TRAVELS OF WATERFOWL 



circle was reduced to a series of loops, the bird turning at intervals into the 

 air stream, then swinging around to fly swiftly downwind. 



To the casual observer, this hesitation when the bird flew into the air 

 current appeared to be an awareness of the wind ; but when the pattern of 

 a hooded flight was timed and plotted on paper, it became apparent that the 

 into-wind reduction of ground speed was merely the variation in relative 

 motion due to the bird's position in the moving air mass. Its air speed was 

 constant around the flight circle, as was obvious in a calm. In each into-wind 



Figure 8. Flight patterns of blindfolded birds 



Ot/T OF ilCMT 



100 ft. j «u. t — "■ 



A. Juvenile Yellow-headed Blackbird; wind 2 m.p.h.; flight lasted 55 seconds; bird 

 climbed to 100 feet. 



B. Adult male Redhead; wind 5 m.p.h.; bird flew out of sight at elevation of about 

 300 feet. 



C. Juvenile Yellow-headed Blackbird; wind 2 m.p.h.; flight lasted 50 seconds; bird 

 climbed to 100 feet. 



fXcio Winj 

 Foa Am 1»wtant 



D. Juvenile Yellow-headed Blackbird; wind 4-5 m.p.h.; bird climbed to about 200 

 feet and flew out of sight. 



E. Juvenile English Sparrow; wind 20-25 m.p.h.; bird climbed to about 40 feet. 



F. Juvenile male Green-winged Teal; wind 30-35 m.p.h.; elevation 50 feet; bird flew 

 out of sight. 



