name = Hawk
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The term hawk can be used in several ways:
* In strict usage in
Europeand Asia, to mean any of the speciesin the subfamily Accipitrinaein the genera " Accipiter", " Micronisus", " Melierax", " Urotriorchis" and " Megatriorchis". The large and widespread " Accipiter" genus includes goshawks, sparrowhawks , the Sharp-shinned Hawkand others. These are mainly woodland birds with long tails and high visual acuity, hunting by sudden dashes from a concealed perch.
* More generally (especially in
North America) to mean falcons or small to medium-sized members of the Accipitridae- the family which includes the "true hawks" ( Accipiters) as well as eagles, kites, harriers and buzzards.
* Loosely, to mean almost any
bird of preyoutside of the order Strigiformes(owls).
The common names of birds in various parts of the world often use "hawk" in the second sense. For example, the Osprey or "fish hawk"; or, in North America, the various "Buteo" species (e.g., the
Red-tailed Hawk, "B. jamaicensis").
In February 2005, Canadian
ornithologist Louis Lefebvreannounced a method of measuring avian " IQ" in terms of their innovation in feeding habits. [http://www.eurekalert.org/pub_releases/2005-02/nsae-bit021605.php] Hawks were named among the most intelligent birds based on his scale.
Hawks are widely reputed to have visual acuity several times that of a normal human being. This is due to the many
photoreceptors in the retina(up to 1,000,000 per square mm for "Buteo", against 200,000 for humans), an exceptional number of nerves connecting these receptors to the brain, and an indented fovea, which magnifies the central portion of the visual field.
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