Xviii INTRODUCTION. 



asserts, in the case of the stoat, and some others, that assume 

 a winter's garb) without any actual shedding of their coat, 

 either upon the first variation, or in regaining their sum- 

 mer's hue. It is possible, and there is now some reason 

 for believing, that the edges only of the feather may be shed 

 (but not by a gradual process), thus presenting a newer 

 and brighter surface, either of the same, or, more frequently, 

 of a different shade of colour. In the birds in which this 

 partial change happens, it may even be observed, that, 

 where the feather, as on the head of the Chaffinch, Reed- 

 Bunting, and Stone-Chat, is of two distinct hues, the webs 

 of the exterior one are joined to the main body of the feather 

 by a line of separation of finer texture, thus forming an 

 adscititious margin, as it were, to the inner part. 



In the course of the descriptions of each species, the 

 terms Summer and Winter Visitant, and Polar and Equato- 

 torial Migrant, will frequently occur, which, to general 

 readers, may seem to require explanation. This I will, as 

 briefly as possible, attempt. The Summer Visitant, or 

 Polar Migrant, implies a bird resident, during the summer 

 season, in these kingdoms, as being included in the northern- 

 most parallel of latitude to which its migration extends, 

 from the Equator towards the Pole*. To the Winter Visi- 

 tant, or Equatorial Migrant, these kingdoms are in the 

 southernmost parallel to which their winter's migration 

 reaches, in course from the Pole to the Equator, their sum- 



* Such are many of the Sylviadce ; also the Cuckoo, Night-Jar, Sivalloivs, 

 &c. 



