BIRD NEWS 



and, I now suggest, bearing at mi- 

 gration times a liorde of birds. I 

 believe tliat birds habitually make 

 use of these cyclones as means of 

 traveling from one part of their 

 range to another under the most fa- 

 vorable condition for the exercise of 

 flight. 



This aspect of the wind seems 

 never to have been studied by the 

 holders of the "Head-Wind" or 

 "Beam Wind" theory. I have re- 

 cently come across a passage in 

 Chapman's "Wlid Norway" that 

 leaves little doubt that he has been 

 led towards this point of view, and 

 it is unfortunate that so excellent an 

 observer has not thought fit to go 

 deeper into the subject. As it is, 

 his remarks are apparently merely 

 tentative. I give the passage in full. 

 "Except by aid derived from the op- 

 eration of physical laws, the nature 

 and extent of which are unknown to 

 me, and by taking advantage of 

 'Trade-wind' circulations in the up- 

 per air, I believe that migration is 

 impossible for short-winged forms of 

 sedentary habit. * * * But that aid, 

 and those advantages, may facili- 

 tate, and perhaps vastly accelerate, 

 a process which is otherwise impos- 

 sible." 



I suggest that the bird takes up 

 its position in the nearest part of the 

 rim of the cyclone to its point or de- 

 parture, and flies in the same direc- 

 tion as the wind until that portion of 

 the aerial medium that supports and 

 carries it arrives over that part of 

 the world, or the nearest point, 

 which the bird desires to reach. I 

 will not run the risk of obscuring 

 my point by dealing with anti-cy- 

 clones; the general process would be 

 much the same. The ascending cur- 

 rents of cyclones must be mentioned, 

 for a bird supported in one would 

 soon be carried to a great height, 

 from which it might start a long 



"glide" on open wings, supported by 

 the upward current in the manner 

 of a gull flying above a cliff. 



Mr. Clarke's actual observations 

 support my theory. He points out 

 that favorable conditions for au- 

 tumnal migration are "the presence 

 of a large anti-cyclone over Scandi- 

 navia, and cyclonic conditions to the 

 westward of the British area, with 

 a low pressure center off the west 

 coast of Ireland." There is a strong 

 outward and downward current 

 from above the core of an anti-cy- 

 clone, and this would be most useful 

 to birds crossing the North Sea in 

 autumn. This was the state of af- 

 fairs on September 23rd, 1908, when 

 a large migration was noticed on the 

 coast of Norway. 



EXTRACT OF LETTKK FROM 



COLOMBO, CEYLON 



How nice it must be to have such 

 a large aviary as you have. Mother 

 is very much interested in birds and 

 has watched them from when she 

 was a girl. There are three Robins 

 (so called in Ceylon), two honey- 

 suckers and a tiny grass bird hav- 

 ing a battle royal on our lawn. Just 

 as I am writing they are hopping 

 around each other and making such 

 a noise — it is very funny to watch 

 them. We have never had an aviary, 

 but at various times have had one 

 or two birds in cages. Our last bird 

 was a Myna whose staple food was 

 cheese. He had a fearful flght with 

 an Indian Game Hen and poor old 

 Peter was killed. Perhaps it will 

 interest you to know that about two 

 years ago mother imported some pi- 

 geons from Boston, Mass., and we 

 have about a hundred now — the de- 

 scendents of the Americans. Thank 

 you for that "BIRD NEWS' you sent 

 me. I am going to subscribe to it 

 some day soon. 



