the Collared Petrel on the Welsh Coast. 413 



poleuca. It has, like that bird, the whole of the inner webs 

 of the primaries black to the shafts, and thus resembles 

 CE. mollis, but it is a smaller bird than either of these, and, 

 moreover, has a shorter tail. 



Macgillivray, in his description, alludes to the variation 

 found in the specimens procured by him, which he attributes 

 to difference of age. This variation chiefly affects the colour 

 of the plumage of the under surface of the body, some speci- 

 mens being nearly white, with a broken collar of grey on the 

 breast, and others being grey from the breast downwards, the 

 throat alone being white. It is now pretty well established 

 that this variation is strictly individual, and not due to age 

 or sex. I know of several cases of young birds which still 

 have a good deal of down on their first feathers, which are 

 those of the so-called fully adult, and not of an intermediate 

 dark grey or brown stage. 



The Aberystwith bird, as the Plate shows, is a dark indi- 

 vidual, with the whole under plumage grey, with the exception 

 of the throat. The outer four primaries are old, somewhat 

 worn feathers ; the rest are new quills, so that the bird was 

 moulting when shot. This fact adds to our surprise that it 

 should have strayed so far from its native haunts. 

 • Macgillivray^s description is as follows : — 



" Above light grey, especially on the back, shoulders, and 

 upper tail-coverts ; the feathers of the two first situations 

 often margined w ith white. Crown, back of head and neck, 

 and auriculars sooty brown, which colour behind gradually 

 blends with the grey of the back, and in front extends across 

 the breast from each side to form an indistinct band. Wings, 

 projecting an inch beyond the tail, dark sooty brown; the 

 secondaries tinged with grey. Tail very evenly graduated, 

 of twelve feathers, greyish brown. Face, cheeks, chin, and 

 throat white; on the sides and front of the head the white 

 merely tips the feathers, the base and centre of each being 

 dark, giving a speckled appearance to the rest of that region. 

 Lower surface white, except the undefined pectoral band ; 

 and on the sides, flanks, and under tail-coverts the feathers 

 are minutely speckled with grey, and sometimes also have a 



SER. VI. VOL, III. " 2f 



