The relationship between the anatomy and flying
The anatomy of birds is intimately connected to their ability to fly and this is apparent in the bird shape which offers minimum resistance to the air. Several adaptations result in a low centre of gravity, which tends to prevent the body from turning over during flight. The wings are attached high up on the trunk, as are the light organs such as lungs, whereas heavy flight muscles and muscular digestive organs are positioned ventrally. The pattern, speed and endurance of flight are reflected in the shape of wings. Highly aerial birds; which includes swifts (Apodidae), swallows (Hemiprocnidae), terns (Laridae) and albatrosses (Diomedeidae); have long pointed wings which enable them to soar in the air for long periods using the minimum amount of energy. Other birdspecies have short rounded wings that enable them to take off quickly and fly rapidly for short distances (eg sparrows). Vultures (Accipitridae) which fly in circles at low speeds using thermal air currents have broad rectangular wings that permit slow flight. Humming birds (Trochilidae) are even able to achieve hovering flight, by tilting their bodies so that they are almost upright and they can beat their wings as fast as 80 times per second.