Today tonight or explanation of rynchokinesis

["Philip Veerman" <>]

Sorry I'm lost at the "Today tonight".

 

This is called rynchokinesis and it is potential possible to a limited extent in most birds, however it is well known in several birds and most particularly marked in these waders. It is easy to explain if I have a bird's skull in my hand. Suffice to say the hinge in the jaw of birds is entirely different to mammals (that is to say it is mammals that are strange). The way birds do this is the quadrate bone to which the lower jaw is attached, is moved forwards and the palatine bone slides back and forth, thus enabling the flexible upper mandible to bend upwards or sometimes they can twist as well to add a sideways movement. This hinging obviously can only change the shape of the upper mandible.

 

See this prior message from January 2010:

 

Philip Veerman

24 Castley Circuit

Kambah  ACT  2902

 

02 - 62314041

 

While surfing the net today I came across a request for info about "rhynchokinesis".

For those birdwatchers who have never heard of "rhynchokinesis" and/or have never seen it in action

check out this page of Trevor Ford's website: http://www.sunbittern.com/gallery-rhynchokinesis.html

"Rhynchokinesis" is the ability of some birds to be able to flex their upper mandible.

It is probably most often seen in godwits but I have observed it to some degree or other in several

species of shorebirds and have photographed evidence of it a number of times. Keen bird-photographers (probably not photographers who simply take photos with birds in them)

should carefully examine all of their shorebird photos (in particular) for evidence of the act -

they might be surprised.

Bob Inglis

Sandstone Point

Qld

Australia

http://users.tpg.com.au/inglisrc/

-----Original Message-----From: Bob Rusk [ Sent: Saturday, 8 December 2012 10:00 PM      To: Geoffrey Dabb;       Subject: Re: [canberrabirds] Today tonight

Hi Geoff !

I've seen this done more than a couple of times with Bar-tailed Godwits when "yawning", but when you think about it, the bill would have to be flexible to enable the bird to feed. It would be virtually impossible to open their bills " chop stick fashion" for the intake of food when they are immersed in mud or sand to the full length. Obviously the lower half is flexible and sensitive enough to open at the extremities to enable them to take "prey" with a tweezer like action when detected. What do you reckon.

Bob

PS- No differences of opinion will be tolerated

---

From: Geoffrey Dabb To: Sent: Saturday, 8 December 2012 8:17 PM
Subject: FW: [canberrabirds] Today tonight

Con  -  I have several shots illustrating the curious geometrics of this bird’s open bill.  I do not know what it was doing but Alastair and I speculated it might have been trying to eject something, and we discussed the upcurve of the upper mandible, evident to the naked eye.  (Alastair thought he might have read something about that …)  Clearly the bill is surprisingly flexible.  The below shot is not edited in any material respect. As to what the bird said, well I have had to do a little translating there ..

 

 

 

 

From: Con Boekel Sent: Saturday, 8 December 2012 7:48 PMTo:
Subject: Re: [canberrabirds] Today tonight

 

Geoffry
I hate to snipe at true art, but how come the top bill curves upwards the bottom bill is straight?
regards
Con

 On 8/12/2012 7:36 PM, Geoffrey Dabb wrote: