PREFACE. 



The peculiar geographical position of the British 

 Isles renders them the resort, either permanent or 

 temporary, of a large number of Birds: amongst 

 which are many periodical visitors both from high 

 latitudes, driven southwards in winter by the severity 

 of the cold ; and from Africa, whence they fly north- 

 wards at the opposite season, in order to avoid the 

 intense heat of an intertropical sumiuer. Besides 

 these periodic sojourners, many species, which are 

 properly resident on the European Continent, occa- 

 sionally cross the Channel, and make their appearance 

 amongst us as capricious visitors ; but, whether led 

 hither by choice, or driven by stress of weather, it 

 is impossible to determine. Instances also occur, 

 but at rare intervals, of solitary specimens, which are 

 undoubtedly of American origin. 



It is possible that some of these may have been 

 transported as captives, and may have escaped from 

 confinement; or they may have been introduced 

 and intentionally set at liberty. However this may 



