294 THE SCOTTISH NATURALIST 



of the primaries are broader and tinged with rufous. The 

 comparative wing measurements are: — St Kilda, males, 53 

 mm. (21 in.); females, 50 mm. (1-97 in.). Common Wren, 

 males, 47 mm, (i-86 in. ) ; females, 45-5 mm. (1-78 in.). 



Whilst some of the adult St Kilda birds had completed 

 their autumn moult by mid-September, in others the body 

 feathers had been renewed, but those of the head, chin, and 

 throat were still only half grown by that date. 



First or nestling plumage. — The first plumage of the 

 young birds differs considerably from that of the adults in 

 being much darker on the under-surface, and, in a minor 

 degree, in other respects to be mentioned. 



The feathers of the throat, chest, and upper abdomen 

 vary, being brownish- or buffy-grey, and are delicately fringed 

 with a darker tint which imparts a scaly appearance ; those 

 of the lower abdomen and under tail-coverts have dark bars, 

 and the flanks are washed with pale rufous. The upper 

 plumage, except the head, is slightly more rufous than in the 

 old birds, but the barring on the feathers, though similar in 

 other respects, is less intense ; the superciliary stripe is 

 scarcely perceptible and greyish, and the sides of the throat 

 and cheeks are inconspicuously spotted with grey. The 

 white spots on the wing-coverts are absent, and those on the 

 outer webs of the primaries are white tinged with brown. 



In the Common Wren in the same stage of plumage the 

 upper surface is reddish brown with faint indications of bars 

 on the lower back. The feathers of the chest and abdomen 

 are a mixture of greyish white and brown, and give a mottled 

 appearance to the under plumage. The flanks are reddish 

 brown, the chin and throat grey. There are faint dusky bars 

 on the lower abdomen, under tail-coverts, and flanks. 



Young birds in autumn plumage. — In their second 

 plumage, which is worn until the following autumn, the 

 young birds closely resemble the adults, with the following 

 slight exceptions — the under-surface is less white, being 

 faintly washed with pale brown ; the head and hind-neck are 

 slightly browner, and the mottling on the cheeks and sides 

 of the throat are greyish and comparatively inconspicuous. 



Some of the young birds had completely assumed their 



