142 ANNALS OF SCOTTISH NATURAL HISTORY 



V-shaped band across the vent, and, as in Fig. i, is dark 

 mouse grey in colour, and spotless. 



Fig. 6 is a summer feather taken from the same region, 

 and is similar in colour to I^igs. 2 and 4 with this marked 

 difference that, whereas all the summer feathers of the 

 dorsal region carry two white spots, some of those of 

 ventral band feathers only carry one. 



Briefly then, so far as the dorsal region and the narrow 

 V-shaped band across the vent are concerned, the changes 

 from winter into summer feather follow a fixed type, dark 

 mouse grey spotless feathers in winter changing into glossy 

 black spotted feathers in summer. 



The rectrices (tail feathers), however, apparently show an 

 entirely opposite state of affairs, for it will be noticed that 

 in winter the feathers are black with a white edge to the tips 

 (Fig. 7), and in summer are wholly black, without any white 

 edge or spot (Fig. 8). It has been suggested to me that 

 possibly the feathers of the tail appearing wholly black in 

 summer may be due to abrasion, and that the white edging 

 becomes worn completely away. This may be the explana- 

 tion, but after careful examination of the material at my 

 command, I am inclined to think that the summer tail 

 feathers are grown wholly black from the beginning, and I 

 come to these conclusions after carefully studying the 

 feathers, for I find that the feathers which carry the white 

 edging appear older and more faded in colour than those 

 which are wholly black, and further, these wholly black 

 feathers do not show signs of having lost, by abrasion, so 

 broad and wide an edging as is seen in the white-edged 

 winter feathers, and I therefore judge the wholly black 

 feathers to be new ones, or, at any rate, newer than the 

 white -edged winter feathers. The matter is extremely 

 interesting, and needs further confirmation. 



Figs. 9 and 10 represent the feathers taken respectively 

 from the throat and neck-bands in summer. The general 

 effect produced by these feathers is the formation of lateral 

 lines of white forming three transverse bars, one on each side 

 of the neck, and one across the gula. Although the effect 

 so produced is the same in each case, on examination of the 

 feathers it will be found that the distribution of black and 



