Animal Diversity Web

Diversity

Buteo contains 26 species of raptor commonly referred to as hawks and buzzards. There are many subspecies and some of the confirm species are debated as being subspecies. They have a worldwide range, but they are mostly held together by morphology and diet. Their color patterns have dark reddish-brown feathers usually with white speckled breasts, except Gray Hawks (Buteo plagiatus) which have gray and white speckled breasts. The patterning on their breasts is sometimes how they are distinguished if their geographic ranges overlap. In addition, the predatory behavior of the species is very similar. Hawks and buzzards are sit and wait, predators, who usually find a perch and ambush their predators from above. An exception to this is the Galapagos Hawks (Buteo galapagoensis) which tend to hunt for insects on the ground. They are also all monogamous breeders except Galapagos Hawks (Buteo galapagoensis), which are polyandrous. Hawks and buzzards share in the parental investment of the young. Hawks and buzzards have similar ecological roles, they are mid-level predators, but their diets vary by geographic range. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bierregaard, et al., 2020; Buif, et al., 2016; Dykstra, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Miller and Meyer, 2020; Orta, et al., 2020; Preston and Beane, 2020)

Geographic Range

Hawks and buzzards have a worldwide range. They are found everywhere except the polar regions, most islands and they are also absent on the continent of Australia. There is a lot of overlap between the ranges of different species. They all tend to migrate between breeding and wintering grounds. Galapagos Hawks (Buteo galapagoensis) and Hawaiian Hawks (Buteo solitarius) are exceptions to this, they do not migrate due to their limited to island ranges. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Bierregaard, et al., 2020; Buif, et al., 2016; Cohen, et al., 2011; Corales, et al., 2015; Dykstra, et al., 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Miller and Meyer, 2020; Orta, et al., 2020; Rene de Roland, 2010; Yi-Qun, et al., 2008)

• Biogeographic Regions
• oriental
  • native
• ethiopian
  • native
• neotropical
  • native
• oceanic islands
  • native

• Other Geographic Terms
• cosmopolitan

Habitat

Hawks and buzzards have several different habitat preferences. They are found in tropical forests, deciduous forests. grasslands, semi-arid deserts, savannas, mountains, and coastal cliffs. One consistent feature is large open areas with high perching sites for hunting rodents, small reptiles, amphibians, or insects. Hawks and buzzards are generalists. They have the ability to thrive in many habitats with different prey and different climates. The main necessity for their success is perch sites for hunting. Hawks and buzzards typically nest in trees or cliff walls high above the ground, unless there is no other option than to have low or ground nests. Those nests are at risk for larger predators such as raccoons or foxes so it is not an optimal location. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Bierregaard, et al., 2020; Clark, 2007; Clarkson and Laniawe, 2020; Dykstra, et al., 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Miller and Meyer, 2020; Orta, et al., 2020; Preston and Beane, 2020; The Editors of Encyclopaedia Britannica, 2020)

• Habitat Regions
• temperate
• tropical
• terrestrial

• Terrestrial Biomes
• savanna or grassland
• forest
• rainforest
• mountains

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• coastal

• Other Habitat Features
• urban
• suburban
• agricultural

Systematic and Taxonomic History

Hawks and buzzards are in a family Accipitridae with eagles, and kites. There are many names subspecies, which may be cryptic species. Unsurprisingly, species with wider ranges have more subspecies and more potential cryptic species. There are several synapomorphies that set the hawks and buzzards apart from other species of raptors. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Bierregaard, et al., 2020; Clarkson and Laniawe, 2020; Dykstra, et al., 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Preston and Beane, 2020)

Hawks and buzzards form a polytomy within the Accipitriformes order. This means there is not enough information on these taxa to provide which ones are more related to each other than the others. Hawks and buzzards have some visible synapomorphies that set them apart from other raptors. They have board wings and rounded tails that are distinctive of the taxon. Also, hawks and buzzards have chromosomal synapomorphies that set them apart from other raptors in the taxonomy and making them excellent at soaring. (Lerner and Mindell, 2005; Nie, et al., 2015; Orta, et al., 2020; The Editors of Encyclopaedia Britannica, 2020)

• Synapomorphies

  • Broad wings
  • Rounded tails

Physical Description

Buteo species have small, sharp beaks that curve to a point. Their legs are free of feathers, their talons are sizable with three in the front and one in the back. Hawks and buzzards consist of medium-sized hawks. In addition, they consist of dark reddish-brown feathers and dark brown compound eyes, with excellent vision for hunting from a perch or while soaring. Hawks and buzzards are polymorphic, they have a dark morph and a light morph. The dark morphs are solid brown. The light morphs have white and brown spotted ventral sides, on occasion, they also have black or gray mixed into their pattern. The exception to this is Gray Hawks (Buteo plagiatus) which exhibit similar feather patterns but with gray and white feathers. There is no sexual dimorphism in feather patterns, however, females are larger than males. (Aabech, 2020; Bechard and Swem, 2020; Bibles, et al., 2020; Bierregaard, et al., 2020; Buif, et al., 2016; Clarkson and Laniawe, 2020; Dykstra, et al., 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Miller and Meyer, 2020; Orta, et al., 2020; Preston and Beane, 2020)

• Other Physical Features
• endothermic
• bilateral symmetry

• Sexual Dimorphism
• female larger

Reproduction

Hawks and buzzards are monogamous. When hawks and buzzards arrive at their breeding groups the male performs a sky dance courtship display to impress a female into being his mate. They remain with the same parent through the breeding season. This is except Galapagos Hawks (Buteo galapagoensis), which are polyandrous, one female mating with two or more males. Typically the males stay in the same group of males for each breeding season. Each of the males copulates with the female and the offspring have mixed paternity. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Bierregaard, et al., 2020; Buif, et al., 2016; Clarkson and Laniawe, 2020; Faabog, et al., 1995; Giovanni, et al., 2020; Miller and Meyer, 2020; Naoroji and Forsman, 2001; Orta, et al., 2020; Preston and Beane, 2020; Shafaeipour, 2015)

• Mating System
• monogamous
• polyandrous

Buteo species typically migrate from their year-round habitat to breeding grounds where they find a mate or meet up with their mate. Hawks and buzzards court potential mates through sky dances. The sky dance is not a very stereotypical courtship display. Sometimes it consists of the male and female circle a potential nest site. The male breaks soar and dives until he spreads his wings into a recovery. The male does this until he perches near the nest site. The female may come down and join him if she does then copulation will occur. Another sky dance consists of the female remaining perched and the male performing intricate dives and undulations toward and around the female. The female will give a twittering call to the male if she excepts him as a mate. Then he will join her and copulation will occur. Reproduction occurs at different rates at different latitudes. Breeding season starts with nest building. Most species make or refurbish one to three nests before building the final nest. Hawks and buzzards typically nest in endemic trees, for example, in North America, they nest prefer deciduous trees such as cottonwoods and conifers. Some species that breed on the planes of North America, Asia, and Africa nest in rock outcrops or cliffs. Nest height ranges from 1 meter to approximately 27 meters high. For hawks and buzzard both the male and female share in parental care of the offspring. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Bierregaard, et al., 2020; Clarkson and Laniawe, 2020; Dykstra, et al., 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Miller and Meyer, 2020; Orta, et al., 2020; Preston and Beane, 2020)

The exception to a majority of this reproductive behavior is Galapagos Hawks (Buteo galapagoensis). They are polyandrous. The female mate with two or more males. These males remain in the same group from year to year. Each male copulates with the female. The offspring have mixed paternity. The males still participate in parental care like the males of other hawks and buzzards even though they are not guaranteed to be the father of one of the offspring. (Bierregaard, et al., 2020)

• Key Reproductive Features
• iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• oviparous

Hawks and buzzards share in the parental work. During construction, the male mostly brings the materials to the female who is mostly in charge of the actual composition. Nests are typically composed of twigs, mostly live leafy twigs, hawks and buzzards also add moss, fresh sprigs, and grass to the cup of their nests, which get reapplied throughout the reproduction process. Planes species also on occasion use bones to construct their nests. Nest building in hawks and buzzards also possess a conservation concern individuals have been observed making their nests in degraded habitat and using plastic bags, plastic-coated cords, strands of rope, etc. Hawks and buzzards build their nests near sources of water. Most of the reproduction process takes place from around October to the fledging of their chicks in late June to early August. All exhibit one breeding season except Madagascar Buzzards (Buteo brachypterus). Incubation of eggs takes 30 to 40 days; females do most of the incubation will males bring them prey. After the eggs hatch the male is still the primary prey provider, while the female broods the young. The prey is similar to the parent’s diet consisting of rodents, reptiles, amphibians, and small birds. When the nestlings no longer need roosting the female joins the male in providing prey until the nestling fledge. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Bierregaard, et al., 2020; Clarkson and Laniawe, 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Miller and Meyer, 2020; Orta, et al., 2020; Preston and Beane, 2020)

• Parental Investment
• male parental care
• female parental care
• pre-fertilization
  • protecting
    • male
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• extended period of juvenile learning

Lifespan/Longevity

There is not a lot of information on the lifespan of Buteo species. Most of the information available for the longevity of the taxon comes from the North American species of hawks and buzzards, from this data it can be concluded that hawks and buzzards typically live between 10 and 24 years with an average of 20 years. Like other animals, they live longer in captivity. Much of the data collected was gathered by recovered, banded specimens. However, bands do not necessarily last. This is also possibly why there is little data on the longevity of hawks and buzzards. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Dykstra, et al., 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Preston and Beane, 2020)

Behavior

Hawks and buzzards hunt via flight or perched in trees and typically eat their prey in the trees. Hawks and buzzards are diurnal, solitary predators, however, there is some evidence that juveniles hunting together. They hunt either by sitting and waiting on a perch or actively soaring untilthey find prey, in both methods, they ambush prey from above. When they are not breeding hawks and buzzards are tolerant of other members of the genus and have been observed hunting near each other and possibly cueing each other in the location of prey. They do not share prey. Hawks and buzzards are typically solitary animals except when they are in there are in their breeding pairs. They are usually not territorially aggressive unless it is the breeding season when they establish territories to provide for their nestlings. Hawks and buzzards tend to be very aggressive in chasing off Bald Eagles (Haliaeetus leucocephalus), Great Horned Owls (Bubo virginianus), and Eurasian Eagle Owls (Bubo bubo), who compete for resources and/or prey on their nestlings. Hawks and buzzards can be very aggressive in defending their territory sometimes ending up in talon locks with other birds. Buteo species migrate from year-round habitat to breed; some begin building their nests as early as September and breed around January or February. Some hawks and buzzards migrate to wintering habitats. They do not flock to migrate, but they may flock around abundant food sources in the winter. They also do not tend to migrate very long distances to reach their breeding grounds. Most species are monogamous and remain with their mate at least for the length of the breeding season. To impress a potential mate the males do sky dances courtship display. The exception is Galapagos Hawks (Buteo galapagoensis) which are polyandrous. However, both male and female hawks and buzzards participate in parental care, this is even true for Galapagos Gawks (Buteo galapagoensis). (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Bierregaard, et al., 2020; Boerner and Kruger, 2009; Bollmer, et al., 2005; Clarkson and Laniawe, 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Orellana and Figueroa Rojas, 2005; Orta, et al., 2020; Preston and Beane, 2020)

• Key Behaviors
• arboreal
• diurnal
• motile
• migratory
• solitary
• territorial

Communication and Perception

Courtship communication is derived from sky dances and twittering calls. Buteo species communicate well with their body language. Courting males perform a sky dance where most of the communication is created by intricate flying maneuvers and dives. During the sky dance, the female communicates with the male through body language from a nearby branch or while flying with the male. During the sky dance, the birds do make twittering calls to each other. Hawks and Buzzards tend to be most vocal during the breeding season. Hawks and buzzards have a few different calls some are specific to that species others are intraspecific, mostly calls are alarm calls. Most species only have 2 to 10 different calls since they are mostly solitary animals they do not due much communicating. There have also been some whistling calls and mewing calls observed in some of the North American species, such as Red-tailed Hawks (Buteo jamaicensis), less is known about the vocalization of hawks and buzzards in other regions. Hawks and buzzards also use T-chew calls, and body language to convey aggression. This is mostly shown in territorial disputes. They erect the feathers on their head, neck, and breast to appear large as possible to the intruders. Hawks and buzzards will also hold their beak agape and beat their wings exaggeratedly as a sign of aggression. Another sign of aggression is circling accompanied by T-chew calls, which are threatening calls. However, hawks and buzzards mostly communicate through body language. Finally, hawks and buzzards have very good eyesight to perceive their environment, their eyesight is good enough to detect some targets from the sky or high perches. (Bibles, et al., 2020; Clarkson and Laniawe, 2020; Dykstra, et al., 2020; Farquhar, 1998; Preston and Beane, 2020)

• Communication Channels
• visual
• acoustic

• Other Communication Modes
• vibrations

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Most hawks and buzzards are generalist, opportunistic hunters. They hunt small mammals, small birds, reptiles, amphibians, and invertebrates, such as crayfish, snails, and insects. They typically feed on rodents. This is except the Galapagos Hawks (Buteo galapagoensis) which mainly eat locusts and giant centipedes. Some hawks and buzzards feed on carrion and roadkill during the nonbreeding season. This includes Red-shouldered Hawks (Buteo lineatus), Rough-legged Hawks (Buteo lagopus), Galapagos Hawks (Buteo galapagoensis), and Jackal Buzzards (Buteo rufofuscus). Hawks and buzzards usually find a perch and wait for prey. They ambush their prey from above, grabbing their target with their talons and typically returning to their perch to safely consume their prey. On occasion hawks and buzzards hunt by low soaring in search of prey. When hunting birds, they may give aerial pursuit. Some species such as Galapagos Hawks (Buteo galapagoensis) and Upland Buzzards (Buteo hemilasius) hunt on the ground for insects. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Bierregaard, et al., 2020; Clarkson and Laniawe, 2020; Dykstra, et al., 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Miller and Meyer, 2020; Orta, et al., 2020; Preston and Beane, 2020; The Editors of Encyclopaedia Britannica, 2020)

• Primary Diet
• carnivore
  • eats terrestrial vertebrates
  • insectivore
  • eats non-insect arthropods
  • scavenger

Predation

Few species actively prey on adult hawks and buzzards. Great Horned Owls (Bubo virginianus) and Eurasian Eagle Owls (Bubo bubo) occasionally prey on adults, typically while incubating eggs or nestlings. They also prey on nestlings. Corvids (Corvidae) prey on eggs and nestling of hawks and buzzards. Some foxes, wolverines, and porcupines prey on ground nest of hawks and buzzards and raccoons are a common problem for both ground and tree nests. Hawks and buzzards react aggressively to predators, they are killed more by chasing and fighting than general predation. Hawk and buzzards are most aggressive during the establishment of territories. During this time, they actively chase away predators, such as Great Horned Owls (Bubo virginianus), Bald Eagles (Haliaeetus leucocephalus) and Eurasian Eagle-Owls (Bubo bubo). After a nest is established males do most of the defending by a show of aggression, raised feathers, beating of wings and T-chew calls, which are aggressive warning vocalizations. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Clarkson and Laniawe, 2020; Dykstra, et al., 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Miller and Meyer, 2020; Orta, et al., 2020)

• Anti-predator Adaptations
• aposematic
• cryptic

• Known Predators

  • Great Horned Owls (Bubo virginianus)
  • Eurasian Eagle Owls (Bubo bubo)
  • Bald Eagles (Haliaeetus leucocephalus)
  • Corvids (Corvidae)
  • Raccoons (Procyon)
  • foxes (Canidae)

Ecosystem Roles

Hawks and buzzards are mid-level predators, taking small prey and being preyed on by some larger predators. Mostly, their eggs make food for other predators. They provide population control for these small mammals, reptiles, and insects. They also help with nutrients cycling by feeding on carrion. Hawks and buzzards do not use any other animals as hosts. Little is known about mutualistic behaviors between hawks and buzzards and other species. However, juveniles of different species of hawks and buzzards have been observed hunting together. Not a lot is known about what parasites choose hawks and buzzards. They can get blood parasites Plasmodium and have been observed with several species. The species depend on the region. Hawks and buzzards have been observed with chewing lice (Phthiraptera) and several species of helminth parasites (Raillietina) in their intestines. Some species of flies (Diptera) have been observed laying their eggs in the ears of nestlings of a handful of species of hawks and buzzards, this also depends on the region. All in all, broods and nest tend to show little sign of ectoparasites. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Clarkson and Laniawe, 2020; Dykstra, et al., 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Miller and Meyer, 2020; Orta, et al., 2020; Preston and Beane, 2020)

• Ecosystem Impact
• creates habitat
• biodegradation

Economic Importance for Humans: Positive

There is not a lot of information on the economic benefits of hawks and buzzards. It is possible that they provide some pest control due to their main diet being small mammals, however, there has not been much research done to prove this. Hawks and buzzards due serve some research purposes for understanding the Buteo species and other related species. Hawks and buzzards are often used for public education when kept at wildlife sanctuaries due to the inability to release. They are also commonly used for falconry. (Aabech, 2020; Bechard and Swem, 2020; Bechard, et al., 2020; Bibles, et al., 2020; Clarkson and Laniawe, 2020; Dykstra, et al., 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Miller and Meyer, 2020; Orta, et al., 2020; Preston and Beane, 2020; Rene de Roland, 2010)

• Positive Impacts
• research and education

Economic Importance for Humans: Negative

Hawks and buzzards often interfere with small game birds. This is seen especially with Common Buzzards (Buteo buteo) in Great Britain and Portugal. In these countries hunting of Red Grouse (Lagopus scotica) and Common Pheasants (Phasianus colchicus) are economically important both for private citizens and governmental organizations. It is expensive to get tags to hunt these birds, a brace (two) of pheasants can cost up to 150 euros. The biggest effect is seen in the game estates, where these birds are raised to be hunted. The pen structures provide good perches for hawks and buzzards to hunt. In these areas, Common Buzzards (Buteo buteo) are legally protected and the interaction between protection of this species and hunting interests are creating a conservation problem. This issue is present in Texas with Red-tailed Hawks (Buteo jamaicensis), which migrate there in the winter, prey on Bobwhite Quail (Colinus virginianus), which is a popular game bird there. Some hunting revenue goes back into environmental conservation and management. (Beja, et al., 2008; Francksen, et al., 2019; Hall, et al., 2001; Holschnieder, et al., 2002)

• Negative Impacts
• crop pest

Conservation Status

Most species of hawks and buzzards are listed under least concern by the IUCN red list and most have stable populations. Some species are listed as nearly threatened and vulnerable. Ridgeway Hawks (Buteo ridgewayi) is the only species listed as critically endangered. The biggest threats hawks and buzzards are agriculture, use of biological resources especially hunting and logging and invasive species. However, they mostly have a status of least concern, there is not a lot of conservation efforts occurring, though some species, including Common Buzzards (Buteo buteo), are legally protected in some areas. Conservation of these species includes international management and trade controls and identifying conservation sites. In addition, systematic population monitoring is occurring for Ridgeway Hawks (Buteo ridgewayi) because it is critically endangered. Hawks and buzzards are also often helped through wildlife rehabilitation centers when they have unfortunate encounters with humans. These centers also tend to provide education on local animals, including hawks and buzzards. (Francksen, et al., 2019; "The IUCN Redlist of Threatened Species", 2020)

• IUCN Red List [Link]

  Not Evaluated

Other Comments

Buteo means hawk or buzzard in Latin, curiously there are no synonyms for this taxon even though it is widespread. The spread of this taxon has an interesting effect on its morphology. Many species size, wingspan, and the darkness of their plumage change clinally from south to north. The birds tend to increase in size being smaller in the south and larger in the north. In addition, they are lighter in the south and darker in the north. Hawks and buzzards have also been used for falconry for centuries and in medieval times were used by kings for falconry. (Aabech, 2020; Bechard and Swem, 2020; Bibles, et al., 2020; Clarkson and Laniawe, 2020; Dykstra, et al., 2020; Giovanni, et al., 2020; Goodrich, et al., 2020; Johnson, et al., 2020; Miller and Meyer, 2020; Preston and Beane, 2020)

Contributors

Tori Hasty (author), Colorado State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

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