Galapagos Hawks Buteo galapagoensis are indigenous to a group of islands called the Galapagos Islands. The islands are located 600 miles west of Peru and Ecuador and just south of the equator, covering a 200 square mile range. Currently, this species can be found on the islands of Charles, Chatham, Duncan and Indefatigable. Previously, they were also found on Baltra and Tower islands (Thornton 1971).
Biogeographic Regions: neotropical (Native ); oceanic islands (Native )
- Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2014. The eBird/Clements checklist of birds of the world: Version 6.9. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
Ecuador (Galapagos Islands)
Galapagos Hawks are similar in size and shape to the Red-Tailed Hawk Buteo jamaicensis and the Swainson's Hawk Buteo swainsoni of North America. The hawks are about 55 cm (21.5 in) long and have a wingspan of 120 cm (47 in). The iris of the eye is brown, and the legs, cere and the soft skin at the base of the beak are yellow. The tail is buffy white with lightly barred tail feathers. Females are noticeably larger than the males (sexually dimorphic). Unlike the adults, juvenile hawks are spotted with dark brown specks and pale breasted. Like other members of the Buteo species, these hawks have superior eyesight (Thornton 1971, del Hoyo, J., et al.1994, Wheeler, et al. 1995).
Other Physical Features: endothermic ; bilateral symmetry
This bird can be found throughout all the geographical biomes on the Galapagos Islands. These regions include the shoreline, lava fields, deciduous forest and mountaintops (Thornton 1971, del Hoyo, J., et al. 1994).
Terrestrial Biomes: savanna or grassland ; forest ; rainforest ; scrub forest ; mountains
Habitat and Ecology
Galapagos Hawks are carnivorous and are skilled hunters. Their diet consists of lizards, rats, doves, centipedes, Audubon's Shearwaters Puffinus iherminieri iherminieri, both land and marine iguanas, small goats, boobies, and grasshoppers. They will also scavenge on almost any form of carrion with the exception of marine iguanas, seals and sea lions, the latter maybe due to the hide on the seals and sea lions being too thick to rip open. Galapagos Hawks will occasionally obtain a free meal by following fishing boats and goat hunters who toss out scraps (De Vries, in litt., Thornton 1971, del Hoyo. J., et al.1994, Howard, et al. 1994).
Life History and Behavior
Perception Channels: visual ; tactile ; acoustic ; chemical
The Galapagos Islands are tropical and do not have seasons; therefore, the breeding patterns of the Galapagos Hawk tend to revolve around the island's local weather conditions as opposed to its seasons. The nest is quite large ranging from 80-100 cm (31- 39 in) wide and up to three meters (10 ft) tall. The female will lay one to three eggs and the incubation period lasts for 37-38 days. The young hawks fledge at about 50- 60 days. Both the incubation and fledging periods are longer than other Buteo species. Juveniles will not enter territorial breeding areas until sexual maturity is reached at the age of three (Thornton 1971, del Hoyo, J., et al. 1994).
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Molecular Biology and Genetics
Barcode data: Buteo galapagoensis
Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen.
Other sequences that do not yet meet barcode criteria may also be available.
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Download FASTA File
Statistics of barcoding coverage: Buteo galapagoensis
Public Records: 5
Specimens with Barcodes: 5
Species With Barcodes: 1
Status: Rare (del Hoyo, J., et al. 1994)
CITES: appendix ii
IUCN Red List of Threatened Species: vulnerable
IUCN Red List Assessment
Red List Category
Red List Criteria
Date Listed: 06/02/1970
Lead Region: Foreign (Region 10)
Where Listed: Entire
Population location: Entire
Listing status: E
For most current information and documents related to the conservation status and management of Buteo galapagoensis , see its USFWS Species Profile
CITES Appendix II. Most of the archipelago is under national park and marine reserve protection and, in 1979, was declared a World Heritage Site. The species has been protected by Ecuadorian law since 1959 (de Vries 1973). The possibility of reintroduction to previously inhabited islands has been discussed (de Vries 1984, Faaborg 1984), but advised against as prey-supply may have declined, and the effects may be detrimental to other threatened species (de Vries 1984). Ecological research is ongoing and will result in detailed information on each island population (T. de Vries in litt. 2000, 2007). A study on natal dispersal collected from 1998 to 2009 from a banded population of 25 territorial groups (Rivera et al. 2011). Rats were eradicated from Rábida, Bartolomé and Bainbridge #3 islands in 2011.
Conservation Actions Proposed
Monitor the population. Minimise illegal persecution.
Relevance to Humans and Ecosystems
Galapagos Hawks have posed a problem for the settlers of the islands by preying upon their poultry and livestock (Thornton 1971).
Settlers introduced rats to the Galapagos Islands. Galapagos Hawks now include the rats in their diet, which helps control the rat population. (Thornton 1971).
Galapagos hawks have dark feathers
Similar in size to the red-tailed hawk (Buteo jamaicensis) and the Swainson's hawk (Buteo swainsoni) of North America, but the size is variable across the islands as is recorded for many animals native to the Galapagos. The Galapagos hawk can range from 45 to 58 cm (18 to 23 in) in length from beak to tail with a wingspan of 116 to 140 cm (46 to 55 in). The smallest hawk sizes recorded are on Marchena Island, where males average 844 g (1.861 lb) and females average 1,223 g (2.696 lb). Intermediate in size are the hawks of Santiago Island, on which males weigh an average of 963 g (2.123 lb) while females average 1,295 g (2.855 lb). Largest known are the hawks on Española Island, which are amongst the largest Buteo known anywhere, with males averaging 1,137 g (2.507 lb) and females averaging 1,578 g (3.479 lb). 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.
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 marine and land iguanas, and sea turtle and tortoise hatchlings. This predator has also been spotted near nesting areas of swallow-tailed gulls, 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 hawk 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:
"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 equator, 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 50–60 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.
The call of the Galapagos hawk is a series of short screams similar to the call of the red-shouldered hawk 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”.
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, Daphne, Floreana, San Cristobal, and Seymour.
Study of mtDNA haplotypes (Bollmer et al. 2005) of the Galapagos hawk and its closest relative, Swainson's hawk, 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.)
- BirdLife International (2012). "Buteo galapagoensis". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- Del Hoyo, J., & Elliot, A. i SARGATAL, J. eds. 1994. Handbook of the birds of the World. Vol. 2. New World Vultures to Guineafowl. Lynx Edicions, Barcelona.
- CRC Handbook of Avian Body Masses, 2nd Edition by John B. Dunning Jr. (Editor). CRC Press (2008), ISBN 978-1-4200-6444-5.
- Bollmer, Jennifer L.; Kimball, Rebecca T.; Whiteman, Noah Kerness; Sarasola, José Hernán & Parker, Patricia G. (2005) Phylogeography of the Galápagos hawk (Buteo galapagoensis): A recent arrival to the Galápagos Islands. Molecular Phylogenetics and Evolution 39(1) 237–247. doi:10.1016/j.ympev.2005.11.014 PMID 16376110 (HTML abstract)
- Channing, Keith. 2008. Galapagos Hawk - Buteo galapagoensis. The Hawk Conservancy Trust. 5 March 2008.
- Licon, Daniel. "Buteo galapagoensis: Galapagos Hawk". University of Michigan Museum of Zoology Animal Diversity Web. 2008. 5 Mar 2008 <http://animaldiversity.ummz.umich.edu/site/accounts/information/Buteo_galapagoensis.html>.
- Bollmer, Jennifer L., et al. 2005. Population Genetics of the Galapagos Hawk (Buteo galapagoensis): Genetic Monomorphism Within Isolated Populations. The Auk. 122(4): 1210-1214.
- Delay, Linda S., et al. 1996. Paternal Care in the Cooperatively Polyandrous Galapagos Hawk. The Condor. 98: 300-306.
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