THE COMMON TERN. 283 



eggs : — the latter number had not unfrequently been found by 

 one of our boatmen. The spot from which one or two of the 

 terns rose to-day was kept in view. On going to it the eggs 

 were discovered, and they felt warmer than I thought it possible 

 they could have been from the mere heat of the sun. It is com- 

 monly believed at all the breeding-haunts of terns I have visited, 

 that the bird never sits on its eggs during the day. Our boatmen 

 admitted that although they had never seen terns leave the ground 

 so that they could say they were just off their nests, yet on ob- 

 serving them rise at a distance they have '' marked" the spot, and 

 on going to it found their eggs. The various boatmen who have 

 rowed us to the Mew Island made a similar remark. On the 16tli 

 of July, 1850, an intelligent boatman told us the belief here is 

 that the sun incubates the eggs, which are always placed on the 

 sumiy side of the rocks ; he remarked that it must be so, as the 

 birds do not sit on the nests by day. It is also considered that 

 two birds sometimes lay in the same nest, as six eggs (twice the 

 usual number) have been found together. That the birds do not 

 sit on the eggs during the .day, or do so very rarely, is certainly 

 the case at the several islands visited by myself. If they did so, 

 they would be hardly less conspicuous than " snow upon a raven's 

 back ;" and hence instinct may prompt them — in localities in 

 which they are liable to be disturbed, both for their own sake 

 and that of their eggs — to absent themselves from their nests 

 in the day-time. 



Mr. Garrett has found terns' eggs perfectly fresh on islands in 

 Strangford Lough, about or near which he did not see a tern all day. 



The S. hirundo has, however, not only been seen sitting on their 

 eggs, but shot in rising from them, on bare rocky islets of Bantry 

 Bay."^ Several birds were observed on their nests placed on the 

 short grass of the island off Islay, to be hereafter mentioned. In 

 the latter locality (and probably in the other also) these birds are 

 very rarely disturbed. 



In the month of June 1836 a number of specimens of the com- 

 mon and arctic terns, killed on the islands of Strangford Lough, 

 * Mr. G. JacksoH. 



