HAND

Bird Watching (UK) - - Your View -

Anatom­i­cally, a bird’s ‘hand’ is its outer wing, that is, ev­ery­thing past the wing bend or carpal joint, just as the in­ner wing is re­ferred to as the bird’s ‘arm’. The term is of­ten heard in con­nec­tion with the outer wing of raptors, as many of them have pri­mary feath­ers that ex­tend from the wing in a shape that re­sem­bles the fin­gers of a hand. In fact when it comes to raptors, the hand can be one of the most vis­i­ble aids to iden­ti­fy­ing the species you’ve just spot­ted, and its rel­a­tive age, with ju­ve­niles tend­ing to have nar­rower hands than adults of the same species. The gen­eral shape of the hand is a fairly good guide to the type of rap­tor you are look­ing at, with falcons, for ex­am­ple, usu­ally hav­ing pointed hands, har­ri­ers hav­ing blunt ones with short fin­gers, and ea­gles and vul­tures pos­sess­ing broad hands with prom­i­nent fin­gers. The length of these pri­maries can also aid with dif­fer­en­ti­at­ing be­tween sim­i­lar species; for ex­am­ple, the longer sev­enth finger of the Spot­ted Ea­gle helps to sep­a­rate it from the Lesser Spot­ted Ea­gle where their ranges over­lap. The num­ber of fin­gers on the hand can help, too.

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