Accipitridae
Encyclopedia
The Accipitridae, one of the two major families
within the order
Accipitriformes
(the diurnal birds of prey
), are a family of small to large birds with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-sized mammals, with a number feeding on carrion and a few feeding on fruit. The Accipitridae have a cosmopolitan distribution
, being found on all the world's continents (except Antarctica) and a number of oceanic island groups. Some species are migratory
.
Many well-known birds, such as hawk
s, eagle
s, kites
, harriers
and Old World vulture
s are included in this group. The Osprey
is usually placed in a separate family (Pandionidae), as is the Secretary bird
(Sagittariidae), and the New World vulture
s are also usually now regarded as a separate family or order. Karyotype
data indicated that the accipitrids hitherto analysed are indeed a distinct monophyletic group, but whether this group should be considered a family of the Falconiformes or one or several order(s) on their own is a matter of taste.
, but many of these groups contain taxa which are more aberrant. These are placed in their respective position more for lack of better evidence than anything else. It is thus not very surprising that the phylogenetic layout of the accipitrids has always been a matter of dispute.
The accipitrids are recognizable by a peculiar rearrangement of their chromosomes. Apart from this, morphology and mtDNA cytochrome b
sequence
data gives a confusing picture of these birds' interrelationships. What can be said is that the hawk
s, kite
s, eagle
s and Old World vultures as presently assigned in all likelihood do not form monophyletic groups:
According to the molecular data, the Buteoninae are most likely poly- or paraphyletic, with the true eagles, the sea eagles
, and the buteo
nine hawks apparently representing distinct lineages. These appear to form a group with the Milvinae, Accipitrinae
and Circinae but the exact relationships between the lineages are not at all robustly resolvable with the present data. The Perninae
and possibly the Elaninae are older lineages, as are the Old World vultures. The latter are fairly likely also poly- or paraphyletic, with some aberrant species like the Bearded and Egyptian Vulture
s standing apart from the naked-necked "true" vultures.
The Accipitridae are a diverse family with a great deal of variation in size and shape. They range in size from the tiny Pearl Kite
and Little Sparrowhawk
, both of which are 23 cm (9 in) in length and weigh about 85 g (3 oz), to the Cinereous Vulture, which measures up to 120 cm (47 in) and weighs up to 14 kg (31 lbs). Until the 14th century even these were surpassed by the extinct
Haast's Eagle
of New Zealand, which is estimated to have measured up to 140 cm (55 in) and to have weighed 15 kg (33 lbs). In terms of body mass, Accipitridae is the most diverse family of birds. Most accipitrids exhibit sexual dimorphism
in size, although unusually for birds it is the females that are larger than the males. This sexual difference in size is most pronounced in active species that hunt birds, such as Accipiter
hawks, in which the size difference averages 25–50%. In a majority of species, such as generalist hunters and rodent
, reptile
, fish
and insect
hunting specialists, the dimorphism is less, usually between a 5% to 25% size difference. In the carrion-eating Old World vulture
s and snail eating kite
s, the difference is almost non-existent.
The beaks of accipitrids are strong, hooked (sometimes very hooked, as in the Hook-billed Kite
or Snail Kite
). In some species there is a notch or 'tooth' in the upper mandible. In all accipitrids the base of the upper mandible is covered by a fleshy membrane called the cere which is usually yellow in colour. The tarsi
of different species vary by diet, those of bird hunting species like sparrowhawks are long and thin, while species that hunt large mammals have much thicker, stronger ones, and snake-eagle have thick scales to protect from bites.
The plumage
of the Accipitridae can be striking but rarely utilises bright colours; most birds use combinations of grey, buff and brown. Overall they tend to be paler below, which helps them seem less conspicuous when seen from below. There is seldom sexual dimorphism in plumage, when it occurs the males are brighter or the females resemble juveniles. In many species juveniles have a distinctly different plumage. Some accipitrids mimic the plumage patterns of other hawks and eagles. They may attempt to resemble a less dangerous species to fool prey, or instead resemble a more dangerous species in order to reduce mobbing
by other birds. Several species of accipitrid have crests used in signalling, and even species without crests can raise the feather
s of the crown when alarmed or excited. In contrast most of the Old World vulture
s possess bare heads without feathers; this is thought to prevent soiling on the feathers and aid in thermoregulation
.
The senses of the Accipitridae are adapted to hunting (or scavenging), and in particular their vision
is legendary. The sight of some hawks and eagles is up to 8 times better than that of humans. Large eyes with two fovea
provide binocular vision and a "hawk eye" for movement and distance judging. In addition they have the largest pecten
s of any birds. The eyes are tube shaped and cannot move much in their sockets. In addition to excellent vision many species have excellent hearing, but unlike in owls sight is generally the principal sense used for hunting. Hearing may be used to locate prey hidden in vegetation, but sight is still used to catch the prey. Like most birds the Accipitridae generally have a poor sense of smell; even the Old World vultures make no use of the sense, in contrast to the New World vultures in the family Cathartidae.
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Accipitrids are predominately predators and most species actively hunt for their prey. Prey is usually captured and killed in the powerful talons of the raptor and then carried off to be torn apart with a hooked bill for eating or feeding to nestlings. A majority of accipitrids are opportunistic predators that will take any prey that they can kill. However, most have a preference for a certain type of prey which in harriers
and the numerous buteonine hawks
tends towards small mammal
s such as rodent
s. Raptors who favor small mammals usually soar or hover over openings until they detect their prey and descent down onto them, although may also watch for prey from a perch. In Accipiter
hawks (the most species-rich acciptrid genus), prey is mainly comprised by other bird
s. Accipiter hawks usually ambushed birds in dense vegetation, a dangerous hunting method that requires great agility. Most accipitrids will supplement their diet with non-putrid carrion
but, of course, none specialized with this as well as the vultures
.
A few species may opportunistically feed on fruit and in one species, the Palm-nut Vulture
, it forms the major part of the diet. Most accipitrids will not eat plant material. Insects are taken exclusively by around 12 species, in great numbers by 44 additional species, and opportunistically by many others. The diet of the honey-buzzards includes not only the adults and young of social insects such as wasps and bees, but the honey and combs from their nests. The Snail Kite
and Hook-billed Kite
s are specialists in consuming snail
s. "Eagle
s" are several raptors that are not necessarily closely related but can be broadly defined by large body size and the taking of typically larger prey, including mid-sized mammals and larger birds. Most accipitrids usually hunt prey rather smaller than themselves. However, many accipitrids have been recorded as capturing and then flying with prey of equal weight or even slightly heavier than themselves in their talons, a feat that requires great physical strength. Occasionally, an eagle or other raptor that kills prey considerably heavier than itself (too heavy for the raptor to carry and fly with) and will then have to leave prey where they've killed and later return repeatedly to feed. This has the advantage of providing a surplus
of food but has the disadvantage of potentially attracting scavengers or other predators which can steal the kill or even attack the feeding accipitrid. Using this method, accipitrids such as the Golden
, Martial
and Crowned Eagle
have successfully hunted prey deer
and duiker
s weighing more than 30 kg (66.1 lb), 7-8 times their own mass. The Haliaeetus eagles, the Ichthyophaga
eagles and the Osprey
mainly prefer to prey on fish
(comprising more than 90% of food for the latter 2 genera). These large acciptrids may supplement their diets with aquatic animals other than fish, especially the more generalized Haliaeetus eagles. Reptiles are hunted by almost all variety of acciptrids when the opportunity arises and may even be favored over other prey by some eagles and buteonine hawks
found in the tropics. Bazas
and forest hawks in the genus Accipiter
may take reptiles from trees whilst other species may hunt them on the ground. Snake are the primary prey of the snake-eagles (Circaetus
) and serpent-eagles (Spilornis
and Dryotriorchis).
record of this group is fairly decent from the latter Eocene
onwards (c.35 mya), with modern genera being well documented since the Early Oligocene, or around 30 mya.
Accipitrids are known since Early Eocene times, or about from 50 mya onwards, in fact, but these early remains are too fragmentary and/or basal
to properly assign a place in the phylogeny. Likewise, as remarked above, molecular methods are of limited value in determining evolution
ary relationships of and within the accipitrids. What can be determined is that in all probability, the group originated on either side of the Atlantic, which during that time was only 60-80% its present width. On the other hand, as evidenced by fossils like Pengana
, some 25 mya, accipitrids in all likelihood rapidly acquired a global distribution - initially probably even extending to Antarctica.
Specimen AMNH FR 2941, a left coracoid from the Late Eocene Irdin Manha Formation
of Chimney Butte (Inner Mongolia
) was initially assessed as a basal mid-sized "buteonine"; it is today considered to be more likely to belong in the Gruiformes
genus Eogrus. The Early Oligocene genus Cruschedula
was formerly thought to belong to Spheniscidae, however reexamination of the holotype in 1943 resulted in the genus being placed in Accipitridae. Further examination in 1980 resulted in placement as Aves incertae sedis.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
within the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Accipitriformes
Accipitriformes
The Accipitriformes is an order that has been proposed to include most of the diurnal birds of prey: hawks, eagles, vultures, and many others, about 225 species in all. For a long time, the majority view has been to include them with the falcons in the Falconiformes, but some authorities have...
(the diurnal birds of prey
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....
), are a family of small to large birds with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-sized mammals, with a number feeding on carrion and a few feeding on fruit. The Accipitridae have a cosmopolitan distribution
Cosmopolitan distribution
In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...
, being found on all the world's continents (except Antarctica) and a number of oceanic island groups. Some species are migratory
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
.
Many well-known birds, such as hawk
Hawk
The term hawk can be used in several ways:* In strict usage in Australia and Africa, to mean any of the species in the subfamily Accipitrinae, which comprises the genera Accipiter, Micronisus, Melierax, Urotriorchis and Megatriorchis. The large and widespread Accipiter genus includes goshawks,...
s, eagle
Eagle
Eagles are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species occur in Eurasia and Africa. Outside this area, just two species can be found in the United States and Canada, nine more in...
s, kites
Kite (bird)
Kites are raptors with long wings and weak legs which spend a great deal of time soaring. Most feed mainly on carrion but some take various amounts of live prey.They are birds of prey which, along with hawks and eagles, are from the family Accipitridae....
, harriers
Harrier (bird)
A harrier is any of the several species of diurnal hawks forming the Circinae sub-family of the Accipitridae family of birds of prey. Harriers characteristically hunt by flying low over open ground, feeding on small mammals, reptiles, or birds....
and Old World vulture
Old World vulture
Old World vultures belong to the family Accipitridae, which also includes eagles, buzzards, kites, and hawks.Old World vultures are not closely related to the superficially similar New World vultures and condors, and do not share that group's good sense of smell. The similarities between the two...
s are included in this group. The Osprey
Osprey
The Osprey , sometimes known as the sea hawk or fish eagle, is a diurnal, fish-eating bird of prey. It is a large raptor, reaching more than in length and across the wings...
is usually placed in a separate family (Pandionidae), as is the Secretary bird
Secretary Bird
The Secretarybird or Secretary Bird is a large, mostly terrestrial bird of prey. Endemic to Africa, it is usually found in the open grasslands and savannah of the sub-Sahara...
(Sagittariidae), and the New World vulture
New World vulture
The New World Vulture or Condor family Cathartidae contains seven species in fivegenera, all but one of which are monotypic. It includes five vultures and two condors found in warm and temperate areas of the Americas....
s are also usually now regarded as a separate family or order. Karyotype
Karyotype
A karyotype is the number and appearance of chromosomes in the nucleus of an eukaryotic cell. The term is also used for the complete set of chromosomes in a species, or an individual organism.p28...
data indicated that the accipitrids hitherto analysed are indeed a distinct monophyletic group, but whether this group should be considered a family of the Falconiformes or one or several order(s) on their own is a matter of taste.
Systematics
The accipitrids have been variously divided into some 5–10 subfamilies. Most share a very similar morphologyMorphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
, but many of these groups contain taxa which are more aberrant. These are placed in their respective position more for lack of better evidence than anything else. It is thus not very surprising that the phylogenetic layout of the accipitrids has always been a matter of dispute.
The accipitrids are recognizable by a peculiar rearrangement of their chromosomes. Apart from this, morphology and mtDNA cytochrome b
Cytochrome b
Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...
sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
data gives a confusing picture of these birds' interrelationships. What can be said is that the hawk
Hawk
The term hawk can be used in several ways:* In strict usage in Australia and Africa, to mean any of the species in the subfamily Accipitrinae, which comprises the genera Accipiter, Micronisus, Melierax, Urotriorchis and Megatriorchis. The large and widespread Accipiter genus includes goshawks,...
s, kite
Kite (bird)
Kites are raptors with long wings and weak legs which spend a great deal of time soaring. Most feed mainly on carrion but some take various amounts of live prey.They are birds of prey which, along with hawks and eagles, are from the family Accipitridae....
s, eagle
Eagle
Eagles are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species occur in Eurasia and Africa. Outside this area, just two species can be found in the United States and Canada, nine more in...
s and Old World vultures as presently assigned in all likelihood do not form monophyletic groups:
According to the molecular data, the Buteoninae are most likely poly- or paraphyletic, with the true eagles, the sea eagles
Sea eagle (bird)
A sea eagle is any of the birds of prey in the genus Haliaeetus in the bird of prey family Accipitridae....
, and the buteo
Buteo
Buteo is a genus of medium to fairly large, wide-ranging raptors with a robust body and broad wings. In the Old World, members of this genus are called "buzzards", but "hawk" is used in North America...
nine hawks apparently representing distinct lineages. These appear to form a group with the Milvinae, Accipitrinae
Accipitrinae
The Accipitrinae is the subfamily of the Accipitridae often known as the "true" hawks, including all members of Accipiter and the closely related genera Melierax, Urotriorchis, Erythrotriorchis and Megatriorchis. The large and widespread genus Accipiter includes goshawks, sparrowhawks, the...
and Circinae but the exact relationships between the lineages are not at all robustly resolvable with the present data. The Perninae
Perninae
The raptor subfamily Perninae includes a number of medium-sized broad-winged species. These are birds of warmer climates, although the Pernis species have a more extensive range....
and possibly the Elaninae are older lineages, as are the Old World vultures. The latter are fairly likely also poly- or paraphyletic, with some aberrant species like the Bearded and Egyptian Vulture
Egyptian Vulture
The Egyptian Vulture is a small Old World vulture, found widely distributed from southwestern Europe and northern Africa to southern Asia. It is the only living member of the genus Neophron. It has sometimes also been known as the White Scavenger Vulture or Pharaoh's Chicken...
s standing apart from the naked-necked "true" vultures.
Morphology
Pearl Kite
The Pearl Kite is a very small raptor found in open savanna habitat adjacent to deciduous woodland. It is the only member of the genus Gampsonyx...
and Little Sparrowhawk
Little Sparrowhawk
The Little Sparrowhawk is a species of bird of prey in the Accipitridae family. It is found in Angola, Botswana, Burundi, Democratic Republic of the Congo, Eritrea, Ethiopia, Kenya, Lesotho, Malawi, Mali, Mozambique, Namibia, Rwanda, Somalia, South Africa, Sudan, Swaziland, Tanzania, Uganda,...
, both of which are 23 cm (9 in) in length and weigh about 85 g (3 oz), to the Cinereous Vulture, which measures up to 120 cm (47 in) and weighs up to 14 kg (31 lbs). Until the 14th century even these were surpassed by the extinct
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
Haast's Eagle
Haast's Eagle
Haast's Eagle was a species of massive eagles that once lived on the South Island of New Zealand. The species was the largest eagle known to have existed. Its prey consisted mainly of gigantic flightless birds that were unable to defend themselves from the striking force and speed of these eagles,...
of New Zealand, which is estimated to have measured up to 140 cm (55 in) and to have weighed 15 kg (33 lbs). In terms of body mass, Accipitridae is the most diverse family of birds. Most accipitrids exhibit sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
in size, although unusually for birds it is the females that are larger than the males. This sexual difference in size is most pronounced in active species that hunt birds, such as Accipiter
Accipiter
The genus Accipiter is a group of birds of prey in the family Accipitridae, many of which are named as goshawks and sparrowhawks. They can be anatomically distinguished from their relatives by the lack of a procoracoid foramen. Two small and aberrant species usually placed here do possess a large...
hawks, in which the size difference averages 25–50%. In a majority of species, such as generalist hunters and rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
, reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
, fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
and insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
hunting specialists, the dimorphism is less, usually between a 5% to 25% size difference. In the carrion-eating Old World vulture
Old World vulture
Old World vultures belong to the family Accipitridae, which also includes eagles, buzzards, kites, and hawks.Old World vultures are not closely related to the superficially similar New World vultures and condors, and do not share that group's good sense of smell. The similarities between the two...
s and snail eating kite
Kite (bird)
Kites are raptors with long wings and weak legs which spend a great deal of time soaring. Most feed mainly on carrion but some take various amounts of live prey.They are birds of prey which, along with hawks and eagles, are from the family Accipitridae....
s, the difference is almost non-existent.
The beaks of accipitrids are strong, hooked (sometimes very hooked, as in the Hook-billed Kite
Hook-billed Kite
The Hook-billed Kite, Chondrohierax uncinatus, is a bird of prey in the family Accipitridae, which also includes many other diurnal raptors such as kites, eagles, and harriers...
or Snail Kite
Snail Kite
The Snail Kite is a bird of prey within the family Accipitridae, which also includes the eagles, hawks, and Old World vultures. Its relative, the Slender-billed Kite, is now again placed in Helicolestes, making the genus Rostrhamus monotypic...
). In some species there is a notch or 'tooth' in the upper mandible. In all accipitrids the base of the upper mandible is covered by a fleshy membrane called the cere which is usually yellow in colour. The tarsi
Tarsus (skeleton)
In tetrapods, the tarsus is a cluster of articulating bones in each foot situated between the lower end of tibia and fibula of the lower leg and the metatarsus. In the foot the tarsus articulates with the bones of the metatarsus, which in turn articulate with the bones of the individual toes...
of different species vary by diet, those of bird hunting species like sparrowhawks are long and thin, while species that hunt large mammals have much thicker, stronger ones, and snake-eagle have thick scales to protect from bites.
The plumage
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
of the Accipitridae can be striking but rarely utilises bright colours; most birds use combinations of grey, buff and brown. Overall they tend to be paler below, which helps them seem less conspicuous when seen from below. There is seldom sexual dimorphism in plumage, when it occurs the males are brighter or the females resemble juveniles. In many species juveniles have a distinctly different plumage. Some accipitrids mimic the plumage patterns of other hawks and eagles. They may attempt to resemble a less dangerous species to fool prey, or instead resemble a more dangerous species in order to reduce mobbing
Mobbing behavior
Mobbing in animals is an antipredator behavior which occurs when individuals of a certain species mob a predator by cooperatively attacking or harassing it, usually to protect their offspring. A simple definition of mobbing is an assemblage of individuals around a potentially dangerous predator...
by other birds. Several species of accipitrid have crests used in signalling, and even species without crests can raise the feather
Feather
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...
s of the crown when alarmed or excited. In contrast most of the Old World vulture
Old World vulture
Old World vultures belong to the family Accipitridae, which also includes eagles, buzzards, kites, and hawks.Old World vultures are not closely related to the superficially similar New World vultures and condors, and do not share that group's good sense of smell. The similarities between the two...
s possess bare heads without feathers; this is thought to prevent soiling on the feathers and aid in thermoregulation
Thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different...
.
The senses of the Accipitridae are adapted to hunting (or scavenging), and in particular their vision
Bird vision
Vision is the most important sense for birds, since good eyesight is essential for safe flight, and this group has a number of adaptations which give visual acuity superior to that of other vertebrate groups; a pigeon has been described as "two eyes with wings"...
is legendary. The sight of some hawks and eagles is up to 8 times better than that of humans. Large eyes with two fovea
Fovea
The fovea centralis, also generally known as the fovea , is a part of the eye, located in the center of the macula region of the retina....
provide binocular vision and a "hawk eye" for movement and distance judging. In addition they have the largest pecten
Pecten
Pecten is Latin for "honeycomb." Its genitive form is pectinis, which yields the root pectin-.Pecten may refer to:*Pecten , any honeycomb structure in animals...
s of any birds. The eyes are tube shaped and cannot move much in their sockets. In addition to excellent vision many species have excellent hearing, but unlike in owls sight is generally the principal sense used for hunting. Hearing may be used to locate prey hidden in vegetation, but sight is still used to catch the prey. Like most birds the Accipitridae generally have a poor sense of smell; even the Old World vultures make no use of the sense, in contrast to the New World vultures in the family Cathartidae.
Diet and feeding
Harrier (bird)
A harrier is any of the several species of diurnal hawks forming the Circinae sub-family of the Accipitridae family of birds of prey. Harriers characteristically hunt by flying low over open ground, feeding on small mammals, reptiles, or birds....
and the numerous buteonine hawks
Buteoninae
Buteoninae is a bird of prey subfamily which consists of medium to large broad-winged species.They have large powerful hooked beaks for tearing flesh from their prey, strong legs and powerful talons...
tends towards small mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s such as rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s. Raptors who favor small mammals usually soar or hover over openings until they detect their prey and descent down onto them, although may also watch for prey from a perch. In Accipiter
Accipiter
The genus Accipiter is a group of birds of prey in the family Accipitridae, many of which are named as goshawks and sparrowhawks. They can be anatomically distinguished from their relatives by the lack of a procoracoid foramen. Two small and aberrant species usually placed here do possess a large...
hawks (the most species-rich acciptrid genus), prey is mainly comprised by other bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s. Accipiter hawks usually ambushed birds in dense vegetation, a dangerous hunting method that requires great agility. Most accipitrids will supplement their diet with non-putrid carrion
Carrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...
but, of course, none specialized with this as well as the vultures
Old World vulture
Old World vultures belong to the family Accipitridae, which also includes eagles, buzzards, kites, and hawks.Old World vultures are not closely related to the superficially similar New World vultures and condors, and do not share that group's good sense of smell. The similarities between the two...
.
A few species may opportunistically feed on fruit and in one species, the Palm-nut Vulture
Palm-nut Vulture
The Palm-nut Vulture or Vulturine Fish Eagle, is a very large bird of prey in the family Accipitridae which also includes many other diurnal raptors such as kites, buzzards and harriers, vultures, and eagles. It is the only member of the genus Gypohierax...
, it forms the major part of the diet. Most accipitrids will not eat plant material. Insects are taken exclusively by around 12 species, in great numbers by 44 additional species, and opportunistically by many others. The diet of the honey-buzzards includes not only the adults and young of social insects such as wasps and bees, but the honey and combs from their nests. The Snail Kite
Snail Kite
The Snail Kite is a bird of prey within the family Accipitridae, which also includes the eagles, hawks, and Old World vultures. Its relative, the Slender-billed Kite, is now again placed in Helicolestes, making the genus Rostrhamus monotypic...
and Hook-billed Kite
Hook-billed Kite
The Hook-billed Kite, Chondrohierax uncinatus, is a bird of prey in the family Accipitridae, which also includes many other diurnal raptors such as kites, eagles, and harriers...
s are specialists in consuming snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s. "Eagle
Eagle
Eagles are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species occur in Eurasia and Africa. Outside this area, just two species can be found in the United States and Canada, nine more in...
s" are several raptors that are not necessarily closely related but can be broadly defined by large body size and the taking of typically larger prey, including mid-sized mammals and larger birds. Most accipitrids usually hunt prey rather smaller than themselves. However, many accipitrids have been recorded as capturing and then flying with prey of equal weight or even slightly heavier than themselves in their talons, a feat that requires great physical strength. Occasionally, an eagle or other raptor that kills prey considerably heavier than itself (too heavy for the raptor to carry and fly with) and will then have to leave prey where they've killed and later return repeatedly to feed. This has the advantage of providing a surplus
Surplus
Surplus means when there is more supply than demand, as in extra resources.Surplus may refer to: dumd* "The Surplus", an episode of The Office* Surplus: Terrorized into Being Consumers, a documentary film...
of food but has the disadvantage of potentially attracting scavengers or other predators which can steal the kill or even attack the feeding accipitrid. Using this method, accipitrids such as the Golden
Golden Eagle
The Golden Eagle is one of the best known birds of prey in the Northern Hemisphere. Like all eagles, it belongs to the family Accipitridae. Once widespread across the Holarctic, it has disappeared from many of the more heavily populated areas...
, Martial
Martial Eagle
The Martial Eagle , is a very large eagle found in open and semi-open habitats of sub-Saharan Africa. It is the only member of the genus Polemaetus.-Description:...
and Crowned Eagle
Crowned Eagle
The Crowned Eagle or Crowned Hawk-eagle , is a very large, powerful, crested bird of prey found in sub-Saharan Africa; in Southern Africa it is restricted to suitable habitat in the eastern areas. It is the only extant member of the genus Stephanoaetus...
have successfully hunted prey deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...
and duiker
Duiker
A duiker is any of about 21 small to medium-sized antelope species from the subfamily Cephalophinae native to Sub-Saharan Africa.Duikers are shy and elusive creatures with a fondness for dense cover; most are forest dwellers and even the species living in more open areas are quick to disappear...
s weighing more than 30 kg (66.1 lb), 7-8 times their own mass. The Haliaeetus eagles, the Ichthyophaga
Ichthyophaga
Ichthyophaga is a genus of two species of eagles, closely related to the sea-eagles in the genus Haliaeetus. Both are native to southeastern Asia, from the Indian subcontinent southeast to Sulawesi. They are smaller than the Haliaeetus eagles, though overlapping in size with the smaller species of...
eagles and the Osprey
Osprey
The Osprey , sometimes known as the sea hawk or fish eagle, is a diurnal, fish-eating bird of prey. It is a large raptor, reaching more than in length and across the wings...
mainly prefer to prey on fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
(comprising more than 90% of food for the latter 2 genera). These large acciptrids may supplement their diets with aquatic animals other than fish, especially the more generalized Haliaeetus eagles. Reptiles are hunted by almost all variety of acciptrids when the opportunity arises and may even be favored over other prey by some eagles and buteonine hawks
Buteoninae
Buteoninae is a bird of prey subfamily which consists of medium to large broad-winged species.They have large powerful hooked beaks for tearing flesh from their prey, strong legs and powerful talons...
found in the tropics. Bazas
Aviceda
The bazas, Aviceda, are a genus of bird of prey in the Accipitridae family. The genus has a widespread distribution from Australia to southern Asia and across to Africa. The bazas are sometimes known as cuckoo-hawks....
and forest hawks in the genus Accipiter
Accipiter
The genus Accipiter is a group of birds of prey in the family Accipitridae, many of which are named as goshawks and sparrowhawks. They can be anatomically distinguished from their relatives by the lack of a procoracoid foramen. Two small and aberrant species usually placed here do possess a large...
may take reptiles from trees whilst other species may hunt them on the ground. Snake are the primary prey of the snake-eagles (Circaetus
Circaetus
Circaetus, the snake eagles, is a genus of medium-sized eagles in the bird of prey family Accipitridae which also includes many other diurnal raptors such as buzzards and harriers....
) and serpent-eagles (Spilornis
Spilornis
Spilornis is a genus of bird of prey in the family Accipitridae. As adults all have dark crowns, and bright yellow eyes and cere. These medium-sized raptors are found in forests of southern Asia and are known as serpent-eagles; an English name shared with two African species from the genera...
and Dryotriorchis).
Genera
- Subfamily Elaninae - elanid kites (8 species)
- Genus ElanusElanusBlack-winged Kites is a genus of bird of prey in the elanid kite subfamily. It consists of four species.* Black-winged Kite, Elanus caeruleus* Black-shouldered Kite, Elanus axillaris* White-tailed Kite, Elanus leucurus...
- Genus Chelictinia
- Genus Gampsonyx
- Genus Elanoides
- Genus Elanus
- Subfamily PerninaePerninaeThe raptor subfamily Perninae includes a number of medium-sized broad-winged species. These are birds of warmer climates, although the Pernis species have a more extensive range....
- honey buzzards (c.14 species)- Genus AvicedaAvicedaThe bazas, Aviceda, are a genus of bird of prey in the Accipitridae family. The genus has a widespread distribution from Australia to southern Asia and across to Africa. The bazas are sometimes known as cuckoo-hawks....
- Genus HenicopernisHenicopernisHenicopernis is a genus of bird of prey in the Accipitridae family. It contains the following species:* Black Honey Buzzard * Long-tailed Honey Buzzard...
- Genus PernisPernis (bird)Pernis is a genus of birds in the raptor subfamily Perninae. It consists of three medium-sized broad-winged species.* European Honey Buzzard, Pernis apivorus* Crested Honey Buzzard, Pernis ptilorhynchus...
- Genus LeptodonLeptodonLeptodon is a genus of birds of prey. Its two members are similar, with a grey head, black upperparts and white underparts. They are:* Grey-headed Kite, Leptodon cayanensis* White-collared Kite, Leptodon forbesi...
- Genus ChondrohieraxChondrohieraxChondrohierax is a genus of birds of prey. Its two members are often considered to be conspecific. They are*Hook-billed Kite Chondrohierax uncinatus,*Cuban Kite, Chondrohierax wilsonii...
- Genus Machaerhamphus (Doubtfully placed)
- Genus Aviceda
- Subfamily Aegypiinae - Old World vultures
- Genus Sarcogyps
- Genus Aegypius
- Genus Torgos
- Genus Trigonoceps
- Genus GypsGypsThe Gyps vultures are a genus of Old World vultures in the bird family Accipitridae, which also includes eagles, kites, buzzards and hawks....
- Genus Necrosyrtes
- Subfamily Gypaetinae
- Genus Neophron
- Genus Gypohierax
- Genus Gypaetus
- Genus Eutriorchis
- Subfamily ButeoninaeButeoninaeButeoninae is a bird of prey subfamily which consists of medium to large broad-winged species.They have large powerful hooked beaks for tearing flesh from their prey, strong legs and powerful talons...
- buteonine hawks, true eagles and sea-eagles (c.100 living species, probably poly- or paraphyletic)- Genus Geranoaetus
- Genus ButeoButeoButeo is a genus of medium to fairly large, wide-ranging raptors with a robust body and broad wings. In the Old World, members of this genus are called "buzzards", but "hawk" is used in North America...
(probably paraphyletic, might include Leucopternis in part and Parabuteo) - Genus Parabuteo
- Genus ButeogallusButeogallusButeogallus is a genus of bird of prey in the family Accipitridae. All members of this genus are essentially Neotropical, but the distribution of a single species extends slightly into extreme southern USA. Most are known as black-hawks or mangrove-hawks...
(probably paraphyletic, might include Leucopternis in part) - Genus Busarellus
- Genus LeucopternisLeucopternisLeucopternis is a Neotropical genus of bird of prey in the Accipitridae family. They are generally associated with tropical or subtropical forests, and most are uncommon or rare...
(probably polyphyletic) - Genus Kaupifalco
- Genus ButasturButasturButastur is a genus of bird of prey in the Accipitridae family. It contains the following species:* Rufous-winged Buzzard * Grasshopper Buzzard * White-eyed Buzzard...
- Genus HarpyhaliaetusHarpyhaliaetusHarpyhaliaetus is a genus of eagles. Recent studies have shown that the Solitary Eagle is closely related to the black-hawks, in particular the Savanna Hawk which is smaller and browner but otherwise very similar to "Harpyhaliaetus"...
- Genus Geranospiza
- Subfamily Aquilinae
- Genus SpizaetusSpizaetusSpizaetus is the typical hawk-eagle birds of prey genus found in the tropics of the Americas. It was however used to indicate a group of tropical eagles that included species occurring in southern and southeastern Asia and one representative of this genus in the rainforests of West Africa. The Old...
- Genus NisaetusNisaetusNisaetus is a genus of eagles found mainly in tropical Asia. They were earlier placed within the genus Spizaetus but molecular studies show that the Old World representatives were closer to the genus Ictinaetus than to the New World Spizaetus...
- Genus Lophaetus (possibly junior synonym of Ictinaetus)
- Genus StephanoaetusStephanoaetusStephanoaetus is a genus of very large birds of prey from Sub-Saharan Africa and Madagascar. Only one of the two known species is extant.-Species:* Crowned Eagle or Crowned Hawk-eagle ....
- Genus Polemaetus
- Genus "HieraaetusHieraaetusThe genus Hieraaetus, sometimes known as hawk-eagles, denoted a group of smallish eagles usually placed in the Buteoninae subfamily of accipitrids....
" - Genus "Lophotriorchis"
- Genus AquilaAquila (genus)Aquila is the genus of true eagles. It is often united with the buteos, sea eagles and other more heavyset Accipitridae, but more recently it appears as if they are less distinct from the more slender accipitrine hawks than believed...
(paraphyletic) - Genus Ictinaetus
- Genus Spizaetus
- Subfamily Circinae - harriers (some 16 living species)
- Genus Circus
- Subfamily Polyboroidinae - harrier hawks
- Genus PolyboroidesPolyboroidesPolyboroides is a genus of bird of prey in the Accipitridae family. This genus has two recognized species found in Sub-Saharan Africa and Madagascar. The two species are allopatric and restricted to the Afrotropic ecozone...
- Genus Polyboroides
- Subfamily Milvinae - milvine kites (some 14 species)
- Genus HarpagusHarpagus (bird)Harpagus is a genus of birds of prey in the Accipitridae family. It comprises:*Double-toothed Kite, Harpagus bidentatus*Rufous-thighed Kite, Harpagus diodonBoth live in tropical American forests...
- Genus IctiniaIctiniaIctinia is a genus of birds in the Accipitridae family. It contains two species:* Mississippi Kite * Plumbeous Kite Both of these species are native to the Americas.-References:*...
- Genus Rostrhamus
- Genus Helicolestes - formerly included in Rostrhamus
- Genus HaliasturHaliasturHaliastur is a genus of medium-sized diurnal birds of prey. It consists of two species of kite which form part of the subfamily Milvinae; some authorities place these species in the genus Milvus, despite clear differences in behaviour, voice and plumage....
- Genus MilvusMilvusMilvus is a genus of medium-sized birds of prey. It is an Old World group consisting of three kites which form part of the subfamily Milvinae...
- Genus Lophoictinia
- Genus Hamirostra
- Genus Harpagus
- Subfamily AccipitrinaeAccipitrinaeThe Accipitrinae is the subfamily of the Accipitridae often known as the "true" hawks, including all members of Accipiter and the closely related genera Melierax, Urotriorchis, Erythrotriorchis and Megatriorchis. The large and widespread genus Accipiter includes goshawks, sparrowhawks, the...
- goshawks, sparrowhawks, and relatives (c.55 living species)- Genus AccipiterAccipiterThe genus Accipiter is a group of birds of prey in the family Accipitridae, many of which are named as goshawks and sparrowhawks. They can be anatomically distinguished from their relatives by the lack of a procoracoid foramen. Two small and aberrant species usually placed here do possess a large...
- Genus Urotriorchis
- Genus ErythrotriorchisErythrotriorchisErythrotriorchis is a genus of bird of prey in the Accipitridae family.It contains the following species:* Chestnut-shouldered Goshawk * Red Goshawk -Etymology:...
- Genus Megatriorchis
- Genus Accipiter
- Subfamily CircaetinaeCircaetinaeCircaetinae is a bird of prey subfamily which consists of a group of medium to large broad-winged species. These are mainly birds which specialise in feeding on snakes and other reptiles, which is the reason most are named as "snake-eagles" or "serpent-eagles". The only exception is the Bateleur,...
- snake eagles (about one dozen species)- Genus Terathopius
- Genus CircaetusCircaetusCircaetus, the snake eagles, is a genus of medium-sized eagles in the bird of prey family Accipitridae which also includes many other diurnal raptors such as buzzards and harriers....
- Genus SpilornisSpilornisSpilornis is a genus of bird of prey in the family Accipitridae. As adults all have dark crowns, and bright yellow eyes and cere. These medium-sized raptors are found in forests of southern Asia and are known as serpent-eagles; an English name shared with two African species from the genera...
- Genus Pithecophaga
- Subfamily Haliaeetinae - sea eagles
- Genus Haliaeetus
- Genus IchthyophagaIchthyophagaIchthyophaga is a genus of two species of eagles, closely related to the sea-eagles in the genus Haliaeetus. Both are native to southeastern Asia, from the Indian subcontinent southeast to Sulawesi. They are smaller than the Haliaeetus eagles, though overlapping in size with the smaller species of...
- Subfamily Harpiinae
- Genus Morphnus
- Genus Harpia
- Genus Harpyopsis
- Subfamily Melieraxinae
- Genus MelieraxMelieraxMelierax is a genus of bird of prey in the Accipitridae family.It contains the following species:* Dark Chanting Goshawk * Pale Chanting Goshawk * Eastern Chanting Goshawk...
(Micronisus)
- Genus Melierax
Fossil record
Like with most other birds of prey, the fossilFossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
record of this group is fairly decent from the latter Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
onwards (c.35 mya), with modern genera being well documented since the Early Oligocene, or around 30 mya.
- Milvoides (Late Eocene of England)
- Aquilavus (Late Eocene/Early Oligocene - Early Miocene of France)
- Palaeocircus (Late Eocene/Early Oligocene of France)
- Palaeastur (Agate Fossil Beds Early Miocene of Sioux County, USA)
- PenganaPenganaThe Flexiraptor is an extinct species of bird of prey – the only one of its genus known to date – probably related to harriers. It probably resembled a cross between the Secretary Bird and Crested Caracara, and lived during the Early Miocene .Its remains were found in Riversleigh ,...
(Early Miocene of Riversleigh, Australia) - Promilio (Agate Fossil Beds Early Miocene of Sioux County, USA)
- Proictinia (Early - Late Miocene/Early Pliocene of C and SE USA)
- Neophrontops (Early/middle Miocene - Late Pleistocene) - formerly in Neophron
- Mioaegypius (Xiacaowan middle Miocene of Sihong, China)
- ApatosagittariusApatosagittariusApatosagittarius is an extinct monotypic genus of Accipitridae from the Late Miocene of Nebraska. Only one species has been described, Apatosagittarius terrenus.-Reference:...
(Late Miocene of Nebraska, USA) - Gansugyps (Liushu Late Miocene of China)
- Palaeoborus (Miocene)
- Qiluornis (Miocene of Shandong, China)
- Thegornis (Miocene of Argentina)
- Garganoaetus (Early Pliocene of Gargano Peninsula, Italy)
- AmplibuteoAmplibuteoAmplibuteo is an extinct genus of birds of prey, belonging the family Accipitridae....
(Late Pliocene of Peru - Late Pleistocene of S North America and Cuba) - may belong to extant genus Harpyhaliaetus - Neogyps
- Palaeohierax - includes "Aquila" gervaisii
- Wetmoregyps - formerly Morphnus daggetti
Accipitrids are known since Early Eocene times, or about from 50 mya onwards, in fact, but these early remains are too fragmentary and/or basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
to properly assign a place in the phylogeny. Likewise, as remarked above, molecular methods are of limited value in determining evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
ary relationships of and within the accipitrids. What can be determined is that in all probability, the group originated on either side of the Atlantic, which during that time was only 60-80% its present width. On the other hand, as evidenced by fossils like Pengana
Pengana
The Flexiraptor is an extinct species of bird of prey – the only one of its genus known to date – probably related to harriers. It probably resembled a cross between the Secretary Bird and Crested Caracara, and lived during the Early Miocene .Its remains were found in Riversleigh ,...
, some 25 mya, accipitrids in all likelihood rapidly acquired a global distribution - initially probably even extending to Antarctica.
- Accipitridae gen. et sp. indet. (Huerfano Early Eocene of Huerfano County, USA)
- Accipitridae gen. et sp. indet. (Borgloon Early Oligocene of Hoogbutsel, Belgium)
- Accipitridae gen. et sp. indet. (Bathans Early/Middle Miocene of Otago, New Zealand)
- Accipitridae gen. et sp. indet. MPEF-PV-2523 (Puerto Madryn Late Miocene of Estancia La Pastosa, Argentina)
- "Aquila" danana (Snake Creek Late Miocene/Early Pliocene of Loup Fork, USA) - formerly also Geranoaetus or Buteo
- Accipitridae gen. et sp. indet. (Early/Middle Pliocene of Kern County, USA) - Parabuteo?
- Accipitridae gen. et sp. indet. (Late Pliocene/Early Pleistocene of Ibiza, Mediterranean) - Buteo?
- Accipitridae gen. et sp. indet. (Egypt)
Specimen AMNH FR 2941, a left coracoid from the Late Eocene Irdin Manha Formation
Irdin Manha Formation
The Irdin Manha Formation is a palaeontological formation located in Mongolia. It dates to the Eocene period.-References: ; Wildlife of Gondwana. Reed. ISBN 0-7301-0315-3...
of Chimney Butte (Inner Mongolia
Inner Mongolia
Inner Mongolia is an autonomous region of the People's Republic of China, located in the northern region of the country. Inner Mongolia shares an international border with the countries of Mongolia and the Russian Federation...
) was initially assessed as a basal mid-sized "buteonine"; it is today considered to be more likely to belong in the Gruiformes
Gruiformes
The Gruiformes are an order containing a considerable number of living and extinct bird families, with a widespread geographical diversity. Gruiform means "crane-like"....
genus Eogrus. The Early Oligocene genus Cruschedula
Cruschedula
Cruschedula is an enigmatic bird genus considered to be nomen dubium which consists of the single species Cruschedula revola....
was formerly thought to belong to Spheniscidae, however reexamination of the holotype in 1943 resulted in the genus being placed in Accipitridae. Further examination in 1980 resulted in placement as Aves incertae sedis.
Footnotes
External links
- Accipitridae videos on the Internet Bird Collection
- xeno-canto.org: Accipitridae sounds. Retrieved 2006-DEC-01.