By Kinds of Flocks 



Migratory flights are frequently accomplished in close flock 

 formation, as with shorebirds, blackbirds, waxwings, and especially 

 some of the buntings, longspurs, juncos, and tree sparrows. Other 

 species maintain a very loose flock formation; examples are turkey 

 vultures, hawks, swifts, blue jays, swallows, warblers, and bluebirds. 

 Still others, the grebes, snowy owls, winter wrens, shrikes, and belted 

 kingfishers, ordinarily travel alone, and when several are found in 

 close proximity it is an indication they have been drawn together by 

 unusual conditions, such as abundant food. 



Just as flocking among resident birds provides group protection 

 against predation, flocking in migration greatly facilitates the 

 attainment of destination (Pettingill 1970). The V-shaped flocks often 

 associated with Canada geese have a definite energy conserving 

 function by creating favorable air currents for every member of the 

 flock but the leader; when the leader becomes tired, it will often 

 change places with a member behind. Night migrating flocks 

 generally fly in looser formations than do day migrating flocks. 



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