February 13th, 2025

Happy to be in a New Year!

You may have noticed a lack of blog posts for 2024. That is mainly because we had a very tough start to the year at the Alaska Raptor Center (ARC) and it seemed it was going to continue that way – until August, when things started to look up once again!

So, why was it so tough? January brought the loss of four employees. Some were only short term employees, but others had been with us for many years. One of those we lost was our Executive Director, Jennifer Cross. It was hard to see them go, but we did so, wishing them all best of luck in the future.  

January and February also brought some losses to our avian ambassador team. Two days into the New Year we lost one of our Bald Eagles, Volta. He was such an amazing bald eagle and was one of the very first eagles that I worked with at ARC in 1995. Volta had been with the ARC since he was injured in 1992. He was an adult when he was injured, so we had no way of knowing his actual age. We do know that he was at least 37; although I have a feeling he was a bit older than that. Volta took a piece of my heart when he left us. He was quite a special bird to many.

In addition, we also lost two of our smaller ambassadors; Tootsie, a Northern Saw-whet Owl and Peanut, a Western Screech-Owl. Both of these small owls had lived longer than the average lifespan of their species. They both started having medical issues associated with old age and we had to make the hard decision to let them go. We don’t want our birds living in unnecessary pain. While we were never able to release them back into the wild, we were able to give them a release from their pain.

Moving on to March, wild birds were still battling Highly Pathogenic Avian Influenza (HPAI). It appeared the virus was starting to slow down and just as we were about to reopen the clinic and start treating birds, we started seeing a resurgence of HPAI once again. At this point, the virus has continued to affect birds as well as mammals (fox, bear, sea lions, cows, cats and most recently, ermine) including humans. As with COVID-19, it is a virus and it does mutate, so we may be dealing with HPAI for quite a bit more time.

The end of July brought us good news and bad. After an intensive search, the ARC Board of Directors hired a new Executive Director, Carol Bryant-Martin from Tallahassee, Florida. It was wonderful to get some leadership back at the Center. She is still learning all the ins and outs of the ARC, but things are coming along! We are looking forward to continuing plans for the future developments and big changes to come!  Unfortunately, July also brought the loss of one more avian ambassador, a Great Horned Owl named Owlison. She had been in human care for a number of years before coming to the ARC in 2014. She had developed terrible arthritis in her hips and her back. Again, we made the difficult choice to relieve her of that pain.

We were able to finally move birds into some new enclosures by mid-August. We have a wonderful new building that can house four ambassador birds. Each mew was designed to have an inside space and an outside space. This gives the birds the freedom to choose whether they want to be exposed to the elements and enjoy a view of the woods or move to the back part of the enclosure and be out of the weather or away from things that make them uneasy. They seem to spend most of the time in the front, watching what is going on around them. The ARC team is always working towards improving the quality of life for our avian ambassadors. We are grateful for the support from our members and donors to be able to provide the birds with a more natural environment and allow them to take in the world around them.

The positives just kept coming! Earlier in the summer we admitted a fuzzy bald eagle chick. This was one of the youngest eaglets we had ever admitted. Staff estimated her age to be around 4 weeks old. Her rescuer named the tiny chick Via. ARC avian staff spent the summer making sure that she was getting fed plenty of high quality fish and rats to help her grow. A beautiful makeshift nest was built and she was placed in the nest, along with a stuffed eagle. Housing her in the flight allowed her to see the other eagles, watch their behaviors, and be exposed to the proper amount of light and weather to help her grow. Via is now flying with those eagles and will be released in the spring when the herring are spawning!

Another big positive was the release of our first merlin patient! We don’t seem to get many as patients, even though they are common in southeastern Alaska. Over the years, we have never successfully rehabilitated a merlin to the point of release. They are small falcons and tend to get themselves into trouble by hitting windows or wires and badly injuring their wings. This merlin (named Wizard by the rescuer) had done just that, hit a window while hunting for birds. He ended up with a broken ulna, one of the bones in his wing. We handled him with kid gloves, hoping to not make things worse! A lot of cage rest and then some time building back his strength allowed the bone to heal and we were finally able to release him! It was a huge accomplishment for all the avian staff at the ARC!

The year 2024 was nearing the end, but before that happened, ARC added two new avian ambassadors to the team! We added a beautiful barred owl that had been hit by a car in Ketchikan and broke her wingtip. She was named Varia. While she does have the ability to fly, she makes a lot of noise when doing so and since owls rely on their ability to fly silently in order to catch prey and we felt Varia would not be successful if released. The second bird is a retired falconry bird named Sable. Sable was bred in captivity and is a mix of a gyrfalcon and a peregrine falcon. She was trained and participated in hunting for 15 years by her breeder in Washington. While she no longer hunts, she is a very healthy bird and still has many years ahead of her, educating visitors about falcons and falconry. We are privileged to be able to give her a home in her retirement years.

Now we head into 2025 with hopes for a better year and more blogs about eagles, hawks, owls and much, much more!

Stay tuned!

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.

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.

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!

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.

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.

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!

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/

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 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)

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!

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 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.

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.

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.

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!