76 THE BIRDS OP ION A AND MULL. 



useful, as it may be fixed at the right focus, and so can be pulled 

 out of the pocket, and used by the left hand alone, while the gun 

 may still be retained in the other. A glass of this kind will of 

 course not command such a long range as the telescope, but they 

 are made of very considerable power, sufficient at least for most 

 occasions. It is very useful for detecting birds upon the water, 

 when one is boating, or for discovering them among rocks, or 

 among reeds and cover ; and by twilight it is superior to the 

 telescope, as it contains fewer glasses, and does not consequently 

 absorb so much of the light. 



The Eavens have got their new nest in the locality I expected 

 they were going to adopt. Here, in a high cliff, they have taken 

 up their residence in an old nest formerly built by a Peregrine, 

 but since tenanted by Hooded Crows. The nest being ready 

 built, it only required a fresh lining. The place, I think, is totally 

 inaccessible ; however, I may sacrifice one of the old birds for the 

 sake of its skin, should it be wanted. 



I have got two more Black Guillemots' skins for you which 

 exhibit the changes the plumage undergoes between winter and 

 summer. The Wheatear arrived here on the 21st of March. 



Last Saturday, the 3rd of April, I found a Eock Dove's nest 

 containing young ones, which is unusually early. 



