Gyr Falcon (Falco rusticolus)
The Gyf Falcon is the largest and biggest falcon in the Falco family and enjoys a holarctic distribution covering North America, Europe and Asia.
Description - Characteristics: Gyrfalcon
Breeding – Clutch – Measurements – Habitat – Diet - Threats
Taxonomy:
Order: Falconiformes
Family: Falconidae
Genus: Falco
Species: Gyrfalcon
Scientific Name: Falco rusticolus
Names and Synonyms of the Gyrfalcon
Name in German: Gerfalke
Artname in Französisch: Faucon gerfaut
Artname in Niederländisch: Giervalk
Artname in Italienisch: Girfalco
Artname in Spanisch: Halcón Gerifalte
Artname in Finnisch: Tunturihaukka
Artname in Norwegisch: Jaktfalk
Artname in Dänisch: Jagtfalk
Artname in Schwedisch: Jaktfalk
Artname in Polnisch: Białozór
Artname in Russisch: Kretschet Кречет
Artname in Isländisch: Fálki, Valur, Valur (Fálki)
Artname in Inuktitut: Kingavik, Kissaviarsuk
Artname in Grönländisch: Kingavik, Kissaviarsuk
Artname in Arabisch: نوع من الصّقور الأوربية الضّخمة
Characteristics of the Gyrfalcon
Distribution: Holarctic distribution in New World and Old World. In North America distribution between 82-83° N and 60-65° N in the New World; in Old World distribution between 78° N to 60-65° N, in Asia southern fringe of distribution at 53-59° N, usually wintering south of 55-60°N; circumpolar arctic America and Eurasia: Alaska, Canada, coastal Greenland, Iceland, Norway, northwest Sweden, north Finland, north Russia, northern Siberia to Chukotskiy peninsula and to Kamchatka and Beringa island.
Movements: Adults are mostly sedentary while juveniles are migratrory. Though, juveniles from Scandinavia and Iceland tend remain in this area.
Habitat: arctic and subarctic maritime cliffs, rocky coast and offshore islands, rocky outcrops near rivers and lakes in tundra, wooded tundra and on the edges of taiga, up to sealevels of 1,500 m.
Behaviour Diurnal and crepsucular. Flight at hight speed with low wing beats. Watches prey from low or high perches before attacking in ground-hugging flight; finally rising slightly for short stoop. When unsuccessful continuing the hunt as wild tail-chase, with can take the Gyf Falcon over several kilometres. Foraging also in direct flight low flying at about 5-20 m to flush prey.
Measurements
Size: 50-60 cm (davon 19-24 cm Schwanz)
Weight:
♂ 1000-1400 g Ø ca. 800 g
♀ 1250-2100 g Ø ca. 940 g
Wingspan: 130-160 cm
Wing:
♂: 35.2-38.0 cm
♀: 38.2-41.5 cm
Voice: Silent outside breeding area. Utters shrill calls sounding like „kyak kyak“, loud trilling “gii…” and cackling calls.
Breeding
Maturity: in the 2nd year.
Mating Season: Lifelong monogamous breeding pair.
Clutches per breeding season1 clutch
Breeding: In Northern Europa between early April and mid of July / end of July. In Nordeuropa zwischen Anfang April und Anfang Mai
Nest: Uses nests from raven, Rough-legged Buzzard and also Golden Eagle. Nest sits on cliffs and trees.
Clutch: (rarely 1-) 3-4 (max -5, very rarely 6-7) eggs
Eggs: broad oval eggs, shell light yellow with red stains.
Recurrent Clutches: only after losing clutch, recurrent clutches only up to first half of June.
Laying Interval: 2-3, mostly 3 days.
Begin of Incubating: after laying 3rd or 4th egg.
Incubation: 34-36 days, both parents share the task of incubating
Hatching: within one day with clutches of 4 eggs: with larger clutches then chicken hatch asynchronously.
Fledging: Chicken are huddled intensively by female during the first days. Feeding by ♀, ♂ brings food to the nest. After 3-4 weeks the ♀ participates in hunting and feeding of the juveniles. Fledging after 46-53 days.
Dependency: After fledging the juveniles are still being cared for by parents for another 4-6 weeks until they finally become independent and leave the breeding area.
Miscellaneous
Food: Feeds almost entirely on birds and also on mammals. Bird sizes ranges from finches to Geese, also Capercaillie, Ptarmigan and Willow Grouse; also large gulls. Mammal size ranges from voles to hare, sometimes even carrion. Seaside populations mostly feed on seabirds; tundra populations feed on lemmings and grouse; wetland populations feed on ducks. The abundance of lemmings is a decisive factor for successful breeding.
Longevity: In captivity, Gyr Falcons can reach ages of 19 years, most 15 years. Apparently there are nor records on wild living individuals.
Mortality: no records available.
Threats: Where still allowed, hunting the Gyr Falcon is a threat. Otherwise loss of habitat and declining food basis.
Quellennachweise
Bauer, Hans-Günther, Bezzel, Einhard et. al. (HG), Kompendium der Vögel Mitteleuropas, Band 1+2, Sonderausgabe 2012, Aula Verlag, Wiebelsheim
Bauer, Hans-Günther, Bezzel, Einhard et. al. (HG), Kompendium der Vögel Mitteleuropas, Band 3, Literatur und Anhang, Aula Verlag Wiebelsheim, 2. vollständig überarbeitete Auflage 1993
Bezzel, Einhard, Kompendium der Vögel Mitteleuropas, Non-Passeriformes, Band 1, AULA-Verlag Wiesbaden, 1985
Bruun/Singer/König/Der Kosmos Vogelführer, Franck'sche Verlagshandlung Stuttgart, 5. Auflage 1982
Ciesielski, Lothar C., Der Gerfalke, Die Neue Brehm Bücherei, Band 264, Westarp Wissenschaften-Verlagsgesellschaft mbH Hohenwarsleben, 2007
Ferguson-Lees, James, Christie, David, Raptors of the World, A Field Guide, Christopher Helm London, 2019
Glutz von Blotzheim, Urs et. al (HG), Handbuch der Vögel Mitteleuropas, Band 4, Falconiformes, AULA-Verlag Wiesbaden, 2. durchgesehene Auflage 1989
Mebs, Theodor (†), Schmidt, Daniel, Die Greifvögel Europas, Nordafrikas und Vorderasiens, Franck-Kosmos Verlag Stuttgart, 2. Auflage 2014
Svenson, Lars et. al, Der Kosmos Vogelführer, Franck-Kosmos Verlag GmbH & Co. KG, Stuttgart, 2. Auflage 2011
Bildnachweise
Eggs of the Gyr Falcon - Source: : Attribution: by Didier Descouens - Eigenes Werk, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=17002564