1 
their insertion will provide a sort of mechanical assistance 
to enquirers. Where some fact in the geography of even 
a common animal, struck me as important, I have not 
hesitated to introduce the name in the situation considered 
as uncommon or interesting; and where an animal 
habitually occupies, or has been observed at the times of 
its detection to resort to opposite kinds of habitats, I 
have (if the species be rare, remarkable, or interesting 
in its economy,) noticed it twice or oftener in the maps. 
With some species this occupation of opposite kinds of 
residence is determined by change of season, a fact 
particularly noticed among the Waders, some of which, 
as I shall shew, remove at stated periods to temporary 
new abodes, and are again found after awhile, either in 
an intermediate situation, or in the quarter whence they 
had first set out. In important cases of this description, 
I have judged it useful to give the double, or triple 
insertion of the species. 
