In 2022, an avian flu strain reached the United States. Over the past year, more than fifty-eight million domestic poultry and thousands of wild birds have died from the viral H5N1 flu strain. According to biologists, it is the largest bird flu outbreak in U.S. history and doesn’t seem to be going away. As its name suggests, the virus mainly affects wild and domestic birds but can also infect mammals.
In Alaska, more than twelve hundred chickens and ducks have died from the avian flu, and it has killed more than two-hundred wild birds, including eagles, ravens, and shorebirds. Biologists have also found the virus in wild mammals, including bears and foxes. Migrating wild ducks and geese spread the virus when they defecate contagious droppings across the areas where they travel.
Scientists have no treatment for avian influenza, and the mortality rate is high for poultry and wild raptors such as hawks, eagles, and owls. Symptoms in diseased birds include fatigue, difficulty walking, nasal discharge, decreased egg production, and swollen combs or wattles.
Transmission to humans is rare, but flu viruses tend to mutate easily, so this disease could affect humans in the future. Scientists have already identified the virus in marine mammals around the world. Biologists have detected outbreaks among seals and other marine mammals in Maine, Chile, and Peru.
The remoteness of most areas in Alaska makes it difficult for biologists to know how widespread the disease is here. In October 2022, researchers found a sick black bear cub in Glacier Bay National Park that tested positive for the H5N1 virus. A month later, a deer hunter on Kodiak Island collected the carcass of a dead brown bear cub that tested positive for the virus. A necropsy on the brown bear cub revealed infection in the cub’s brain, lungs, and liver. Biologists suspect both cubs scavenged on wild birds that had died from influenza and inhaled the virus while tearing the birds apart. Luckily, at this point, the virus cannot be transmitted from bear to bear.
Kodiak bears are at risk if a deadly novel virus spreads among them. A 1998 study on the genetic diversity of North American brown bears indicated that Kodiak bears have less genetic diversity among them than other populations of North American brown bears. Several of the genetic samples from bears on Kodiak showed identical genotypes, meaning the bears were so genetically similar that biologists could not measure the differences between them. According to a 2006 report conducted for the Kodiak National Wildlife Refuge, the genetic variation among Kodiak bears is much lower than the variation found among any other brown bear population. While the Kodiak bear population presently remains healthy, this low genetic variability makes this population susceptible to decimation by novel parasites or pathogens, which could reach Kodiak and infect bears.
If you see a sick wild bird in Alaska, report the animal to a hotline managed by the U.S. Fish and Wildlife Service at 866-527-3358 or by email at ak_mbm@fws.gov. In particular, look for signs of disorientation, twitching, or tremors, and birds with necks twisted back.
For those of you in the Anchorage area, I have a book signing at Barnes and Noble on Saturday, May 27th, from 1-5 p.m. Please stop by and say hi. I would love to meet you. I will be at Mosquito Books at the Anchorage airport on Tuesday, May 30th.
When I reach the end of a manuscript, I dread writing the conclusion because a conclusion requires a great deal of thought and effort. Just as we were nearly done polishing my non-fiction book, Kodiak Island Wildlife, the editor said he believed the book needed a conclusion, and I groaned, but I also agreed with him.
I don’t know how long I stared at a blank computer screen, but I could think of nothing to write. How do you sum up a book about wildlife? Then, as I stood on our boat one morning, watching giant fin whales with our guests, the conclusion for my book popped into my mind, fully formed. When I read it to my husband, tears came to my eyes, and I knew I had done my best work. My editor agreed, and he said it was the perfect ending. The following is the conclusion for my recently released book, Kodiak Island Wildlife.
Emerald cliffs plunge into the gray ocean, and only a slight breeze stirs the surface of the water. In front of our boat, three huge fin whales feed, frequently surfacing to breathe. Their exhalations sound like cannon shots, and our guests capture every moment with their cameras. A sea otter bobs placidly a short distance from our boat, and a bald eagle circles overhead. I have seen all of this many times, but still, it takes my breath away, and a chuckle escapes my lips. How have I managed to live my life in one of the most beautiful places on the planet? To me, Kodiak is paradise. Sure, the weather here throws frequent tantrums, and mistakes in the hostile wilderness do not go unpunished, but I have found nowhere else I would rather live.
One of my greatest joys is to guide visitors into the Kodiak wilderness. I love the look on a newcomer’s face the first time she sees a Kodiak bear or watches a sea otter eat a crab. I wrote this book to honor the wild animals we’ve watched over the years and to thank the many folks who have visited our lodge. I know they would tell you that Kodiak is a special place. The island is mysterious and magical.
It is a short conclusion, but it sums up how I feel and accurately describes my motivations for writing the book. I am grateful for the many experiences I’ve enjoyed. My life is an adventure filled with wonder in the Kodiak wilderness, and I can’t imagine living anywhere else.
Speaking of wildlife, I hope to return to regular and more frequent posts soon. The past two months have been hectic. I’m writing this while I sit on our boat. We are cruising 100 miles around Kodiak Island from our lodge to the town of Kodiak, where we will have our boat lifted out of the water so that we can clean and paint the bottom. As soon as we return home, we have endless jobs awaiting us before our summer season begins. Meanwhile, I am trying to promote my new book and keep up with my scheduled newsletters and podcasts. I realize I’ve let my blog posts fall through the cracks, and I vow to make my posts more of a priority in the future. Thank you for your patience.
Three weeks after hatching, eagle chicks, or eaglets, molt to a thicker, darker down which remains until the first set of feathers develop. At this stage, one of the parents remains near the nest to shelter the chicks from direct sunlight, inclement weather, and anything else that can harm them.
When an eaglet first hatches, its bill and eyes are dark-colored. Over the course of three to four years, the bill lightens to a swirl of shades of brown, then to yellow-brown, and finally to bright yellow. The eyes lighten to buff yellow by one-and-one-half-years, light cream by age two-and-one-half, and pale yellow by three-and-one-half.
As the chicks develop feathers and grow, the parents spend less time at the nest and more time hunting for food. The eaglets grow very rapidly as long as the parents can provide sufficient food. If the parents are unable to find enough food, the smallest chicks might die.
At one-and-one-half to two-weeks, most young eagles weigh one to two lbs. (500 to 900 grams). Between 18 – 24 days, chicks gain four ounces (100-130 grams) per day, a faster weight gain than at any other stage of their development. Eaglets begin feeding themselves around the sixth to seventh week, and by eight weeks, they can stand and walk around the nest. At sixty days, eaglets are well-feathered and have gained 90% of their adult weight. Large nestlings consume nearly as much food as adults.
Chicks remain in the nest for ten to twelve weeks. A week or two before they fledge, they can be seen on the rim of the nest exercising their wings and holding onto the nest with their talons. They flap their wings and may even lift off the nest. A chick can fall or be blown off a nest while exercising, and if it can’t make it to another branch, it might fall to its death. Biologists estimate one in seven eaglets fledges prematurely, either falling or jumping from the nest before it can fly.
Once their muscles and wings are strong enough, eaglets are ready to leave the nest. What prompts the chicks to fledge is a matter of speculation, but at some point, the parents cut back on the amount of food they provide their young, and they may even use food to lure the chicks away from the nest. Males fledge at an average of 78 days, and females fledge at an average of 82 days. Research in Southeast Alaska shows fledging there occurs on average in mid-August.
The first several flights of a fledgling are very clumsy, and their first few landings are usually crash landings. Juvenile birds have longer wings and tails than adults, and this makes learning to fly easier for them. As an eagle matures, its wings become shorter and narrower, and the tail gets shorter with each molt.
Immature eagles usually stay within a half-mile radius of the nest for the first six weeks after fledging, and they may even continue to receive food from their parents during this time. Eight to ten weeks after fledging, they seem to develop a stronger instinct to move further away from the nest.
Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game,Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
Bald eagles lay their eggs in mid to late May in southern areas of Alaska, although one study in Southeastern Alaska indicated that they might lay their eggs as late as early June. The female lays between one and three off-white-colored eggs in a span of one to three days. The eggs range in size from 2.76 inches by 2.09 inches (70mm by 53 mm) to 3.31 inches by 2.36 inches (84 mm by 60mm).
The eagle pair begins incubating the eggs as soon as they are laid. The male and female share the incubation duties, and each mate hunts for its own food. Studies show that for 98% of the day, either the male or female sits on the eggs. The incubating bird stands up about once per hour and may change positions. A study at several nesting sites on Admiralty Island in Southeast Alaska found eggs were incubated for 95% of the daylight hours with females sitting on the eggs 53% of the time, and males tending the eggs 42% of the time. Brooding time dropped to 79% of the day for the first 10 days after the eggs hatched and by 41 to 50 days after hatching, the brooding time decreased to only 6% of each day. Brooding time increased when it was rainy and decreased when it was sunny. The incubation period takes 34 to 36 days. Since individual eggs may be laid a few days apart, they will not all hatch at the same time.
The hatching process is slow and arduous. It takes chicks twelve to forty-eight hours to fully emerge from the egg. The chick makes the first crack in the shell with its egg tooth, a small, hard bump on the top of the bill. After resting awhile, it then chisels around the large end of the egg. It eventually pushes off the end of the egg and wriggles out of the shell. The egg tooth dries up and falls off four to six weeks after hatching.
During hatching, a chick must undergo several physiological adaptations. Before it hatches, a chick absorbs oxygen through the mat of membranes under the shell. During the hatching process, it must cut the blood supply to these membranes and trap the blood within its body. At the same time, it must also inflate its lungs and begin breathing air once it has cracked the shell. The chick must also absorb the yolk sack into its body and seal off the umbilicus.
Newborn chicks are wet, exhausted, nearly blind, and extremely needy. Since a newly-hatched chick can’t regulate its body temperature, the parents must keep it warm. The chick is covered with pale gray down. The skin and scales of the legs are bright pink, the bill is a grey-black with a white tip, and the talons are flesh-colored. After the first week, the legs begin to turn yellow.
Eagles lay one to three eggs, but usually, only one or two chicks survive. Survivability is directly correlated to age. The first chick to hatch will be one to two days older than its siblings, so it will be larger and stronger and able to out-compete its nestlings if food is limited. If a brood has three chicks, the smallest chick usually dies within a week of hatching. Death is not normally caused by injuries from fighting with its siblings, but the chick simply starves to death because the older nestlings get all the food. The older chicks peck the young chick into submission to prevent it from eating enough to survive. By doing this, the older chicks ensure they have plenty of food.
Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
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Spring is a time for nest building; whether it’s a new nest made from twigs or a hollow spot in a rock needing only a fresh supply of moss for padding, birds know they must prepare their homes for the eggs and chicks that will soon follow.
Our weather is slowly warming here on Kodiak Island. Most days we creep into the forties, but then we drop back into the low thirties at night. I see a few sprouts popping through the ground, but mostly, it still looks like winter here.
Animals are the one, true indication spring is right around the corner. I hear whales exhaling in the pass near our lodge, signaling they are following the krill and small fish into the bay. In turn, the krill and fish are here to feed on the phytoplankton which blooms as the water warms. Yesterday, kittiwakes arrived in a big swarm to repopulate the rookery in front of our lodge. Puffins and arctic terns should be here soon.
The surest promise of spring, though, is the circling eagles high in the sky as they perform their mating ballet. Soon, they will begin repairing their homes as they prepare for their young to be born.
Bald eagles build the largest nest of any North American bird. The nest may be as large as 8 ft. (2.44 m) across and weigh one ton (907 kg). An eagle pair often uses and adds to the same nest every year, causing the nest to grow over time.
Bald eagles build their nests in large trees near the water. In Alaska, nests are usually found along saltwater shorelines or rivers, and in many parts of Alaska, eagles nest in old-growth timber. On Kodiak Island, eagles prefer to nest in black cottonwood trees, but in areas where black cottonwoods are not available, nests can be found on rocky cliffs or at the bases of alder trees on cliffs along the coast.
The nest is usually built in the crotch of the last set of branches one-third to one-quarter of the way down from the top of the tree. Eagles tend to nest in trees with sparse foliage near the edge of a habitat, so they can fly to and from the nest without having to navigate through a canopy of trees.
The nests are built of sticks, and each year the eagle pair adds new branches and other vegetation to the nest to cover over food remains, feathers, and other debris left from the previous year. Branches and twigs are placed on the edge of the nest, while softer vegetation such as leaves, grass, and moss are placed in the center. An eagle pair continues to add branches, moss, and grass to the nest all summer until the chicks are nearly grown. Researchers believe the reason for this may simply be to keep the nest cleaner. Waste, rotting fish, and even the bodies of chicks that have died in the nest are not tossed out of the nest but are buried by moss, grass, and other greenery. It is important to keep the nest clean, so parasites don’t infest the chicks.
An eagle pair usually uses a nest until either the eagles die or something happens to the nest or the tree holding the nest. Mates may build two, three, or even four nests in their breeding territory, and scientists are unsure what the purpose is for these multiple nests.
The average distance between occupied nests is usually 1 to 2 miles (1.6 – 3.2 km), but nest sites are often closer to each other in areas where food is plentiful. A 2007 nesting and productivity study on the Kodiak National Wildlife Refuge identified 1141 nests with 439 (38%) of those nests active. This was down from a 55% occupancy rate found in a 2002 study. Of the 439 active nests in 2007, 208 of the nests (48%) were successful in producing young. The researchers suspected the harsh spring weather in 2006 and 2007 might have contributed to the reduction of nesting effort.
Nesting and breeding bald eagles are territorial and defend their nests from other animals, including other eagles. Adults spend much of the day perched in prominent trees near the nest, perhaps to make themselves more visible to intruders. A resident eagle will warn an approaching eagle with a loud call consisting of grunts followed by a high-pitched screech. Sometimes the resident eagle quietly escorts an intruder out of the area, but occasionally, one of the two birds will attack the other, resulting in a display known as cart-wheeling, where one eagle descends on the other eagle, and the other bird rolls onto its back while both eagles grasp talons. The two birds then tumble toward the ground, separating just before they crash.
I welcome the birds back after a long winter. They are often noisy neighbors, but their cries herald birth, life, and spring!
Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game,Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
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Summer Friends at Amook Pass is a post by my friend, Marcia Messier. I love this humorous story about her animal encounters while she worked for us at Munsey’s Bear Camp. What Marcia doesn’t tell you in this piece is that I named our goat visitor Marcie because the goat’s daring trip each summer from the mountains to the ocean, reminded me of Marcia’s adventurous spirit. Prepare to smile as you read about Marcia’s adventures!
During the summer months at Amook Pass, the animals were my friends. That sounds a bit corny, but they were amusing, startling, and comforting, all that friends should be. I looked forward and anticipated who might stop by for a visit during my busy days.
House Animals
I was privileged to know Gizzy, Fletcher, Elsie, and Olive during my summers at Munsey’s Bear Camp. They were my very best animal friends. I thought it was interesting that Gizzy and Olive had similar personalities as did Fletcher and Elsie; even though, they had never met. Gizzy and Olive were the sweet ladies, soft-spoken, polite, accommodating for a photo, well groomed, and perhaps just a little bit shy of visitors. Fletcher and Elsie, on the other hand, were true wilderness cats. Fletcher was getting along in years when I first met him, but he told me many a hair-raising tale about his hunting skills as a younger gentleman. Elsie was in her prime, and she loved to stalk bears for days on end. Many a time as Robin and I were mourning her early demise, we would hear Mike yell, “Elsie’s back!”, and there she would be, dragging herself through the door, ragged, dirty and ravenously hungry after her latest adventure.
Fletcher and Elsie loved to hunt voles, the tiny mouse-like creatures close to the bottom of the Kodiak food chain. They must be a very tasty snack because twice daily I’d find their tiny blue and green left-over parts deposited on the front door step. I used to tell myself they were loving gifts, but then again, whoever left the pieces always seemed slightly amused when I reached down to pluck the bits off the doorstep while making slight gagging sounds.
Freddie the Weasel became a daily late-afternoon house guest. Maybe the sound of the old generator starting up interrupted his afternoon nap. He’d shoot in the backdoor, zip through the kitchen and take cover under the couch in the living room to watch and learn about life in the big house. At first, I jumped and shrieked thinking he must be some kind of Kodiak rat, but later in the day, Robin calmly explained about weasels.
Gizzy and Fletcher were still with us then but getting along in years. They knew their limitations, so they decided to pretend Freddie was just a figment of my over-active imagination. Not wanting to insult them, I went along with the game and soon we all looked forward to Freddie’s daily antics. I knew when he heard the boat motoring up to the mooring; I would see the tail end of Freddie flip out the front door.
Yard Animals
Early in the summer season, the female Sitka deer would bring their fawns into the yard to nibble the bright green salad-like greens growing around the cabins. Sometimes there would be twins, and I would think happy thoughts as I watched them through the kitchen window while preparing breakfast.
One day I came nose to nose with a deer! I was hurrying to the cabin with a load of fresh laundry, and we met coming around the corner at the same instant. We were both startled and just stared dumbfounded into each other’s eyes for a moment. I’m not sure who moved first, but a hunter later told me I was lucky it hadn’t given me a good kick in the shins before it bolted off! I guess that happens, but ours was a peaceful meeting, and I will forever remember that instant.
I live in Arizona, so the first time I saw a fox on the pathway, I excitedly reported to Mike I had seen a coyote in the yard that day. Laughing, he looked at me like I was nuts and said, “There are no coyotes on Kodiak Island!”. I felt a little foolish but still maintain at a distance, a big healthy Kodiak fox looks very much like a thin Arizona coyote in the summertime!
I’ve seen Bald Eagles before, but in Arizona, they are a special sighting. On Kodiak, they are commonplace, and I was thrilled to see a nesting pair close to camp. On my mid-day break, if the weather was good, I’d sit in a lawn chair facing the bay and watch the eagles fish. It was entertaining; an eagle would fly over the water and scope out a fish, and then in an amazing feet-first dive, catch the fish in its talons. After this, it was usually impossible to get airborne once again, so it had to row itself and the fish, still clutched in its talons, ashore with its wings. There, after expending so much energy, it would devour the fish and do it all over again.
More than once, on a nice day, while taking a siesta in the hammock, enjoying the warm sun on my face, I’d hear and feel the strong wing beats of a very large bird flying close over me, and I’d know I had been checked out by a Bald Eagle!
Some of you may have read my “Encounter” with a bear. I was walking along the path up to the guest cottage one afternoon, my mind far away, when I heard a “horse” snort. The sound brought me back to the present in a flash, and I must say, I have never confused the sound of a bear with that of a horse again!
A secret I’d like to reveal is Mike used to make a bear playground out of old red mooring buoys a distance up behind the generator shed. I heard him and Robin laughing once about how much fun the bears had rolling, tossing and chewing these old red buoys. I never did venture up past the generator shed and burn barrel. Wearing a red jacket, I didn’t want the bears to make a mistake. I did wonder if mother bears warned their cubs, “never go near that playground as there is a dangerous human there who makes frightening loud, smoky blasts come out of the shed and soon after makes fire leap high into the sky out of a barrel!” Thinking back, I was probably quite safe.
Marcie was my favorite yard animal. One warm July day, we spotted a solitary mountain goat strolling along the beach near camp. Mike and Robin reported this was indeed a rare sighting. We couldn’t help ourselves, Robin christened her Marcie, and we began to speculate about her life and why she was here on our beach. She was a rebel. Marcie was tired of billies, she had too many youngsters to raise, and the constant stress of all those steep icy mountain ledges was wearing her down. Maybe she had arthritis in her knees. Maybe she just wanted a vacation at the beach! We happily welcomed her, and for a number of years, she would appear for her annual July vacation at Munsey’s Bear Camp. One year she didn’t arrive. We looked and looked, but no Marcie. Right away we decided, instead of feeling sad, we would celebrate her life. We had a toast to Marcie, how brave she was to break away from the herd and dare to be different!
Sea Animals
The sea otter is a zen-like sight floating on its back, paws pressed together as if in meditation pose. It’s a sweet maternal picture with mom floating on her back and a tiny baby resting on her belly. And how clever of them to use tools! They often are observed with a rock balanced on their belly, happily cracking open clams for lunch. Brilliant!
At Munsey’s Bear Camp, I often saw sea otters floating in the cove in front of the lodge, and the sea otters kept to themselves. Their cousins the river otters, however, were a different matter. A family of river otters took up residence under the dock. This dock was now their home, and no one else was welcome. The dock became their dining room and their toilet. A mop had to be stationed on the dock so that the horrid stinky mess could be swabbed away. The mop could also be used as a defensive tool.
River Otter
With guests arriving and departing from the dock every five days, caution had to be observed. One day stands out in my mind. It was a beautiful, sunny Kodiak day, and we were all on deck welcoming new guests. As they were embarking from the float plane and luggage was being handed down, I took a step back and slid on an unseen mound of otter poo. I wanted to vaporize as I fell on my backside in an ungraceful plop! Afterward, we laughed about this incident, but I never forgot, and every time I saw a sweet little otter posing for pictures, I saw two little horns poking up through the top of its head.
I grew up near Cape Cod where everyone loved to fish. I didn’t. To me, the whole process from baiting the hook, to dragging the poor thing out of its natural habitat with a hook in its mouth, to butchering it, to stinking up the house with fried fish was cruel and disgusting. Fast forward 40 years and I’m a cook in a fishing camp. I politely listened and smiled at all the fish stories and quietly cooked the fish, wondering what all the commotion was about. One day my perception changed. Robin and Mike asked me if I’d like to go out on the boat with them for the day. We had only one guest, and it was a great day to get out of the house. Yes, I wanted to go! Like a good sport, I purchased my fishing license, and away we went. Mike anchored in a pretty cove, and as I sat down in the deck chair ready to enjoy the sunshine, Robin stuck a baited pole in my hands and showed me where to drop the line. Still not paying much attention, suddenly the pole was nearly yanked out of my hands, and the line was whizzing off the reel. “What’s going on?”, I hollered. Robin and Mike replied, “You’ve caught a fish.” They proceeded to give me instructions. Suddenly, the scenario was hilarious, like an old re-run of “I Love Lucy.” I couldn’t stop laughing which in turn made my arms weak and unable to reel in the line. In a second, Robin strapped a belt-like thing around me to support the fishing pole so that I could reel. Now we are all laughing hard, but with perseverance and aching arms, the fish finally emerged from the deep. I was leaned over the rail gasping in amazement at “my halibut” when all of sudden, Mike, with an expert jerk of his pliers, freed my fish from the hook and off it swam! Hey! At that moment I was totally conflicted. On the one hand, I proudly wanted to bring my halibut home for supper, but on the other, I wished it well and was happy it was able to live another day in Uyak Bay.
An eagle can rise on thermals and gain altitude until it is only a speck in the sky, and then it soars until it sees prey and can swoop down and make a kill. When an eagle spots a fish from the air, it begins to glide toward the water. As it nears its prey, it extends its legs and opens its talons. It soars just over the surface of the water and then plunges its legs into the water. The talons strike the fish, and the eagle immediately closes the talons, driving them deep into its prey. The eagle then flaps its wings to pull the fish out of the water and maintain enough speed to remain airborne. If the eagle cannot lift the fish, the bird may be dragged under water and forced to swim for shore. Eagles are strong swimmers, but if the water is cold, they may be overcome by hypothermia and drown.
It is a common misconception that once an eagle grasps its prey with its talons, it cannot let go. While eagles can lock their talons, it is a voluntary action. An eagle can release a fish that is too heavy for it to lift, but sometimes it holds on anyway, perhaps deciding the prize is worth the swim to shore.
Biologists estimate an eagle can only lift a maximum of four to five pounds, but since lift is dependent on both wing size and air speed, the faster the eagle flies, the greater its lift potential. An eagle that lands to grab a fish and then takes off again can manage less of a load than one that swoops down at a high rate of speed and plucks its prey from the water. Speed and momentum allow the eagle to carry more weight.
An adult bald eagle needs between 0.5 lbs (.23 kg.) and 1.5 lbs (.68 kg) of food per day. A study done in Washington State found an eagle needs to consume between 6% and 11% of its body weight per day. If an eagle eats a three-pound (1.4 kg) fish one day, though, it does not need to eat again for a few days. Bald eagles living in coastal Alaska feed mainly on fish such as herring, flounder, pollock, and salmon. They may also prey upon seabirds, small mammals, sea urchins, clams, crabs, and carrion.
In the summer and fall on Kodiak Island, eagles congregate along salmon streams or near the ocean where salmon are likely to school. Large numbers of eagles also gather near fish canneries where they feed on the fishy discharge from the processing plants. Both mature and immature eagles feed on carrion, but research indicates young eagles are more dependent on carrion, and they eat carrion while they develop and hone their hunting skills. Adults, on the other hand, more actively hunt live prey, particularly fish.
The bill and neck muscles of a bald eagle are adapted to allow the bird to gorge itself quickly. An eagle can eat a 1 lb. (.45 kg) fish in only four minutes, and it can hold onto a fish with one talon while it grips its perch with the other talon and tears apart the fish with its bill.
Eagles are the masters of their domain and consider any animal they can lift as a suitable meal. If an eagle flies over a seagull rookery, all the birds on the rookery take flight to chase away the menacing predator. Between fish, birds, voles, weasels, and hares, eagles on Kodiak Island have plenty to eat.
Don’t forget to sign up for my Mystery Newsletter. In March, Steven Levy, a respected author and historian from Anchorage, will be the guest author for my newsletter and will write about historical crimes in Alaska.
If you look up on a windy day on Kodiak Island, you will likely see several eagles soaring high in the sky. Bald eagles are built for flight, particularly for soaring and gliding. An eagle expends a great deal of energy flapping its large wings, so to conserve energy when gaining and maintaining altitude, it utilizes thermal convection currents or “thermals,” which are columns of warm air generated by terrain such as mountain slopes. It has been estimated a bald eagle can reach flying speeds of 35-43 mph (56-70 kph) when gliding and flapping and 30 mph (48 kph) while carrying a fish. While not known as particularly fast fliers, eagles can soar and glide for hours at a time.
The construction of an eagle’s wings and tail make soaring and gliding possible. The wings are long and broad and are covered by a layer of lightweight feathers arranged to streamline the wing. The primary feathers, or primaries, provide lift and control an eagle’s flight during turning, diving, and braking. An eagle can tilt and rotate individual feathers to maneuver and brake. The tail also assists in braking and stabilizes the eagle when it dives toward prey. While soaring, tail feathers spread wide to maximize surface area and increase the effect of updrafts and thermals.
When an eagle finds an air current or a thermal, it can gain altitude without flapping its wings. If it is dead calm with no air currents moving up or down, eagles cannot soar, and that is why you see more eagles soaring on windy days or sunny afternoons and sitting on their perches on calm, cool mornings.
When a young eagle first leaves the nest, its wing and tail feathers are longer than those of an adult. As an eagle matures, its wing and tail feathers become shorter and narrower with each successive molt. The larger wings of a juvenile make it easier for the bird to catch an updraft or weak thermal and to fly slower and in tighter circles than an adult. The downside of the larger wings and tail is the juvenile rises slower, sinks faster, and cannot soar as far as the adult. Adult bald eagles can flap their wings faster and fly at a greater speed than immature eagles, making them more efficient at chasing down live prey.
Female bald eagles are larger than males, and while their wings are also slightly larger, the larger wing size does not make up for the increased weight of the female. Therefore, females require more wind or stronger thermals than males to be able to gain altitude and soar. Since thermals are weaker during the morning and evening hours, females are more likely to remain on their perches during these times and soar when it’s windy or in the afternoon when thermals are stronger.
An eagle’s large wings make landings and takeoffs tricky, and landing on a perch is something eagles manage to do gracefully only after much practice. A newly-fledged juvenile looks very awkward when it tries to land on a perch and may even crash land or swing upside down if it grabs the perch while it still has too much forward momentum.
An eagle’s acute vision allows it to see prey while soaring high in the air. The eyes of an eagle are larger than those of an adult human, and an eagle’s eyesight is at least four times sharper than that of a human with perfect vision. An eagle flying at an altitude of several hundred feet can spot a fish under water. The eyes are protected by a nictating membrane, and each eye has two fovae or centers of focus, letting the bird see both forward and to the side at the same time. Eagles have binocular vision, so they can perceive depth, allowing them to judge how far away their prey is when they begin a dive.
Next week, I’ll write about what bald eagles eat and how they hunt. Once again, I want to remind you to sign up for my free monthly Mystery Newsletter and read about true crime in Alaska.
The bald eagle (Haliaeetus leucocephalus) is only found in North America. Its range stretches from northern Mexico to Canada and Alaska and covers all the continental United States. Due to a variety of factors, including the use of the pesticide DDT, bald eagles nearly became extinct in the contiguous United States by the 1950s. The 1940 Bald Eagle Protection Act prohibited commercial trapping and killing of bald and golden eagles, and more significantly, DDT was banned in 1972 when it was proven the pesticide interfered with the eagle’s calcium metabolism, causing either sterility or unhealthy eggs with brittle shells. In 1973, Congress passed the Endangered Species Act, and the bald eagle was listed as an endangered species. In 1995, when eagle populations in the continental U.S. began to rebound, the bald eagle was removed from the endangered species list and transferred to the threatened species list. On June 28, 2007, bald eagles were removed from the List of Endangered and Threatened Wildlife.
While Alaska’s eagles were never threatened by the use of DDT, Alaska has its own nefarious history with bald eagles. In 1917, commercial salmon fishermen convinced the Alaska Territorial Legislature that eagles killed large numbers of salmon and were competing with the fishermen’s livelihoods. This claim was later shown to be false, but the legislature enacted a bounty system on eagles that paid two dollars to anyone who turned in a pair of eagle legs. This bounty system lasted for thirty-six years and led to the killing of a confirmed 120,195 eagles, plus countless others that were never turned in for a bounty. The bounty system ended in 1953, and when Alaska became a state in 1959, its bald eagles were officially protected under the Federal Bald Eagle Protection Act of 1940. Alaska’s eagle population is now considered healthy, and one-half of the world’s 70,000 bald eagles live in Alaska. Twenty-five-hundred bald eagles reside on the Kodiak National Wildlife Refuge.
The genus Haliaeetus, the sea eagles (in Latin, hali means salt and aeetus means eagle), includes eight of the sixty species of eagles. The sea eagles live along sea coasts, lakes, and river shores. The species Haliaeetus leucocephalus (leuco means white and cephalus means head) consists of two subspecies. The southern bald eagle, Haliaeetus leucocephalusleucocephalus, is found from Baja California and Texas to South Carolina and Florida, south of 40 degrees north latitude. The northern bald eagle, Haliaeetus leucocephalusalascanus occurs north of 40 degrees north latitude. Northern bald eagles are larger than their southern cousins
Eagles are well-insulated by their feathers and are good at regulating their body temperature. Unlike many birds, they do not need to migrate to warmer areas each winter, but in many parts of the country they do migrate, sometimes long distances, in response to varying food supplies. Due to its abundant year-round food supply, Kodiak has a non-migratory eagle population. Furthermore, hundreds of eagles from the Alaskan mainland migrate to Kodiak for the winter months. Effluent from canneries and fish processing plants in the town of Kodiak provides a consistent source of food for these birds in the winter months, and hundreds of eagles can be seen in town perched in trees, on cannery rooftops, on the edges of dumpsters, and even on pickup trucks. In Uyak Bay and other remote bays on Kodiak, eagles stay near their nests all winter, feeding on fish and winter-killed deer among other things.
Since the ban on DDT and related pesticides in 1972, bald eagle populations around the country have rebounded to some degree. The bald eagle population in Alaska is healthy and stable and has never been listed as endangered or threatened by the Federal Government. Eagles in Alaska never suffered the scourge of DDT poisoning, and even now in most areas, they live in a relatively contaminant-free environment.
The Bald Eagle Protection Act imposes a fine of $10,000 and two years imprisonment for anyone who harms a bald or golden eagle. It is illegal to even have an eagle feather in your possession without a proper permit. Nevertheless, humans are still responsible for many bald eagle deaths. On Kodiak, Refuge biologists have recovered eagles that have starved to death, been killed by airplanes and cars, caught in traps, and oiled by fish slime or fossil fuels. The Exxon Valdez oil spill killed hundreds of eagles in Alaska. In January 2008, fifty eagles swooped down on a dump truck filled with fish guts outside a Kodiak seafood processing plant. Twenty of the eagles were drowned or crushed, and the rest were so slimed they had to be cleaned. Bait left unattended on a fishing boat can cause a frenzy when eagles land and start fighting over their find. If their feathers become oiled by fish slime, they become less-waterproof, and then if the eagle falls into the water, it is more susceptible to hypothermia.
In 2009, the Kodiak Electric Association (KEA) erected three wind turbines on Pillar Mountain near the town of Kodiak and added an additional three turbines in 2012. Many people worried the turbines would be a danger to eagles since turbines elsewhere in the U.S. kill an estimated 573,000 birds a year. KEA funded a study to address the concerns, and researchers determined that eagles went out of their way to avoid crossing the ridge among the turbines. No eagles were killed during the study, and according to avian biologist, Robin Corcoran, she has never received a report of a dead eagle near the turbines.
Eagles do die from electrocution on Kodiak. Many of the power poles near town are fitted with devices designed to protect eagles, but in January 2011, an eagle was electrocuted when she landed on the lowest of three cross bars on a power pole. That particular crossbar did not have a protective device because utility authorities believed there was not enough room for an eagle to land on it. The dead eagle had been banded years earlier by the Alaska Department of Fish and Game, so biologists knew she was 25 years old, the second-oldest bald eagle documented in Alaska, and one of the oldest-documented eagles in the country.
While these manmade disasters are tragic, they are uncommon and do not appear to be a threat to Alaska’s bald eagle population. A greater and less-obvious threat is the destruction of eagle-nesting habitat by logging and commercial and residential development. Eagles tend to nest in large, old trees that are not easily or quickly replaced once they are removed.
Once an eagle attains its adult plumage, it is impossible to determine its age unless it has been leg-banded by biologists. For this reason, we have limited data on the life span of bald eagles. Biologists believe 50-70% of all juvenile bald eagles die in their first year, and as many as 90% die before they are fully mature. Eagles in captivity may live 40 to 50 years. The oldest documented eagle resided in Stephentown, New York and lived to be 48-years old. On average, eagles live 15 to 20 years in the wild, and the oldest documented wild eagle was a 32-year-old bird from Maine. Alaska’s oldest eagle was a 28-year-old from the Chilkat Valley.
Eagles are fascinating birds and have been studied a great deal. Later this winter, I will dedicate more posts to eagle biology. Please leave a comment if you have a question or anything you would like to share about eagles.
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More than 240 species of birds have been identified in the Kodiak Island Archipelago. Kodiak is not on a major flyway, but many species migrate to Kodiak in either the summer or winter, and many other species are year-round residents. Common species include golden-crowned sparrows, Wilson’s warblers, fox sparrows, black-capped chickadees, hermit thrushes, and winter wrens.
Varied Thrush
Due to its mild maritime climate in the winter, wide variety of habitats, and plentiful food supply, the Kodiak Archipelago is a winter home to more species and numbers of birds than anywhere else in Alaska. Over a million sea ducks and other aquatic migratory birds flock to Kodiak in the winter. Sea ducks commonly seen in the archipelago in the fall and winter include harlequins, surf scoters, buffleheads, Barrow’s Goldeneye, oldsquaws, and mergansers.
In the spring, Arctic terns arrive from as far away as Antarctica, and bank swallows return from South America. Horned and tufted puffins fly from their winter home on the deep North Pacific Ocean to the rocky cliffs of the archipelago where they nest.
Tufted Puffin
Without question, the bald eagle is Kodiak’s most noticeable bird, and with 600 nesting pairs on the archipelago, biologists believe the nesting real estate is saturated, and many adult eagles here may never mate. In the winter, hundreds of eagles congregate near the town of Kodiak where they feed on cannery effluent and scraps of fish from boats when the fishermen offload their catch. Many of these eagles seen near town in the winter are seasonal migrants from the mainland.
Over the next few weeks, I will cover a few of these bird species in more detail, including bald eagles, tufted and horned puffins, Arctic terns, and oystercatchers.
Bald Eagle
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