BIRDING THE LUNE ESTUARY THE FOREST OF BOWLAND AND BEYOND..................................................................................................................SUNRISE PETE WOODRUFF

Monday, 11 April 2016

The Appliance Of Science.

Black-tailed Godwit Martin Jump

Martin Jump was it touch recently to tell me about the image of a Black-tailed Godwit the likes of which he'd never seen before, and that he found the image whilst looking through some of his stock files. After Martins explanation of the circumstances and the image he sent me, I told him this was new to me too, and that he had been photographing this bird just at the precise moment in time to catch this amazing shot as evidence of the behaviour of this individual. 

So I did some research and found that Distal Rhynchokinesis is a little known phenomenon related to the ability of shorebirds to open up the tip of the bill to be able to feed in mud, silt, or soil.

Snipe. Howard Stockdale. 

Some further searching lead me to Howard Stockdale who has excellent photo documentation of a Snipe showing side on the gradual change in the upper mandible shape.

This is all fascinating stuff, and thanks to Martin for getting in touch and drawing my attention to it, and to Howard for allowing me the use of his sequence of the Snipe.


'The use of Distal Rhynchokinesis (DR), which consists of the movement of the distal part of the upper jaw with respect to the cranium, is well documented in long-billed shorebirds (Scolopacidae), commonly being associated with the deep probing feeding method. However, the functional and evolutionary significance of DR and other cranial kinesis is unclear. We report for the first time the use and occurrence of DR in wild long-billed shorebirds feeding on small prey items suspended in water. We tested whether prey size in captive Dunlins Calidris alpina influences the occurrence of DR during feeding and also whether its use affects foraging efficiency. We found that wild Dunlin, Curlew Sandpiper Calidris ferruginea, Sanderling Calidris alba and Little Stint Calidris minuta commonly use DR to strike, capture and transport small prey items. Prey size influenced the occurrence of DR during the transport phase, with this type of cranial kinesis being more frequently used with larger prey. The rhynchokinesis protraction angle (a measure of bill tip elevation) during prey strike and transport was affected by prey size, and bill gape was modulated through the use of DR in relation to prey size. Finally, the use of DR throughout intra-oral prey transport was related to shorter transport times, which improved foraging efficiency. We conclude that DR is a mechanism that could contribute to the flexible feeding behaviour of long-distance migratory shorebirds, enhancing small prey profitability and so improving foraging efficiency, and may have played a role in the evolutionary radiation of Scolopacidae (Charadrii)'....This summary is taken from a lengthy and scientific page on Distal Rhynchokinesis Here 

I'd sooner be birding!....And that's what I'm about to go and do right now, but to be honest too windy on the coast for my liking.


Richard Pegler said...

I had to check the date of your post, Pete, to check that you hadn't published this post 10 days earlier!

That's an astonishing phenomenon that I was totally unaware of. I don't fully understand how this ability helps with feeding, but I shall be watching out for it in future - that's for sure (or should that be 'for shore'!).

Best wishes - - - Richard

P.S. For, probably, the first time in my life, whilst on the Scillies I fell in love with a bird. I mention this because it was a female Stonechat (I know they're a favourite with you). She was a plucky little bird with a damaged foot and was there in the same area every day. I spent a lot of time with her!

Pete Woodruff said...

Not sure I fully understand all this either. I recall seeing a shot of a duck showing this phenomenon but can't remember where, must take a closer look at this.

Thanks for your little tale about the Scillies Stonechat Richard.

Bob Bushell said...

Fabulous images Pete.

Pete Woodruff said...

Thanks Bob, and it's good for me to put my congratulations on Birds2blog about the photograph on your website of the beautiful and priceless granddaughter Scarlet.