leaping over occurs in other species as well, including the bluebird 

 (Pinkowski 1971). 



Vertical Migration 



In the effort to find winter quarters furnishing satisfactory living 

 conditions, many North American birds fly hundreds of miles across 

 land and sea. Others, however, are able to attain their objectives 

 merely by moving down the sides of a mountain. In such cases a few 

 hundred feet of altitude corresponds to hundreds of miles of latitude. 

 Movements of this kind, known as "vertical migrations," are found 

 worldwide wherever there are large mountain ranges. Aristotle first 

 mentions vertical migration: "Weakly birds in winter and in frosty 

 weather come down to the plains for warmth, and in summer migrate 

 to the hills for coolness . . ."(Dorst 1962). The number of species that 

 can perform this type of migration pattern is obviously limited to 

 those species adapted to breeding in alpine areas. 



In the Rocky Mountain region vertical migrations are particularly 

 notable. Chickadees, rosy finches, juncos, pine grosbeaks, William- 

 son's sapsuckers, and western wood pewees nest at high altitudes and 

 move down to the lower levels to spend the winter. The dark-eyed 

 juncos breeding in the Great Smoky Mountains make a vertical 

 migration, but other members of the species, breeding in flatter 

 areas, make an annual north-south migration of hundreds of miles 

 (Van Tyne and Berger 1959). There is a distinct tendency among the 

 young of mountain-breeding birds to work down to the lower levels as 

 soon as the nesting season is over. The sudden increases among birds 

 in the edges of the foothills are particularly noticeable when cold 

 spells with snow or frost occur at the higher altitudes. In the Dead 

 Sea area of the Middle East, some birds that breed in this extremely 

 hot desert move up into the surrounding cooler hill during the winter 

 (Thomson 1964). 



The vertical migrations of some mountain dwelling gallinaceous 

 birds (mountain quail and blue grouse) are quite interesting because 

 the annual journey from breeding to wintering grounds is made on 

 foot. Mountain quail make this downward trek quite early in the fall 

 well before any snows can prevent them from reaching their goal. 

 Blue grouse perform essentially the same journey in reverse. During 

 midwinter, these birds can be found near timberline eating spruce 

 buds protruding above the snow. 



These illustrations show that the length and direction of a 

 migration route are adapted to the needs for survival and are met in 

 some cases by a short vertical movement or great latitudinal travels 

 in others. 



Pre-migratory Movements 



Recent banding studies have demonstrated many migrants, 

 especially young of the year, have a tendency to disperse after 

 fledging. These premigatory movements have also been called "post- 

 fledging dispersal," "reverse migration," and "postbreeding north- 



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