52 AMID THE HIGH HILLS 
swift can attain when the necessity arises, but the 
main point is that this, the fastest of birds, can in- 
crease his feeding speed of, say, 70 miles per hour, to 
a velocity which must exceed 100 miles per hour." 
In the tables given above ^ Colonel Meinertz- 
hagen estimates the speed of the normal and 
migratory rate of flight of falcons at 40 to 48 
miles an hour, whilst Captain Portal estimates 
the maximum speed of the peregrine falcon in 
level flight through still air at 62 miles an hour. 
Captain Portal adds that the speed given is for 
a good trained bird, and that a wild bird is faster. 
In view of Colonel Meinertzhagen's observa- 
tions from his aeroplane and the figures given 
above, it would appear to be certain that the 
Alpine swift is faster than the peregrine falcon in 
horizontal flight. 
We have now to consider the speed of the 
spine-tailed or needle-tailed swift. There seems to 
be no doubt that this bird is a much faster flier 
than the Alpine swift, though at first sight and 
without a careful examination of the skeletons, it is 
difficult to state why this should be so. I have com- 
pared various specimens of the two birds, and there 
appears to be little diff'erence in their size. Colonel 
Meinertzhagen, who has been so kind as to discuss 
1 Pp. 35, 36. 
