Things Of Birds. Peaks and Paws

BIRDS MATTER: BEAKS AND LEGS It is not uncommon for books on birds to have a chapter dealing with the shape of beaks and legs. Beaks tell us what certain species feed on, whereas legs inform us about their habitat. Both are useful as a criterion for the classification and identification of the different species. In the XIX Century, Charles Darwin – in the course of his famous journey to the Galapagos Islands - noticed that finches had different beaks according to the food available to them in each island. This helped him to elaborate the Theory of Evolution by means of Natural Selection. Whether he was right or not, we can see that every beak is specifically designed for the food it consumes. The beak is made up by two bony mandibles without teeth and covered by a corneous case called rhamphotheca. Quite often this case is vividly coloured and some species are able to moult it. Sometimes the colour of beak, legs, or even feathers, is due to nutrition. Flamingos feed by filtering the mud and catching small animals that feed on bacteria that produce their distinctive pink pigment. As a result, a young flamingo can be distinguished from an adult because it has not accumulated enough pigment. The beak is a useful tool for almost everything, from combing to building the nest; though drinking is a bit uncomfortable, since it cannot suck but must be filled up as a dipper. Typically, the beak is used to eat. To look for food underwater is anything but easy. Swans need suitable legs to get impelled when swimming. The toes are webbed together and the legs are situated more towards the back, which is why swans look somewhat clumsy as they try to walk. Some waterfowl dive fully. In this case, each toe is independent, but it still has a flat shape to facilitate the swimming process. To capture small prey peaks are also small and very thin. Insectivorous birds are very voracious and remove large quantities of insects that are annoying for people, such as mosquitoes. Raptors are the experts at catching larger prey. Their adaptations give them high efficiency to hunt. The curved, hooked beak is custom-made to tear the meat. The strong, sharp claws prevent the prey from escaping once it has been caught. In addition, hunting species have both eyes pointing forward, which creates a perfect three-dimensional view, very useful for evaluating the distances. In contrast, birds that are prey have eyes on the sides of the head and a wider angle of vision to detect predators. It is unclear whether this separation of the eyes forces to have a long beak or having a long beak facilitates the separation of the eyes. But often most birds present an intermediate situation. Herons, with their dagger-shaped beak, are able to spear frogs and fish precisely while being alert to the presence of enemies. The long legs keep the body out of the water and give them a higher perspective. Egrets appear to be wearing socks: toes are in that distinct colour to blend in with the sandy bottom and legs look like branches of vegetation under which fish can shelter. When the peak has no special shape, birds adapt their behaviour with amazing hunting techniques. The Turnstone is not named this way by chance: it looks for food hidden under pebbles on the shore. Spoonbills have a huge spoon as a beak, but it does not tell us what they eat until we see them in action. The arrival of a bank of fish has not only attracted the Spoonbills. A group of annoying Cormorants want to join the party. They often hunt in groups, diving and taking advantage of stampedes caused by other birds. As we can see, birds have a great variety of beaks and legs designs that are adapted to the specific habitats in which they live. We have the opportunity to preserve these ecosystems so that we can keep on talking about Bird Matters in the future.