\AO Allen, Gatke's 'Heligoland,' L April 



Asia, pass Heligoland, and later turn southward to reach their 

 winter quarters in southwestern Europe, crossing in their west- 

 ward autumnal journey, nearly at right angles, all the principal 

 mountain chains and rivers of northern Asia and Europe. River 

 valleys being " generally endowed with a very varied vegetation 

 and a rich insect life " are consequently " welcomed by the 

 majority of migrants as most desirable feeding-places," and they 

 are hence used as halting stations for " rest, food, or water," — 

 which fact, Giitke claims, has given rise to the idea, in the minds 

 of superficial observers, that the migrants here met with are fol- 

 lowing the courses of the streams. 



Herr Giitke recognizes at Heligoland two distinct lines of 

 autumnal migration, — one from east to west, and another, of 

 equal importance, from north to south (p. 37). The spring migra- 

 tion, in the case of the east to west migrants, differs markedly 

 from the autumnal movement, in that the spring journey is much 

 more rapid and made along the shortest line between the winter 

 quarters and the breeding stations, whereas in the fall migration 

 it describes two sides of a triangle, — namely, from eastern Asia 

 to the coast of central Europe and thence abruptly south to 

 northern Africa. It is further affirmed that " birds perform the 

 journey from their winter quarters to the breeding stations, if 

 possible, in one uninterrupted flight." That such is not the case 

 in North America is amply proven, were there no other evidence, 

 by the data given in Gooke and Merriam's ' Bird Migration in the 

 Mississippi Valley,' where the daily progress of some sixty species 

 has been traced from the Gulf of Mexico to Ganada and has been 

 found to be only from about fifteen to thirty miles per day, accord- 

 ing to the species, and whether the species is an early or a late 

 migrant. This seems much better evidence than the avowed 

 basis of Herr Giitke's assumption, namely, "observations made 

 here [at Heligoland] incidentally during the capture of birds at 

 night at the lighthouse " (p. 44). 



Ghapter III (pp. 46-62) is devoted to 'Altitude of the Migra- 

 tion Flight.' On this point, in speaking of " migration proper," 

 or "those large, extensive movements" which on the one hand 

 conduct our migrants from their breeding homes to or very near 

 their winter quarters in one uninterrupted flight, " and on the othen 



