Accipitridae

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Accipitridae
Temporal range: Eocene – present, 50–0  Ma
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Spizaetus-ornatus-001.jpg
Juvenile ornate hawk-eagle
Spizaetus ornatus
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family:Accipitridae
Vieillot, 1816
Subfamilies

The Accipitridae, one of the four families within the order Accipitriformes (the others being Cathartidae, Pandionidae and Sagittariidae [1] ), 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.

Family is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy; it is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as being the "walnut family".

In biological classification, the order is

  1. a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family. An immediately higher rank, superorder, may be added directly above order, while suborder would be a lower rank.
  2. a taxonomic unit, a taxon, in that rank. In that case the plural is orders.
Accipitriformes order of birds

The Accipitriformes are an order of birds that includes most of the diurnal birds of prey – including hawks, eagles, and vultures, but not falcons – about 217 species in all.

Contents

Many well-known birds, such as hawks, eagles, kites, harriers and Old World vultures 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 vultures are also usually now regarded as a separate family or order. Karyotype data [2] [3] [4] indicate the accipitrids analysed are indeed a distinct monophyletic group, but whether this group should be considered a family or one or several order(s) on their own is a question still to be resolved.

Hawk group of diurnal birds of prey

Hawks are a group of medium-sized diurnal birds of prey of the family Accipitridae. Hawks are widely distributed and vary greatly in size.

Eagle large carnivore bird

Eagle is the common name for many large birds of prey of the family Accipitridae. Eagles belong to several groups of genera, not all of which are closely related. Most of the 60 species of eagle are from Eurasia and Africa. Outside this area, just 14 species can be found—2 in North America, 9 in Central and South America, and 3 in Australia.

Kite (bird) bird of prey

Kite is a common name for certain birds of prey in the family Accipitridae, particularly in subfamilies Milvinae, Elaninae, and Perninae.

Systematics

The accipitrids have been variously divided into some five to 10 subfamilies. Most share a very similar morphology, but many of these groups contain taxa that 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.

In biological classification, a subfamily is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoological names with "-inae".

Morphology (biology) In biology, the form and structure of organisms

Morphology is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features.

The accipitrids are recognizable by a peculiar rearrangement of their chromosomes. [5] Apart from this, morphology and mtDNA cytochrome b sequence data give a confusing picture of these birds' interrelationships. What can be said is that the hawks, kites, eagles and Old World vultures as presently assigned in all likelihood do not form monophyletic groups:

Cytochrome b A mitochondrial protein involved in the respiratory chain

Cytochrome b is a protein found in the mitochondria of eukaryotic cells. It functions as part of the electron transport chain and is the main subunit of transmembrane cytochrome bc1 and b6f complexes.

According to the molecular data, the Buteoninae are most likely poly- or paraphyletic, with the true eagles, the sea eagles, and the buteonine 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 vultures standing apart from the naked-necked "true" vultures. [6]

<i>Buteo</i> genus of birds

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. As both terms are ambiguous, buteo is sometimes used instead, for example, by the Peregrine Fund.

Milvinae subfamily of birds

The Milvinae kites are found in the family Accipitridae. Many taxonomic authorities have the subfamily under revision.

Accipitrinae subfamily of birds

The Accipitrinae are 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 sharp-shinned hawk and others. They are primarily woodland birds that hunt by sudden dashes from a concealed perch, with long tails, broad wings and high visual acuity facilitating this lifestyle. In light of recent genetic research, the kites of the traditional subfamily Milvinae may also belong to this group.

Morphology

Portrait of a bald eagle, showing its strongly hooked beak and the cere covering the base of the beak. Bald.eagle.closeup.arp-sh.750pix.jpg
Portrait of a bald eagle, showing its strongly hooked beak and the cere covering the base of the beak.

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 (Gampsonyx swainsonii) and little sparrowhawk (Accipiter minullus), both of which are 23 cm (9 in) in length and weigh about 85 g (3 oz), to the cinereous vulture (Aegypius monachus), which measures up to 120 cm (47 in) and weighs up to 14 kg (31 lbs). Wingspan can vary from 39 cm (15 in) in the little sparrowhawk to more than 300 cm (120 in) in the cinereous and Himalayan vultures (Gyps himalayensis). In these extreme species, wing chord length can range from 113 to 890 mm (4.4 to 35.0 in) and culmen length from 11 to 88 mm (0.43 to 3.46 in). Until the 14th century, even these huge vultures were surpassed by the extinct Haast's eagle (Harpagornis moorei) of New Zealand, which is estimated to have measured up to 140 cm (55 in) and to have weighed 15 to 16.5 kg (33 to 36 lb) in the largest females. [7] [8] In terms of body mass, the Accipitridae are the most diverse family of birds and may also be in terms of some aspects of linear size diversity, although lag behind the true parrots and pheasant family in length diversity. [9] Most accipitrids exhibit sexual dimorphism in size, although, unusually for birds, it is the females that are larger than the males. [10] This sexual difference in size is most pronounced in active species that hunt birds, such as the 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 30% size difference. In the carrion-eating Old World vultures and snail eating kites, the difference is almost non-existent. [9]

Pearl kite species of bird

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. The scientific name commemorates the English naturalist William Swainson.

Little sparrowhawk species of bird

The little sparrowhawk is a species of Afrotropical bird of prey in the family Accipitridae. It is the smallest member of the genus Accipiter and forms a superspecies with the red-thighed sparrowhawk.

Cinereous vulture one of the two largest old world vultures

The cinereous vulture is a large raptorial bird that is distributed through much of Eurasia. It is also known as the black vulture, monk vulture, or Eurasian black vulture. It is a member of the family Accipitridae, which also includes many other diurnal raptors such as kites, buzzards and harriers. It is one of the two largest Old World vultures, attaining a maximum size of 14 kg,, 1.2 m long and 3.1 m across the wings.

The beaks of accipitrids are strong and 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, such as sparrowhawks, are long and thin, whilst species that hunt large mammals have much thicker, stronger tarsi, and the tarsi of the snake-eagles 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. [11] 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. [12] Several species of accipitrid have crests used in signalling, and even species without crests can raise the feathers of the crown when alarmed or excited. In contrast most of the Old World vultures possess bare heads without feathers; this is thought to prevent soiling on the feathers and aid in thermoregulation. [13]

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 pectens 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 behavior

Palm-nut vulture is an unusual frugivorous accipitrid, but will also consume fish, particularly dead fish Palmnutvulture.jpg
Palm-nut vulture is an unusual frugivorous accipitrid, but will also consume fish, particularly dead fish
Shikra Accipiter badius in Hyderabad, India Shikra (Accipiter badius) in Hyderabad W2 IMG 8968.jpg
Shikra Accipiter badius in Hyderabad, India
Oriental honey-buzzard Pernis ptilorhyncus Oriental Honey-buzzard (Male) I IMG 9740.jpg
Oriental honey-buzzard Pernis ptilorhyncus

Accipitrids are predominantly 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 (including more than 30 species in the genus Buteo ) tends towards small mammals such as rodents.

Among the raptors that mainly favor small mammals, harriers generally hunt by hovering over openings until they detect their prey and descend upon them. Due to the specificity of their hunting style, prey preferences, and habitat preferences, usually only one harrier species tends to be found per region. [14]

Buteonine hawks usually watch for prey from a perch but most species will also readily hunt on the wing, including from a high soar. Many buteonines are amongst the most generalized feeders, often feeding on any active small animal they find, and will generally eat whatever diurnal rodent or lagomorph is most locally common. Some buteonines, however, are more specialized, such as certain species in the genus Buteogallus , which have evolved to specialize in feeding on crabs. Larger Buteogallus, namely the solitary eagles, and Geranoaetus , are much larger than other buteonines and seem to have become avian apex predators of specific habitat niches, i.e. savanna, cloud forest and páramo in South America and are thus honorary "eagles". [15] [16]

In Accipiter hawks (the most species-rich accipitrid genus with nearly 50 extant species), prey is mainly other birds. Accipiters are in general forest- and thicket-dwelling species. Accipiter hawks usually ambush birds in dense vegetation, a dangerous hunting method that requires great agility. Many smaller tropical species of Accipiter eat nearly equal portions of insects and reptiles and amphibians as they do of birds while some of the larger species have become more generalized, and may feed extensively on rodents and lagomorphs as well as other various non-avian animals.

Most accipitrids will supplement their diet with non-putrid carrion but, of course, none specialized with this as well as the 14-16 species of vultures, which have evolved very large bodies (which leave them equipped to fill their crop with carrion), weaker, less specialized feet relative to other accipitrids, large wingspans to spend extensively periods of time in flight over openings scanning for carcasses and complex social behavior in order to establish a mixed species hierarchy at carrion. The New World vultures have attained several similar characteristics, but only through convergent evolution and are seemingly not directly related to Old World vultures and other accipitrids. The lammergeier (Gypaetus barbatus) is an aberrant cousin of the Old World vultures that has maintained strong feet in order to carry and drop large bones in order to crack them open to feed on bone marrow, their primary food, a technique they also sometimes use for live prey items, like tortoises. [9]

A few species may opportunistically feed on fruit. In one species, the palm-nut vulture (Gypohierax angolensis) (possibly not closely related to other "vultures"), it may form more than half of the diet. [17] 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 a great many others. [11] 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. [18]

The snail kite (Rostrhamus sociabilis), slender-billed kite (Helicolestes hamatus) and hook-billed kites (Chondrohierax uncinatus) are specialists in consuming snails, which usually constitute 50-95% of their diet. Other "kites" are divided into two groups, a loose assemblance of smallish raptors, many of which are strong fliers. One, exclusively in the Old World, milvine or "large" kites, are relatively large, often quite common, very generalized and often weakly predaceous feeders whereas the other kites, also known as elanine or "small" kites and mostly found in the New World, are supremely aerial, active hunters that generally alternate their primary food between insects and small mammals. One species allied with the latter kite group, the bat hawk (Macheiramphus alcinus), has come to specialize in hunting bats. [19]

"Eagles" are several raptors that are not necessarily closely related, but can be broadly defined by large body size (larger than other raptors excluding vultures) and the taking of typically larger prey, including mid-sized mammals and larger birds. The most diverse group of eagles is the "booted eagles", a variable group of c. 30 species, defined by their feathering covering their legs (shared by only a couple of buteonine species).

Most accipitrids usually hunt prey rather smaller than themselves. However, many accipitrids of almost all sizes 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) will then have to leave prey where they've killed and later return repeatedly to feed or dismember and bring to a perch or nest piece by piece. 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 (Aquila chrysaetos), wedge-tailed (Aquila audax), martial (Polemaetus bellicosus) and crowned eagles (Stephanoaetus coronatus) have successfully hunted ungulates, such as deer and antelope, and other large animals (kangaroos and emus in the wedge-tailed) weighing more than 30 kg (66 lb), 7–8 times their own mass. More typical prey for these powerful booted eagle species weigh between 0.5 and 5 kg (1.1 and 11.0 lb). [9] [20]

The Haliaeetus eagles, the Ichthyophaga eagles and the osprey (Pandion haliaetus), possibly in its own monotypical family, 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, which also hunt large numbers of water birds and are expert kleptoparasites.

Reptiles and amphibians are hunted by almost all variety of acciptrids when the opportunity arises and may be favored over other prey by some eagles, i.e. Spizaetus hawk-eagles and the "eagles" in Buteogallus , and several species of 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. Snakes are the primary prey of the snake-eagles ( Circaetus ) and serpent-eagles ( Spilornis and Dryotriorchis ). Apparently, the mammal-hunting, huge and endangered Philippine eagle (Pithecophaga jefferyi) is most closely related to the snake eagles. [11] [9] Another handsome aberration of the snake-eagle lineage (although, unlike the Philippine, has long been known to be a snake-eagle) is the bateleur (Terathopius ecaudatus), which has evolved unusually bright plumage in adults, with a huge red cere, red feet, bright yellow bill, and boldly contrasting grey-and-white markings over black plumage. The bateleur has specialized to feed extensively on carrion and almost any other feeding opportunity that presents itself. [21] [22]

Reproductive biology and populations

In terms of their reproductive biology and socio-sexual behavior, accipitrids share many characteristics with other extant groups of birds that appear not be directly related, but all of which have evolved to become active predators of other warm-blooded creatures. Some of the characteristics shared with these other groups, including falcons, owls, skuas and shrikes, are that the female is typically larger than the male, extreme devotion for breeding pairs to each other and often to a dedicated nesting site, strict and often ferocious territorial behavior, and, on hatching, occasional competition amongst nestlings, including regular siblicide in several species.

Before the onset of the nesting season, adult accipitrids often devote a majority of their time to excluding other members of their own species and even of other species from their nesting territories. In several species, this occurs by territorial display flights over the border of their breeding ranges. In several forest dwelling varieties, however, vocalizations are used to establish territories. Due to the density of the habitat, display flights are apparently impractical.

While a single devoted breeding pair is considered typical, research has revealed that in varied accipitrids, multiple birds engaging in nesting behavior is more commonly than previously thought. Some harriers have evolved to become polgynous, with a single smaller male breeding with and then helping multiple females raise young. [23] The most extreme known species of accipitrid in terms of sociality is the Harris's hawks (Parabuteo unicinctus), which up to seven fully-grown birds may hunt, nest and brood cooperatively, with the additional birds typically being prior years' offspring of the two most mature hawks. [24] [25]

Unlike the other two larger groups of raptorial birds, the owls and most falcons, accipitrids typically build their own nest. Nest sites are typically in relatively secure places, such as the crook of a large tree or an ample cliff ledge, and can vary in elevation from the flat ground of prairies or steppe to near the peaks of the tallest mountains such as the Himalayas. Accipitrids will readily return to use a nest site repeatedly, which has resulted in several of the largest bird's nests known, as a single nest may see decades of use, with more material added each breeding season. The single largest known tree nest known for any animal, belong to a bald eagle (Haliaeetus leucocephalus), was found to be 6.1 m (20 ft) deep, 2.9 meters (9.5 ft) across, and to weigh 3 short tons (2.7 metric tons). [26] Some species, especially eagles, will build multiple nests for use in alternating years. Although they usually use nests they build themselves, accipitrids sometimes use abandoned nests build by other animals or pirate nests from other birds, typically other types of accipitrid.

Compared to most other types of birds, the stretch from egg-laying to independence in young birds is very prolonged. In accipitrids, the breeding season ranges from about two to three months to roughly a year and a half, the latter in some of the larger tropical eagles. Species inhabiting temperate ranges as a rule have shorter breeding seasons due to the shorter stretches of warm weather that facilitates ready capture of prey.

Usually from 2 to 6 eggs are laid in accipitrids, a relatively small clutch, and some species may lay only one egg. In almost all accipitrids, eggs are laid at intervals rather than all at once and in some larger species the intervals can be several days. This results in one of the hatchlings being larger and more advanced in development than its siblings. The benefits of siblicide, which is at least occasionally recorded in many species and almost always occurs in some, such as tropical members of the booted eagle group, is that the smaller siblings are a kind of insurance policy that if the oldest, strongest nestling dies, one of the smaller siblings may take its place. In most species that have displayed siblicide, times of food plenty may result in two or more the nestlings being successfully raised to fledging.

In most accipitrids, the smaller males typically attain food both for the incubating and brooding female and the nestlings. Males, however, occasionally take a shift incubating or even more sporadically of brooding of the nestlings, which allows the female to hunt. Most accipitrids feed their nestlings by feeding them strips of meat or whole prey items, but most vultures feed their nestlings via regurgitation.

Fledgling often takes considerable effort for young birds and may take several weeks as opposed to days in many other types of birds. Once independent of their parents, young accipitrids often most wander for considerable stretches of time, ranging from 1 to 5 years before they attain maturity. Most accipitrids have distinct plumages in their immature stage, which presumably serves as a visual cue to others of their species and may allow them to avoid territorial fights. Shortly after attaining mature plumages, pairs form with a male typically displaying, often in flight but sometimes vocally, to win over a female. Many accipitrids breed with the same mate for several years or for life, although this is not the case for all species and, if a mate dies, the widowed bird will typically try to find another mate the following breeding season. [9] [27]

Genera

Fossil record

Neophrontops americanus fossil Neophrontops americanus.jpg
Neophrontops americanus fossil
Neogyps errans fossil Neogyps errans.jpg
Neogyps errans fossil

As with most other birds of prey, the fossil record of this group is fairly decent[ vague ] 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 evolutionary 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"; [34] it is today considered to be more likely to belong in the Gruiformes genus Eogrus . [35] 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. [36] Further examination in 1980 resulted in placement as Aves incertae sedis. [37]

Footnotes

  1. "Catalogue of Life" . Retrieved 2016-06-19.
  2. de Boer 1975.
  3. Amaral & Jorge 2003.
  4. Federico et al. 2005.
  5. Nanda, I.; Karl, E.; Volobouev, V.; Griffin, D.K.; Schartl, M.; Schmid, M. (2006). "Extensive gross genomic rearrangements between chicken and Old World vultures (Falconiformes: Accipitridae)". Cytogenetic and Genome Research . 112 (3–4): 286–295. doi:10.1159/000089883 . Retrieved 30 September 2011. "The karyotypes of most birds consist of a small number of macrochromosomes and numerous microchromosomes. Intriguingly, most accipitrids which include hawks, eagles, kites, and Old World vultures (Falconiformes) show a sharp contrast to this basic avian karyotype. They exhibit strikingly few microchromosomes and appear to have been drastically restructured during evolution."
  6. Wink, Heidrich & Fentzloff 1996.
  7. Brathwaite 1992.
  8. Worthy, T. & Holdaway, R., The Lost World of the Moa: Prehistoric Life of New Zealand. Indiana University Press (2003), ISBN   978-0253340344
  9. 1 2 3 4 5 6 Ferguson-Lees & Christie 2001.
  10. Paton, Messina & Griffin 1994.
  11. 1 2 3 Thiollay 1994.
  12. Negro 2008.
  13. Ward et al. 2008.
  14. Hamerstrom, F. (1986). "Harrier, hawk of the marshes: The hawk that is ruled by a mouse." Smithsonian Institution Press"" Washington, DC, USA.
  15. Amadon, D. (1949). "Notes on Harpyhaliaetus." The Auk 53-56.
  16. Lerner, H. R., & Mindell, D. P. (2005). "Phylogeny of eagles, Old World vultures, and other Accipitridae based on nuclear and mitochondrial DNA." Molecular Phylogenetics and Evolution 37(2), 327-346.
  17. Although not the entire diet. Thomson & Moreau 1957.
  18. Shiu et al. 2006.
  19. Mikula, P., Morelli, F., Lučan, R. K., Jones, D. N., & Tryjanowski, P. (2016). "Bats as prey of diurnal birds: a global perspective." Mammal Review.
  20. Watson, Jeff (2010). The Golden Eagle. A&C Black. ISBN   978-1-4081-1420-9.
  21. Steyn, P. (1980). "Breeding and food of the bateleur in Zimbabwe (Rhodesia)." Ostrich 51(3); 168-178.
  22. Moreau, R. E. (1945). "On the Bateleur, especially at the Nest." Ibis 87(2): 224-249.
  23. Korpimäki, E. (1988). Factors promoting polygyny in European birds of prey—a hypothesis. Oecologia, 77(2), 278-285.
  24. Bednarz, J. C. (1987). "Pair and group reproductive success, polyandry, and cooperative breeding in Harris' Hawks." The Auk 393-404.
  25. Bednarz, J. C., & Ligon, J. D. (1988). "A study of the ecological bases of cooperative breeding in the Harris' Hawk." Ecology 1176-1187.
  26. Erickson, L. (2007). "Bald Eagle, About Bald Eagle Nests". Journey North.
  27. Eagles, Hawks and Falcons of the World by Leslie Brown & Dean Amadon. The Wellfleet Press (1986), ISBN   978-1555214722.
  28. 1 2 3 4 5 6 7 8 9 Lerner & Mindell 2005.
  29. Specimen AMNH FR 7434: Left carpometacarpus of a snail kite-sized bird: Cracraft 1969.
  30. Tarsometatarsus of a bird the size of a Eurasian sparrowhawk: Smith 2003.
  31. Specimens Museum of New Zealand S42490, S42811: Distal left tibiotarsus and distal right ulna of a bird the size of a smallish eagle: Worthy et al. 2007.
  32. Distal tibia quite similar to Harris's hawk: Miller 1931.
  33. Alcover 1989.
  34. Wetmore 1934.
  35. AMNH 2007.
  36. Simpson, G.G. (1946). "Fossil penguins" (pdf). Bulletin of the American Museum of Natural History. 81. Retrieved 2011-05-26.
  37. Olson, S. L. (1985). "Faunal Turnover in South American Fossil Avifaunas: The Insufficiencies of the Fossil Record" (pdf). Evolution. 39 (5): 1174–1177. doi:10.2307/2408747 . Retrieved 2011-05-26.

Related Research Articles

Bird of prey species of bird that primarily hunt and feed on vertebrates that are large relative to the hunter

Birds of prey, or raptors, include species of bird that primarily hunt and feed on vertebrates that are large relative to the hunter. Additionally, they have keen eyesight for detecting food at a distance or during flight, strong feet equipped with talons for grasping or killing prey, and powerful, curved beaks for tearing flesh. The term raptor is derived from the Latin word rapio, meaning to seize or take by force. In addition to hunting live prey, most also eat carrion, at least occasionally, and vultures and condors eat carrion as their main food source.

Falconidae family of birds

The falcons and caracaras are around 60 species of diurnal birds of prey that make up the family Falconidae. The family is divided into two subfamilies, Polyborinae, which includes the caracaras and forest falcons, and Falconinae, the falcons, kestrels and falconets. They differ from the eagles of Accipitridae, in that falcons kill with their beaks instead of their taloned feet. They have a "tooth" on the side of their beak for this purpose.

Coopers hawk species of bird

Cooper's hawk is a medium-sized hawk native to the North American continent and found from Southern Canada to Northern Mexico. As in many birds of prey, the male is smaller than the female. The birds found east of the Mississippi River tend to be larger on average than the birds found to the west. Other common names for the Cooper's hawk include: big blue darter, chicken hawk, flying cross, hen hawk, quail hawk, striker, and swift hawk.

Buteoninae subfamily of birds

The Buteoninae are a subfamily of birds of prey which consists of medium to large, broad-winged species.

African hawk-eagle species of bird

The African hawk-eagle is a large bird of prey. Like all eagles, it belongs to the family Accipitridae. The African hawk-eagle breeds in tropical Sub-Saharan Africa. It is a bird of wooded hills, building a stick nest about 3 feet in diameter in the fork of a large tree. The clutch is generally one or two eggs. The African hawk-eagle hunts small mammals, reptiles, and birds. The call is a shrill kluu-kluu-kluu.

Lizard buzzard species of bird

The lizard buzzard or lizard hawk is a bird of prey in the family Accipitridae. It is native to Sub-Saharan Africa. Despite its name, it may be more closely related to the Accipiter hawks than the Buteo buzzards.

Mountain hawk-eagle species of bird

The mountain hawk-eagle or, alternately, Hodgson's hawk-eagle is a large bird of prey native to Asia. The latter name is in reference to the naturalist, Brian Houghton Hodgson, who described the species after collecting one himself in the Himalayas. A less widely recognized common English name is the feather-toed eagle. Like all eagles, it is in the family Accipitridae. Its feathered tarsus marks this species as a member of the subfamily Aquilinae. It is a confirmed breeding species in the northern part of the Indian subcontinent, from India, Nepal through Bangladesh to Thailand, Taiwan and Japan, although its distribution could be wider still as breeding species. Like other Asian hawk-eagles, this species was earlier treated under the genera of Spizaetus but genetic studies have shown this group to be paraphyletic, resulting in the Old World members being placed in Nisaetus and separated from the New World species. As is typical of hawk-eagles, the mountain hawk-eagle is a forest dwelling opportunistic predator who readily varies its prey selection between birds, mammals and reptiles along with other vertebrates. Although classified currently as a least-concern species due its persistence over a rather wide distribution, this species is often quite rare and scarce and seems to be decreasing, especially in response to large-scale habitat degradation and deforestation.

Bicolored hawk species of bird

The bicolored hawk is a species of bird of prey in the Accipitridae family. It is found in forest, woodland, second growth, plantations, and wooded savanna in southeastern Mexico, Central America, and northern and central South America. Though generally uncommon, it is the most common species of Accipiter in most of its range, but it does not occur at altitudes above 2,700 metres (8,900 ft) such as the highest parts of the Andes.

Hensts goshawk species of bird

Henst's goshawk is a species a bird of prey in the family Accipitridae. It is a large diurnal bird endemic to the island of Madagascar. It is an obligate forest species that occurs at very low densities on island and is rarely seen. It can only occupy the primary and secondary forests found within the island. Its natural habitats are subtropical or tropical dry forest, subtropical or tropical moist lowland forest, subtropical or tropical moist montane forest, and plantations.

Grey-bellied hawk bird: Grey-bellied Hawk

The grey-bellied hawk or grey-bellied goshawk is a fairly large and rare species of forest-dwelling South American bird of prey in the family Accipitridae.

Fiji goshawk Species of bird

The Fiji goshawk is a species of bird of prey in the family Accipitridae. It was once considered to be the same species (conspecific) as the brown goshawk of Australia and New Caledonia. It is endemic to Fiji, where it occurs on the larger islands of Viti Levu, Vanua Levu, Taveuni, Kadavu, Gau and Ovalau. It occupies a range of wooded habitats in Fiji, from natural rainforest to coconut plantations and urban gardens and parks.

<i>Buteogallus</i> genus of birds

Buteogallus 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 the extreme southwestern United States. Many of the species are fond of large crustaceans and even patrol long stretches of shore or riverbank on foot where such prey abounds, but some have a rather different lifestyle. Unlike many other genera of raptor, some members are referred to as "hawks", and others as "eagles".

Barred hawk species of bird

The barred hawk is a species of bird of prey in the family Accipitridae. It has also been known as the black-chested hawk.

Buteogallus borrasi is a species of giant buteonine hawk which went extinct in the early Holocene. Formerly endemic to Cuba, this huge bird of prey probably fed on Pleistocene megafauna. Little is known about its appearance and ecology, so no common name has been given.

Chilean hawk species of bird

The Chilean hawk is a bird of prey species belonging to the typical hawks. It breeds in Andes forests from central Chile and western Argentina south to Tierra del Fuego, from sea level to 2,700 m altitude. Some winter apparently in the lowlands of NW Argentina.

Aquilinae subfamily of birds

The Aquilinae are a subfamily of eagles of the Accipitridae family. The general common name used for members of this subfamily is "booted eagle", although this is also the common name of a member of the subfamily. At one point, this subfamily was considered inclusive with the Buteoninae based probably on some shared morphological characteristics. However, research on the DNA of the booted eagles has shown that they are a monophyletic group that probably have had millions of years of separation from other extant forms of accipitrid.

Northern goshawk species of bird

The northern goshawk is a medium-large raptor in the family Accipitridae, which also includes other extant diurnal raptors, such as eagles, buzzards and harriers. As a species in the genus Accipiter, the goshawk is often considered a "true hawk". The scientific name is Latin; Accipiter is "hawk", from accipere, "to grasp", and gentilis is "noble" or "gentle" because in the Middle Ages only the nobility were permitted to fly goshawks for falconry.

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See also