THE INFLUENCE OF BAD WEATHER 



at the same time that many other migrants are traveling northwest with 

 the southeast wind on their tails. I have seen both ducks and geese flying 

 against winds of fifteen to twenty miles an hour. At such times the slower- 

 flying passerines generally remain grounded, but I have watched Crows and 

 blackbirds migrating against winds of such velocity as to make their ground 

 speed almost nil. 



On April 15, 1954, with Aldo Missio, Weather Forecaster for the R.C.A.F. 

 MacDonald Weather Station, I departed by car at 10 a.m., going northwest 

 to Minnedosa, Manitoba. Missio, who had just left his weather charts, ad- 

 vised me of the approach of a cold front from the northwest; and, indeed, 

 we could see the long line of cloud ahead that marked the edge of the front. 

 The wind was from the northwest at about 20 m.p.h. A dozen Red-tailed 

 Hawks, three flocks of blackbirds, and one flock of Golden Plover were seen 

 migrating to the northwest between Macdonald and Neepawa, where we 

 met the front at 11:30 a.m. There was a sudden drop in temperature from 

 45° to 30° F., a rise in wind velocity to 35-40 m.p.h., reaching 45 m.p.h. in 

 gusts, with light snow flurries. These conditions of wind and temperature 

 remained the same all afternoon till dusk. After the front had passed, we 

 noticed much more activity among blackbirds, Crows, and hawks. In some 

 this seemed restiessness, as in the blackbirds that rose from a field, settled, 

 then rose, flying around the brow of a hill, settled again, only to take wing 

 once more. This restlessness soon resolved into a migration into the north- 

 west; and as we ranged about the rolling country south of Minnedosa from 

 noon until 3 p.m. there was a light but steady passage of Red-tailed Hawks, 

 blackbirds, Crows, and a few Robins. The hawks were lower than we usu- 

 ally see them; they seemed to take advantage of hills and bluffs of trees, 

 and often were seen to make their greatest headway against the wind in 

 long dives, by which they gained speed as they lost altitude. The recorded 

 velocity of the wind was greater than the ground speed of blackbirds, 

 Crows, or Robins ; and yet they gained ground against the wind by flying 

 close to the earth, sometimes only a foot or two high, swinging behind clumps 

 of trees, around hills and up gullies, reaching an objective, such as a group of 

 trees, then stopping briefly, only to start on again. Their movements, how- 

 ever roundabout, always carried them into the northwest. Waterfowl were 

 seen flying to sheltered situations, but none migrated. 



It is not always possible, of course, to judge the relation of wind to mi- 

 gration. On April 13, 1954, there was a grand arrival of waterfowl from the 

 south and southeast from 7 a.m. until noon, the birds reaching Delta at ele- 



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