40 



or injury. In the spring the order is altered, the adult males 

 leading, the females following, then the young birds, and lastly the 

 injured or weakly ones. The time of day of migratory flight 

 varies a good deal. Some birds migrate by day, but the great 

 majority do so at night or above the range of human vision. The 

 punctuality of the arrival of birds is very remarkable. Some may 

 be looked for almost to the day after a flight of some thousands 

 of miles. The arrival of some sea birds at their breeding places is- 

 so regular that it forms a date in the calendar of men most con- 

 cerned in the event. The date varies much with different species, 

 some arriving earlier, some later, but as a rule the first to arrive 

 • are the last to depart, and the last to arrive stay the shortest time, 

 and are the first to leave. 



During the height of migration, unfavourable weather will 

 sometimes delay a considerable number of migrants, and then a 

 favourable change will cause an immense rush of innumerable 

 birds, these rushes being more frequent in autumn than spring. 



Perhaps on no point of migration is there greater difference of 

 opinion than on the question of speed. Whilst some observers 

 consider 2,000 or 8,000 miles in one night is nothing unusual, 

 others consider about 300 miles in 24 hours to be a good average. 

 Some observers think that birds travel by stages, staying here and 

 there on the way to rest ; others that they usually perform the 

 greater part of the flight of 2,000 miles or more in one or two 

 stages. The dotterel breeds on the tundras of Arctic Europe and 

 Asia, and winters in Africa, north of the equator. Its spring 

 migration is late and rapid, and as the bird is scarcely ever seen in 

 intermediate localities during this season (Heligoland Records but 

 few in May), we are forced to the conclusion that this enormous 

 flight of quite 2,000 miles is performed without a rest, and between 

 sunset and sunrise. If the dotterel were to start in the evening, 

 gloom from its African haunts, say at 7 p.m., it would reach the 

 moors of the Arctic regions, by flying 200 miles per hour, about 

 five the following morning — a record of speed that makes the 

 highest pace of our '• Fying Scotchman," " Wild Irishman," or 

 " Dutchman," appear but the creep of a snail by comparison, and 

 of astounding endurance, which may well fill us with genuine 

 admiration and wonder. This account is given by Mr, Charles 

 Dixon in his book, " The Migration of Birds," from which I have 

 derived much of what I am narrating to-night. But, on the 

 opposite page, he has already written that probably migratory 

 birds do not average more than 300 miles per day. I shall refer 

 later on to this question of speed and other disputed points when. 

 I tell you of Herr Gatke's work in Heligoland. Let us now 

 consider the height at which birds fly during migration. This is 



