Under the Feather

November 16th, 2023

Species Spotlight: American Kestrel (Falco sparverius)

American Kestrels are just cute. Cute little killers of bugs, small rodents and birds. They are certainly the most colorful of all the raptors found in North America. Kestrels are one of the first raptors I learned to identify as a beginner birder mostly because they were everywhere! Growing up in southern Wisconsin/northern Illinois, one could easily find kestrels sitting on utility wires along the edges of fields or hovering out over the fields in search of their next meal. Besides just being fun to look at, kestrels are a very important bird in North America and unfortunately, their population is in decline and scientists are not sure why. So, let’s take a closer look at kestrels and what we can do to help keep them around.

A male and female kestrel perched atop a nest box.

American Kestrels are small falcons with females weighing between 120-165 grams. Males are slightly smaller with average weights between 102-120 grams. They are one of the few species of raptors that are sexually dichromatic meaning that the males and females have different coloring. Both female and male have two vertical black lines on the cheeks and a rufous colored back and tail. The female has the same rufous coloring on her wings while the male has beautiful slate-blue colored wings.

 

Range map of the American Kestrel

Kestrels are the smallest, most numerous and widespread of all the North American Falcons. They prefer to hunt in open areas covered by shorter vegetation and hunt for their prey from perches along roadsides. They are very adaptable birds that will utilize pastures and parklands, and aren’t shy about hunting near areas of human activity. Kestrels can often be seen hovering, especially on windy days. They will fly off the perch, face into the wind and then flap their wings quickly while maneuvering their tail to stay in one spot. The most intriguing part of watching a kestrel hover is experiencing their ability to keep their head perfectly still while focused on looking for prey!

This video shows a common kestrel (Falco tinnunculus) hovering over a grassy field in England.
An American Kestrel with a dragonfly. Juvenile kestrels will follow dragonfly migrations to take advantage of the abundant prey during their first migration.

By far the largest part of a kestrel’s diet is insects and other invertebrates. These prey items make up 74% of their diet.  Common foods include grasshoppers, cicadas, beetles and dragonflies; butterflies and moths; scorpions and spiders; voles, mice, shrews, bats and small songbirds. They will sometimes eat small snakes, lizards and frogs and have been reported taking larger prey such as red squirrels.  Kestrels normally hunt during the day, pouncing on their prey from above. An interesting correlation was made in September 1995 when a veteran hawk counter and bird bander named Frank Nicoletti discovered that dragonflies serve as an important food source for juvenile kestrels during fall migration. He had observed that there seemed to be more kestrels around when the dragonflies were migrating and decided to count the numbers of kestrels that were flying by, as well as count the number of dragonflies for an entire month. He used his data to show that kestrel and dragonfly migrations are definitely associated. By moving with the dragonflies, the juvenile kestrels had an easier time feeding themselves during their first migration because of the abundant prey.

While kestrels are still considered a species of least concern, their numbers are declining. Since it hasn’t yet been identified what factors are causing the decline, it is difficult to stop or reverse the trend. Recently, researchers have started putting more effort into filling in the gaps of knowledge when it comes to a kestrel’s life cycle. For instance, data currently being recording is how the birds fare over the winter months, their migratory routes, and their survival rates. They are also looking at historic data from North American hawk counts in fall and spring and through other citizen science projects like eBird that record locations and numbers of birds seen.  

Luckily for us, there are some things that we can do to help support kestrel populations!  One of the easiest things to do is to start recording sightings of kestrels on eBird or volunteer as a hawk watcher in the spring and fall. Avoid using chemicals to kill insects and rodents. Using alternative methods like mouse traps and citronella candles or bug lights will help keep kestrels from the secondary effects of those chemicals. Kestrels don’t build their own nest, they utilize natural cavities or make use of old nests from woodpeckers, but also easily adapt to using a nest box. If you have kestrels in your area and are interested in building a nest box for a kestrel family, you can find directions on how to make a box and where to place it at this link: https://nestwatch.org/learn/all-about-birdhouses/birds/american-kestrel/. A final thing that you can do is support organizations in your area the provide care for injured birds of prey. Most of them are non-profits and are always looking for volunteers and donations.

A female kestrel with her chicks in a man-made nest box.

The Alaska Raptor Center has a resident American Kestrel named Fe. She came to us from the New Mexico Wildlife Center in 2021. Fe was found as a starving young bird. Once she was admitted to rehabilitation, the staff noticed that she didn’t want to have anything to do with the other kestrels in the enclosure where she was housed. When a person would enter, she would fly right over to them. It was decided that Fe was too comfortable around people and because of that would not be a good candidate for release.  As a Raptor-in-Residence here, Fe is available for symbolic adoption, which helps pay for her daily care and feeding.  When you adopt Fe or another of our birds, you receive a photograph, biography, natural history, and a year-long membership https://alaskaraptor.org/adopt-a-raptor/

Sources:
Birds of the World, The Cornell Lab of Ornithology, https://birdsoftheworld.org/bow/home
Mock, Jillian. (2023, Spring). The Mysterious Decline of the American Kestrel. Audubon, pp.20-27.
NestWatch, The Cornell Lab of Ornithology, https://nestwatch.org/learn/all-about-birdhouses/birds/american-kestrel/
Dragonfly Migration, Journey North, https://journeynorth.org/tm/fall/DragonflyMigration.html

August 18th, 2023

Busy, busy, busy!

Wow, it has been such a busy year so far that I haven’t written a new blog entry in over 6 months!  I decided to make time because there are so many updates to share on all the happenings around the Alaska Raptor Center (ARC).

In the last blog, we mentioned helping a young snowy owl from Utqiagvik, AK. We had her in our care for a week before sending her to Wild Skies Raptor Center in Montana. They took great care of her and in June 2023 she was flown back to Utqiagvik for release! Click on the links to watch the video of her release and a video update on how she has been doing since release!  Big thanks to Brooke Tanner at Wild Skies Raptor Center and Denver Holt of the Owl Research Institute. We are so happy to have played a part in getting this beautiful girl back where she belongs!

Otus, our newest owl ambassador, perched in his hutch where he feels more protected. He has been spending time getting more comfortable around his trainer and learning to “step up” on the glove

After two rounds of voting to narrow down the name choices, we have officially named our newest western screech-owl ambassador, Otus! The name comes from the former scientific name of these small owls, Otus. In 2003 the genus was changed to Megascops after DNA sequencing, location, and natural history data confirmed that they were different from other owls in the Otus genus. He is currently in training and learning how to stay calmly on the glove and be comfortable around people. We are hopeful that he will be doing some educational programs this winter! For now, here are some photos and a cute video of him interacting with some enrichment!

(Otus, interacting with some enrichment in his mew. We like to give our birds different enrichment each day to help them build confidence and be more comfortable with new things in their space.)
This small storage area off to the side of our vertical mews was the perfect space for a quarantine area.

We are still dealing with Highly Pathogenic Avian Influenza (HPAI), although our cases this year have been much lighter than in 2022. After some unanticipated delays, our quarantine area is finally up and running and the space is working well for us. We have already been able to treat a bald eagle, an American crow and a common raven.  A big thanks goes out to everyone who helped us get this new area supplied by purchasing items off of our Amazon Wishlist!

With some concrete, a little paint and added lighting, we now have a great space to treat patients while keeping our education birds safe from HPAI
Visitors overlooking the open-air eagle habitats from our deck.

Visitor season is in full swing! It has been one of the busiest summers we have ever had! While it is a bit hectic at times it is also rewarding to be able to educate so many people about what we do here at the ARC. On many visitor days we have an added 5,000-7,000 cruise ship passengers in Sitka. The population of Sitka is currently around 8,500 so having that many extra people in town for a day is something to see!

A group of visitors learning about two of our education ambassador birds in the weathering yard.

Last but not least, we recently produced a design for our new ambassador bird housing! We plan to complete two of these buildings in 2024 and each building will contain four ambassador bird enclosures.  The new enclosures will have an open outdoor area and an enclosed, protected space in the back. This will allow the birds to choose whether they want to be inside or outside, as well as doubling the size of their current spaces!  These two buildings are the first significant step towards the growth of the campus with an anticipated cost of approximately $500,000 each.  Keep reading to find out how you can help us make these buildings a reality!

This is the design for the two new enclosures we plan to build in 2024. Each building will house four ambassador birds.

Matching Your Gifts

From Jennifer Cross, Executive Director

Thanks to a generous $500,000 matching pledge from the Suzanne and Walter Scott Foundation, The Center is essentially half-way towards that goal!  All donations directed towards this initiative will be matched, dollar-for-dollar by the Foundation up to $500,000.  To help drive support, all eight mews are available for perpetual sponsorship at $50,000 each. 

If you would like to help us get these enclosures built and double your support, you can donate online or send us a check to 1000 Raptor Way, Sitka, AK, 99835.  Just indicate “new mews” in the memo of the check or at checkout. If you are looking for a lasting memorial for a loved one or to honor your friend, family, or company in a unique and meaningful way, considering sponsoring a mew and your support will be acknowledged permanently and prominently on the enclosure in perpetuity.  Contact Jennifer Cross at Jennifer.cross@alaskaraptor.org for more information or to pledge your support today! 

January 26th, 2023

A quick look back before moving forward

Having recently completed our permit reports, I thought it would be a great time to share some numbers and take a quick look back at 2022.  We saw a surprising number of birds for having closed our rehabilitation down for four months due to the current strain of highly pathogenic avian influenza (HPAI).

Over all, we admitted a total of 152 birds of 43 different species, of those 15 tested positive for HPAI. The positive HPAI birds were 8 bald eagles, 5 common ravens, a swan and a gull.  HPAI is still occurring in southeast Alaska and we continue to do all we can to keep our education birds safe while still helping injured birds get the care they need.

and in December 2022, picking on some deer bones in a Sitka resident’s yard (photo by Don Kluting). Zoë was released from our care on March 30, 2022.
Zoë as an eaglet in main flight

While 2022 was far from normal for us, there were still some great moments! We released 12 bald eagles back to the wild. One of them was a young eagle we named Zoë (BE2153). Zoë was banded with a USFWS band and was recently resighted here in Sitka and seems to be doing well! There was also another banded eagle with Zoë that turned out to be an eagle that we released in 2021 named Rockfish!

 

This young snowy owl was sent to us from Utqiagvik, AK. It was with us for a week before we sent it on for further rehabilitation to Montana where it is doing well!
This young snowy owl was sent to us from Utqiagvik, AK. It was with us for a week before we sent it on for further rehabilitation to Montana where it is doing well!

We helped a snowy owl from Utqiagvik (formerly Barrow), AK. This was a young snowy owl that was the last chick hatched from the only nest found around Utqiagvik this year. Researchers from the Owl Research Institute based in Montana contacted us and asked if we could assist getting the bird to Montana for further rehabilitation. They have been studying the snowy owl population around Utqiagvik for 31 years. Of course, we were happy to help! It was fun to see a snowy owl that young and still showing gray downy feathers.  We usually don’t see them in rehab until they are older and in the typical juvenile snowy owl plumage. If you are interested in finding out more about how the chick is doing or other interesting research on owls, visit their website at https://www.owlresearchinstitute.org/

Koyu is a light morph Harlan’s red-tailed hawk. She was found by a falconer in Huslia, AK and is one of our newest ambassador birds.

Also, in 2022 we added two new ambassador birds to our team! Koyu is a light morph Harlan’s red-tailed hawk. She came to us from Huslia, AK, a village outside of Fairbanks. A falconer found her alongside a road and we presume that she was hit by a vehicle of some kind. Luckily, there were no broken bones, but she did have damage to her left eye. With sight in only one eye, she has trouble targeting her prey and would not survive in the wild. She is very different in color from our more typically colored Harlan’s red-tailed hawk, Kily.  She has been a quick study with her training and we are hoping to have her on the glove and helping to educate visitors this coming summer.

Our other new ambassador bird is this little western screech-owl. It is currently in training and doing well. We are excited to announce a new name in the coming weeks!

Our second new addition is a western screech-owl. We haven’t quite decided on a name for it yet, but when we do we will be sure to let everyone know! This little owl was found in a local Sitkan’s yard not looking very well. We picked it up we found it was very thin. After taking an x-ray we found that it had broken some bones in the wingtip. Due to this injury the owl cannot fly well enough for release. It is a young bird and we hope it will be helping us deliver our educational message later this year.

Looking forward, we cannot predict the prevalence of HPAI in Southeast Alaska, so we are proactively building a quarantine room so that we can continue admitting patients onsite without putting our ambassadors at risk.  We are also planning to build some enhanced housing for our ambassador birds! Get out your shades because our future is looking bright!

October 25th, 2022

Species Spotlight: Great Gray Owl (Strix Nebulosa)

Range of the Great Gray Owl in North America.

Of all the birds found in North America, I have always felt that the owls were the best named. For the most part they either describe exactly what the owl looks like, sounds like or does. For example, Great Horned Owls are large owls with long feather tufts that resemble horns; the Northern Saw-whet Owl was named for the “skiew” call that it makes when alarmed. This sound is said to resemble the whetting of a saw; Burrowing Owls nest in open areas in a burrow dug out by other animals.

Like many other people that I know, I have a soft spot for owls. Maybe it’s because they are birds that are active mainly at night and are not seen as often as other birds? Maybe it’s those forward-facing eyes that make them more relatable to humans? It’s probably a little bit of both, but whatever it is, I am fascinated by these birds!

Taxidermy comparison of a Great Gray Owl on the left and the actual size of the skeleton on the right. Their size is very deceiving due to the many feathers on their body. All the feathers help to insulate the bird from the cold weather in their preferred habitat.

I want to take a closer look at one of my favorites, the Great Gray Owl. Again, fittingly named as they are a large, gray owl! It is a bird that is exciting to see, although you won’t see them often if you don’t live in the north. The preferred habitat for the Great Gray Owl is the boreal forest, which cover large parts of Alaska, Canada and Russia. There is however, a small portion of their normal range that dips down into Washington, Oregon, Idaho and California. In these areas, they have adapted to living in the coniferous habitat of the northern Rocky and Sierra mountains.

They are the tallest and one of the largest owls found in North America and are a bit of an optical illusion as much of the bulk of the Great Gray Owl is made up of feathers. This is possibly to help them survive in the cold climates that they inhabit. Despite their outward appearance, the Great Gray Owl is 15% smaller than the more common Great Horned Owl. In fact, both the Great Horned Owl and Snowy Owl appear smaller than the Great Gray Owl, but both easily outweigh them.

The coloration and pattern of the feathers on Great Gray Owls helps them camouflage into their surroundings.

The Great Gray Owl has a large, rounded head with a prominent facial disk that lacks ear tufts. Their yellow eyes appear small for the size of their head and may convey a look of “surprise” to the observer. The beak is yellow with a black patch below that is surrounded by a “bow-tie” pattern of white. The tail is wedge-shaped and long. The overall appearance of their feathers is mottled gray, brown and white coloration, making them exceptional at camouflaging themselves.

Some owl species, such as barn owls, have asymmetrically set ear openings (one ear is higher than the other). This allows the bird to triangulate the exact location of their prey. ©From “How Does an Owl’s Hearing Work?” BBC Earth

Great Gray Owls prefer hunting in areas that border open spaces such as montane meadows, bogs, muskegs, or marshes usually hunting early in the morning and again in the late afternoon and near dusk. Like other owls, the Great Gray has asymmetrical ear openings giving them incredible hearing and allowing them to detect their prey by sound alone. They use their large facial disk to direct sound to their ears, helping them to triangulate the exact location of their prey. Not only can they hear voles and other rodents running through the forest floor, but they can also detect their prey beneath snow as deep as 45 cm (17 in). Their diet consists of mainly rodents, voles in particular. They are considered a “sit and wait” predator meaning that they capture prey by sitting on a perch, listening and watching the ground intently, just waiting to detect a sound or see some movements below them. Once they have located prey, they pounce, surprising it from above.

A Great Gray Owl with her chicks in the nest on top of a dead tree. This is a great example of the preferred nesting sights of this owl species.

As many other species of owls, Great Gray Owls do not construct a nest. They prefer to use abandoned nests of other birds of prey or may choose to nest in broken-topped dead trees, at the fork of large branches or on human-made platforms. The female may scratch a depression in the bottom of the nest, but does not add any materials to it. Pairs have been known to reuse nesting sights for several years with an average clutch size of three to five eggs.

Great Gray Owls are not globally threatened and have a conservation status of least concern. The populations do fluctuate widely depending on availability of food, their estimated population size is 50,000-100,000 individuals worldwide.

The Alaska Raptor Center has a resident Great Gray Owl named Boris. He came to us from the Bird Treatment and Learning Center in Anchorage, Alaska in 2007. Boris has arthritis in his right wrist and can no longer move that joint. Because of this injury he would not be able to hunt well enough to survive in the wild. As a Raptor-in-Residence here, Boris is available for symbolic adoption. If you would be interested in adopting him and helping the Alaska Raptor Center continue providing food and medical care for Boris, visit Alaskaraptor.org/adopt-a-raptor/

Sources:
-Birds of the World, The Cornell Lab of Ornithology, https://birdsoftheworld.org/bow/home
-Owl Research Institute, https://www.owlresearchinstitute.org/
-Gaukel-Andrews, Candice, Video: Owls Have Heads Designed for Hearing https://www.nathab.com/blog/video-owls-have-heads-designed-for-hearing/
-Cascades Raptor Center, https://cascadesraptorcenter.org

September 1st, 2022

Aging Birds

A very common question we hear at the Alaska Raptor Center is, “How old is that bird?” For many of our birds the answer is that we really don’t know. Different species of birds mature at different ages. We know this because they go through changes in their feather patterns and coloration from a juvenile to an adult.

A good example of this is with our avian ambassador goshawk, Flash. Northern goshawks take two years to mature into their adult plumage. They change from a medium brown coloration to an all-over gray coloration. There are also noticeable changes to the feather pattern and eye color. You can see these changes in the photos below.

Many raptors have a juvenile plumage that differs from their adult plumage. Usually these changes take place over a one- or two-year process, like Flash. Bald eagles, however, are the champions when it comes to plumage changes. It takes a bald eagle five years to change from the dark chocolate colored plumage of their hatch year to the iconic white head and tail of adulthood. Now, this doesn’t mean that it takes five years for them to be fully grown, that only takes about four months!

Let’s take a closer look at how the feathers, beak and eye color change in the first five years of a bald eagle’s life. For this, I have enlisted the help of one of our avian ambassador bald eagles named Spirit. She came to us during her first year (around 6 months old) after being hit by a car in Juneau, AK. Now six-years-old, she is one of the Center’s main ambassadors and helps us educate visitors about bald eagles and the dangers they face in the wild. It is important to remember that eagles, like people, are all different and mature at different rates. No two birds will look exactly the same during the molting (feather replacement) process that occurs each year.

When eagles leave the nest, they are around 4-5 months old. At this point of their lives they are a dark, chocolate brown color. They have dark brown eyes and a completely black beak. We didn’t have any photos of Spirit at this age, so I am using a photo of a different patient. Notice how black and shiny the beak looks. One thing that I recently learned is that the beak and back talon (hallux) are not fully grown when the young eagles fledge. They will continue to grow and reach full size by the second or third winter. Maybe that is why they always look so sweet to me, because they have a little beak.

A bald eagle at one year is going to have feathers that are a bit lighter than the deep chocolate brown of the first year. They begin to show more white splotching, especially on the smaller body feathers. The head remains mostly brown, while the eyes and beak begin to get a bit lighter in color. The tail will begin to show a mix of brown and white. If you look at the image of Spirit’s head you can see that her beak is lighter in color at the base while the tip remains very black.

At two years of age, bald eagles start showing changes in their head coloration, it almost looks like they are wearing a light brown cap. Body feathers remain mostly brown with white showing through and the belly may be more milk chocolate in color. The eyes become a lighter brown and the beak starts to look more gray than black. The tail feathers remain a speckled brown and white coloration.

The third year is when bald eagles go through the biggest changes in feather coloration. They develop a dark eyeline that gives the appearance that they are wearing a mask. The cap on top of the head turns a mottled white and brown, while the feathers underneath the beak and onto the throat turn lighter brown to white. Some eagles will develop a speckled white belly and others may develop a brown spotted white triangle area between the wings. The eyes are now more of a khaki color and the beak shows more yellow, but still contains some gray. The tail will remain a speckled brown and white coloration. The photos below are all of three-year-old bald eagles. The first image is a bird without the white belly, middle is the white belly and the last photo is of the white triangle markings on the back. There are two images of Spirit, left is at the beginning of her third year and right is towards the end of that same year. Notice the very subtle changes in her beak and the feathers on top of her head.

At four years of age most bald eagles are going to look very close to the final adult plumage. It may look like they have dirt on their head and beak, but there is no mistaking that you are looking at a bald eagle! The eyes will range from a khaki color to a yellowish-white color while the head will be mostly white with small specks of brown. The beak will be more yellow than gray at this point and the tail feathers will range from all white to white with brown along the edges.

Finally, when they reach five years old they will have a white head, yellowish-white eyes, yellow beak and white tail. This is the feather pattern that they will keep for the remainder of their lives.

All of this information comes from my 27 years of living in Sitka, watching, treating, and working with bald eagles. There is a paper that was written in March 1989 that is the definitive paper on molting sequence and aging of bald eagles. That paper can be found at the following web address if you are interested in reading it: MOLTING SEQUENCE AND AGING OF BALD EAGLES

There are many other websites where this information can be found. A fascinating website that I found recently is www.elfruler.com/. There is a lot of good information on bald eagles there, including photos of nestling bald eagles from hatch until fledging.

July 10th, 2022

Enrichment: Keeping our birds busy and happy!

Back in 1995 when I first arrived at the Alaska Raptor Center (ARC) as an intern, we never used the word enrichment. But, as always, things change with time and current best practices in animal training suggest a more choice-based training system. Today, ‘enrichment’ is a daily part of our vocabulary and is very important to the health and well-being of the ambassador birds. So, what is enrichment and why is it so important? 

Providing daily enrichment helps satisfy both the physical and psychological needs of the birds and allows them opportunities to make choices. The enrichment offered helps to stimulate the senses, increase confidence in new environments, increase physical movement/exercise, support natural behaviors and reduce stress and boredom.  

If you have a pet at home, you most likely participate in some kind of daily enrichment. Think of taking your dog for a walk and letting it sniff things along the way. You may choose to walk a different trail or route each day for your own mental wellness, but it affects your dog in a very similar way. All the new smells and different scenery help to both mentally and physically exercise your dog.  Providing fake mice or other toys for your cat to chase encourages natural hunting behaviors. Giving a pet bird or Guinea pig different toys in its enclosure helps stimulate curiosity and gives them something to chew on. Giving our pets choices and mental stimulation helps to make their lives better.  

Enrichment is usually broken down into five different categories; cognitive (problem solving), sensory, food, environmental (changes to enclosure), and behavioral (training). We try to offer our birds something from each of these categories on a weekly basis. There is always a bit of trial and error and some birds just don’t enjoy every bit of enrichment that we give them. That’s what enrichment is all about, giving them the choice to interact or not interact.

We do research into the natural history of the birds in our care so that we know that the types of enrichment offered to them are something they might enjoy. We know eagles don’t mind water and love to take baths, this makes taking them to the river to bathe a much more attractive enrichment for them than it would be for an owl. Ravens and crows are some of the most intelligent birds so they will get more benefit from a difficult problem-solving puzzle than a hawk might. It also pays to know your birds. For instance, Volta, one of our retired eagle ambassadors LOVES rats. He doesn’t get them often because rats are expensive, but for the 20th anniversary of his admit date, I gave him a whole rat! I like to think that Volta enjoyed eating it as much as I enjoyed watching him rip into it!

Some of the enrichment we offer to the birds is a natural behavior that they would normally partake in like bathing or eating a particular food. However, much of the enrichment offered is something that they wouldn’t encounter naturally in the wild. Because of this, we need to train the birds to the enrichment. For instance, if I want to have one of our red-tailed hawks rip open a bag containing food, I might start with a flat piece of paper. Then fold the paper in half and put the food inside the fold, but keep it easy to see and access. Next, I could put the food inside a bag, but leave the bag open at the top so that the bird can easily see and retrieve it. Eventually the bird will associate a bag with food and know that it will need to rip it open to get to dinner. We also have to make sure that the enrichment that we provide is safe for the birds. If the bird can get entangled in the enrichment or ingest any parts of it then that particular enrichment would be pulled from that bird. 

For me, the best part of giving enrichment to the birds is watching them interact with it. I always leave with a huge grin on my face when one of the birds is really into figuring out or destroying the enrichment given to them. I know that our birds are healthy, mental stimulated and it seems like, enjoying the interaction!

I am going to end it here. Enrichment is a big topic and I could probably write five different blogs about it. For now, I will leave you with this introduction and some photos and videos of our birds interacting with different kinds of enrichment!

Sources:
Behavior Works, www.behaviorworks.org
Buhl, Gail. Raptor Enrichment, presented at the NWRA 2016 Annual Conference.
Buhl, Gail and Lisa Smith editors. Wildlife in Education: A Guide for the Care and Use of program Animals. 2016. NWRA publisher.
Flanders, Abby. Establishing Objective Assessment for Environmental Enrichment. International Association of Avian Trainers and Educators (IAATE) The Flyer, Spring 2021. Pp4-7.
Martin, Steve. Positive Reinforcement Training as an Enrichment Technique. International Association of Avian Trainers and Educators (IAATE) The Flyer, Winter 2016. pp4-6.
Shape of Enrichment, www.enrichment.org
Stankiewicz, Megan. Training for Enrichment. International Association of Avian Trainers and Educators (IAATE) The Flyer, Fall 2021. Pp6-7

May 30th, 2022

There’s a first time for everything

The Alaska Raptor Center (ARC) has stopped taking in rehabilitation patients until further notice. It was a very difficult decision to make, but in order to protect our avian ambassadors from the highly pathogenic avian influenza, it was necessary.

I stood in a parking lot watching a three-year-old bald eagle. The eagle seemed fine, maybe just stunned, until we approached it. As we got closer, the bird began to get stressed and attempted to get away from us. It tried to run but was unbalanced, wings out to its side, turning in small circles, and beak chattering, unable to control its muscle function. This is how a raptor reacts when it is infected with HPAI. It is not a pleasant thing to see. Dr. Vosburg, veterinarian at the Alaska Raptor Center, gets her supplies ready. Bags, swabs, test tube, latex gloves and finally, euthanasia solution. There is nothing else we can do for this young eagle but end its suffering. Once the bird has passed, she collects samples from the mouth and the cloaca and carefully puts the bird in bags.

We believe that this bird was suffering from highly pathogenic avian influenza (HPAI). Avian influenza, more commonly known as bird flu, has been around for many years. The first strain of the virus we are currently experiencing originated around 1996 and was first found in a domestic goose in China. The virus has mutated and persisted causing the first major wild bird outbreak around 2005 in central Asia. Continuing to mutate, the next outbreak was seen in 2014 in the U.S., entering through the Pacific Northwest and now we have the current 2022 outbreak, which has been the worst so far for the U.S. and wild birds.

This photo of a young eagle, taken by a local resident, was found in the Sitka National Historical Park. We suspect that it was infected with HPAI. It was humanely euthanized and samples were sent in for testing. We should have results back in about ten days.

HPAI is difficult because it is a virus and there is no treatment. It can be carried by waterfowl, ducks and geese in particular, and these species often show no symptoms even if they have it. They spread it through their feces and saliva both on land and in water. HPAI likes water and colder temperatures, even freezing does not kill the virus.  Scientists have found that the 2022 version has infected about 40 different species of birds including birds like crows and sparrows, as well as raptors. In fact, it has been quite deadly to raptors with a 95-99% chance that if a raptor is infected, it will die. In Minnesota, there have been complete failures of great horned owl nests with both the parents and chicks succumbing to HPAI. This is the reason we had to make so many changes in the way we care for our avian ambassador birds and it is the primary reason we made the decision to temporarily suspend our rescue and rehabilitation services. 

For the staff at the Alaska Raptor Center, HPAI has been overwhelming. We are still getting calls about injured birds, but are left feeling helpless. It is so difficult to tell people who call about an injured bird that there is nothing we can do and we have to let nature take its course. Most of us chose this line of work because we care. It goes against our nature to do nothing and our #1 goal has always been to heal injured birds so that they can be released back into the wild.

We did some improvising to protect our great horned and great gray owls. The tarps are a temporary fix for the time being.
Our open-air eagle habitat sits empty. We have moved the eagles into their covered enclosure to protect them from HPAI.

We currently have 26 avian ambassadors in our care. We are permitted through the U.S. Fish and Wildlife Service (USFWS) to provide forever homes for these birds. Under those permits are a lot of regulations that we must follow to ensure that we are caring for them using the most current and best practices. We go above and beyond to keep these birds happy, healthy, safe and enriched. For us to lose one of these birds to something that we could have prevented would be devastating. So, we have made changes to help ensure their safety. Our eagle habitats sit empty because we have chosen to keep the five eagles that live in them inside their covered sheltered area so that they aren’t accidentally exposed. Our raven has been moved inside and two of our owls have had the netting on top of their enclosures covered with tarps until we can come up with a better solution. Our glove-trained eagles have had corrugated plastic installed over the open slatted areas of their enclosures. All of this is to ensure that no feces from wild birds can get into their spaces. As bird trainers and handlers, we are changing our shoes or using shoe covers before entering any of the enclosures to keep out any virus that might be on our shoes. Has it been difficult? You bet it has. We have all had to stop and think about what we need to do before entering or leaving a space. Is it worth it? One hundred percent! So, while there may not be as many birds to see at the ARC, there are still birds to see and we are doing everything we can to keep it that way!

For more information on HPAI, click on the following links:

https://www.usgs.gov/centers/nwhc/science/distribution-highly-pathogenic-avian-influenza-north-america-20212022

https://raptor.umn.edu/about-us/our-research/HPAI

 

Sources used: 
Tufts University. “Avian influenza: How it’s spreading and what to know about this outbreak: A new study details which species are super spreaders.” ScienceDaily. ScienceDaily, 19 May 2022. www.sciencedaily.com/releases/2022/05/220519140432.htm
The Raptor Center, University of Minnesota. “A conversation about Highly Pathogenic Avian Influenza.” University of Minnesota webinar. 30 April 2022.

April 24th, 2022

Male or Female?

One of the most frequently asked questions we get from our visitors each summer is “Is that bird a male or a female?” Depending on the bird that we happen to be looking at, it can be easy to tell by the color of the feathers or a little more difficult because males and females look the same.  

An example of the size difference between a male and female bald eagle. Male in the front and female in back.

In raptors, one can tell the difference between males and females by the size of the bird. Unlike most bird species where the male is the larger of the two, raptors have reverse sexual dimorphism where the females are the larger bird. Sexual dimorphism is a fancy way of saying that there is some recognizable difference between the males and females. This could be a size, shape or color difference.  Scientists can’t quite agree on why this is. One of these theories is that the female is larger as a form of protection from aggressive males. It is thought that over time (think evolutionary time), females have chosen to mate with smaller males and by selecting for smaller sizes, the males eventually evolved to be smaller than the females.  Another theory proposes that the size difference allows the birds to hunt different sized prey in the same territory. A larger female will be able to kill larger prey than a smaller male would attempt to kill. Which of these theories is correct? No one knows for certain!  

Lucky for us, there is another way to tell males from females in some species of raptors. That is a difference in plumage between the sexes. There are only a handful of them, but as a bird watcher it is exciting to know that you are looking at a male or female when you see a raptor in the field. Let’s take a closer look at a few of these raptors with differences in plumage.

American kestrels have one of the most striking plumage differences. Kestrels are the smallest falcon found in North America. They are flashy little birds with vertical black stripes on their face. The difference in color for these birds is found on the wings. Females have a rusty orange coloration on the body and wings while males have a beautiful slate-blue color on their wings. With wings of different colors, there really is no doubt when you see a kestrel whether it is a male or female!

A female (left) and male (right) pair of American kestrels perched atop their nest box. Note the slate-blue color of the male’s wings.
The gray coloration of the male northern harrier (left) compared with the browns seen in the female (right).

Northern harriers are a type of hawk that can be found soaring over open fields looking for rodents to eat. Harriers are unique because they have a facial disc like an owl and use their hearing to help them capture prey. No other hawks found in North America have this adaptation. The color difference between male and female harriers is extreme. As immature birds, males and females look the same, a dark chestnut brown covering their entire body. However, when they mature, females retain a lighter brown coloration with a streaked breast while males molt from the chestnut brown to a beautiful light gray.  The contrast of the gray with the white rump and black wingtips of a male harrier is quite a sight to see.

The final example that I want to share can be a little tricky to discern initially. Immature snowy owls are white with very heavy black spotting or barring on their feathers. During winter months when snowy owls migrate into the northern United States it is often these young birds that can be seen as they travel south looking for food. It can be very difficult to tell anything about the sex of a snowy owl when seeing these young birds. However, as they age and molt in new feathers, the black spotting begins to fade. If you see a snowy owl that is almost totally white, it is a male. Females will retain more of the black spotting on their white feathers, but it will not be as heavy as when they were immature birds.  Qigiq, the snowy owl at the Alaska Raptor Center is a male and has gotten lighter since first arriving here in 2012 as an immature bird.

A very white male snowy owl on the left as compared to the female on the right.

These images really show how Qigiq’s spotting has changed since his arrival in 2012 (left) to his current plumage in 2021 (right).

These are just three of the different species of raptors that can be sexed by the color of the feathers. There are more, but I will let you do some sleuthing on your own and list the other raptors with plumage differences between the sexes. See if you can find the differences between males and females. Some of them are very subtle and it takes a practiced eye to tell the difference!
Raptors with plumage differences between male and female birds:

  • American Kestrel
  • Merlin
  • Hook-billed Kite
  • Snail Kite
  • Northern Harrier
  • Rough-legged Hawk
  • Short-eared Owl
  • Snowy Owl
Sources used:
Ehrlich, P. R. (1988). The Birder’s handbook: Natural history of North American birds. Simon & Schuster.
National Geographic Society. (2002). National Geographic Field Guide to the birds of North America.
Sibley, D. (2000). The Sibley Guide to birds. Knopf.
Birds of the world – comprehensive life histories for all bird species and families. Birds of the World – Cornell Lab of Ornithology. (n.d.). Retrieved April 15, 2022, from https://birdsoftheworld.org/

March 24th, 2022

What is a raptor anyway?

It’s in our name. Alaska Raptor Center. It is a much more common word used in our vocabulary since the movie Jurassic Park introduced many of us to velociraptors. These days, the word raptor could describe a bird of prey, dinosaur, truck or plane. But let’s get down to the nitty gritty and figure out what the word raptor really means.
According to Vocabulary.com “a raptor is a bird of prey, a large, strong bird that feeds on smaller animals”. Essentially, a bird that feeds on living creatures. Don’t most birds feed on smaller animals? Herons, loons and grebes all feed on fish, robins eat worms and warblers catch and eat insects. Does that make them all raptors as well?

Nope.

Before the word was used to describe a type of bird, raptor meant “abductor, robber or plunderer”. These terms all come from the Latin rapere meaning “to seize”. This is a perfect word to describe these beautiful birds of prey, since they use their feet for seizing and killing their food. There are, in fact, three specific characteristics that separate raptors from other birds of prey (besides just being really cool!)

All birds called raptors possess the following characteristics:
Sharp talons – Raptors have powerful legs and toes that end with sharp talons. This makes their feet lethal weapons. Their feet are perfectly designed to catch, hold, and carry prey. The length and size of a raptor’s toes, and the curvature and thickness of its talons are related to the type of prey it pursues. Most birds of prey have three toes pointing forward and one pointing backward. Osprey and owls have one hinged toe that can be held in a forward or back position. This allows them to hold prey with two talons on each side for a secure grip.

Hooked beak – The raptor’s beak sets it apart from other birds. All raptors have the same beak design, curved at the tip with sharp cutting edges to rip and tear apart their prey. Unlike most raptors, falcons use their beak, rather than talons to kill their prey. A specialized, added hook on their beak known as a tomial tooth. This added “tooth” is used to kill their prey by severing the spinal cord.

Keen eyesight – Raptors have very keen eyesight. Diurnal or daytime hunting raptors have full color vision and two areas of sharp vision on the retina where humans have only one. This sharpest point of vision is called the fovea. When the raptor’s two fovea work in unison, they give them very accurate depth perception which aids in catching moving objects. Nocturnal raptors, like owls, have an added advantage of remarkable night vision. Owls have a higher concentration of rods in their retina that are used to see in low light conditions.

There you have it! Now you can quiz all your friends and see if they know what distinguishes any other bird of prey from a raptor. There are so many reasons to love not only raptors, but all birds. We want this blog to not only keep you up to date on what is happening in the clinic with our patients, but also help you learn more about what makes all birds so special!

This blog is brought to you by Jen Cedarleaf, the Avian Director at the Alaska Raptor Center (ARC). Jen has been a bird nerd since the early 1990’s and enjoys both watching and learning about all species of birds. Many of her vacations are spent searching different parts of the country for new birds that she has not seen before. Jen has worked at the ARC in many different capacities since she first came to Sitka as an intern in 1995.