1 92 1,] Velocitij of Migratory Flight among Birds. 237 



and 50 miles or so in distance seems nothing to these 

 incomparable fliers. I have had splendid opportunities of 

 observing botii the Alpine, Common, and Spine-tailed 

 (Chcetura) Swifts, and it has been a great disappointment 

 to me that I have never been able to get a satisfactory- 

 estimate of their rate of flight, as they never continue 

 on an even course. On a small island off the coast of 

 Crete, I was recently given a good exhibition of what an 

 Alpine Swift can do. I was watching some of these birds 

 feeding round cliffs in which several pairs of Eleonora's 

 Falcon were about to breed. Now, this delightful Falcon is no 

 mean flier, and as these Swifts passed their cliff, the Falcons 

 would come out against them like rockets. The Swifts 

 would accelerate, and seemed to be out of sight before the 

 Falcons were well on their way. So confident were the Swifts 

 in their superior speed, that every time they circled round 

 the island they never failed to " draw '' the Falcons, and 

 seemed to be playing with them. I may add that these 

 same Falcons have little difficulty in overhauling and striking 

 a llock-Pigeon — itself no mean performer. I have also 

 seen on record the case of Falcons and Swifts somewhere 

 in India, when the former failed time after time to come 

 up with his quarry. I unfortunately cannot trace the 

 reference. 



I hesitate to even guess at the speed to which a Swift can 

 attain when the necessity arises, but the main point is that 

 this, the fastest of birds, can increase his ',' feeding " speed 

 of, say, 70 miles per hour to a velocity which must exceed 

 100 miles per hour. There is little doubt that the speed of 

 the Golden Plover in the table is an accelerated speed. 

 Pilots in Mesopotamia have told me that whereas Geese 

 cannot to any great extent accelerate, Duck, when pressed, 

 could attain a speed of about 60 miles per hour. 



To conclude, 1 find that birds have two speeds — a normal 

 rate which is used for every-day purposes and also for 

 migration, and an accelerated speed which is used for pro- 

 tection or pursuit, and which in some cases nearly doubles 

 tiie rate of their normal speed. Some of the heavier birds 



