[ 269 ]' 
The Scotch Ptarmigan frequents the higheft- 
ground ot any Britifh bird, and he takes but very 
(hort flights. 
Biu it. is alfo urged by fome, that the reafon why 
feamen do not regularly fee the migration of birds, is 
becaufe. they choofe the night, and not the day, for 
the paffage *. 
Now though it may be allowed, that poffibly birds 
may crofs from the. coaft of Holland to the Eaftern 
coaft of England (for example) during a long night, yet 
it mufl.be dark. nearly as long as it is within the Ardic 
circle to afford time for a bird to pafs from the Line 
to many parts of Europe, which Monf. de Buffom 
calculates, may be- done in about eight or nine 
days -fv . 
If the paffage happened in half the nights of the 
year, which have the benefit of moonlight, the birds 
would be difcovered by the failors almoff as well as 
in the day time •, to which I muff add that feveral 
fuppofed birds of paffage (the Fieldfare in particular) 
always call when on their flight, fo that the feamen 
muff be deaf as well as blind, if fuch flocks of birds 
efcape their notice. . 
Other objections however remain to this hypa- 
thefis of a paffage during the night. 
*'Mr, Catefoy fuppofes that they may thus pafs in the night 
time, to avoid birds of prey. Phil. Tranf. Abr. Vol. II. p. 887. 
But are not owls then ftirring ? 
On the other hand, if they migrate in the day time, kites, 
hawks, and other birds of prey, muft be very bad fportfmen not 
to attend (like Arabs) thefe large and periodical caravans. 
f In the preface to the .firft volume of his- lately publifhed 
Ornithology, p. 32. 
Ninety*- 
