Birds are a class of vertebrates with more than 18,000 different species. Of the various features that are common to all birds, perhaps the most characteristic is their beak. All birds have one, but it has evolved differently in each species has evolved to improve its functions in response to its environment. These functions include feeding, defending themselves, mating, regulating their body temperature or building nests.
Classifying the different types of peaks that exist is not an easy task. The adaptations are very diverse and in some cases so specific that it is difficult to group them together.
But what exactly is a beak?
In biological terms, it is a type of mouth in which the jaws are covered by a horny layer of keratin (like the nails or horn of a rhinoceros) and have no teeth at all. It is characteristic of birds however other animals also have beaks. For example platypus and echidnas (monotreme mammals), turtles and some cephalopods, such as squid.
What are the different types of beaks?
Generally, bird beaks are categorised according to their shape and the function. There are two types of birds: generalists, who use different techniques to obtain food, whose beaks do not have specific shapes; and specialists, whose beaks are adapted for a single function. This could be for obtaining food in a certain way, for mating or for building nests. Here are the main groups of specialist beaks:
Birds that feed on vertebrates have strong, hooked beaks with the upper part protruding over the lower part. They are securely attached to the skull. They use it to tear and pull the flesh of their prey. Birds of prey such as eagles and falcons, and scavengers such as vultures are a clear example of this.
In fact, according to one study, these birds are the only ones whose beaks do not depend on adaptations to feeding habits, but on their size. The shape of their beaks is not very varied among the different species within this group.
This group of birds feed mainly on seeds. In many cases, they have a short, robust beak that ends in a conical shape, allowing them to break seeds. Goldfinches, sparrows and canaries are all good examples.
Although they feed on fruit, whether meaty or dried, these birds can also feed on seeds. Their beaks are specialised at dealing with fruit, which they open to obtain the pulp or seeds. They usually have a short, curved beak with a specialised tip for extracting the edible part of the seeds.
The lower part of this kind of beak is flat and sharp, ideal for splitting the hard fruits. In addition, they are the only birds capable of moving the upper part of the beak independently. This allows them to exert more force, either to break seeds and fruit or to hold on to branches. Parrots, parakeets, cockatoos and macaws are all in this group.
There are several ways of hunting insects. In the case of birds that hunt insects in the air, they do so with their mouths open. Therefore, the beak is usually short, wide and flat. Examples of this include the swallow and the swift. Other birds prefer to catch insects when they are still. These have short, straight, thin beaks, such as the bee-eater or robin.
Those that feed on insects and invertebrates in the ground, such as hoopoes, have thin, elongated beaks. Finally, those that pierce the bark of the trees to remove larvae, such as
, have straight and very strong beaks that allows them to penetrate the bark.
These are waterfowl that have long beaks with different shapes, adapted to searching for invertebrates at the bottom of ponds and marshes, while keeping their heads out of the water. The stork (main picture) or spoonbill would be examples of this type of bird.
These birds feed on fish that they catch by diving into the water. In most cases they have large, strong beaks with a curved tip or serrated ridges to prevent their prey from escaping. This group includes birds like seagulls and albatrosses. In other cases, such as pelicans, they may have a flexible pouch beneath the beak, where they can store fish once they have been caught (along with big gulps of water).
Filter feeding birds
These birds have wide, flat beaks. In some cases, such as flamingos, they are very specialised in obtaining food from pond and riverbeds. These beaks have a filtering system whereby the bird removes the water and separates out the organisms on which these birds feed. Swans and ducks are also in this group.
These birds feed on the nectar of the flowers by inserting their beaks inside them. They tend to have thin, long beaks, although the shape can vary depending on the kind of flowers they feed on. There are some species of hummingbirds that feed on flowers inaccessible to most animals, making them the main pollinators. They depend on each other in perfect symbiosis.
The rarest bird beaks in the world.
What we’ve seen so far is a very general classification, based on the feeding habits of the different species. However, not all species comply with this classification. In fact, some species of birds have very strange beaks adapted to specific functions, which give them a unique, fascinating appearance.
The New Zealand plover is the only bird that can move its beak to one side to catch may flies in the rivers. The recurve-billed bushbird has beak that curves upwards, allowing it to catch tiny prey. The black skimmer is the only bird with a lower part of the beak longer than the upper part. This allows them to catch fish by trawling their beaks through the water as they fly. The curlew has a beak that’s longer than its body. And toucans use their huge beak to regulate their body temperature.
There is even a kind of finch that has two curved beak parts that do not fit together. This helps them to extract the seeds from the pineapples. The shoebill (main picture) has a huge scaly beak with which it can crush almost anything, including small vertebrates. Rhinoceros hornbills have a bump on their beaks that helps amplify sounds and male puffins have very colourful and ornate beaks that help them attract females.
Finally, hummingbirds with beaks adapted to certain flowers, pelicans with their large pouches and flamingoes and spoonbills with their rare-shaped filters complete this small list – some of the most bizarre bird beaks in the world!