LETM5 



VELOCITY OF FLIGHT AMONG BIRDS. 

 To the Editors o/ British Birds. 



Sirs, — The velocity at which birds fly must always be a matter 

 of great interest to ornithologists, if only from the bearing which 

 it has upon some of the problems of migration. 



I am under the impression that there is, perhaps, at the present 

 time a tendency rather to underestimate than overestimate this velocity, 

 the result possibly of reaction from a belief in the incredible velocities 

 attributed to certain birds by the late Herr Gatke in his well-known 

 took on Heligoland. 



The only bird whose speed can alwaj^s be accurately ascertained 

 over any measured distance is the Homing Pigeon, and Col. 

 Meinertzhagen, in a very interesting paper on the ' ' \'elocity of Migratory 

 Flight Among Birds" (Ibis, April, 1921), in which he gives the results 

 of some two hundred observations made upon over fifty species of 

 wild birds timed by means of theodolites or stop watches, quotes 

 several velocities made by Racing Pigeons in the past. 



As, however, he gives no more recent records than some of thirty 

 years ago, and as most ornithologists seem to have very little knowledge 

 of the distances over which Pigeons race nowadays, or the velocities 

 they make, I thought the following six examples, taken from a list 

 of recent record velocities published in the Racing Pigeon in 192I; 

 might be of interest. Unfortunately no information is given as to the 

 direction or force of the wind, so that these cannot, of course, be 

 regarded as real, or air, velocities. Nevertheless they give some 

 indication of a Pigeon's speed over various distances. 



Velocity. 



Yards per 

 Minute. 



Miles per 

 Hour. 



Referring again to the paper by Col. Meinertzhagen, I find that, 

 as the result of his observations, he is only able to record two velocities 

 which exceed that of No. i Pigeon, these being Lammergeiers', which 

 were descending to earth from a height (79] m.p.h. and no m.p.h.) 

 and which may, I think, for this reason be disquahfied. In the data 

 of the " Roubaix Swallow " (106 m.p.h.) which he quotes. Col. 

 Meinertzhagen states that he does not place much rehance. 



* In a race of this distance, where a Pigeon does not home on the day of 

 liberation, the hours of darkness are deducted from the time taken in estimating the 

 velocity. 



