Hawks and eagles

(Accipitridae)

Class Aves

Order Falconiformes

Suborder Accipitres

Family Accipitridae

Thumbnail description
Powerful predators with broad wings, hooked beaks, strong legs and feet, sharp talons, and keen sight; carnivorous hunters and scavengers

Size
7.9–59 in (20–150 cm); 2.6–441 oz (75–12,500 g)

Number of genera, species
64 genera, 236 species, and 535 taxa (species or subspecies)

Habitat
Most habitats from seacoasts to mountains, deserts to wetlands, woodlands and lush forests, remote wilderness and isolated islands to farmlands, suburbs, and cities

Conservation status
Critical: 8, Endangered: 4, Vulnerable: 22, Not Threatened: 24, Data Deficient: 1

Distribution
Worldwide, except the Antarctic and extreme northern Arctic

Evolution and systematics

There are two diurnal raptor families, Accipitridae (hawks, eagles, and allies) and Falconidae (falcons, caracaras, and allies), which have no obvious relatives among the other birds; it is not even agreed that they are closely related to each other. Their similarities, which include strong, sharp beaks, feet, and talons, and forward-directed eyes for stereoscopic vision, may well be evolutionary convergent adaptations to similar lifestyles rather than indicative of taxonomic affinity. This is almost certainly so for the New World vultures, which are now thought to be allied with the storks.

The accipitrid family can be split into two subfamilies. The subfamily Pandioninae has only one representative, the osprey, whose relationship to the other hawks and eagles remains controversial. Hence it is sometimes placed in its own monospecific family. Its fossil record extends back at least to the Miocene—10–15 million years ago (mya). By the late Miocene, the osprey was already widespread with virtually the same form and distribution as today.

Fossil representatives of the other subfamily, the Accipitrinae (the hawks, eagles, and allies), have been found in Tertiary deposits (30–50 mya). These were buzzard-like raptors that bear no obvious relationship to any living raptor. They first appeared in South America and were widespread by the Miocene. Also widely distributed at this time were the Old World vultures, which no longer occur in the Americas, a clear indication that present day distributions do not necessarily reflect evolutionary origins. By the end of the Miocene (5 mya), when the fossil record improves, many of the modern raptor forms had already appeared.

The number of species and subspecies in taxonomic lists of the family varies depending on the views of the author, and molecular studies have been of limited use in clarifying relationships. Some genera such as Morphnus have only one representative (monotypic). At the other extreme, the genus Accipiter contains about 50 species (polytypic). Some species have been split into a multitude of subspecies—the aptly named variable goshawk (Accipiter novaehollandiae) has about 23—others are monotypic. A good many of these arrangements do not stand close scrutiny, particularly for little known taxa.

For convenience, the accipitrids are often split into groups of like species. These "natural" groups attempt to reflect general evolutionary trends within the family, from the so-called "primitive," less predatory species to the more "advanced," highly predatory forms:

1. The kites lack the bony eye shield ("brow") which gives many of the other accipitrids a fierce expression. The (a) white-tailed kites (Elanus, Chelictinia, Gampsonyx) have ungrooved talons, unlike the other accipitrids, and eat mammals and insects. Arguably, the most primitive group of kites are (b) unusual specialist feeders (Aviceda, Macheiramphus, Pernis, Leptodon, Chondrohierax) that eat caterpillars and mantids (Aviceda), bats (Macheiramphus), wasp nests (Pernis, Leptodon), and arboreal snails (Chondrohierax). On the one hand, they link to the (c) Australasian endemic kites, which include Lophoictinia, Hamirostra, and Henicopernis, and, on the other, to (d) the South American forms Rostrhamus, Ictinia, and Harpagus. In turn these (c and d) are linked to the next group of kites, (e) the typical kites Milvus and Haliastur, by the fact that that they all have the basal joint of the middle toe fused with the next joint. The (f) fish-eagles (Haliaeetus, Ichthyophaga) are basically large typical kites represented by 10 species which replace each other geographically. Several other, large, powerful Australasian/South American species (g) including Erythrotriorchis, Megatriorchis, Harpia, Harpyopsis, and Pithecophaga may also be offshoots or relict forms of the kite radiation.
2. Old World vultures, 15 species, all scavengers. For example, Gypaetus, Gyps, and Torgus, whose closest relatives are probably the fish-eagles.
3. Serpent-eagles, made up of 15 species of snake eaters, such as Circaetus, Terathopius, and Spilornis, possibly also have close links with the kites.
4. Harriers (Circus) and harrier-hawks (Polyboroides), the latter most closely related to the serpent-eagles.
5. Goshawks, containing about 58 species of "true" hawks, including chanting goshawks (Melierax), goshawks, and sparrowhawks (Accipiter).
6. Buzzard-like hawks, a grab-bag of species that may not all belong together, including Parabuteo, Buteogallus, Butastur, and Geranoaetus.
7. Typical buzzards (Buteo) with 28 species.
8. Typical eagles containing 33 species, including Aquila, Hieraaetus, and Spizaetus, which, like Buteo, have feathered legs.

Physical characteristics

The familiar characteristics of the birds of prey include the strongly hooked beak and, at is base, the bare, often brightly colored cere in which the nostrils are situated. Features that distinguish the hawks and eagles (accipitrids) from the other raptorial family, the falcons and caracaras, include several skeletal differences, yellow, red, or hazel eyes (vs. brown), well-developed nest-building behavior (vs. absent or poor), and the forceful squirting of excreta (vs. dropping of excreta).

Members of the family range in size from tiny active hunters, the South American pearl kite (Gampsonyx swainsonii) and African little sparrowhawk (Accipiter minullus), both weighing less than 3.5 oz (100 g) and with wingspans of 21 and 39 in (54 and 39 cm), respectively, to the Himalayan vulture (Gyps himalayensis), a hulking scavenger with a wingspan exceeding 9 ft (3 m) and weight reaching to 26 lb (12.5 kg), and the fearsome harpy eagle (Harpia harpyja) and Steller's sea-eagle (Haliaeetus pelagicus), both reaching 20 lb (9 kg) and the largest of all flying predators.

The hawks and eagles occur in a great variety of forms. The basic types are kites and vultures, hawks and eagles, and within each there are weaker and stronger forms, and mildly predatory and highly predatory species. For example, all the vultures are scavengers but some have immensely robust beaks to tear tough skin and tendons, whereas others have long, lightweight beaks to reach deep into the carcass to nibble tender parts and still others rely on scraps left by large vultures and other predators. The vultures have rather weak feet and stubby, flattish talons that are not used to clutch prey, compared with the eagles with their powerful grasp and dagger-like talons that hold and squeeze the prey. The more powerful eagles that hunt large, difficult prey have deep powerful bills and stout legs, whereas those that eat smaller, more easily captured prey have quite gracile bills and slender legs. The long, double-jointed legs of the harrier-hawks (Polyboroides) allow them to reach deep in to tree holes to extract nestling birds.

Form also reflects function in wings and tail shapes. Short-winged, long-tailed hawks are adept at flight through the confines of forest; long, broad-winged, broad-tailed forms are soarers that ride wind currents to great height and cover vast distances effortlessly. Both the African bateleur (Terathopius ecaudatus) and Australian black-breasted buzzard (Hamirostra melanosternon) have long, broad wings and very little tail, characteristics of hawks that glide low for long distances and have little need of agility. Migrants are longer-winged than nonmigrants, particularly those that use active flight to travel across the world. Even within a species, such as the osprey, migratory populations are longer-winged than those that are sedentary.

Vultures and other scavenging raptors that delve into carcasses have parts of their face, head, and even neck bare of feathers, presumably for cleanliness. Most species are rather cryptic shades of gray, brown, or whitish, often streaked or barred ventrally, depending upon their typical habitat. A few hawks have plumage morphs such that two or more color forms occur and interbreed.

In most species the sexes share similar plumage, although the male may be slightly brighter; exceptions include several harriers in which the female is brown and the male gray (dichromatism). Immatures tend to be more brown or heavily marked than adults or, in species with sexual dichromatism, most like the adult female. An interesting feature of the family is that females are larger than males (dimorphism). This is most obviously so in the species that kill relatively large prey that is difficult to catch. Hence the vultures are only slightly dimorphic, whereas in many of the sparrowhawks the female is twice as heavy as the male.

All raptors have keen eyesight, with particular sensitivity to movement. To help them distinguish their green insect prey from green vegetation, the eyes of bazas (Aviceda) have red oil droplets that act like filters. Bazas and other similar kites, which are relatively non-predatory, have quite laterally placed eyes, whereas active pursuers such as accipiters have more forward placed eyes for greater stereoscopic vision. Crepuscular hunters and the few species that are truly nocturnal, such as the letter-winged kite (Elanus scriptus), also depend on sight and have relatively large eyes and hunt by moonlight. A few species, including the bat hawk and harriers, are quite reliant on hearing to help them locate concealed prey and have a facial disc of stiff feathers that funnels sounds to their large ear openings. The sense of smell does not seem to be particularly important. Unlike some of the New World vultures, the accipitrid vultures do not have well-developed sense of smell to lead them to carrion.

Distribution

The family has an almost world-wide distribution although only one species occurs in the high Arctic and none in the Antarctic. Some genera, such as Accipiter, are extremely widespread, occurring on many islands and all continents except Antarctica. Others have a much more restricted distribution; for example, the great Philippine eagle (Pithecophaga jefferyi) is found only on large islands of the Philippines.

Many species with Arctic breeding grounds vacate them after breeding for more benign climates, sometimes flying across the globe, from North to South America or Europe to Africa. Where the climate is stable or moderate all year species tend to be resident. Elsewhere, they may escape the harshest

season: in some species the population simply shifts its range slightly southwards, other species stay put in some regions and all or part of the population migrates from other regions.

Only one species has been successfully introduced to a part of the world where it was not endemic. The Pacific marsh harrier (Circus approximans) was taken to Tahiti in about 1885 to control rodents, and self-spread to other islands in the Society Group. Races of several other species have been translocated as part of reintroduction programs for conservation purposes.

Habitat

The hawks, eagles, and their allies are found in most habitats throughout the world. Forests and woodlands support the most species, especially in tropical areas. Poorer, less varied habitats such as tundra, desert steppe, and intensive agriculture support few species. Small or isolated oceanic islands may have one or no species. Even the large islands of New Zealand have only one species, the Pacific marsh harrier.

Many raptors prefer particular habitats, for example, the goshawks and sparrowhawks, genus Accipiter, favor forest and woodland, and the harriers (Circus) require flat, treeless areas. Other species, such as Swainson's hawk (Buteo swainsoni), are more generalized, ranging over many habitats.

Sea coasts from Asia to the arctic support sea-eagles, and they are joined by ospreys (Pandion haliaetus) and Brahminy kites (Haliastur indus) on warmer Asian-Australasian coasts, and also frequent large inland waterbodies. Several species frequent ecotones, where two or more habitats meet. The Australian black-breasted buzzard may nest and roost along broad, dry inland watercourse but hunts far out into the surrounding desert and savanna. Sea-eagles require trees or cliffs for nesting but hunt along shoreline and in-shore waters. Some species, such as the kites (Elanus) and harriers, can hunt where groundcover is long, others need lower groundcover to hunt successfully. Indeed structure seems to be more important than vegetation composition.

Migrants tend to occupy similar habitats at either end of their migration path. The pallid harrier (C. macrourus) moves from breeding grounds in the grassy plains and dry steppes of middle Europe to similar "wintering" habitats in Africa and India. Its congener, the western marsh harrier (C. aeruginosus), makes the same trip, but favors reedy wetlands.

Towns and cities with parks, open spaces, and abundant prey can support a number of species including sparrowhawks. Where sanitation is poor and rubbish dumps common a number of species live communally with humans. For example, black kites (Milvus migrans), hooded vulture (Necrosyrtes monachus), and Indian white-backed vulture (Gyps bengalensis) thrive around settlements and cities in parts of Africa and India.

Behavior

Most hawks and eagles are active by day, usually during the period when their prey is most mobile. Some of the largest species are dependent on the heat of the day to create thermals to help them get them airborne and carry them high and far. When resting they perch quietly, often in a sheltered position on a cliff or among foliage. At the perch, they spend considerable time in feather maintenance, keeping their plumage clean, parasite free, and well aligned. Most species have an oil gland at the base of the tail from which they spread oil through the feathers, although a few, such as the Elanus kites, have powder down (special feathers that flake into a fine powder that is spread through the plumage to clean it). Many species bathe, sometimes by flying through wet foliage but mostly by wading into water.

The majority of hawks and eagles are solitary but several are colonial and hunt, roost, and breed in numbers. Even some solitary species, such as the steppe eagle (Aquila nipalensis), become more gregarious outside the breeding season and forage and roost with other individuals or species where food is plentiful.

Even though they are capable predators, aggressive encounters between individuals seldom progress beyond displays and bluffing. The naked skin on the head of the lappet faced vulture (Torgos tracheliotus) "blushes" with emotion. Several species, for example, the long-crested eagle (Lophaetus occipitalis) and booted eagle (Hieraaetus pennatus), have crests which they raise when threatened.

Hawks and eagles make greatest use of their voices during the breeding season, to defend and advertise territories and in courtship and breeding. For any particular species the range of calls used is usually very limited: often simply repeated whistles, mews, barks, cackles, yelps, or chitters. A few species have far-carrying melodic calls. The whistling kite (Haliastur sphenurus) throws its head back to make a single leisurely, descending whistle followed by a staccato series rising in pitch. In contrast, its larger cousin the white-bellied sea-eagle (Haliaeetus leucogaster), which also throws its head back, emits a series of goose-like honks that echo across the landscape. The vultures hiss and spit when squabbling but are otherwise silent. In fact, outside the breeding season, most hawks and eagles are seldom vocal.

Especially in the northern hemisphere, species or populations in cooler areas often vacate their breeding grounds to travel to milder climates, where food is more plentiful, in the non-breeding season. Broad-winged species, such as the broad-winged hawk (Buteo platypterus), use thermals and updraughts to fly long distances with few stops. Other species, including Eurasian sparrowhawks (Accipiter nisus) and pallid harrier (C. macrourus), are more active fliers and frequently stop to feed in suitable habitat between breeding and wintering grounds. Where migration routes are channeled at narrow sea crossings, land bridges, or between mountains, migrating raptors may fill the sky. The autumn movement of raptors of several species between North and South America concentrates spectacularly at the isthmus of Panama; 2.6 million have been counted passing through.

Feeding ecology and diet

All the hawks and eagles are carnivorous and most eat only freshly caught prey. Some eat carrion at times or almost exclusively, although rarely truly putrid flesh, and a few eat vegetable and other organic matter.

Crabs gathered from coastal mangroves are almost the exclusive diet of the crab hawk (Buteogallus aequinoctialis), whereas the white-necked hawk (Leucopternis lacernulata) appears to specialize on insects, especially those flushed by ants, monkeys, birds, and humans, and only takes a few vertebrates. The bat hawk (Macheiramphus alcinus) has a wide gape to swallow bats whole. Wasps and hornets, larvae, pupae, and adults, plucked from the comb, are the favored food of the honey-buzzards (Pernis apivorus). Palm nuts are the main food of the palm nut vulture (Gypohierax angolensis), although it does eat some invertebrates, fish, crabs, and carrion, and the bearded vulture (Gypaetus barbatus) lives on bones left by other scavengers. The osprey (Pandion haliaetus) rarely eats anything but fish. The dynamics of Elanus kite populations are closely tied to cyclic populations of the rodents on which they are dependent. At the other extreme, the generalist feeder, the red kite (Milvus milvus) hunts small animals and eats almost anything organic, alive or dead.

Some of the larger eagles are among the most potent of predators, regularly overpowering prey as large or larger than themselves. The most powerful hunt big, dangerous prey: the South American harpy eagle (Harpia haryja) takes adult monkeys, sloths, porcupines, and the largest of the massive-billed parrots; in Africa, the crowned eagle (Stephanoaetus coronatus) weighs 6–8 lb (3–4 kg) but hunts monkeys, small antelope, and other animals up to 40 lb (20 kg) and the 2–3 lb (1–1.5 kg) ornate hawk-eagle (Spizaetus ornatus) hunts toucans, macaws, squirrels, and agoutis. The 6–8 lb (3–4 kg) Australian wedge-tailed eagle (Aquila audax) eats a range of prey, including medium-sized birds, mammals, reptiles, and carrion, and occasionally hunts cooperatively to exhaust and kill adult kangaroos and dingoes many times its own weight. In contrast, the very similar Verreaux's eagle (Aquila verreauxii) of Africa specializes on hyrax, which it takes by surprise from

rock outcrops. Several of the accipiters (goshawks and sparrowhawks) are among the swiftest and most agile of aerial hunters, overtaking birds after a brief pursuit through forest or woodland.

Within species, prey captured varies seasonally, young individuals take easier prey (especially abundant invertebrates) and, during the breeding season, adults tend to take more vertebrates than in other seasons.

Searching and hunting methods vary according to the main prey types and habitats. Vultures and some larger open country eagles soar to great height and search over great distances. The bateleur spends long hours on the wing effortlessly gliding low (about 16 ft [50 m] above ground) to search for, surprise and flush prey from the ground. The harriers quarter open country, flapping slow and low, up and down a field or wetland. Still other species sit and wait at a perch and make short sallies out to pursue passing prey. The Elanus kites hover into the slightest breeze and drop onto small mammals below. Especially in the non-breeding season, many species gather opportunistically at termite agates and rodent and locust plagues. Species with the most generalized of diets usually use the most diverse range of hunting techniques. The sea-eagles wade into water after fish, swoop from the air to scoop it from the water, pursue rabbits across the land, scavenge along the shoreline, and frequently harry other predators for their kill.

Some species use assisted hunting, either with their own kind or with other animals, machinery, or fire. Pairs of the great Philippine eagle (P. jefferyi) hunt cooperatively: one bird distracts the monkey troop while the other strikes. The plumbeous kite (Ictinia plumbea) feeds in association with marmosets as they move through the forest, catching the cicadas they flush. Attracted for miles by the smoke, roadside hawks (Buteo magnirostris) gather at fires to catch animals fleeing the flames.

Small hawks and eagles must feed more often than large ones, and species that eat easily captured prey may have to spend more time gathering or locating prey than those that eat large, difficult prey. Sparrowhawks hunt at least daily, eagles typically hunt every few days, and a large vulture may need to gorge only once a fortnight or so.

Hunters of live prey mostly capture and kill with their feet, and the bill is used in opposition to the feet to dissect prey. The snail eaters have their own characteristic techniques: the hook-billed kite (Chondrohierax unicinctus) uses its robust upper mandible to forcefully break open the whorls of the shell, whereas, with their long modified bills, the snail kites (Rostrhamus) sever the columellar muscle that attaches the snail to the shell.

Reproductive biology

Most raptors defend a breeding territory from conspecifics and other intruders. This may be the area immediately around the nest or a wider area. Spacing between nests tends to be quite regular, where nest sites allow. Pairs of colonial species, such as Rüppell's vulture (Gyps rueppellii) and letter-winged kite, nest on the same cliff or share a tree with other pairs. The larger predatory species space more widely, tens of kilometers apart, closer where food is most available. Territorial activity is usually most vigorous as the breeding season approaches, when boundaries are advertised in some species by spectacular display flights.

Most species are monogamous and only a handful vary from this. Polygamy is known to be common only in three harrier species, including Montagu's harrier (Circus pygargus), for which breeding resources (food and nest sites) are concentrated. Experienced males are able to defend and support two or more females, although the primary female and her brood get the larger share of food captured by the male. In parts of their range where food is less available, Harris' hawks (Parabuteo unicinctus) breed in cooperative groups, where the core pair are assisted by unrelated helpers and young from the previous breeding attempt.

Typically, in the more predatory species the male feeds the female as part of courtship and continues to supply food during incubation and when the chicks are small; once the nestlings can maintain their own body heat, the female also hunts. In all but the vultures, which share nest duties, the female tears up the food and distributes it among the young.

All accipitrids build a nest of sticks lined with softer material. Nest sites are usually in a commanding position on a cliff or in a tree, but a few species such as the harriers nest on the ground. In some species successive generations return to reuse a traditional site for decades.

Most species breed annually, in the season when food is predictable and abundant, usually spring. The largest eagles attempt to breed every second year. Species that depend on prey that has extremes of population size, such as the plaguing rodents, tend to breed when the opportunity arises, regardless of season, and continue to breed until prey numbers subside.

The eggs are oval, mainly white marked with shades of brown, red, and purplish gray. Larger species tend to lay one or two eggs and smaller species three or more; and clutch sizes tend to be larger in harsher climates. Rodent specialists, such as the rough-legged buzzard (Buteo lagopus), show the greatest extremes; they lay very large clutches in years of plenty and have small clutches or do not breed in poor rodent years.

The length of the incubation period ranges from about three-and-a-half weeks in small sparrowhawks to 21 weeks in the harpy eagle. Chicks stay in the nest for a similar period and, once fledged, are dependent for several more weeks as they gradually learn to hunt.

A feature of some species is siblicide, in which the first hatched chick kills its sibling. In a few species, including Verreaux's eagle, this is obligatory and no second chicks survive. In other species it depends on the availability of food and brood size is adjusted to suit the conditions: when food is scarce weak nestlings are killed and eaten so that there is no wastage and the chances of survival of the remaining chick(s) improve.

Conservation status

In the 2000 IUCN world listing 34 species are assessed as Threatened—8 Critically Endangered, 4 Endangered, and 22 Vulnerable. None have become extinct since 1600, but several species were lost from large islands in historical times, following early colonization by humans, among them Haast's eagle (Harpagornis moorei), a huge moa-eating eagle of New Zealand.

Not surprisingly, species with small distributional ranges tend to be most vulnerable and these are often on islands. Among the most endangered species, two are in Cuba, where less than 250 individuals of the Cuban kite (Chondrohierax wilsonii) and about 300 of Gundlach's hawk (A. gundlachii) survive and continue to decline from deforestation and persecution. The Reunion harrier (C. maillardi) is under pressure from increasing urbanization, persecution, and poaching but since protection was tightened in the 1970s, public awareness has increased and numbers have increased to 200–340. On continents, species with very small distributions include the white-collared kite (Leptodon forbesi) of the humid forests of north-east Brazil, where there has been massive logging; this population is thought to number less than 250 individuals. The Spanish imperial eagle (Aquila adalberti), with an estimated total population of 252, is declining from deforestation and persecution, in this case by poisoning at game hunting reserves.

The large island of Madagascar has the greatest number of Threatened species. The Madagascar harrier (Circus macrosceles), serpent-eagle (Eutriorchis astur), and fish-eagle (Haliaeetus vociferoides)—the latter two of which are thought to have populations of less than 250 individuals—are all declining and threatened by habitat loss and degradation. The fish-eagle also suffers from human hunting and persecution. Another two species are Near Threatened: Henst's goshawk (A. henstii) and the Madagascar sparrowhawk (A. madagascariensis) are confronted by problems from widespread deforestation.

More specialized species suffer more particular threats. The huge vultures—white-rumped (Gyps bengalensis), long-billed (G. indicus), Cape griffon (G. coprotheres), and lappet-faced—fall victim to poison left in carcasses for control of other predators and, at the same time, find fewer carcasses and refuse on which to feed, in part because of competition from humans. Human pressure—from such threats as over-fishing, coastal development, and hydroelectric schemes—is a common problem to another three sea-eagles Sanford's, Steller's (H. pelagicus), and Pallas's (H. leucoryphus). Yet, human caused habitat loss to development and natural resource harvesting threatens by far the greatest number of species.

Remedial action has re-established or stabilized some species. The organochlorine pesticides (including DDT, which causes raptors to lay thin-shelled eggs, and dieldrin, which causes direct mortality) caused massive population decreases in species such as the Eurasian sparrowhawk (Accipiter nisus) in the 1960s and 1970s; populations began to recover when until the chemicals were banned in developed countries. Many countries give raptors full legal protection, which has lessened persecution and disturbance. Some populations have been assisted by hands-on conservation efforts. The whitetailed eagle (H. albicilla), which last bred in the British Isles in 1908, has been successfully reintroduced to Scotland. Northern goshawk (A. gentilis) and red kite, absent from Britain for more than a century, have also been re-established, the former aided by escaped falconers birds. By protection, provision of food, and careful attention to their sociable nature, the Eurasian griffon (Gyps fulvus) has been returned to the mountains of south-central France. Nest protection, erection of artificial nest sites, and breeding manipulation by double-clutching and egg and nestling translocation has benefited the recovery of species such as the bald eagle (Haliaeetus leucocephalus) in the United States and the osprey in Britain. A handful of species has adapted to life in cities, croplands, and plantations, but for the majority of accipitridae, particularly those that are large or highly specialized, the long-term prognosis is poor.

Significance to humans

Birds of prey have long been admired for their hunting prowess and powers of flight and sight. Paradoxically, they are also despised for their depredations on livestock and perceived cruelty; their fortunes fluctuating with the times.

In ancient Egypt, the Eurasian griffon was worshipped, appearing in the crown of the goddess of childbirth Nekhebet, and a vulture headdress was the privilege of a queen. On victory steles, vultures carried away bodies of vanquished. In some parts of the world supernatural hawks took on a part-human form or were fearful messengers of more human-like gods. Greek legend has Zeus's eagle stealing the beautiful Ganymede to make him cupbearer to the gods of Olympus. Garuda, the steed of the Hindu god Vishnu, has the red wings and white face of the Brahminy kite; its image guards the sacred temples at Angkor and elsewhere. The thunderbird of many tribes from the Americas to the Cook Islands often took the form of a terrifying, eagle-like bird that brought rain or created the world. From Tibet to the Nile Valley mythical eagles were worshipped as harbingers of the wind, stars, sun, and rain and protectors of the gods and their earthy representatives, including the Inca emperors. In early Christianity the eagle signified escape and fulfillment. Because of such associations, they were often an essential part of the trappings of nobility. The German imperial two-headed eagle of medieval heraldry signified the power of emperors. Even today images of eagles appear on coats of arms and company logos, symbols of strength and reliability.

One of the closest relationships between humans and raptors is falconry or hawking. As early as 2000 b.c. in Asia, humans were hunting with trained hawks. The practice flourished in Europe and the middle East from a.d. 500 to 1600 and was practical, providing fresh meat for the table, as well as recreational. In these feudal societies there was often strict hierarchy: the upper classes were allowed the more prestigious species including the larger falcons and eagles and the middle classes less desirable birds such as Eurasian sparrowhawk and northern goshawk. There are still devotees of the sport, particularly among Arabian royalty, and the custom continues in some central Asian tribes, where golden (Aquila chrysaetos) and imperial eagles (A. heliaca) are used to hunt wolves, foxes, and gazelles from horseback. However, in many developed countries falconry is not allowed, mainly for conservation and ethical (animal rights) reasons. Where it is legal, there are restrictions on the keeping of birds and taking from the wild and many are now bred in captivity.

The modern era brought a lessening of superstitions and with the widespread introduction of firearms hawks were no longer a useful means of hunting. Fear and loathing replaced the general reverence for raptors and they were persecuted in their millions, sometimes fueled by government sponsored bounties. Although a few larger species occasionally prey on young livestock such as cattle, sheep, reindeer, or poultry, their impact on healthy herds is invariably exaggerated. Even harmless species, tarred with the same brush, have suffered. Today, livestock is better managed, and as many raptor populations dwindle there is increasing concern for their conservation and appreciation of their beauty and role in nature. Large-scale egg and specimen collecting, popular for much of the 1900s and which had a local impact on thinly scattered, already beleaguered raptor populations, is no longer fashionable. Nevertheless, many hawks are still are trapped, shot, or poisoned to protect livestock and thousands are destroyed (sometimes for food or medicine) where they gather in numbers on migration through Europe, China, and elsewhere. Body parts of the critically endangered Madagascar fish-eagle (Haliaeetus vociferoides) continue to be used in traditional medicines. Conversely, in the Solomon Islands, breakdown of traditional taboos now allows hunting that threatens Sanford's sea-eagle (H. sanfordi).

Species accounts

List of Species

Osprey

Pandion haliaetus

subfamily

Pandioninae

taxonomy

Falco haliaetus Linnaeus, 1758, Sweden. Four subspecies.

other common names

English: Fish hawk; French: Balbuzard pêcheur; German: Fischadler; Spanish: Aguila Pescadora.

physical characteristics

21.7–22.8 in (55–58 cm); male 2.6–3.5 lb (1.2–1.6 kg), female 3.5–4.4 lb (1.6–2 kg). Brown upperparts with white legs and chest, accented with speckled necklace.

distribution

P.h. haliaetus: Scandinavia to Japan, the Mediterranean, Red Sea, and Cape Verde Islands; wintering in South Africa, India, Indonesia, and the Philippines. P.h. carolensis: Labrador to Alaska to Florida and Arizona, wintering in Peru and South Brazil. P.h. ridgwayi: Caribbean. P.h. cristatus: Australia to New Caledonia to New Guinea, Java, and Sulawesi.

habitat

Low altitude inland and shallow marine waters, including marshes, lakes, reservoirs, bays, sea coasts and islands, estuaries, and, less often, rivers. Almost exclusively coastal and sub-coastal in Australasia and much of Asia.

behavior

Solitary, pairs, or family groups, occasionally larger groups; northern populations, where winter sends fish to deeper water, are migratory, southern populations are sedentary.

feeding ecology and diet

Feeds almost exclusively on live fish, rarely turtles and seabirds, and fish found dead or dying.

reproductive biology

Breeds in solitary pairs (e.g., Australia and Britain) or loose colonies (e.g., Mediterranean and United States), sometimes of

hundreds of birds; usually monogamous but polygynous trios found; large stick nest lined with flotsam, seaweed, dead grass or leaves, near water, on islet, sea-cliff, mangrove or other tree, man-made structure, or on ground on predator-free island. Annual breeding season, usually starting winter-spring (into summer in the north). Usual clutch is three eggs; incubation about five weeks; fledge at about seven weeks; fledglings remain with adults two to eight weeks until migration in northern populations, longer in resident populations.

conservation status

Not threatened. Generally common and locally abundant throughout much of range.

significance to humans

Occasionally regarded as a competitor for fish and can be a nuisance at inland fisheries/hatcheries and when nesting on powerpoles (shorting-out electricity).

Madagascar cuckoo-hawk

Aviceda madagascariensis

subfamily

Accipitrinae

taxonomy

Pernis madagascariensis A. Smith, 1834, Madagascar. Monotypic.

other common names

English: Madagascar baza, Madagascar cuckoo-falcon; French: Baza malgache; German: Lemurenweih; Spanish: Baza Malgache.

physical characteristics

15.7–17.7 in (40–45 cm). Dull brown wings, barred tail, mottled brown and white underparts.

distribution

Much of Madagascar.

habitat

Evergreen and dry deciduous forest interior and edge; clearings in forest, villages within forest and palm plantations.

behavior

Poorly known. Apparently non-migratory. By night, roosts in the canopy. Hunts by day and, perhaps, crepuscularly.

feeding ecology and diet

Main prey is large insects and small reptiles and frogs snatched from foliage. Perches in canopy to glide down onto prey; sometimes flies low over canopy in search of prey or hawks aerial insects.

reproductive biology

Little known. Distinctive rocking with wings held high and tumbling courtship flight. Breeds in solitary pairs, laying in October to December. Builds small, flimsy nest lined with green leaves, high in the canopy. Clutch size unknown, probably two to three eggs. Incubation probably about 32 days and fledging about five weeks as in other Bazas.

conservation status

Not threatened. Fairly common in forested areas but deforestation an increasing threat.

significance to humans

None known.

Hook-billed kite

Chondrohierax uncinatus

subfamily

Accipitrinae

taxonomy

Falco uncinatus Temminck, 1822, Brazil. Three subspecies.

other common names

French: Milan bec-en-croc; German: Langschnabelweih; Spanish: Milano Picogarfio.

physical characteristics

15–16.5 in (38–42 cm); male about 8.8 oz (250 g); female 9–12.7 oz (255–360 g). Large hooked bill with green and yellow cere. Extreme variation in plumage, with males typically bluish gray.

distribution

C.c. uncinatus: western Mexico and extreme southern United States, southwards to northern Argentina. C.c. wilsonii: eastern Cuba.

habitat

Lower canopy and dense understorey of rainforest, seasonally flooded forest and montane tall forest. Also low forest on Grenada and acacia thorn-scrub in Mexico, forest edge and clearings.

behavior

Apparently sedentary. Unobtrusive, most often seen as it soars over forest.

feeding ecology and diet

Feeds mainly on tree snails in the understorey. Occasionally takes lizards, frogs, salamanders, freshwater crabs, slugs, and insects. Hops about in the canopy or glides down from a perch to snatch prey.

reproductive biology

Monogamous. Builds a rather small, flimsy nest of sticks high, and often precariously, in the canopy. Lays one or two eggs in late dry season. Chicks fledge in the rainy season to take advantage of the plentiful tree snails.

conservation status

Not yet considered globally threatened. Continental subspecies C. u. uncinatus is widespread and generally uncommon. Cuban subspecies (which has yellow bill), now confined to eastern Cuba, is Critically Endangered and on the verge of extinction due mainly to habitat destruction by logging; some persecution because of mistaken belief that it preys on poultry; harvesting of snails has also depleted its prey. Grenadan subspecies C. u. mirus is also Endangered because of habitat loss and introduced snails, thought to be too large for the kite to prey on, which feed on the native snail. Recommendations for conservation action include protection by law, protection of remaining habitat, public awareness campaigns to reduce persecution and protection of snails on which the species preys.

significance to humans

None known.

Long-tailed buzzard

Henicopernis longicauda

subfamily

Accipitrinae

taxonomy

Falco longicauda Garnot, 1828, New Guinea. Monotypic.

other common names

English: Long-tailed honey-buzzard; French: Bondrée à longue queue; German: Langschwanzweih; Spanish: Abejero Colilargo.

physical characteristics

19.7–23.6 in (50–60 cm); male 15.9 oz (450–630 g), female 20.1–25.7 oz (570–730 g). Mottled brown and honey colored upperparts with barred tail, and neck and chest streaked with white.

distribution

New Guinea and western Papuan and Aru islands.

habitat

Tropical rainforest and forest edge from lowlands to mid-mountain (c. 9,200 ft [2800 m]).

behavior

Usually seen singly, in pairs or trios. Thought to be sedentary.

feeding ecology and diet

Hunts by day and at dusk. Preys on wasps and their larvae, ants, grasshoppers, mantids, and other invertebrates, small birds and their eggs and nestlings, and small lizards.

reproductive biology

In display, the pair wheel over the forest; as they pass, one bird rolls on back to present talons to other. Monogamous. Builds a stick nest high in a tree, less often on a cliff ledge. Laying recorded May and August. Little else known.

conservation status

Not threatened. Quite common and widespread although deforestation and hunting for traditional uses have caused it to become scarce in some areas. New Britain honey-buzzard is poorly known and may be declining due largely to clearing to establish oil palm plantations.

significance to humans

The buzzard's flight (wing and tail) feathers feature in ceremonial headdresses of some New Guinea tribes.

Black-breasted buzzard

Hamirostra melanosternon

subfamily

Accipitrinae

taxonomy

Buteo melanosternon Gould, 1841, inland New South Wales. Monotypic.

other common names

English: Black-breasted kite, black-breasted buzzard-kite; French: Milan à plastron; German: Schwarzbrustmilan; Spanish: Milano Pechinegro.

physical characteristics

19.7–23.6 in (50–60 cm); male c. 1.3 lb (1.3 kg); female c. 3.3(1.5 kg). Heavy build. Short legs with large white feet. Black and brown body with white accents.

distribution

Mainly arid central and tropical northern Australia.

habitat

Arid deserts, grasslands and plains, especially along wooded creek lines, and tropical woodlands, grasslands, and savannas.

behavior

Usually solitary or in pairs or family groups but gathers in small numbers (up to nine recorded) at large carcasses. Movement by part of the population northward in winter for the dry season, but many birds resident year round. In summer, escapes tropical coasts (wet season) and hottest deserts.

feeding ecology and diet

Spends much time on wing in search of prey, soaring, gliding, or low quartering; also walks across the ground in search of prey. Main prey is medium-sized mammals (such as young rabbits), birds, large lizards, and nestlings of other birds including raptors. One of the few raptors to use a tool (see also Egyptian vulture): mainly, picks up a rock in the beak and hurls it at large eggs (e.g., Emu eggs) to gain access to their contents. Also breaks egg directly with bill and by throwing egg itself. Scavenges carrion and occasionally catches snakes and large insects. Not a powerful predator like the superficially similar Wedge-tailed eagle (Aquila audax).

reproductive biology

Usually nests as solitary pair but one polyandrous trio recorded. Builds a large platform of sticks lined with leaves in a living or dead tree in the open. Typically, lays a clutch of two eggs in August–October. Incubation about 36 days; chicks fledge after about seven or eight weeks.

conservation status

Not threatened. Widely but thinly distributed across range and generally uncommon. Declined in south-east of range due to habitat degradation and loss of prey species.

significance to humans

Susceptible to poisoning when scavenging on baited carcasses, but harmless to stock. Traditionally hunted by some aboriginal tribes and feathers used in hairbelts and other decorative products, but custom largely lapsed.

Letter-winged kite

Elanus scriptus

subfamily

Accipitrinae

taxonomy

Elanus scriptus Gould, 1842, Cooper Creek, South Australia.

other common names

French: Élanion lettré; German: Schwarzachselaar; Spanish: Elanio Escrito.

physical characteristics

13.4–14.6 in (34–37 cm); male about 9.2 oz (260 g); female 11.3 oz (320 g). Distinctive black band around eyes.

distribution

Mainly Central Australia.

habitat

Arid and semi-arid grasslands and tree-lined watercourses. Following irruptions may reach more coastal grasslands and open woodlands.

behavior

One of the few truly nocturnal accipitrids. Roosts by day in leafy trees, sometimes in colonies of hundreds when not breeding. Follows cycles of main rodent prey, especially long-haired rats (Rattus villosissimus), which plague irregularly every five to 10 years following good rains that fill inland waterways. Breeds when rats abundant, then disperses widely, often reaching coastal areas as rat numbers wane, then usually perish. Presumably a core of adults remains inland to repopulate when conditions allow.

feeding ecology and diet

A rodent specialist, mostly long-tailed rat, but also takes other small mammals and lizards, and large insects. Usually hunts by night when main prey active; quarters the ground, hovers, and drops vertically onto prey.

reproductive biology

Typically, breeds in loose colonies in coolibahs along inland (arid zone) watercourses whenever food is abundant. Monogamous. Builds a nest of small sticks lined with leaves or dung. Egg-laying mostly in late-winter to spring and autumn. Clutch size is usually four or five incubation about 31 days; nestlings fledge at about five weeks.

conservation status

Not threatened. Generally rare and rather mysterious due to poor knowledge of movements (here today, gone tomorrow habits) and boom and bust breeding strategy. Some threat from overgrazing of already fragile landscape and breeding colonies sometimes invaded by feral cats.

significance to humans

None known.

Black kite

Milvus migrans

subfamily

Accipitrinae

taxonomy

Falco migrans Boddaert, 1783, France. Seven subspecies.

other common names

French: Milan noir; German: Schwarzmilan; Spanish: Milano negro.

physical characteristics

21.7–23.6 in (55–60 cm); 19.8–33.5 oz (560–950 g) (measurements varies with race) female larger and heavier than male. Mostly reddish brown. Plumage and bill color vary with race.

distribution

M.m. migrans: northwest Africa, Europe to central Asia and south to Pakistan; winters in Africa, south of the Sahara. M.m. lineatus: Siberia to Amurland, Japan, India, Burma, and China; winters in Iraq, India, and southeastern Asia. M.m. formosanus: Taiwan and Hainan, China. M.m. govinda: Pakistan to India, Sri Lanka, Indo-China, and the Malay Peninsula. M.m. affinus: Sulawesi to New Guinea, New Britain, and Australia. M.m. aegyptius: Egypt, Arabia, coastal eastern Africa to Kenya. M.m. parasitus: Africa south of Sahara to Madagascar.

habitat

Desert to grassland, savanna and woodland, but avoids dense forests. Often near wetlands and found in suburbs and towns, around rubbish tips, abattoirs.

behavior

Migratory or partly so, particularly in Europe and Asia, from which it migrates after breeding to sub-Saharan Africa, the Middle East, southeastern Asia and Indian subcontinent. Migrates in flocks and gathers to cross sea straits in tens of thousands. Elsewhere, such as Australia, New Guinea, and Egypt, some populations resident, movements less regular or nomadic. Gregarious, often in forages in large flocks, sometimes roosts communally (in trees), and may breed in very loose colonies.

feeding ecology and diet

Feeds on a wide variety of prey, live or dead, and scraps. Offal, garbage, excrement, fish, invertebrates, some vegetable matter such as oil palm nuts. Steals from other raptors and waterbirds. Also catches small mammals, birds, reptiles, and amphibians snatched from the ground, foliage, or water.

reproductive biology

Often returns to traditional nest sites on return from migration. Monogamous. Nests as solitary pair or in loose colonies of tens of pairs. Usually builds a stick nest in a tree, less often on a cliff, lined with rubbish such as rags, dug, and fur. Timing depends on region, usually the dry season. Clutch size two or three eggs. Incubation about 31 days; chicks fledge after six or seven weeks.

conservation status

Not threatened. Nevertheless, sometimes poisoned or shot because it steals young poultry, feeds on stock carcasses.

significance to humans

Traditionally trapped by several indigenous people for food and decoration and feature in their legends. For example, thought to spread fire by some Australian aboriginal tribes, presumably because of their habit of travelling from far and wide to congregate at fires and swooping at prey among the flames.

Steller's sea-eagle

Haliaeetus pelagicus

subfamily

Accipitrinae

taxonomy

Aquila pelagicus Pallas, 1811, islands in the sea of Okhotsk.

other common names

English: White-shouldered sea-eagle; French: Pygargue empereur; German: Riesenseeadler; Spanish: Pigargo Gigante.

physical characteristics

33.5–94 in (85–94 cm); 10.8–19.8 lb (4.9–9 kg); female larger and heavier than male. Blackish brown all over, except white tail and shoulders. Morph "niger," found in Korea, is all black.

distribution

Coastal west Bering Sea and Sea of Okhotsok, wintering further south as far as Korea. Breeds mainly Kamchatka Peninsula, Sea of Okhotsk the lower reaches of the Amur River, and on northern Sakhalin and Shatar, Russia.

habitat

Coast and lower reaches of rivers, less often inland along rivers and lakes where fish are abundant. Most often in forested river valleys which provide trees for nesting.

behavior

Shift in population southward for the winter. Some stay at Kamchatka and on the Okhotsk coast; most winter in Japan, reaching north-east China, North and South Korea.

feeding ecology and diet

Mostly large fish, alive or dead, especially Pacific salmon, but will catch a variety of other prey and scavenge.

reproductive biology

Monogamous. Mostly nests in large trees, but also sea cliffs and cliffs far inland near lakes and larger rivers. Lays in April–May in a large stick nest. Clutch size usually two; incubation about seven weeks, fledging about 10 weeks.

conservation status

Vulnerable. Total world population is estimated at 5,000 birds and declining. Main threats are felling of old forest and building of hydroelectric plants, over-fishing and lead-poisoning from shot in deer carcasses left by hunters. Recommendations for alleviation of threats include minimizing the impact of industrial development in Russia, establishing artificial feeding sites, encouraging sustainable management of fishing stocks and protection of salmon spawning grounds.

significance to humans

None known.

Egyptian vulture

Neophron percnopterus

subfamily

Accipitrinae

taxonomy

Vultur perenopterus [sic] Linnaeus, 1758, Egypt. Two subspecies.

other common names

English: Scavenger vulture; French: Vautour percnoptère; German: Schmutzgeier; Spanish: Alimoche Común.

physical characteristics

22.8–27.6 in (58–70 cm); 3.5–4.9 lb (1.6–2.2 kg). Distinctive contrasting coloration between white head and body and black flight feathers.

distribution

N.p. percnopterus: Europe to central Asia and northwest India, south to Tanzania, Angola, and Namibia; also Canary and Cape Verde Islands and Socotra. N.p. ginginianus: India and Nepal.

habitat

Frequents extensive open country of dry, arid regions: steppe, scrub, desert, pastures, and cereal crops. Also in flat mountainous areas usually at low to moderate altitudes, cities and towns (especially Africa and India). Nests in rocky areas.

behavior

Usually solitary or in pairs but a hundred or more may congregate where food is abundant and at roosts on cliffs, trees or on buildings. In north of range migrate to Africa just south of Sahara and north of the equator. In India, Arabia, sub-Saharan Africa, Balearic and Canary Islands apparently sedentary or make local movements.

feeding ecology and diet

Opportunistic feeder, dependent on rubbish dumps and carcass disposal sites; carrion and refuse is main food. Less often, catches live prey, usually sick or otherwise vulnerable. Also insects, crustaceans lifted from the water and birds' eggs; large eggs broken by throwing a stone.

reproductive biology

Usually, breeds as solitary pair but occasionally two nests in close proximity. Monogamous. Builds a substantial, untidy nest of sticks lined with wool, rags and hair in a cleft, cave or narrow ledge at height on a cliff, often overhung; also on ruins, date palms and other trees where no cliffs. Typically, lays two eggs in March–May (earlier in some areas); incubation 42 days; fledges at about 11 weeks. Unlike most raptors, regurgitates food for chicks.

conservation status

Not threatened. Population has undergone a general decline but may now be stable. Main European population is now Spain; main population is Ethiopia. Fewer carcasses, reductions in small prey species, poisoning and persecution all thought to be factors in decline.

significance to humans

Its image was carved into Egyptian monuments but apparently the species was never worshipped, as was the more powerful Eurasian griffon (Gyps fulvus).

White-rumped vulture

Gyps bengalensis

subfamily

Accipitrinae

taxonomy

Vultur bengalensis Gmelin, 1788, Bengal. Monotypic.

other common names

English: Indian white-backed vulture, white-backed vulture; French: Vautour chaugoun; German: Bengalengeier; Spanish: Buitre Dorsiblanco Bengalí.

physical characteristics

29.5–33.5 in (75–85 cm); 7.7–13 lb (3.5–6 kg). Blackish bird, distinguished by white lower back and underwing coverts.

distribution

From south-east Iran to Pakistan, through India to south-central China, Indochina, and the northern Malay Peninsula.

habitat

Mainly open plains near villages, towns, and parks. Also into hilly woodlands of Himalayan foothills to 4,900 ft (1,500 m).

behavior

Apparently sedentary. A social species, usually found in non-specific flocks. Also roosts in large flocks in trees.

feeding ecology and diet

Feeds on carrion, largely dead livestock, and human remains. Gorges then rests for an extended period on ground or in tree while heavy load of food is digested.

reproductive biology

Breeds in small colonies, often in tall trees near human habitation, along canals or streams. Monogamous. Builds a large nest of sticks. Lays a single egg clutch in about October-November. Incubation 45 days and fledging after about three months.

conservation status

Critically Endangered. Previously widespread and abundant across its distributional range. East of India the species has been all but extinct since the early 1900s probably due to the rarity of wild large mammals and consumption of dead livestock by humans. Now rare in China and remaining strongholds are Pakistan and India. However, recently (2000) upgraded to Critically Endangered because of rapid population decline: in mid-2000, across Nepal, Pakistan and India, large numbers of Gyps vultures were found dead and dying. The cause is unknown but may have been viral. Other threats include poisoning, pesticides, and changes in processing of dead livestock and other waste.

significance to humans

Traditionally, the Parsee of India dispose of their dead by leaving bodies on special towers so that the vultures can carry the remains heavenward. The vultures' habit of roosting habitually in large flocks at the same site can kill trees through accumulation of excrement and can be a problem in coconut plantations and mango groves.

Lappet-faced vulture

Torgos tracheliotus

subfamily

Accipitrinae

taxonomy

Vultur tracheliotus J. R. Forster, 1791, South Africa. Three sub-species.

other common names

English: African black vulture, African king vulture, Nubian vulture; French: Vautour oricou; German: Ohrengeier; Spanish: Buitre Orejudo.

physical characteristics

45.3 in (115 cm); 11.9–20.7 lb (5.4–9.4 kg). Very large bird, with bald pinkish head and lappet, wings dark brown and chest white with brown accents.

distribution

T.t. tracheliotus: southwest to Morocco, southern Mauritania to Ethiopia, Kenya, and South Africa. T.t. nubicus: Egypt and northern Sudan. T.t. negevensis: Israel and Arabian peninsula.

habitat

Semi-arid areas and desert with scattered trees and short grass. Occasionally into mesic open savanna and grassland.

behavior

No regular migration known but some local movement to avoid the rainy season. Sociable, congregates at carcasses (up to 50 recorded in company of other vultures) but often in pairs.

feeding ecology and diet

Mainly a scavenger, feeds on carrion, skin, and bone fragments from large carcasses. Dominant to other vultures when hungry, aggressively bounding at them, but often socializes around carcass before feeding.

reproductive biology

Monogamous. Nests as solitary pair in flat-topped thorny trees. Builds a large platform of sticks lined with grass. Lays a single egg in the dry season, beginning about October–December, depending on region. Incubation about 55 days; fledging at about four months.

conservation status

Vulnerable. Formerly thinly scattered throughout wide range. In 2000 only a small, declining population remained, estimated at about 8,500 individuals. Accidental poisoning from baits left by farmers for predators and persecution in the mistaken belief that the vulture preys on livestock are problems. Increasing numbers of recreational off-road vehicles may also be a threat because of the species' sensitivity to nest disturbance.

significance to humans

None known.

Andaman serpent-eagle

Spilornis elgini

subfamily

Accipitrinae

taxonomy

Haematornis elgini Blyth, 1863, South Andaman Island. Monotypic.

other common names

English: Andaman dark serpent eagle; French: Serpentaire des Andaman; German: Andamanenschlangenweihe; Spanish: Culebrera de Andamán.

physical characteristics

19.3–21.3 in (49–54 cm); 27.9–35.3 oz (790–1,000 g). Plumage mainly dark brown with small white spots.

distribution

Andaman Islands.

habitat

Mainly forests and forest clearings of inland, occasionally on hillsides with scattered trees.

behavior

Sedentary.

feeding ecology and diet

Not well known. Takes a variety of prey, including birds, frogs, lizards, snakes, and rats; perhaps catches mainly reptiles, as do other serpent-eagles.

reproductive biology

Mutual soaring and calling over territory. No other information. Perhaps a small clutch, of one egg, as S. cheela.

conservation status

Near Threatened. Most numerous raptor in the Andaman Islands but listed as rare or Near Threatened because of very small distributional range and anticipated increasing threats. Hunting is common and may also be a problem for the eagle.

significance to humans

None known.

Hen harrier

Circus cyaneus

subfamily

Accipitrinae

taxonomy

Falco cyaneus Linnaeus, 1766, Europe. Two subspecies.

other common names

English: Northern harrier, marsh harrier; French: Busard Saint-Martin; German: Kornweihe; Spanish: Aguilucho Pálido.

physical characteristics

16.9–20.5 in (43–52 cm); male approx. 12.3 oz (350 g); female 18.7 oz (530 g). Pale gray upperparts, with blackish gray band on secondary feathers.

distribution

C.c. cyaneus: Europe and northern Asia to Kamchatka, wintering from Europe to northern Africa, southern Asia, southeastern China, and Japan. C.c. hudsonius: North America, wintering as far south as northern South America.

habitat

Open country with grasses, shrubs, or young trees, grassland, steppe, swamps and other wetlands, young plantations, croplands, and meadows.

behavior

Sits tall and slender, often on the ground, but also posts, rocks, or trees. Flaps low, on upswept wings, over open country. Roosts communally in winter on the ground, often at traditional roosts with tens of other individuals, occasionally hundreds. At northerly latitudes, entire population migrates, on a broad front, southwards for the winter.

feeding ecology and diet

Hunts by day but also quite crepuscular, active into dusk. Feeds mainly on mammals such as mice, rats, voles, and young rabbits and hares, which it often locates in vegetation by sound, also on birds (usually passerines), frogs, birds' eggs, and insects.

reproductive biology

Nests as solitary pair in a loose colony around a marsh or similar, also polygamous, two or three females to a male, rarely up to seven. Lays in the northern spring-summer, mainly May; earlier at more southern latitudes. Nests on the ground in dense grass, rushes, shrubs, crops or young pine plantations in a nest of grasses and small sticks. Clutch of three to six eggs; incubation about 30 days. Fledges at four to five weeks.

conservation status

Not threatened. Main threats include habitat loss to intensified agriculture, drainage of wetlands, reforestation, and, locally, severe persecution by gamekeepers.

significance to humans

None known.

African little sparrowhawk

Accipiter minullus

subfamily

Accipitrinae

taxonomy

Falco minullus Daudin, 1800, Gamtoos River, South Africa. Monotypic.

other common names

English: Little sparrowhawk; French: Épervier minule; German: Zwergsperber; Spanish: Gavalancito Chico.

physical characteristics

9.1–10.6 in (23–27 cm); male 2.6–3 oz (74–85 g); female 2.4–3.7 oz (68–105 g). Small gray hawk with lightly barred underparts.

distribution

Africa: southern Sudan and Ethiopia, south to South Africa, and west to Angola and Namibia.

habitat

Woodland and forest patches, often along rivers or in valleys. Occasionally, small plantations of exotics in savanna.

behavior

Apparently sedentary.

feeding ecology and diet

A tiny but bold hunter. Typically, flies at speed from perch, winding agilely through foliage, to catch prey on wing. Specializes on small birds from 0.4–1.4 oz (10–40 g). Occasionally takes small bats, lizards, and insects.

reproductive biology

Breeds as solitary pair in March–April in northeast Africa, mostly October–November in southern Africa. Monogamous. Builds a small stick nest of twigs lined with green leaves, high in a tree fork. Usually two eggs; incubation 31 days; fledging about 26 days.

conservation status

Not threatened. Widespread and common in appropriate habitat and quickly colonizes new habitat such as plantation.

significance to humans

None known.

Northern goshawk

Accipiter gentilis

subfamily

Accipitrinae

taxonomy

Falco gentilis Linnaeus, 1758, Alps. Eight subspecies.

other common names

English: European goshawk; French: Autour des palombes; German: Habicht; Spanish: Azor Común.

physical characteristics

18.9–27.2 in (48–69 cm); male 18.2–41.3 oz (515–1170 g); female 28.9–53.3 oz (820–1510 g). Brownish gray upperparts and barred underparts with geographical variation among sub-species in size, plumage, and color.

distribution

A.g. gentilis: Europe and northwest Africa. A.g. arrigonii: Corsica and Sardinia. A.g. buteoides: Northern Eurasia from Sweden to River Lena, wintering south to central Europe and central Asia. A.g. albidus: Siberia and Kamchatka. A.g. schvedowi: Asia from the Urals to Amurland and south to central China, wintering south to the Himalayas and Indochina. A.g. fujiyamae: Japan. A.g. atricapillus: North America. A.g. laingi: Queen Charlotte and Vancouver Islands, British Columbia.

habitat

Mature woodlands—mainly coniferous, also deciduous and mixed—especially edges and clearings; from lowlands to the treeline. Occasionally in small isolated woods and town parks.

behavior

Mainly sedentary. Migratory in northernmost parts of range, departs mainly October–November and returns March–April. Irruptions of goshawks from Arctic, some reaching southern limits of distribution, following seasons of superabundant prey, about every 10 years.

feeding ecology and diet

Hunts by day; takes small to medium-sized birds and mammals as large a grouse or hare, mainly on the ground. Prey varies geographically.

reproductive biology

Nests as solitary pair in large territory. Monogamous. Builds a stick nest, lined with fresh leaves, in the fork, or on a branch near the trunk, of a large tree. Lays in April–May; most common clutch three or four eggs; incubation about 36 days; fledging at about five or six weeks.

conservation status

Not threatened. Decline in Europe since nineteenth century but populations now mostly stable and some recovering. Extinct in Britain since 1800s because of pesticides, persecution, nest robbing for falconry, and deforestation; re-established in the late 1960s apparently from escaped falconers' birds. Population stable in North America, increasing in Russia. Still killed in places (e.g., Finland) by hunters and vulnerable to poisoning from baits left for other predators. Reforestation is beneficial.

significance to humans

Used by falconers for centuries. Remains the most popular hawk among falconers.

Harris' hawk

Parabuteo unicinctus

subfamily

Accipitrinae

taxonomy

Falco unicinctus Temminck, 1824, western Minas Gerais, Brazil. Two subspecies.

other common names

English: Bay-winged hawk; French: Buse de Harris; German: Wüstenbussard; Spanish: Busardo Mixto.

physical characteristics

19–22 in (48–56 cm); male: 25 oz (725 g), female: 34 oz (950 g). Sooty brown body, with rufous accents on shoulders, thighs, and underwings, and black tail.

distribution

P.u. harrisi: southwest United States to Mexico, Central America, western Colombia, Ecuador, and Peru. P.v. unicinctus: Northeastern Colombia and western Venezuela to Bolicia, Brazil, Chile, and southern Argentina.

habitat

Seasonally dry desert, Chaco and savanna, occasionally swampland. In more arid regions, near large waterbodies.

behavior

Largely sedentary.

feeding ecology and diet

Hunts large prey for its size, mostly mammals, up to the size of rabbits and jackrabbits, also birds including flickers and rails. Also reptiles (snakes and lizards) and insects. Hunts larger prey co-operatively, social groups of two to six gather at dawn to work through territory to flush, ambush, and sequentially attack rabbits.

reproductive biology

Typically monogamous, usually nesting as solitary pair. Builds a stick nest, lined with moss, grass and leaves, in a tree. Lays one to four eggs in June–July. Incubation about 34–35 days; fledging about 40 days. Some pairs renest in late summer or early

autumn, even following a successful first (winter) nesting attempt. Cooperative breeding reported in United States but not elsewhere: one to five juvenile or adult helpers bring food and defend the nest of the dominant (alpha) pair. The beta birds appear to be unrelated to the breeding pair and the gamma birds are often young from the previous breeding attempt.

conservation status

Not threatened. Occasionally poisoned by strychnine-baited carcasses left by sheep farmers for other predators. Reintroduced to California, where small population established.

significance to humans

None known.

Rough-legged buzzard

Buteo lagopus

subfamily

Accipitrinae

taxonomy

Falco lagopus Pontoppidan, 1763, Denmark. Four subspecies.

other common names

English: Rough-legged hawk; French: Buse pattue; German: Rauhfulßbussard; Spanish: Busardo Calzado.

physical characteristics

19.7–23.6 in (50–60 cm); male 21.2–48.7 oz (600–1380 g); female 27.5–58.6 oz (780–1660 g). Brown and white mottled

plumage varies in intensity among subspecies. White tail with dark subterminal band.

distribution

B.l. lagopus: northern Eurasia from Scandinavia to River Yenisey, wintering south to central Europe and central Asia. B.l. menzbieri: northeastern Asia, wintering south to central Asia, northern China, and Japan. B.l. kamtschatkensis: Kamchatka, wintering south to central Asia. B.l. sanctijohannis: Alaska and northern Canada, wintering south to central and southern United States.

habitat

Mainly treeless tundra, but also wooded tundra and extreme northern taiga when lemmings and voles are abundant. Usually flat low country. Wintering grounds are also mainly flat, open country, including prairie, cropland, and marsh.

behavior

Clear migrant with separate breeding and wintering grounds. Depart breeding grounds about September–October and return about April–May. Timing and extent of migration depends on seasonal prey abundance at either end.

feeding ecology and diet

Mainly preys on mammals, especially voles and lemmings. Also takes birds, other vertebrate including fish, insects and carrion, particularly when main prey scarce. Hunts by day, but occasionally crepuscular.

reproductive biology

Breeds as solitary pair, laying in May–June. Monogamous. Usually nests on a protected ledge, high on a riverbank, cliff or rocky outcrop, rarely in tree. Builds a bulky nest of sticks lined with grass and prey remains; three to five eggs; greater number (up to seven) in good seasons when food abundant. Incubation about 30 days; fledging about five or six weeks.

conservation status

Not threatened. No obvious threats in breeding grounds but winter quarters are subject to habitat disturbance and other human pressures.

significance to humans

None known.

Gurney's eagle

Aquila gurneyi

subfamily

Accipitrinae

taxonomy

Aquila (? Heteropus) gurneyi G.R. Gray, 1860, Bacan, Moluccas. Monotypic.

other common names

French: Aigle de Gurney; German: Molukkenadler; Spanish: Aguila Moluqueña.

physical characteristics

29.1–33.9 in (74–86 cm); female 107.9 oz (3,060 g); males are smaller than females. Chocolate brown plumage.

distribution

New Guinea and larger surrounding islands including Misool, Waigeo, Salawati, Aru, Yapen, Normandy and Goodenough, West Papuan, and Aru Islands, and the Moluccas, including Morotai, Halmahera, Ternate, Bacan, Ambon, and Seram.

habitat

Hillside and lowland primary rainforest and swamp forest. Hunts into nearby littoral zone, cultivated farmland and grassland. Inland but usually within 9.3 mi (15 km) of coast.

behavior

Uses uplifts to soar along hillsides and cliffs; soars to great height on thermals. Usually solitary in pairs or trios, the latter possibly family groups. Adults apparently sedentary.

feeding ecology and diet

Reported to take cuscus and other arboreal mammals. Slowly quarters forest canopy or ground, patrols seashore.

reproductive biology

Not known.

conservation status

Not threatened. Uncommon and seldom encountered. Deforestation of lowlands may be a threat.

significance to humans

None known.

Harpy eagle

Harpia harpyja

subfamily

Accipitrinae

taxonomy

Vultur harpyja Linnaeus, 1758, Mexico. Monotypic.

other common names

French: Harpie féroce; German: Marpyie; Spanish: Arpía Mayor.

physical characteristics

35–41.3 in (89–105 cm); male 8.8–10.6 lb (4–4.8 kg); female 16.8–19.8 lb (7.6–9 kg). Large, regal raptor with gray head, white breast, and long barred tail.

distribution

Southern Mexico through Central America to Columbia, east through Venezuela and south through Bolivia, Brazil, and north-east Argentina.

habitat

Lowland tropical forest, mostly up to about 2,950 ft (900 m). Occurs in uninterrupted forest, but will nest where high-grade trees have been logged and hunt through forest remnants intermixed with pasture.

behavior

Occasionally, in the early morning sunbathes on prominent perches emerging from the forest. Rarely, if ever, soars, unlike typical eagles. Thought to be largely sedentary but suggestion that the population in southern Atlantic forests may be migratory.

feeding ecology and diet

One of the most powerful of avian predators. Preys on large, difficult vertebrates including howler, capuchin and saki monkeys, sloths, opossums, porcupines, and anteaters. Also reptiles, such as snakes and iguanas, and ground mammals, such as agoutis, domestic pigs and young deer. Bird prey include curassows, macaws, and seriemas. Hunts from a perch at the forest edge or clearing, at rivers and beside salt licks.

reproductive biology

Monogamous. Lays in June in Guyana, September–November in Brazil. Builds a bulky nest of large sticks, usually in enormous, emergent tree. Clutches of incubation is 56 days; fledge at about give months. Unusually, male brings prey to nest only twice a week during first half of nestling period.

conservation status

Not globally threatened but considered Near Threatened. Uncommon and sparsely distributed throughout range. Has all but disappeared from large parts of former range, notably north and central South America. Extensive deforestation is a significant and continuing threat.

significance to humans

None known.

Resources

Books

BirdLife International. Threatened Birds of the World. Barcelona and Cambridge: Lynx Edicions and BirdLife International, 2000.

Brown, L. H., E. K. Urban, and K. Newman. The Birds of Africa. Vol. 1. London: Academic Press, 1982.

Coates, B. J. The Birds of New Guinea. Vol. I, Non-Passerines. Dove Publications: Alderley, 1985.

Cramp, S., ed. The Birds of the Western Palearctic. Vol. II, Hawks to Bustards. Oxford: Oxford University Press, 1980.

del Hoyo, J. A., A. Elliot, and J. Sargatal, eds. Handbook of the Birds of the World. Vol. 2, New World Vultures to Guineafowl. Barcelona: Lynx Edicions, 2000.

Ferguson-Lees, J. Raptors: An Identification Guide to the Birds of Prey of the World. Academic Press: New York, 2001.

Fox, N. Understanding the Bird of Prey. Surrey: Hancock House, 1995.

Long, J. L. Introduced Birds of the World. Sydney: Reed, 1981.

Marchant, S. and P. J. Higgins, eds. Handbook of Australian, New Zealand and Antarctic Birds. Vol. 2, Raptors to Lapwings. Oxford: Melbourne, 1993.

Newton, I., and P. Olsen, eds. Birds of Prey. London: Merehurst, 1990.

Olsen, P. Australian Birds of Prey. University of Sydney and Baltimore: New South Wales Press and Johns Hopkins, 1995.

Poole, A. F. Ospreys: A Natural and Unnatural History. Cambridge University Press: Cambridge, 1989.

Organizations

The Hawk and Owl Trust. 11 St Marys Close, Newton Abbot, Abbotskerswell, Devon TQ12 5QF United Kingdom. Phone: +44 (0)1626 334864. Fax: +44 (0)1626 334864. E-mail: [email protected] Web site: <http://www.hawkandowltrust.org>

Raptor Research Foundation. P.O. Box 1897, 810 E. 10th Street, Lawrence, Kansas 66044-8897 USA. Web site: <http://biology.biosestate.edu/raptor>

World Center for Birds of Prey, The Peregrine Fund. 566 West Flying Hawk Lane, Boise, Idaho 83709 USA. Phone:(208) 362-3716. Fax: (208) 362-2376. E-mail: [email protected] Web site: <http://www.peregrinefund.org>

World Working Group on Birds of Prey and Owls. P.O. Box 52, Towcester, NN12 7ZW United Kingdom. Phone: +44 1 604 862 331. Fax: +44 1 604 862 331. E-mail: [email protected] Web site: <http://www.raptorsinternational.de>

Penny Olsen, PhD