Hawk

Hawks are birds of prey of the family Accipitridae. They are widely distributed and are found on all continents except Antarctica.

* The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks and others. This subfamily are mainly woodland birds with long tails and high visual acuity. They hunt by dashing suddenly from a concealed perch.
* In America, members of the '' Buteo'' group are also called hawks; this group is called buzzards in other parts of the world. Generally, buteos have broad wings and sturdy builds. They are relatively larger-winged, shorter-tailed and fly further distances in open areas than accipiters. Buteos descend or pounce on their prey rather than hunting in a fast horizontal pursuit.

The terms ''accipitrine hawk'' and ''buteonine hawk'' are used to distinguish between the types in regions where ''hawk'' applies to both. The term ''"true hawk"'' is sometimes used for the accipitrine hawks in regions where ''buzzard'' is preferred for the buteonine hawks.

All these groups are members of the family Accipitridae, which includes the hawks and buzzards as well as kites, harriers and eagles. To confuse things further, some authors use "hawk" generally for any small to medium Accipitrid that is not an eagle. Debus writes that the osprey is "a large aquatic hawk, with adaptations for catching fish by plunge-diving into water"; the elanid kites are "small, gull-like, grey-and-white hawks with black forewing patches"; and, of the harriers, that the "hawks in this cosmopolitan genus ('circling hawk') are so-called because of their low harrying flight". But he refers to the "typical or milvine kites" as "large kites", not hawks.

The common names of some birds include the term "hawk", reflecting traditional usage rather than taxonomy. For example, some people may call an osprey a " fish hawk" or a peregrine falcon a " duck hawk".

History

Falconry was once called "hawking" and any bird used for falconry could be referred to as a hawk.

Aristotle listed eleven types of (''hierakes'', hawks, singular ''hierax''): aisalōn (merlin), asterias, hypotriorchēs, kirkos, leios, perkos, phassophonos, phrynologos, pternis, spizias, and triorchēs. Pliny numbered sixteen kinds of hawks, but named only aigithos, epileios, kenchrēïs (kestrel), kybindis, and triorchēs (buzzard).

Groups

''Accipiter'' group

The accipitrine hawks generally hunt birds as their primary prey. They are also called "hen-hawks", or "wood-hawks" because of their woodland habitat.

The subfamily Accipitrinae contains '' Accipiter;'' it also contains genera '' Micronisus'' (Gabar goshawk), '' Urotriorchis'' (long-tailed hawk), and ''Megatriorchis'' (Doria's goshawk). '' Melierax'' (chanting goshawks) may be included in the subfamily, or given a subfamily of its own.

'' Erythrotriorchis'' (the red and chestnut-shouldered goshawks) is traditionally included in Accipitridae, but is possibly a convergent genus from an unrelated group (see red goshawk taxonomy).

''Buteo'' group

The " ''Buteo'' group" includes genera '' Buteo'', ''Parabuteo'', '' Geranoetus'', and most of '' Leucopternis''. Members of this group have also been called "hawk-buzzards".

Proposed new genera ''Morphnarchus'', ''Rupornis'', and ''Pseudastur'' are formed from members of ''Buteo'' and ''Leucopternis''.

The "'' Buteogallus'' group" are also called hawks, with the exception of the solitary eagles. ''Buteo'' is the type genus of the subfamily Buteoninae. Traditionally this subfamily also includes eagles and sea-eagles. Lerner and Mindell (2005) proposed placing those into separate subfamilies (Aquilinae, Haliaaetinae), leaving only the buteonine hawks/buzzards in Buteoninae.

Characteristics

Intelligence

In February 2005, Canadian ornithologist Louis Lefebvre announced a method of measuring avian " IQ" by measuring their innovation in feeding habits. Based on this scale, hawks were named among the most intelligent birds.
The hawk is very intelligent towards humans and other hawks.

Eyesight

Hawks, like most birds, are tetrachromats having four types of colour receptors in the eye. These give hawks the ability to perceive not only the visible range but also ultraviolet light. Other adaptations allow for the detection of polarised light or magnetic fields. This is due to the large number of photoreceptors in the retina (up to 1,000,000 per square mm in ''Buteo'', compared to 200,000 in humans), a high number of nerves connecting these receptors to the brain, and an indented fovea, which magnifies the central portion of the visual field.

Migration

Like most birds, the hawk migrates in the autumn and the spring. Different types of hawks choose separate times in each season to migrate. The autumn migrating season begins in August and ends mid-December. It has been studied that there are longer migration distances than others. The long-distance travelers tend to begin in early autumn while the short distance travelers start much later. Thus, the longer the distance the earlier the bird begins its journey. There have been studies on the speed and efficiency of the bird's migration that show that it is better for a hawk to arrive at its destination as early as possible. This is because the first bird that arrives has the first pick of mates, living area, food, and survival necessities. The more fat a bird has when it starts its migration, the better chance it has of making the trip safely. Kerlinger states that studies have shown that a bird has more body fat when it begins its migration, before it leaves, than when has arrived at its destination.

One of the most important parts of the hawk's migration is the flight direction because the direction or path the bird chooses to take could greatly affect its migration. The force of wind is a variable because it could either throw the bird off course or push it in the right direction, depending on the direction of the wind. To ensure a safer journey, a hawk tries to avoid any large bodies of water in the spring and fall by detouring around a lake or flying along a border.

Hawkwatching is a citizen scientist activity that monitors hawk migration and provides data to the scientific community.

Habitat and distribution

The red-tailed hawk is the most common hawk in North America. Past observations have indicated that while hawks can easily adapt to any surrounding, hawks prefer a habitat that is open. Hawks usually like to live in places like deserts and fields, likely as it is easier to find prey. As they are able to live anywhere, they can be found in mountainous plains and tropical, moist areas. Hawks have been found in places such as Central America, the West Indies, and Jamaica.

Behavior

Starting in the hawk's early life, it is fed by its parents until it leaves the nest. The young hawk, while still in its fledgling phase, will leave its nest as early as six weeks old. Once the bird is older it begins to hunt. The hawk kills its prey with its talons as opposed to other predator birds, such as the falcon. The falcon uses its talons to catch the prey but kills the small animal with its beak instead of its talons. The hawk's preferred time for hunting is usually just before nightfall when daylight lessens. Although the hawk is known for being a violent predator