1G0 WONDERS OF OKGANIC LIFE. 



northern. Thus, clutterels forsake the Gram- 

 pians about the beginning of August, and quit 

 Scotland at the end of that month, while 

 they remain about our southern shores to the 

 latter part of September, or even the beginning 

 of November. Dr. Fleming states, that a dif- 

 ference of nearly a month takes place between 

 the departure of the goatsucker from Scotland 

 and the south of England. 



It must not be supposed that migratory birds 

 perform their voyage by one continuous flight 

 to the place of their winter rest, or of their 

 summer sojourn. They rest by the way, and 

 many, as the swallow and the wheatear, travel 

 during the night. At the same time, they can- 

 not spend much time in rest, for Adanson 

 observed the swallow in Africa in the month of 

 October, after its return from Europe — most 

 probably from the countries bordering the 

 Mediterranean. M. Prelong says, " I have 

 observed, as Adanson also has, that our swal- 

 lows and our wagtails arrive in the torrid zone 

 eight or ten days after the period of their depar- 

 ture from our climates. In 1788, I saw the 

 yellow wagtails, (Bergeronettes clu printems,) and 

 the grey wagtails, on their arrival at Goree on 

 the 14th of September. Adanson says that he 

 has seen swallows arrive at Senegal on the 9th 

 of October ; now I recollect that they quit the 

 department of the High Alps about the end of 

 September — thus making the time to tally."* 



The migratory movement is far more exten- 

 * Annates de Chimie, torn. xvii. p. 272. 



