Hand swing
As primaries ( remiges primarii ), the outer large, strong and stable are springs of the bird's wing , respectively. They sit on the metacarpal bone ( carpometacarpus ) and on the bones of the third and second fingers of the wing.
The number of fully developed hand swings is usually ten, a maximum of 11 (e.g. grebes ). In some groups of birds, such as the passerine birds , the outermost hand wing is significantly reduced. Regardless of this, a small spring is often also formed on the tip of the second finger, the remicle .
The numbering is generally carried out from the wrist (carpal joint) outwards, i.e. from the area near the body ( proximal ) to the area remote from the body ( distal ). The length of the bones of the hand wing in relation to the total wing length is used in the hand wing index as a measure of the bird's ability to fly.
The length of the hand swing becomes larger towards the outside and then significantly smaller again. The position of the longest spring depends on the type of flight and is between the fifth (e.g. titmouse ) and ninth (e.g. common swift ) swing arm. Generally speaking, the feathers become more pointed from the inside out. The feathers are clearly asymmetrical. The outside flags get narrower from the inside out, the inside flags get wider. In many bird species, the outer hand wings in the upper part show strong indentations on the outer and / or inner plumes for aerodynamic reasons (see picture of the sparrowhawk feathers).
Web links
literature
- G. Hummel: anatomy and physiology of birds . Ulmer, Stuttgart 2000, ISBN 3-8252-2144-X .
- R. Brown, J. Ferguson, M. Lawrence, D. Lees: Feathers, Traces & Signs. 4th edition. Aula, Wiesbaden 2003, ISBN 3-89104-666-9 .
- L. Svensson: Identification Guide to European Passerines. 4th edition. Self-published, Södertälje (Sweden) 1992, ISBN 91-630-1118-2 .