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itself nntoncbed) ; from the Riviera to Tunisia, via Corsica and Sardinia; from 

 Sicily to Tripolitauia ; from Asia Minor to the delta of the Nile. 



From the north-sdnth direction in the fertile and rich valleys of tlie Rhine 

 and Rhone liirds are made to deviate in two directions — hack npwards along the 

 Riviera, in order to get across the narrower passages by Corsica and Sardinia, 

 and over to the Spanish coast, in order to get the shorter crossing from Valencia 

 to Oran. On which facts are and can be these conclnsions based ? On the facts 

 that countless birds are observed in the Rhine and Rhone valleys, that many 

 people visit the Riviera and see numerous migrants, and that it seemed more 

 convenient to cross the Mediterranean where it is narrowest. Similar reasons will 

 no doubt exist for the other crossing-lines. 



My reasonings lead to exactly opposite conclusions. 



Wherever ornithological observers have chosen places which can easily be 

 surveyed and taken under observation, and watched birds in Europe, migrants 

 were observed in great quantities. In the Mediterranean, for example, there is so 

 far no reason whatever to snpposc that they only cross along the given routes, 

 and thus strike the African coast in five or six belts only; but on the contrary 

 migrants have been observed in great numbers wherever ornithologists or collectors 

 have been. 



According to those methods we shonid have at once to construct a mighty 

 route of migration throngli El-Golea, which is a bird-migration paradise; but 

 suppose I had not stayed in El-Golea, and gone down from Onargla through the 

 Great Western Erg by Ai'n Taiba to Tidikelt, I might liave concluded that no 

 bird migration of any extent goes through that part of the Sahara, because I had 

 passed through districts unsnitable for birds to alight and to feed — for few birds 

 will stop in the foodless Erg or desolate Hammada. 



Moreover, how can birds see what ronte they take at night ? and if they see 

 the route by day-time, how can they know that it is their route, especially when 

 they see it for the first time ? These questions have often been put and ventilated, 

 and I answer them unhesitatingly — without going here again into the questions 

 of leadership and others — They cannot. 



And what advantage could it be to any of the more powerful fliers — and all 

 trne migrants are good fliers — to gain those narrower passages in the Mediterranean 

 My answer is : ITone whatever. 



There is, however, the fact that birds migrate in one direction, and another 

 that they have a great inclination and tenacity of following extended coast-lines ; 

 these facts are based on countless observations, and are established beyond doubt. 



Thus the majority of birds travel in the autumn in a north-easterly to south- 

 westerly direction, while some species go in the opposite one (in a south-eastern 

 line), thus crossing the lines of other species. This fact, together with the N.E. 

 to S.W. main direction of the West European coasts, brings at once a great mass 

 of migrants down our West European shores, and when they cannot go any farther 

 in Europe they cross over to N.W. Africa. No observations exist to show tli;it 

 this cro.ssing takes place more near the Straits of Gibraltar than farther westwards : 

 in fact, many birds keep on in their south-westerly direction and most unwisely 

 visit the < Canaries and even tin; Azores and Cape Verde Islands, instead of sticking 

 to the hospitable shores oi' Africa, where they winter. Moreover, some birds miss 

 liie land altogether and jierish in the ocean, as is evidenced by tlieir frequent 

 alighting on 8hi|>s in mid-ocean in a tired state. 



