112 MIGRATION AND FLIGHT. 



of some miles, and then turned loose. In three 

 days it was again found in the greenhouse. 



One other peculiarity in the periodical visits of 

 birds to their breeding stations, is the punctuality of 

 their arrival. There is seldom the difference of a 

 week, and frequently not that of a day, in the time 

 of the appearance of some particular species. Of 

 course we cannot be accurate in most cases, from 

 not being able to fix on the exact moment of a bird's 

 arrival ; but in some instances, circumstances afford 

 us the means of speaking more positively. Thus, on 

 a well-known rocky island called the South Stack, 

 near Holyhead, the lighthouse-keepers assured us 

 that the Gulls, which seldom visit the island for two- 

 thirds of the year, arrive on the same night, namely, 

 February 10th, for the purpose of breeding. They 

 are regularly warned of the arrival of their summer 

 guests, about midnight, by a great noise, as it were 

 a mutual greeting and cheering ; and from that 

 moment they remain till their broods are reared, 

 and the business for which they resorted thither 

 entirely at an end. 



The light-keepers spoke with pleasure of the arri- 

 val of the birds, stating that they looked to their 

 return as that of so many old acquaintances after a 

 long absence, announcing the spring to be at hand, 

 and the winter to be over and gone. 



It has been observed, that the time of departure of 

 certain birds, is by no means so exact as that of their 

 arrival ; which may be accounted for by a natural 

 disinclination on the part of the old ones to desert 

 the nests of young ones, still requiring their care. 

 But even this most powerful of all instincts, the 



