SiG IXTEOnUCTIOIT TO ZOOLOGY. 



seen fixed under the eaves of houses, and the upper angles of 

 windows. They are sometimes placed under the arch of 

 a bridge, and the magnificent headlands of basalt on the 

 county of Antrim coast, are favourite haunts. 



The House-martins return to their old abodes. Mr. Thomp- 

 son records an instance in the neighbourhood of Belfast, in 

 which a pair found their nest occupied by a Sparrow, who 

 seemed determined to keep possession. The Martins departed, 

 returned with about twenty of their kindred, and built up the 

 entrance to the nest, inclosing the offender within. Next 

 morning the pair of Martins commenced the construction of a 

 new nest, against the side of their old one, and in it, undis- 

 turbed, reared their brood. After some time the proprietor of 

 the cottage had the curiosity to pull down both nests, and in 

 that occupied by the Sparrow found its "rotten corpse," 

 together with several eggs. Mr. Thompson suggests that 

 the Sparrow allowing herself to be entombed alive, may pro- 

 bably be explained on the supposition that the eggs were in 

 the last state of incubation, as at such times' birds will occa- 

 sionally allow themselves to be hfted in the hand, and when 

 placed again continue to sit as intent upon their hatching as if 

 they had not been disturbed.* 



The Sand-martin or Bank-martin {H. riparia) is smaller in 

 size than either of those mentioned, and is the earliest to arrive 

 in these countries. It has been seen in the neighbourhood of 

 Belfast on the 29th of March. It forms excavations in sand- 

 banks, and in these constructs its nest ; from this habit the 

 name is derived. 



The Common Swift (Cypselus murarius) is distinguished by 

 its greater expanse of wing, its darker colour, and by having 

 all the four claws of its foot pointing forward, instead of three 

 forward and one backward, as in the Swallow and the Martins. 

 It prefers for its building-sites lofty towers and church steeples, 

 but when these are not to be had, it very wisely contents it- 

 self with more lowly stations, such as the eaves or thatch of 

 dwelling-houses. It also frequents the romantic precipices 

 which are resorted to by the Martin. t It usually arrives the 

 first week in May, and departs in August, though an occa- 

 sional straggler may be seen after that period. 



* Mag. Annals of Natural History, vol. x. p. 50. References are there 

 given to other notices of similar events, 

 f Thompson. 



