252 STUDIES IN BIRD-MIGRATION 



inodorum). These dangerous slopes are much resorted 

 to as feeding - grounds by the smaller species of 

 migratory birds, for amid the shelter afforded, they 

 are comparatively safe from the assiduous attentions 

 of an ever - present Peregrine, and the occasional raids 

 of the Merlin. There is no cover elsewhere, unless 

 some short, narrow runnels, connecting a series of 

 diminutive pools, on the exposed plateau, can be regarded 

 as such. 



There are three ancient dwellings on the island. 

 The chief of these resembles a large dog-kennel, has 

 a low entrance, is supposed to have been built for 

 devotional purposes, and is named on the Ordnance 

 Map the " Blessing House." Far more interesting are 

 two brochs, in an excellent state of preservation, each 

 with a couple of square chambers, and surmounted with 

 a beehive-shaped roof. 



The islands are resorted to annually as breeding- 

 stations, by hosts of sea-birds, the foremost among which, 

 in point of numbers, is the Puffin ; and the most interest- 

 ing, the Fork-tailed Petrel and the Fulmar. 



Ornithologically, however, the islands are chiefly 

 remarkable for the streams of birds which visit them in 

 spring when on passage to their northern summer 

 homes, and in autumn when returning to their southern 

 winter retreats. These movements are surprising for 

 the number of species and individuals visiting Eilean 

 Mor, when its situation, its very limited area, and its 

 singularly few attractions for migrants are taken into 

 consideration. 



The data amassed regarding these passage move- 

 ments cover a period of no less than twelve years, and 

 afford valuable information on the dates between which 



