H. LYNES: MIGRATION OF BIRDS. 71 



that one feels at a loss to say exactly how it has all 

 been done. 



With regard to departures of birds at Port Said all I 

 ever noticed was a restless movement in a southerly 

 direction in the evenings. As already described the birds 

 were from twenty to a hundred and fifty feet high, but 

 I have little doubt that if particular attention had been 

 paid to the point, some of them might have been noticed 

 mounting to their passage altitude during the short 

 Egyptian twilight. 



F. Speed. 



The only passage speeds I was able to deal with were 

 those of some of the species which arrived flying low. 

 The best observations were made on the Quails by 

 timing them from the moment they crossed the fore and 

 aft line of the ship to the moment that, with a pair of 

 glasses, they could be seen to fly into a Quail net exactly 

 500 yards distant. 



The result gave a speed of just fifty knots an hour. 

 Corn-Crakes, Water-Rails and Spotted Crakes arriving 

 appeared to be going just about the same speed, but 

 proper time-observations of them were never obtained. 

 No matter whether at the sea-shore or in the harbour, the 

 speed of these particular birds as they came in never 

 appeared to be appreciably different, but whether it was 

 that at which the whole passage across the sea had 

 actually been made is, of course, impossible to say. 



I question much, however, whether these and like 

 species of birds that possess a continuous whirring flight 

 on migration are capable of any but a very limited 

 increase of their ordinary speed on the horizontal, or of 

 much diminution of it without intervals of "soaring." 

 On downward grades, no doubt, almost any speed is 

 possible, but this cannot apply to long distance flight. 

 In a ship, an increase of a few knots on the normal speed 

 requires a disproportionately high relative increase of 



