The largest species of the falcon is regarded as a bird of prey. The coasts of the tundra, Artic, islands of Northern North America, and the region of Eurosiberia are where the Gyrfalcon breeds on.
After the season of breeding, some Gyrfalcons are widely scattered but the aforementioned breeding coast and regions are the primary habitat of the gyrfalcon.
When wandering individually, these birds can travel long distances, but worthy of note is that there is a variation in their feather with locations with different colorations.
The disparities in the color of these birds are called Morphs. The gyrfalcon, just like other falcons displays sexual dimorphism with the male smaller than the female.
The gyrfalcon has been regarded as a hunting bird for many years.
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Scientific Classification
- Scientific Name: Falco Rusticolus
- Kingdom: Animalia
- Phylum: Chordata
- Class: Aves
- Order: Falconiformes
- Family: Falconidae
- Genus: Falco
- Subgenus: Hierofalco
- Species: F. rusticolus
Description
In terms of size, the gyrfalcon is as large as the largest buteos in size but fairly heavier than the buteos of buzzards as they are otherwise called.
Below are the body measurements of the male gyrfalcon.
- Length: 19-24in
- Wingspan: 43-51in
- Weight: 1.8lbs-3lbs
- Average weight: 2.5lbs
The female gyrfalcons are usually bigger and bulkier, compared to the males, below are the body measurements of the female gyrfalcon.
- Length: 20-25.5in
- Weight: 2.6-4.6lbs
- Wingspan: 49-63in
- Average weight: 3.4-3.6lbs
Compared to the Peregrine falcon, the Gyrfalcon is far more surpassing in size, length of tail, and broadness of the wing. It is distinguished from the buteo in structure generally, as it has pointed wings.
The species of gyrfalcon are very polymorphic in nature which explains the variations in their plumage.
The prototypal Morphs are referred to as brown, white, black, and silver although, on a spectrum, they can still be colored from all-white to very dark.
The cream streaking on the scruff and crown is what differentiates the gyrfalcon from the peregrine falcon. The most widespread form of gyrfalcons is the white gyrfalcons.
The silver gyrfalcons look much more like the light grey lanner falcon which also large in size. The gyrfalcon species do not exhibit sex-based color disparities though the younger Species are darker and more brownish in color than the adults.
Ecology
Originally, the gyrfalcon was thought to be a bird of the mountains and the tundra; it was discovered that the gyrfalcon can spend a moderate period of time on the sea ice in the winter distant from the land. It preys on mammals and birds, feeding more consistently on the birds than other species of Falco.
The gyrfalcon hunts in a horizontal pursuit. The majority of the prey captured by the gyrfalcon is killed mostly on the ground, even if it was captured in flight, it will be forced to the ground. The diet is opportunistic to some extent, but most breeds and hunts tally with ptarmigan and seabird colonies.
Bird prey sizes can range from redpolls to geese and include corvids, smaller passerines, gulls, waders, and other birds of prey (up to the size of buteos).
Threat from climate change
In the early 2000s, as climate change began to moderate the Arctic summers, it was observed that peregrine falcons broaden their range northward and competed with gyrfalcons.
Although specifically adapted for life in the High Arctic and larger than the peregrine falcon, the gyrfalcon is less aggressive and conflict-averse and therefore cannot match up with peregrine falcons, which regularly attack and outshine the gyrfalcons.
There are concerns that gyrfalcons will become extinct in their previous range in the next five to ten years.
Breeding
The gyrfalcon nearly always nests on cliffs. Breeding pairs do not construct their own nests and mostly use a bare shelf or the deserted nest of other birds, especially golden eagles, and common ravens.
The clutch can range from 1 to 5 eggs but is mostly 2-4. The average size of an egg is 2 1⁄4 in by 1 3⁄4 in; The average weight is 0.062 kg. The period of incubation averages 35 days with the chicks hatching weighing approximately 0.052kg.
The chicks usually incubate for 10-15 days and leave the nest after 49 days to 56 days. By 3 to 4 months of age, the immature Gyrfalcons become separated from their parents to begin living independently of their parents, although they may bond with their siblings the following winter.
Golden eagles are the only natural predators of the gyrfalcons, seldom engaging with these terrifying falcons. The record has shown that the gyrfalcons have been very aggressive and violent towards animals that come close to their nests, though ravens are the only birds known to have successfully picked off the gyrfalcon eggs.
Survey has shown that humans are the leading cause of most deaths of gyrfalcons be it accidentally or purposely.
