On the Occurrmce of the Black Redstart in Stirlingshire. 143 



alar patch is also a symptom of inmiaturity. Altliougli seen 

 in old birds (and in adult males in winter occasionally), the 

 alar patch is absent or very faint, as pointed out by several 

 authors.* 



A furtlier distinction may be found in the generally 

 lighter colour of the under parts of Rttticilla phcenicicrus as 

 compared with the same parts of Ruticilla tithys, which, as in 

 this specimen, are uniform, or almost uniform, with the upper 

 plumage. 



Although so rare in Scotland, this species may be con- 

 sidered as a res^ular winter visitant to the coasts of Eno;- 



o o 



land. It has occurred in Faroe (Yarrell), Norway, and 

 at its farthest northern point in the middle districts of 

 Sweden. I find no record of it in North Eussia, north of 

 60° N.E. Although its occurrence in Scotland must be con- 

 sidered exceptional, still, I think we can hardly class it as 

 purely accidental, as I believe it will be found there is a 

 natural law accounting for many occurrences of Continental 

 species as far north in Great Britain as the present example. 

 Indeed, I think the suggestion may be hazarded that if 

 certain species extend their northerly breeding limit on the 

 Continent, we may safely calculate upon their occasionally 

 alighting on their autumn migration farther to the north in 

 the British Isles than they would otherwise do. What we 

 have for a long time considered as accidental (purely 

 accidental) occurrences of Continental species ought, I think, 

 in many instances rather be held as indications of extension, 

 towards the north, of breeding limits on the Continent. This 

 supposition would seem to be borne out by what we know of 

 the regular occurrence of many rare eastern species in the 

 island of Heligoland, where almost every autumn such species 

 as Phylloscopus superciliosus and P. horealis occur on migra- 

 tion, species which have their breeding quarters, so far as is at 

 present known, in the Eastern Palaearctic Eegion, and at 

 Archangel and in North-East Eussia. The present species has 

 also ocurred in Heligoland in autumn on migration sparingly, 

 and I am inclined to think that the specimens so occurring 



* Mr Gatcombe, quoted by Mr Dresser, " Birds of Europe," double part, 

 Nos. xxix, XXX. J, H. Gurney, Jun., "Rambles of a Naturalist," p. 162, 



