THE INFLUENCE OF BAD WEATHER 



In all these catastrophes the migrants probably started out in fair 

 weather, but moving faster than the weather itself, they overtook storm. 

 Once the flight is started, the members of mass migrations seem compelled 

 to continue on, as if set for a journey of a certain time and length, not to 

 be cut short by storm. Even where they might stop, as at Delta, they often 

 continue their flight. The local birds, as we have seen, do not join these 

 travelers passing over in storm, and I have never known mass migrations to 

 leave Delta except under fair sky. 



On their local range, ducks prefer not to fly in the rain, and a rainy day 

 is generally a poor one for gunning. A very heavy influx of ducks, mostly 

 Blue-winged Teal and Baldpate, arrived at Delta during a torrential down- 

 pour in the late afternoon of September 28, 1954; and then, as these new 

 arrivals scurried about in search of a resting place, the few wet gunners on 

 the marsh had fine gunning and bags were filled quickly. 



The gyrations of migrants reaching Delta in storm or under heavy cloud 

 overcast, suggest that the sun or the sun's light (such as the glow of sun- 

 set) may be important by way of directional reorientation; but we know 

 that birds do carry on into weather situations in which there is no possibility 

 of their gaining directional cues from any celestial source. It likewise holds 

 that migrants may and do travel over cloud, so that they have no reference 

 to terrestial cues. On the evening of October 17, 1952, Trans Canada Air- 

 fines personnel reported Blue and Lesser Snow Geese migrating heavily 

 over North Bay, Ontario, the birds coming from the direction of James Bay 

 and traveling south. Mr. K. R. Esselmont, T.C.A. Station Manager at North 

 Bay, writes (letter) that the geese "were first spotted by the Department 

 of Transport Met. Observer on duty, who saw them approach from the 

 northeast, flying in a southerly direction. There were three separate flocks 

 at intervals of perhaps 5 to 10 minutes. The weather was clear from our 

 station north, and the overcast, consisting of alto cumulus, began just over 

 head and extended south. The first flock, estimated at close to 200, ap- 

 proached the station in formation and immediately above they broke forma- 

 tion, flying in all directions, then reassembling just prior to entering the 

 overcast, estimated at 8,000 feet. This first group was not seen again. The 

 second and third groups, not so large in numbers, reacted in the same man- 

 ner in that, directly over the station, they broke formation and then reas- 

 sembled. Both these flocks, however, remained below the overcast. There 

 were two notams on the DOT teletype advising that geese were flying at 



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