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discussed, further shows how little in need of rest birds are 

 during their migration flight. Large sections of the migratory 

 streams of these birds which are directed towards South America 

 fly across Bermuda in immense quantities. As long as fair 

 weather prevails not one of these birds rests upon its migration 

 journey ; only a storm will induce them to alight (J. M. Jones, 

 naturalist in Bermuda). This, too, in spite of the fact that they 

 have already travelled over a distance of 1,200 miles from Labra- 

 dor." In view of this evidence, why assert that the time during 

 which a bird can maintain its flight without food and rest is 

 limited to fifteen hours ? Of course the power of abstaining from 

 food for any length of time will vary both with individuals and 

 species. It may, however, be pointed out that the birds of prey 

 are credited with the ability to undergo abstention for several days 

 without their being weakened thereby. A plover might not be 

 able to accomplish so much as this, but forty-eight hours does not 

 seem an impossible period even to the latter, the migratory flight 

 being continued in the meantime. The hordes of birds which 

 sometimes arrive on Heligoland late in the winter, which have 

 been fairly driven from other haunts by the absence of food, 

 and which arrive in the emaciated condition described by Herr 

 Gatke, are still capable of making flights of considerable length. 

 Nearly all species wintering in the British Isles, for a period of 

 three months, undergo a daily fast averaging fifteen hours' dura- 

 tion. For from mid November to mid February, roosting time is 

 about 4 p.m., and birds are rarely on the feed before 8 a.m. the 

 following morning. In foggy weather the period of fast is often 

 greatly lengthened. Of course they are at rest all the time. 



It is of little moment as regards the extent of time during 

 which the particular species under notice could remain on the 

 wing, for Herr Gatke points out that there is nothing to prevent 

 their resting on the surface of the sea, even when moderately 

 agitated, as other species have been observed to do. 



But all these estimates of speed, and powers of abstention 

 and endurance, are based on pure assumption, the same is the 

 case with the assertion that these particular flights of plovers are 

 travelling from Labrador to Northern Brazil. It is the theory of 

 a broad migration front travelling in a rigidly maintained north to 



