 times more than females.  Adult male Stellers average 1500 lbs. (750 kg) and are 9 ft. (2.7 m) in length.  A maximum-sized male can weigh as much as 2500 lbs. (1120 kg) and be 10 -11 ft. (3-3.4 m) in length.  Females average 600 lbs. (272.7 kg) and are 7 ft (2.1 m) in length, but may weigh as much as 770 lbs. (350 kg).

A Steller sea lion has a hefty body and a blunt snout.   A male has a distinctive forehead and a mane of long hair on the back of his neck, shoulders, and chest.  This mane not only protects him from cold air and water temperatures and from jagged rocks on his haul-outs and rookeries, but it also protects him when fighting with other males.  Pups are dark brown at birth, and since the tips of their hair are colorless, they appear frosty.  Their hair lightens after their first molt.  Adults are blonde to reddish- brown with dark- chocolate-brown on their undersides and flippers.  Females are usually lighter in color than males.  A Steller’s fur is thick and coarse, and they shed or “molt” their fur every year.  The molt takes approximately four weeks and occurs in the late summer or early fall.

A sea lion has a streamlined body shaped like a torpedo, which reduces drag when moving through the water.  This streamlining is due to a thick layer of blubber under the skin.  Stellers have long, wing-like fore flippers that they stroke up and down to thrust themselves through the water in a movement that resembles flying.  They use their hind flippers for steering.  Unlike harbor seals, sea lions are able to fold their hind flippers under their bodies to walk on land.  They are quite agile on land, and an adult male Steller can easily out-run a human.

Stellers, like all eared seals, have small, external ear horns. Biologists believe that hearing is one of the most important senses for a sea lion, and they probably have acute hearing under water and fairly good hearing in air.

Steller sea lions are very vocal.  At a haul-out, you may hear growls, roars, and grumbles from the older sea lions, along with lamb-like vocalizations from young pups.  Unlike California sea lions, Stellers do not bark.

I’ll have more about Stellers next week. Meanwhile, if you haven’t already done so, visit my home page and sign up for my Mystery Newsletter.

 

 

Sea Otters Part 2

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Sea otters are well adapted to their marine environment.  Their nostrils and ears can close when diving, and they are able to change the refractive power of their lenses so they can see clearly in water as well as in air. The skeleton of a sea otter is loosely articulated and has no clavicle, allowing the animal a great deal of flexibility when swimming and grooming. A sea otter’s hind feet are flattened and webbed much like flippers, and the fifth digit on each foot is elongated, allowing the otter to swim more efficiently on its back. The front paws are short and have extendable claws and tough pads on the palms, enabling the otter to grip slippery prey, and the teeth are adapted for crushing hard-shelled invertebrates.  Sea otters have large, lobulated kidneys that allow them to conserve water and maintain water balance while living in a saltwater environment, Their kidneys efficiently absorb water and eliminate excess salt in urea, a waste product more concentrated than sea water. Sea otters are very buoyant due to their large lungs, which are two-and-one-half times bigger than those of a similar-sized land mammal.

Sea otters are not particularly streamlined, and because of this, they are the slowest swimming of all marine mammals. Top speed for a sea otter is 5.6 mph (9 km/hr), but speeds of 2 to 3 mph (3.2 to 4.8 km/hr) are more common. Sea otters usually swim on their backs while paddling with their hind flippers, but when an otter needs to travel quickly, it swims on its stomach and undulates its entire body. Sea otters are graceful in the ocean, but they aren’t built to travel on land.  It is rare to see a sea otter on land, but some like to haul out on rocks, and on Kodiak, we occasionally see sea otters resting on blocks of ice in the winter.  When they do travel on land, they travel at a clumsy, rolling gait or run in a bounding motion.

Otters generally dive and feed in fairly shallow water, less than 60 ft.(18.3 m), and they normally only stay under water for one to two minutes, but they have been known to dive as deep as 330 ft. (100.58 m) and remain submerged for as long as four to five minutes.  They are able to stay under water this long because of their large lungs that can store an abundant supply of oxygen, and because of their flexible ribs that allow their lungs to collapse under pressure.

Sea Otter eating an octopus
Sea Otter eating an octopus

A marine mammal must maintain a body temperature near 100° F (37.8° C), and in Alaska, where the water drops as low as 35° F (1.67° C), this can be a challenge.  Other marine mammals have a thick layer of blubber to insulate themselves from the cold, but sea otters have very little fat and depend mainly on their fur to keep them warm.  Sea otters have the thickest fur of any animal, with 850,000 to one million hairs per square inch (up to 150,000 per square centimeter). It is their dense, beautiful fur that made them so valuable to fur traders in the 1700’s and 1800’s.

 

The fur consists of two layers.  Long guard hairs form the outer layer, and these provide a protective coat that keeps the underfur dry.  It is this extremely dense underfur that keeps the otter warm, but to insulate efficiently, the fur must be clean, so sea otters spend a large portion of each day grooming and cleaning their fur.   In addition to cleaning his fur, an otter will somersault in the water and rub his body to trap air bubbles in his fur.  These bubbles not only provide insulation but also help to keep the skin dry. Since sea otters must have clean fur to stay warm, they are particularly susceptible to the ravages of an oil spill.  If their fur becomes oiled, it loses its insulating properties. And when an otter tries to clean his oiled fur, he ingests the toxins from the oil.  An otter’s underfur ranges from brown to black, with guard hairs that may be light brown, silver, or black. Alaskan sea otters often have lighter fur on their heads, and the fur usually lightens as an otter ages.

 

In addition to their warm fur, sea otters maintain their body heat by burning calories at a rapid rate.  A sea otter’s metabolism is two to three times higher than that of a similar-sized land mammal.  Because its metabolic rate is so high, a sea otter must eat 23 to 33 percent of its body weight each day.  That means that a fifty-pound otter will eat 11 to 16 lbs. (5 to 7.3 kg) of food every day.  Sea otters also maintain their body heat by keeping their forepaws out of the water and their hind flippers folded over their abdomens when resting and floating.  An otter’s paws are covered by very little fur and lose heat rapidly when submerged in cold water.