BIRD-MIGRATION AT ST KILDA 187 



valuable co-operation I should not have ventured to 

 St Kilda so late in the season. 



Quite a number of descriptions have been published 

 of the five islands and the several stacks which form the 

 St Kilda archipelago. Such being the case, it is only 

 necessary to give a short account of the topography of 

 the main island, Hirta, the scene of the investigations. 

 Hirta is some two and a half square miles in area, and 

 is an island of mountains and high ground. It falls 

 naturally into two halves or basins, an eastern and a 

 western, each of which is drained by a moderately sized 

 burn. The low ground in both areas is of very limited 

 extent. 



The eastern section of the island is the site of the 

 village and the cultivated ground, and has for its sea 

 front a fine bay, which affords the only suitable 

 landing-place in the island. This lowland area is most 

 effectually sheltered from the east, north, and west, by a 

 picturesque series of hills — namely, Oisaval (930 feet), 

 Connacher (1372 feet), Mullach Mor (1153 feet), and 

 Mullach Sgail (705 feet), which are connected by high 

 ridges ranging from 540 to 850 feet. The village and 

 the crofts are thus flanked on all the landward sides by 

 high ground, while the long narrow island of Dun shields 

 them from the south. The crofts, amid which the village 

 stands, are surrounded by a stone wall, the object of 

 which is to keep out the cattle and sheep which feed on 

 the slopes beyond. The area thus enclosed is probably 

 about 100 acres, but the actual amount under cultivation 

 does not exceed some 50 acres. The sides of the hills 

 surrounding the crofts rise rapidly, and, when free from 

 masses of rough boulders and great screes, are clothed 

 with short grass, intermixed with which is a little thin 



