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probably far greater than is usually thought. Swallows and 

 swifts will soar very high just previous to their departure ; and 

 migratory birds will drop perpendicularly from the sky with start- 

 ling suddenness when their flight is arrested by change of weather. 

 Migrants scarcely ever strike lighthouses and the like, excepting 

 during sudden darkness from fog or clouds. Birds may be actually 

 observed migrating as high as they are visible. Gatke mentions 

 rooks on passage so high that they looked like dust, and were only 

 recognized by their cries. Mr. Dixon thinks the greatest gain of 

 this high altitude is the increased expanse of the earth that is 

 visible ; but as most migration is at night this seems doubtful. 

 Another possible advantage of which Herr Gatke takes more 

 notice is the diminished resistance of the air at great height, and 

 consequently less impediment to great speed, and diminished 

 fatigue. The currents of air at a great altitude may also be more 

 uniform and favourable, and there may be a greater immunity from 

 enemies. Some species of birds are very noisy during their 

 flight, keeping up quite a chorus of cries. Often in the early 

 autumn have I heard them passing over Folkestone at about 10 out 

 11 p.m., the cries being usually those of the wader family. Crows 

 travel silently, larks are incessantly calling to one another. 

 Migration is much interfered with by storms. The most favourable 

 wind for this part of Europe seems to be a S.E. wind for birds 

 flying S. or E., and not a wind blowing directly behind them. A 

 great deal has been written about the various routes of migration, 

 and Mr. Dixon says " The great routes of migration, whether over 

 land or sea, are closely connected with the configuration of the 

 earth's surface. We may, for the sake of convenience, divide them 

 into four very marked classes, viz., sea routes, coast routes,, 

 mountain routes, and river or valley routes." On this matter,, 

 later on, I will read to you what Herr Gatke says. The perils of 

 migration are both numerous and deadly, and due partly to fatigue, 

 partly to the natural enemies each species meets with on its; 

 journey, and partly to blunders on the way, and accidents, such as 

 gales and storms. Some ornithologists think that the mortality 

 list of migration is more than 50 per cent., and of those that 

 perish, it is thought that more than half perish at sea. Instances 

 are on record of great numbers of drowned migratory birds being, 

 washed ashore, especially after stormy weather. Tired birds will 

 settle on the sails and decks of vessels in the Atlantic, or in the 

 middle of the Mediterranean. Water rails, sandpipers, and cross- 

 bills have flown on board a vessel more than 1000 miles from land. 

 Dixon mentions the arrival of flocks of golden crested wrens on 

 the east coast of England after a stormy passage. He says 

 *^ Before sunrise on the chilly late October mornings, I have seen 



