I advance this obvious remark with the more confi- 

 dence, because my brother has always found that 

 some of his birds, and particularly the swallow kind, 

 are very sparing of their pains in crossing the Medi- 

 terranean ; when arrived at Gibraltar, they do not 



" Ranged in figure wedge their way, 



and set forth 



Their airy caravan high over seas 

 Flying, and over lands with mutual wing 

 Easing their flight ; " Milton — 



but scout and hurry along in little detached parties 

 of six or seven in a company ; and, sweeping low, 

 just over the surface of the land and water, direct 

 their course to the opposite continent at the narrow- 

 est passage they can find. They usually slope across 

 the bay to the south-Avest, and so pass over opposite 

 to Tangier, which, it seems, is the narrowest space. 



In former letters we have considered whether it 

 was probable that woodcocks in moonshiny nights 

 cross the German ocean from Scandinavia. As a 

 proof that birds of less speed may pass that sea, con- 

 siderable as it is, I shall relate the following incident, 

 which, though mentioned to have happened so many 

 years ago, was strictly matter of fact: — As some peo- 

 ple were shooting in the parish of Trotton, in the 

 county of Sussex, they killed a duck in that dreadful 

 winter of 1708-9, with a silver collar about its neck,"^ 



* White adds in a note, " I have read a like anecdote of a swan." 



158 



