Rhynchokinesis
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2007-01-13T22:58:14Z
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Date/fix the maintenance tags using [[Project:AWB|AWB]]
'''Rhynchokinesis''' is an ability possessed by some [[bird]]s to flex their [[upper mandible]]. Rhynchokinesis is one of two types of [[cranial kinesis]], the other being [[prokinesis]], in which the upper mandible moves at the point where it is [[hinge]]d with the bird's [[skull]]. Rhynchokinesis on the other hand involves flexing at a point some way along the mandible - either upwards, in which case the upper and [[lower mandible]]s diverge, resembling a [[yawn]], or downwards, in which case the tips of the mandibles remain together while a gap opens up between them at their midpoint.
Unlike prokinesis, which is widespread in birds, rhynchokinesis is only known in [[crane (bird)|crane]]s, [[shorebird]]s, [[swift]]s and [[hummingbird]]s.
Species in which this has been recorded photographically include the following species: [[Short-billed Dowitcher]], [[Marbled Godwit]], [[Least Sandpiper]], [[Common Snipe]], [[Long-billed Curlew]], [[Pectoral Sandpiper]], [[Semipalmated Sandpiper]], [[Eurasian Oystercatcher]] and [[Bar-tailed Godwit]] (see Chandler 2002 and external links).
==External links==
Photographs of birds performing rhynchokinesis can be found here:
* [http://birdcentral.net/SBdowitcher1B.jpg] - a [[Short-billed Dowitcher]]
* [http://www.photos-of-the-year.com/image/nature/632/3593open_beak_godwit-med.jpg] - a [[Marbled Godwit]]
* [http://www.birdforum.net/attachment.php?s=30bab082f6b003975d2f1fcf23344ee1&attachmentid=10972] - a [[Least Sandpiper]]
==References==
* ''A functional and evolutionary analysis of rhynchokinesis in birds'' by Richard L Zusi, Smithsonian Institution Press, 1984.
* Chandler, Richard (2002) PhotoSpot - Rhynchokinesis in waders ''[[British Birds (magazine)|British Birds]]'' Vol 95 p395
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[[Category:Ornithology]]