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The Gyrfalcon Falcon (Falco rusticolus) is species of raptor in the genus Falco, a group of birds of prey with approximately 40 species found worldwide. Members of this genus generally have sharp, pointed wings and fly very fast. The majority of falcons eat predominantly other birds, which they hunt and catch in flight. This specific species’ name is pronounced “jur-fal-con,” with the first syllable sounding like the beginning of the work “jury.”
Falcons are distinguished from other species of birds of prey by several anatomical features. One is a feature found on their sharp, hooked bill. The bills of falcons have a special adaptation for killing their prey called a tomial tooth. This tomial tooth is a notch in the sides of the upper mandible of the bill, and it is used to dislocate the neck vertebra of their prey and kill them swiftly. Falcon have a couple of common hunting strategies. One is to hunt by spotting their prey from high above and then attaching in a high-speed dive, striking their target (usually with their feet closed into a fist). A second common hunting strategy begins when the falcon spots a potential prey from a stationary perch from where the falcon will then begin pursuing their prey through the air. These chases can last for several minutes and include dynamic and impressive maneuvering.
As is common with birds of prey, male and female birds of this species are different in body size. However, this difference is rather small in Gyrfalcons, with the females being only about seven percent larger than males.
The Gyrfalcon has no officially recognized subspecies; however, several subspecies have been proposed and are being debated by taxonomists. This species is very closely related to the Lanner Falcon of Africa and southern Europe, with which it sometimes even hybridizes.
Taxonomy at a Glance
- Domain: Eukaryota
- Kingdom: Animalia
- Phylum: Chordata
- Class: Aves
- Order: Falconiformes
- Family: Falconidae
- Genus: Falco
- Species: Falco rusticolus
How to Identify a Gyrfalcon
Gyrfalcons are large, heavy-bodied, deep-chested falcons. They have sharply pointed wings that are broader than those of most falcons and a straight tail that is longer than that of most falcons.
Gyrfalcons have three distinct color morphs: the white morph, the grey morph, and the dark morph. And each color morph has adult and juvenile plumages.
White Morph
As its name suggests, the white morph Gyrfalcon is a largely white bird. This color morph is the rarest of the three. These birds are spectacular and striking. The backs of white morph birds have a scattering of dark barring that ranges from quite dense to almost absent. The face, breast, and belly have markings in the form of narrow streaks or arrowheads that are lightly scattered. A small amount of the wingtips are black. Juvenile white morph birds are similar to but a bit more heavily marked than adults. These birds are generally found in Iceland.
Grey Morph
This color morph is the most common of the three. These birds vary in hue from slate-colored to a range of grey-browns. The backs of these birds are almost completely grey, while the underside is streaked with a similar color. The face has a narrow malar stripe. Overall the appearance of the grey morph Gyrfalcon is similar to a Prairie Falcon, except that they have more grey markings instead of the brown of the Prairie Falcon, and Gyrfalcons lack the dark wingpits. Juvenile birds are similar to but a bit more heavily marked than adults.
Dark Morph
These birds are almost completely dark greyish-brown to nearly black in color. The coloration on the back can sometimes be broken by fine light barring. The coloration on the breast and belly can be likewise sometimes broken by fine light streaking. The head is completely hooded, though some birds can show some lighter areas on the neck. Again, juvenile birds are similar to but more heavily marked than adults.
When in flight, Gyrfalcons beat their wings more slowly, stiffly, and more shallowly than other falcons. Flapping distinctly deepens when a bird is pursuing prey. This species soars on flat wings or sometimes slightly bowed wings. This species does hover sometimes.
Where Do Gyrfalcons Live: Habitat
Gyrfalcons live in the cold northern tundra and often along coasts. Their breeding range includes the farthest northern portions of Canada, Alaska, Greenland, Iceland, Scandinavia, and Russia. During winter, these birds can migrate south somewhat but still remain very northern birds, with the birds moving the farthest still, only barely crossing into the northern parts of the lower 48 USA states and central Russia.
This species also wanders across northern sea ice, where individuals can spend significant amounts of time living and hunting far from land.
Gyrfalcon Diet and Feeding
Gyrfalcons are very aggressive hunters. They are able to kill and lift prey as much as three times their own body weight. These prey include mostly birds, but mammals do make up a significant portion of their diet, with Gyrfalcons hunting more mammals than most other species of falcon. Birds range in size from geese down to finches and everything in between. Ptarmigan, in particular, make up a large part of this species’ diet. Mammals range from large hares down to voles. When lemming and Arctic Hare populations peak, they become a common prey species. Gyrfalcons in Alaska eat ground squirrels so often that they can make up as much as half of their diet.
This species will often spot and watch a potential prey from a perch (can be high or low) and then approach it in a very low, ground-hugging flight. Once the distance is closed, a tail-chase may start that can cover several kilometers. When hunting, Gyrfalcons strike their prey to stun them more often than grabbing them out of the air.
Gyrfalcons use their size and stamina to outlast some birds by forcing them into the air and then preventing them from landing until they are exhausted, which makes them easier targets for the Gyrfalcon to bring down.
Gyrfalcon Breeding
Male Gyrfalcons advertise territories and potential nest locations in the hope of attracting a female. Both the female and male Gyrfalcon then spend time exploring potential nest sites. Once one is selected for use in a given breeding season, actual breeding generally begins in late April or early May and will extend into August.
Gyrfalcon Nesting
They breed almost exclusively on cliffs where overhangs of rock can protect the ledge where the eggs are laid from wind and other severe weather. They will also use the nests of other species (such as Golden Eagles, Common Ravens, etc.) built in conifer trees. Rarely, this species may even nest on oil pipelines, buildings, or other human-made structures.
The cliff nests have very little in the way of construction. The adults (both the male and female of a pair) generally use their feet to scrape a shallow depression in the dust and gravel on the cliff ledge that will hold the eggs.
Clutch size ranges from 1 to 5 eggs. The incubation period lasts for 34 to 36 days. The male provides food to the female during this period as she incubates the eggs.
The word for a baby falcon is an “eyas.” Eyas fledge out of the nest about 45 to 50 days after hatching, which is a long time as compared to the fledging time of other falcons. After this fledgling period, the eyas take their first flight.
Gyrfalcon Eggs
Eggs are generally laid in the shallow depression made on the scrape or ledge. One egg is laid at a time until the female is done laying her full clutch. The eggs are rounder in shape than a chicken egg and a bit smaller, about 2.0 to 2.4 inches in length. They have a base shell color that ranges from white to reddish to brown, with cinnamon markings variably scattered across the surface.
Gyrfalcon Population
By assessing data gathered as part of the North American Breeding Bird Survey, scientists are able to determine that Gyrfalcon population numbers have been roughly stable in the past few decades. The wide geographic range of this species and the large numbers of countries included in that range make the Gyrfalcon relatively resistant to localized threats.
The most accurate global population estimates that the breeding population is approximately 70,000 individuals.
Is the Gyrfalcon Endangered?
This species is of low conservation concern. The population has been stable in recent decades, so there is little concern that the species will go extinct in the very near future.
However, humans pose both direct and indirect threats to this species. A direct threat is because Gyrfalcons are a popular and highly sought-after species in falconry. As a result, there is a regular trade in both birds captured in the wild and in eggs taken from nests. This happens more in Scandinavia than in any other part of the species range. An indirect threat, and one of the most significant drivers of this species toward eventual extinction, is climate change. As the global temperature continues to rise, polar habitats will be impacted and changed dramatically. These changes in temperature and habitat will likely have detrimental effects on Gyrfalcons.
Gyrfalcons are also sometimes entangled and killed in traps meant for ptarmigan or foxes.
Gyrfalcon Habits
Gyrfalcons are very aggressive birds. This and their size are some of the reasons they have so few predators. Gyrfalcons defend their nesting areas fiercely and will attack and strike at all intruders, be they birds or mammals (including humans).
Gyrfalcon Predators
Gyrfalcons have few natural predators, and they are rarely predated upon. For adult Gyrfalcons, the only natural predator is the Golden Eagle, and predation events of this type are unusual. Ravens have been observed to kill and eat nestling Gyrfalcons and also to steal Gyrfalcon eggs. Again, these events are unusual. So, overall, Gyrfalcons face little predation in the wild.
Gyrfalcons do face an issue when it comes to falconry. Because of their large size and aggressive nature, Gyrfalcons are popular among falconers and have been for hundreds of years. The white morph has been particularly sought after and was often reserved for princes and kings alone. This high prestige has led to extensive removal of nestling wild Gyrfalcons from nests. This has been especially dramatic in Iceland, where the white morph is most commonly found. The pressure to remove wild birds from nests is decreasing due to a growing number of captively bred Gyrfalcons.
In addition, several laws and treaties have come into effect, such as the Endangered Species Act and the Migratory Bird Treaty Act protect Gyrfalcons and many other species of bird from human threats.
Gyrfalcon Lifespan
Gyrfalcons that survive their first year tend to live an average of between twelve and fifteen years in the wild, though some individuals live as long as twenty years. As is common in birds of prey, juvenile mortality is high, so many individuals do not survive to adulthood.
FAQs
Answer: Two different possible explanations for the meaning of Gyr have been proposed, but neither has been confirmed as the correct one. One possible explanation is that the Gyr comes from the proto-germanic word giri, which means ‘greed’ or ‘vulture’ and may be a reference to the fact that this falcon species is larger than other falcon species. The second possible explanation is that Gyr comes from the Latin word gyrus, which means ‘to circle’ and may be a reference to the circling hunting flights of this species which are unusual compared to how other falcon species hunt.
Answer: The term “holarctic” is a term applied to combined regions of the various types of arctic regions all around the north polar region. In other words, it is the part of the world at the northern part of the globe all the way around. It includes Alaska, northern Canada, Greenland, Iceland, Scandinavia, northern Russia, the various islands in the Arctic Ocean, and the Arctic Ocean itself. Since this is the geographic range of the Gyrfalcon, it is often referred to as a holarctic species. Polar Bears are another holarctic species.
Answer: Yes! The Gyrfalcon is the largest species of falcon in the world. Large females can weigh as much as 3.5 pounds, about the same size as a Red-tailed Hawk. The second largest falcon species in the world is the Saker Falcon, which is a half-pound lighter.
Research Citations
- Ferguson-Lees, J. and D. A. Christie. (2001). Raptors of the World. Houghton Mifflin Company, New York, NY, USA.
- Johnsgard, P. A. (1990). Hawks, eagles, and falcons of North America. Smithsonian Institution Press, Washington D.C., USA.
- Pyle, P. (1957). Identification Guide to North American Birds: a Compendium of Information on Identifying, Ageing, and Sexing “near-Passerines” and Passerines in the Hand. Slate Creek Press, Bolinas, CA, USA.
- Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.
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