Wildlife TV

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Birds’ Beaks: Demonstrating Diversity

on June 1, 2013

You may or may not know that birds and reptiles are very closely related groups of animals and there was in fact a time when the distinction between the two was hard to define. It was in the age of the dinosaurs that birds began to separate themselves from other reptiles but during that transition, some 160 million years ago, many animals existed that had both reptilian and avian features.

So what are birds? How do we define them? Well there are some obvious characteristics such as wings, feathers and beaks but even these are not exclusive to birds. Studies by palaeontologists have shown that many dinosaurs had feathers including the infamous tyrannosaurus rex and velociraptor and that wings may have evolved to help these mighty predators find their balance when standing on top of a fresh carcass.

But what of beaks? Several species other than birds have beaks: tortoises, squids, even some fish, but of course we associate beaks mostly with birds, but this has not always been the case. Famously, the first bird has thought to have been Archaeopteryx lithographica but this has recently been put into doubt by the discovery of the fossilised Aurornis xui, a small bird that predates archaeopteryx by 5 to 10 million years, making it the first bird so far known. But this bird was very different from the birds we know today: it had a long bony tail, claws and probably couldn’t fly. It is also interesting to note that this primitive bird didn’t have a beak like modern birds: it had teeth instead. The birds of today have given up on teeth altogether and diversified to a huge range of feeding habits and diets that are very different from their carnivorous dinosaurian ancestors. The evolution of beaks has given birds a versatile tool that has allowed them to adapt to huge variety of different environments.

Aurornis xui, 'the first bird'. From National Geographic News.

Aurornis xui, ‘the first bird’.
From National Geographic News.

In Africa today, you can see the magnificent extent to which birds have diversified; from the mighty ostrich (Struthio camelus) to the fearsome martial eagle (Polemaetus bellicosus) to the pretty European bee-eater (Merops apiaster). Simply looking at birds’ beaks can help to identify them and also to learn a little bit about their behaviour or even their diet; for example you can easily see how the amethyst sunbird (Chalcomitra amethystine) would use its long, thin beak to probe into flowers to feed on nectar, or how the lappet-faced vulture (Torgos tracheliotos) uses its strong, hooked beak to tear at animal flesh. But it’s not all about feeding, birds can use their beaks for range of different purposes, from excavating holes in which to nest, to even, most extraordinarily, using simple tools. Let’s look at a range of different African species and see how their beaks are ‘fit for purpose’.

This blue waxbill (Uraeginthus angolensis) is a member of the family of weavers and finches which are granivores, specialists in eating seeds. Their beaks are short and conical, ideal for picking seeds off of plants and also strong enough to crush them if necessary.

This blue waxbill (Uraeginthus angolensis) is a member of the family of weavers and finches which are granivores, specialists in eating seeds. Their beaks are short and conical, ideal for picking seeds off of plants and also strong enough to crush them if necessary. Photo credit.

The European bee-eater is a beautiful bird and as the name suggests, specialises in eating bees (as well as other insects). Its beak is reasonably long and has a sharp tip; this allows it to catch and kill bees without having to risk the stinger getting too close to its face.

The European bee-eater (Merops apiaster) is a beautiful bird and as the name suggests, specialises in eating bees (as well as other insects). Its beak is reasonably long and has a sharp tip; this allows it to catch and kill bees without having to risk the stinger getting too close to its face. Photo credit.

Vultures are strict carnivores and most often scavenge. This lappet-faced vulture (Torgos tracheliotos) has a large and powerful peak with a razor sharp hook at the tip which it uses to tear pieces of meat away from the carcass on which it is feeding.

Vultures are strict carnivores and most often scavenge. This lappet-faced vulture (Torgos tracheliotos) has a large and powerful peak with a razor sharp hook at the tip which it uses to tear pieces of meat away from the carcass on which it is feeding. Photo credit.

A greater flamingo (Phoenicopterus roseus) feeds by filtering through water and sediment for the small invertebrates and plant matter which it requires. Flamingos' bills are designed to sift through material so that they can feed without swallow large amounts of useless material.

A greater flamingo (Phoenicopterus roseus) feeds by filtering through water and sediment for the small invertebrates and plant matter which it requires. Flamingos’ bills are designed to sift through material so that they can feed without swallow large amounts of useless material. Photo credit.

Nectar-feeding birds such as this amethyst sunbird (Chalcomitra amethystina) specialise in retrieving nectar (a sugary substance) from flowers. This sunbird's beak is long and thin and allows it to reach deep into tubular flowers.

Nectar-feeding birds such as this amethyst sunbird (Chalcomitra amethystina) specialise in retrieving nectar (a sugary substance) from flowers. This sunbird’s beak is long and thin and allows it to reach deep into tubular flowers. Photo credit.

You’ve seen only a small portion of the variety of beaks in birds in this article. Birds are a wonderfully diverse class of animals and their beaks are a testament to this. They have certainly come a long way from their primitive, tooth-bearing ancestors; they have spread across the entire world and conquered the land, air and sea, and Africa hosts a beautiful collection of birds, from cute little finches to fearsome raptors.

Much love,

-Nick

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2 responses to “Birds’ Beaks: Demonstrating Diversity

  1. There are some strikingly similar examples of beaks evolving in parallel, namely in the the family Balistidae (triggerfish), where each species has fusiform dentition specifically adapted to its feeding strategy. Some, like the Picasso/Humu Humu Triggerfish, have a “beak” angled forward for pursuit. Others, like the Clown Trigger, have an upward-facing mouth aiding them in pulverizing benthic invertebrates.

    It’s clear that the beak has evolved a number of times across the animal kingdom; what’s interesting is that flight may not have. Paleontologists in China and Brussels keep re-shuffling the phylogeny of Auronis xui and Archeopteryx in determining whether the flapping mode of flight evolved twice in birds/reptiles.

    I actually just did an article on it yesterday, but you probably know much more about the evolutionary history and classification of these adaptations.

    • Wildlife TV says:

      Convergent evolution is definitely a topic that I can get excited about; it is truly astonishing how completely different animals can produce such remarkably similar adaptations even if disconnected, sometimes by whole continents or oceans, or even millennia.

      Certainly the debate over the origin of flight is one that is fierce and forever changing. As I understand it, the archeopteryx has been shuffled on and off the evolutionary line between reptiles and birds many times, but hopefully eventually the evidence will be able to tell us conclusively whether our cute little budgies can call that bizarre creature their ancestor.
      There are many explanations for the origin of flight; ‘top-down’, ‘bottom-up’ etc. but I was very intrigued when I read only recently about the hypothesis that predatory therapod dinosaurs might have used flapping wings as stabilisers when stood upon carcasses. I’m sure there’s plenty more research to be done before an explanation for the origins can be decided upon, I’d even like to imagine that there are multiple origins in different phylogenies but I’d definitely have to do A LOT more reading before I could make any guesses!

      I would love to read your article and learn more about the subject!

      Thanks for reading and liking my post!

      -Nick

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