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Monday, May 10, 2010

birds of prey - owl

10th May 2010


The Owls are the order Strigiformes, comprising 200 extant bird of prey species. Most are solitary, and nocturnal, with some exceptions (e.g. the Northern Hawk Owl). Owls hunt mostly small mammals, insects, and other birds, though a few species specialize in hunting fish. They are found in all regions of the Earth except Antarctica, most of Greenland, and some remote islands. Though owls are typically solitary, the literary collective noun for a group of owls is a parliament. Living owls are divided into two families: the typical owls, Strigidae; and the barn-owls, Tytonidae.

Owls have large forward-facing eyes and ear-holes, a hawk-like beak, a flat face, and usually a conspicuous circle of feathers, a facial disc, around each eye. Although owls have binocular vision, their large eyes are fixed in their sockets, as with other birds, and they must turn their entire head to change views. Most birds of prey sport eyes on the sides of their heads, but the stereoscopic nature of the owl's forward-facing eyes permits a greater sense of depth perception necessary for low-light hunting.Owls are farsighted and are unable to see anything clearly within a few centimeters of their eyes. Caught prey can be felt by owls with the use of filoplumes, which are small hair-like feathers on the beak and feet that act as "feelers". Their far vision, particularly in low light, is exceptionally good. Contrary to popular myth, an owl cannot turn its head completely backwards. It can turn its head 135 degrees in either direction; it can thus look behind its own shoulders, with a total 270-degree field of view.

Grosbeak a form taxon containing several species of seed-eating passerine birds with large beaks. Although they all belong to the superfamily Passeroidea, they are not a natural group but rather a polyphyletic assemblage of distantly related songbirds. The cover shows rose breast bird.

Here under I post a beautiful first day of issue cover of USA with stamps of owl and grosbeck and also one ordinary cover having picture of owl. The cover is cancelled on 28th May 1988 at Arlington, USA.. The stamps used on the cover are taken out from stamp book.



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