Routes of migrating soaring birds

摘要: Soaring migrants travelling through Israel use three principal routes which are used in the opposite directions during spring and autumn: (1) Western Route lies mainly along western edge of central mountain range, (2) Eastern Jordan Valley, crossing range part day, continuing southward Dead Sea towards Sinai, joining autumn (3) Southern-Elat Mountains Route. The geomorphological structure Israel, with a dividing country roughly into landscape units, plays role route selection. In autumn, migration axis is deflected at beginning day from east to west for 10–25 km, depending on weather conditions flock's roosting locations. Between 10.00 h 11.00 h, daily breeze blowing Mediterranean influences axis, slowly back east. A parallel deflection occurs autumn. moves southwest over eastern slopes morning hours slope, absorbs direct radiation sun, creating good soaring conditions. Towards late afternoon, when sea starts, east, Valley. Elat Mountains, wind flow similar role, but because topography southern Arava Valley causes change direction, north-south direction. addition movement scale, seasonal also exists. During migration, early (e.g. White Storks Ciconia ciconia) tend travel an route, while Pelican Pelecanus onocrotalus) coast. This fluctuation was probably sub-optimal coastal plain August. September, temperature differences between land decrease influence marine inversion gradually declines, until its disappears completely October. comparison numbers birds seen shows significant various routes. For example, only one species, Steppe Eagle Aquila nipalensis, flies compared more than 30 species spring. pass whereas spring, about half migrating storks range. Honey Buzzards Pernis apivorus fly large concentrating almost totally These related global breeding wintering grounds relation Red Sea, avoid crossing, thus causing them follow different