View From The Shed by Volunteer Shaun - WHO KNOWS THE NOSE?

WHO KNOWS THE NOSE?

In last week’s VIEW FROM THE SHED I looked at evolution and how there’s usually a cause for the changes that improve a bird's chances of survival, however large or small. Yet there was a bit I missed out (I did say that I’d simplified it somewhat) and one reader left a great comment which, to me, summed it up perfectly. They said, “Evolution as a process has no idea of purpose. Changes are made due to genetic mutations that are either beneficial to the individual and therefore they successfully live to pass on their genes, or they’re not useful, or indifferent.” I couldn’t have put it better myself.

This week I’m going deeper with the subject, focussing on one particular body part. After some deliberation as to which one, I decided to pick my nose. Thank you.

Imagine you’re a dinosaur. Specifically, you’re a Theropod, such as the greatest of all, the Tyrannosaurus Rex. Or maybe you’d prefer to be one of the smaller versions of this terrible lizard such as the Velocoraptors from ‘Jurassic Park’. They’re much cuddlier. Whichever you choose, imagine what your face looks like. It’s all scaley and sharp, perfect for the job of ripping up smaller creatures like small herbivores and cheap film extras. But then…

Your face begins to change. Your nostrils start to slither inwards from the end of your nose back towards the eyes. Feathers sprout out all over your head and body but not, crucially, on your lizard snout. This grows harder as if your skull were fusing with the surrounding flesh. The scaly skin becomes redundant and peels away as the underlying bone bursts through it. And finally those reptilian teeth, so perfectly designed for tearing flesh from your prey, align and fuse together to form a solid smooth surface. A layer of keratin (the same stuff as our fingernails) grows over this to form the rhamphotheca. That’s the external beak part that can be used for crushing and grinding as well as tearing, but it’s much more manipulative, almost as useful as an ape’s hand.

Other, similarly gruesome changes occur throughout your entire being, inside, outside and even mentally. Oh, and did I mention that you’ve decreased in size quite a bit too? You have changed from being one of the mightiest predators this planet has ever known to one of the humblest. Going from nine tons of terrible lizard to a little cheery Robin is quite an impressive feat.

Of course this great evolution didn’t happen overnight. We’re talking millions of years here but the basic theory is sound, even if I’ve thrown in a few horror film details to make it a bit more interesting.

Along with feathers, beaks are probably the most important feature that makes a bird a bird. They all have them in some shape or form and they’re adapted quite magnificently for their individual requirements. Beaks come in many different shapes and sizes but they’re all perfectly adapted to give the bird to which they’re attached its best possible life.

Take the Finches and the way they eat hard seeds. Their sharp-edged beaks almost seem to be a sloping extension of their foreheads with (relatively) powerful muscles built for crushing seeds and nuts. Look at how a Greenfinch or Bullfinch mangles its crunchy nut breakfast, just like me. The most specialised of this group is the Crossbill. Sadly they’re very rarely seen around our Dearne Valley but they’re so unusual that they’re worth mentioning because they really do have what their name suggests. The top and bottom halves of their bills cross over at the end, allowing them to insert it into their favourite food - pine cones - and prise each individual section of the cone apart to get at the seed within. It’s a fantastically precise adaptation and a great example of how a creature has adapted to fill a feeding niche. 

This is very different from the beaks of Warblers. Their beaks are thinner so that they can probe for insects and grubs within reeds and bark but light and agile enough to grab their prey once they’ve found it. Their live food is much softer than the Finches’ seed meals so their beaks don’t need to be as tough. “Slimy, yet satisfying”, as a certain Disney warthog once said.

Ducks have flattened, wider beaks for rooting around in weeds and grasses. On the inside many of them have a series of thin membranes called lamellae. These are designed to filter tiny items of food as they stuff their faces down into silt and mud. Just look at the bill of a Shoveler duck for a great example of this kind of adaptation. If you’ve never seen one, you should at least Google the Shoveler. Or better yet, try to find one in the wild. You can usually see them here at Old Moor and they’re great fun to watch. Just don’t expect to see that famous shovel very often as they spend most of their time with it either underwater, feeding, or under their wing, asleep. That’s my kind of life.

And then there are the hawks, harriers and other raptors, closest of all to their fossilised ancestors. They have lost their teeth but make up for it by the addition of a vicious hook on the end of their beaks. This is perfect for ripping into flesh yet can be delicate enough to pass the tiniest morsels of meat to their newly hatched chicks. No mother ever showed more dedication. 

So that’s a quick look at how different birds have evolved different beaks for their individual requirements. Each is perfect for the job at hand… wing… whatever.  But just don’t ask me about the mighty Shoebill. I have absolutely no idea why it should have what looks like a wooden clog stuffed into the front of its face. It’s ugly/beautiful in equal measures. It’s just a shame we don’t get them in our Dearne Valley.