Tail (bird)
Right: the tail of a modern bird ( Pygostylia ). The last caudal vertebrae are fused into a pygostyle.
The bird's tail is formed in the skeleton of birds (aves) by the end section of the spine and the tail feathers . In the course of the evolution of birds , the caudal spine has shortened and the last vertebrae have fused to form the pygostyle , which forms the stable base for the tail feathers.
The tail takes on the role of flight control and is therefore very posable. For example, the common swift ( Apus apus ) as a flight acrobat can completely close its tail to reduce air resistance and open it again like a pair of scissors for quick turning maneuvers. The smaller the ratio of wing area to weight, the more control springs are needed to hold the flight path. In the case of European bird species, the number of tail feathers varies between ten (typical representatives are common swifts or silkworms Cettia cetti ) and 24 (in the mute swan Cygnus olor ). A bird's tail that is longer than average improves maneuverability, for example when pursuing or fleeing.
Often the tail is also used for threatening gestures , courtship or showing off . Well-known examples are the wheel of the peacock or that of the wood grouse to impress. The noise characteristic of the common snipe ( Gallinago gallinago ) during courtship flight is caused by vibrations and twitching of the tail feathers.
In field ornithology, the tail is often used as a marker for species that are difficult to distinguish. Often the color is decisive, but sometimes also the length and shape of the individual tail feathers. The age of the observed bird can also often be deduced from this based on color variations.
See also :
Web links
literature
- Brown / Ferguson / Lawrence / Lees: " Feathers, Traces & Signs " 2nd (unconditional) edition. AULA, Wiesbaden 1993, ISBN 3-89104-539-5 , p. 98
- Glutz von Blotzheim / Bauer / Bezzel: " Handbook of the birds of Central Europe - Volume 7 ", AULA, 1985, ISBN 3-923527-00-4