I A 2 Allen, Galkes 'Heligoland.' LApril 



In Chapter IV (pp. 63-73) the 'Velocity of the Migration 

 Flight ' is considered. On this subject there is unfortunately very 

 little positive information ; hence the field is a tempting one for 

 conjecture and inference, and Herr Giitke has not neglected to 

 make use of it. The actual data bearing on the subject which he 

 is able to cite does not by any means favor the high rate of speed 

 he assigns to migrating birds; namely, 180 to 240 geographical 

 miles per hour, not for a single hour but for many hours consecu- 

 tively ! The character of his proof of this proposition is fairly 

 shown by the following. His crucial test, and the main basis of 

 his assumption, is the spring migration of the Red-spotted Blue- 

 throat (Cyanecula sued en), a bird which winters in Egypt and the 

 neighboring countries and breeds mainly north of the 60th parallel 

 in northern Europe. On the negative evidence that it has not 

 been recorded as occurring anywhere in numbers in spring 

 between the Nile Valley and Heligoland, it is assumed as beyond 

 question that the majority of the individuals of this species, " under 

 normal conditions, and in the absence of meteorological influences 

 of a disturbing nature, accomplish their migration in one uninter- 

 rupted nocturnal flight, . . . thus accomplishing a distance of at 

 least 1600 geographical miles within the space of nine hours" 

 (pp. 65, 266), hence maintaining an average rate of speed of 180 

 miles an hour. The Bluethroat is cited as positive proof that other 

 birds having the same winter quarters and breeding range must 

 also migrate in the same way (p. 67). But he goes even further 

 than this, citing as " the most striking and incontestable proof " of 

 his assumption the American Golden Plover {Charadrius domin- 

 icus), which, he affirms, migrates in autumn from Labrador to 

 northern Brazil in a single uninterrupted flight, over a distance of 

 3000 geographical miles. He says. " we may probably assume 

 fifteen hours as the longest spell during which a bird is able to 

 remain on the wing without taking sustenance of any kind " ; and the 

 velocity of flight of these birds would, on this assumption, " amount 

 to 212 geographical miles per hour" (p. 69). Even this astonish- 

 ing rapidity of flight he believes is not to be regarded as " either 

 exceptional or isolated," and that the same birds "may be able 

 to accomplish even greater feats during the spring migration." 

 Indeed, recurring again to the Bluethroat, he believes that those 



