Galápagos Hawk
Encyclopedia
The Galapagos Hawk is a large hawk endemic to the Galapagos Islands
.
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Similar in size to the Red-tailed Hawk
(Buteo jamaicensis) and the Swainson's Hawk
(Buteo swainsoni) of North America
, the Galapagos Hawk is about 55 cm from beak to tail with a wingspan of 120 cm. The adult Hawk has various colouring within the species. The adult Galapagos Hawk is generally a sooty brownish black colour; the crown being slightly blacker than the back. Its feathers of the mantle are partially edged with paler brown, grey, or buff, with their white bases showing to some extent. Their tail coverts are also barred with white.The tail itself is silvery grey above, with about ten narrow black bars; below it is quite pale. The wing feathers are paler on inner webs, barred with white.
Below it has indistinct rufous edges to the feathers of the flanks and lower abdomen. The under-tail coverts are barred with white. Under-wing coverts are black, contrasting with the pale bases of the wing quills. The eyes are brown, the beak greyish black, paler at its base which is known as the 'cere', legs and feet are yellow. The male Hawk is smaller than the female hawk,as with many birds of prey. The young hawks however, appear quite different from the adults in that they are well camouflaged with an overall brown appearance with varying amounts of striping below and paler mottling above. Their eyes are light grey-brown, and the beak black, blue-grey at its base. The cere is grey-green, the feet pale yellow-green. When the immature plumage becomes badly worn, the pale areas become almost white.
The Galapagos Hawk has broad wings and a broad tail. It is an apex predator
and possesses excellent vision. Their young appear different from adults because they are darker and have camouflage which aid them in remaining protected from potential predators until they are fully grown.
and land iguanas
, and sea turtle
and tortoise
hatchlings. This predator has also been spotted near nesting areas of Swallow-tailed Gull
s, where it steals eggs as well as young. Even extremely rancid carrion is picked apart by their sharp, forceful beaks. Their feet and talons are also strong like those of the closely related Red-backed Buzzard and White-tailed Hawk
.
Hunting in groups of two or three, the hawks soar at a height of 50 to 200 meters in the sky. When one of the birds spots prey or a rotting carcass, they signal to the other members. The dominant hawk of the group feeds from the prey until it is satisfied, as the other hawks in the family group submissively wait their turn to feed. It prefers to perch on a lava outcrop or high branch when hunting, yet it also spends some of its time on the ground.
Fearless of man, the young especially being quite curious, they often wander around human camps and scavenge for scraps of food. In 1845, Charles Darwin
wrote:
, there is no regular mating season. Mating takes place a few times a day on a nearby perch or in flight. It begins when males make fake attacks on the female from behind by dive bombing her, and then the male follows the female as she descends to the trees below. While males tend to be monogamous, the females will mate with up to seven different males during mating season. Throughout the entire nesting period, the female and her males take turns protecting the nest and incubating the eggs, even participating in the feeding.
Nests are built low in trees, on lava ledges, or even on the ground at times. Used for many years and nesting periods, they become quite large, sometimes even four feet in diameter. Stick structures are lined with grass, bark, clumps of leaves, or other available soft materials. The mating pair is together the majority of the time at the prime of egg-laying season, and usually stays close to the nesting site. The nest is maintained constantly with fresh, green twigs. Normally one to three eggs are laid, green-white in color, but only one young is reared. Young hawks leave the nest around 50–60s days after hatching. Juvenile hawks will not enter the territorial breeding areas until they reach the age of three, becoming sexually mature. Although these birds are generally fearless, they will abandon their nest if it has been tampered with by humans.
that have been described as a “keer, keeu,” or an inflected “kwee”. Especially noisy during breeding season, their call softens to a “kilp, kilp, kilp”.
, Floreana, San Cristobal
, and Seymour
.
, indicates that the former's ancestors colonized the islands approximately 300,000 years ago, making the birds the most recent arrival known. (Compare to Darwin's finches, which are estimated to have arrived some 2–3 million years ago.)
Galápagos Islands
The Galápagos Islands are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, west of continental Ecuador, of which they are a part.The Galápagos Islands and its surrounding waters form an Ecuadorian province, a national park, and a...
.
Physical description
Red-tailed Hawk
The Red-tailed Hawk is a bird of prey, one of three species colloquially known in the United States as the "chickenhawk," though it rarely preys on standard sized chickens. It breeds throughout most of North America, from western Alaska and northern Canada to as far south as Panama and the West...
(Buteo jamaicensis) and the Swainson's Hawk
Swainson's Hawk
The Swainson's Hawk , is a large buteo hawk of the Falconiformes, sometimes separated in the Accipitriformes like its relatives. This species was named after William Swainson, a British naturalist...
(Buteo swainsoni) of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, the Galapagos Hawk is about 55 cm from beak to tail with a wingspan of 120 cm. The adult Hawk has various colouring within the species. The adult Galapagos Hawk is generally a sooty brownish black colour; the crown being slightly blacker than the back. Its feathers of the mantle are partially edged with paler brown, grey, or buff, with their white bases showing to some extent. Their tail coverts are also barred with white.The tail itself is silvery grey above, with about ten narrow black bars; below it is quite pale. The wing feathers are paler on inner webs, barred with white.
Below it has indistinct rufous edges to the feathers of the flanks and lower abdomen. The under-tail coverts are barred with white. Under-wing coverts are black, contrasting with the pale bases of the wing quills. The eyes are brown, the beak greyish black, paler at its base which is known as the 'cere', legs and feet are yellow. The male Hawk is smaller than the female hawk,as with many birds of prey. The young hawks however, appear quite different from the adults in that they are well camouflaged with an overall brown appearance with varying amounts of striping below and paler mottling above. Their eyes are light grey-brown, and the beak black, blue-grey at its base. The cere is grey-green, the feet pale yellow-green. When the immature plumage becomes badly worn, the pale areas become almost white.
The Galapagos Hawk has broad wings and a broad tail. It is an apex predator
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...
and possesses excellent vision. Their young appear different from adults because they are darker and have camouflage which aid them in remaining protected from potential predators until they are fully grown.
Habitat and diet
This hawk lives mainly on insects such as locusts and giant centipedes, as well as small lava lizards, snakes and rodents. It is not uncommon for it to take young marineMarine iguana
The Marine Iguana is an iguana found only on the Galápagos Islands that has the ability, unique among modern lizards, to live and forage in the sea, making it a marine reptile. The Iguana can dive over 30 ft into the water. It has spread to all the islands in the archipelago, and is...
and land iguanas
Galapagos Land Iguana
The Galapagos Land Iguana is a species of lizard in the Iguanidae family. It is one of three species of the genus Conolophus...
, and sea turtle
Sea turtle
Sea turtles are marine reptiles that inhabit all of the world's oceans except the Arctic.-Distribution:...
and tortoise
Tortoise
Tortoises are a family of land-dwelling reptiles of the order of turtles . Like their marine cousins, the sea turtles, tortoises are shielded from predators by a shell. The top part of the shell is the carapace, the underside is the plastron, and the two are connected by the bridge. The tortoise...
hatchlings. This predator has also been spotted near nesting areas of Swallow-tailed Gull
Swallow-tailed Gull
The Swallow-tailed Gull is an equatorial seabird in the gull family Laridae. It is the only species in the genus Creagrus, which derives from the Latin Creagra and the Greek kreourgos which means butcher, also from kreas, meat; according to Jobling it would mean "hook for meat" referring to the...
s, where it steals eggs as well as young. Even extremely rancid carrion is picked apart by their sharp, forceful beaks. Their feet and talons are also strong like those of the closely related Red-backed Buzzard and White-tailed Hawk
White-tailed Hawk
The White-tailed Hawk is a large bird of prey species found in tropical or subtropical environments across the Americas.-Description:...
.
Hunting in groups of two or three, the hawks soar at a height of 50 to 200 meters in the sky. When one of the birds spots prey or a rotting carcass, they signal to the other members. The dominant hawk of the group feeds from the prey until it is satisfied, as the other hawks in the family group submissively wait their turn to feed. It prefers to perch on a lava outcrop or high branch when hunting, yet it also spends some of its time on the ground.
Fearless of man, the young especially being quite curious, they often wander around human camps and scavenge for scraps of food. In 1845, Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
wrote:
"A gun is here almost superfluous; for with the muzzle I pushed a hawk out of the branch of a tree.."
Behavior and breeding
Because the seasons of the island are unchanging due to the close proximity of the equatorEquator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
, there is no regular mating season. Mating takes place a few times a day on a nearby perch or in flight. It begins when males make fake attacks on the female from behind by dive bombing her, and then the male follows the female as she descends to the trees below. While males tend to be monogamous, the females will mate with up to seven different males during mating season. Throughout the entire nesting period, the female and her males take turns protecting the nest and incubating the eggs, even participating in the feeding.
Nests are built low in trees, on lava ledges, or even on the ground at times. Used for many years and nesting periods, they become quite large, sometimes even four feet in diameter. Stick structures are lined with grass, bark, clumps of leaves, or other available soft materials. The mating pair is together the majority of the time at the prime of egg-laying season, and usually stays close to the nesting site. The nest is maintained constantly with fresh, green twigs. Normally one to three eggs are laid, green-white in color, but only one young is reared. Young hawks leave the nest around 50–60s days after hatching. Juvenile hawks will not enter the territorial breeding areas until they reach the age of three, becoming sexually mature. Although these birds are generally fearless, they will abandon their nest if it has been tampered with by humans.
Voice
The call of the Galapagos Hawk is a series of short screams similar to the call of the Red-shouldered HawkRed-shouldered Hawk
The Red-shouldered Hawk is a medium-sized hawk. Its breeding range spans eastern North America and along the coast of California and northern to northeastern-central Mexico.-Description:...
that have been described as a “keer, keeu,” or an inflected “kwee”. Especially noisy during breeding season, their call softens to a “kilp, kilp, kilp”.
Status
Although the exact number of these birds is unknown, there are believed to be only around 150 mating pairs in existence today. This statistic has improved slightly from past years, but it is far from the abundance they were found in on all the islands of Galápagos when they were discovered. Due to human disturbance to their natural habitat, a dwindling food supply because of new predators introduced to the islands, and predation by humans, they are now extinct on the islands of Baltra, DaphneDaphne Major
Daphne Major is a volcanic island just north of Santa Cruz Island and just west of the Baltra Airport in the archipelago Colon, commonly known as the Galápagos Islands...
, Floreana, San Cristobal
San Cristóbal Island
San Cristóbal is the easternmost island in the Galápagos archipelago, and one of the oldest geologically.Its Spanish name "San Cristóbal" comes from the patron saint of seafarers, St. Christopher...
, and Seymour
Seymour
- Places :Antarctica* Seymour Island, an island off the tip of Graham Land on the Antarctic PeninsulaAustralia*Seymour, Victoria*Electoral district of Seymour, an electoral district in VictoriaCanada...
.
Evolution
Study of mtDNA haplotypes (Bollmer et al. 2005) of the Galapagos Hawk and its closest relative, Swainson's HawkSwainson's Hawk
The Swainson's Hawk , is a large buteo hawk of the Falconiformes, sometimes separated in the Accipitriformes like its relatives. This species was named after William Swainson, a British naturalist...
, indicates that the former's ancestors colonized the islands approximately 300,000 years ago, making the birds the most recent arrival known. (Compare to Darwin's finches, which are estimated to have arrived some 2–3 million years ago.)
External links
- BirdLife Species Factsheet.
- ARKive: images and movies of the Galapagos hawk (Buteo galapagoensis)
- AnimalsandEarth: photos of the Galapagos hawk (Buteo galapagoensis)