366 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1921. 



usually leisurely flapping rook can attain from the moment he 

 realizes he is the quarry. 



I have seen rooks traveling on migration, and accurate observation 

 gives their pace as from 38 to 40 miles per hour. Now these migra- 

 tory rooks were traveling in their usual leisurely fashion, and not at 

 anything like the speed they can use when attacked by a falcon. All 

 other migrations which I have witnessed in many and various parts 

 of the world confirm my belief that migratory flight differs in no 

 way from every-day movement, except that it is steadier and possibly 

 a trifle slower. 



So in dealing with this question, I shall consider estimates of any 

 normal flight as the normal velocity which birds attain on migration. 

 That birds can hurry I do not doubt, but such effort could not be long 

 sustained, and would be of little use to them in the long-distance 

 migratory journeys they are accustomed to take. 



I shall first deal with those estimates of velocity which previous 

 writers have recorded, but which can not be regarded as reliable. 

 Gatke claims that hooded crows fly at 108 miles per hour and blue- 

 throats at 180 whilst on passage, and especially in the spring. He 

 claims that bluet hroats pass from between 10° and 27° of northern 

 latitude to the fifty-fourth degree of northern latitude in 9 hours. 

 He also assumes that the American golden plover takes but 15 hours 

 from Labrador to northern Brazil, supporting this theory by his per- 

 sonal observations on godwit and curlew covering over 7,000 yards in 

 60 seconds, or at the rate of over 4 miles a minute ! 



His estimate of hooded crow flight is based on the assumption that 

 their line of flight is from east to west over Heligoland, and that 

 they make for the east coast of England. This apparently is not 

 the case, for their line of autumnal flight over Heligoland is from 

 northeast to southwest, and these are probably not the birds which 

 arrive in such numbers on our central east coast. The bluethroat 

 estimate is based on the assumption that birds fly direct from Egypt 

 to Heligoland in one night, which is certainly not the case. His 

 estimate of the flight of godwit and curlew, on which he bases his 

 estimate of the flight of the American golden plover, is, I fear, but 

 an example of the tremendous enthusiasm of this charming character 

 for his subject. 



But Giitke is not alone in overestimating the velocity of flight. 

 Many other writers have erred through basing a theory on bad evi- 

 dence or no evidence at all, one of the most remarkable of these being 

 Crawfurd (" Bound the Calendar in Portugal ") , who convinced him- 

 self that turtledoves flew at such an astonishing pace that by leaving 

 Kent at dawn they would be in Portugal a few hours later. 



