128 
THE NATURAL HISTORY 
[LETT. 
swift, and of several other small birds, but cannot bring tbeni to 
any criterion. 
As I have often remarked that redwings are some of the first 
birds that suffer with us in severe weather, it is no wonder at 
all that they retreat from Scandinavian winters : and much 
more the orclo of grallm which, all to a bird, forsake the northern 
parts of Europe at the approach of winter. " Gralhie tanquam 
conjuratfe unanimiter in fugam se conjiciunt ; ne earum unicam 
quidem inter nos habitantem invenire possimus ; ut enim restate 
in australibns degere nequeunt ob defectum himbricorum, ter- 
ramque siccam ; ita nec in frigidis ob eandem causam," says 
Ekmarck the Swede, in his ingenious little treatise called " Migra- 
tiones Avium," which by all means you ought to read while your 
thoughts run on the subject of migration. — "The grallce, as 
though they had conspired, take themselves to flight in an un- 
mannerly fashion; nor can we find even one dwelling amongst 
us ; for as they cannot live in the south during summer because 
of the dryness of the ground, so neither can they live in the 
cold countries of the north in winter for the contrary reason." 
Birds may be so circumstanced as to be obliged to migrate in 
one country and not in another : but the grallce (wdiich procure 
their food from marshes and boggy grounds) must in wunter 
forsake the more northerly parts of Europe, or perish for want 
of food. 
I am glad you are making inquiries from Linnpeus concerning 
the woodcock: it is expected of him that he should be able to 
account for the motions and manner of life of the animals of 
his own Fauna." 
Eaunists, as you observe, are too apt to acquiesce in bare 
descriptions and a few synonyms : the reason is plain ; because 
all that may be done at home in a man's study, but the investi- 
gation of the life and conversation of animals is a concern of 
m.uch more trouble and difficulty, and is not to be attained but 
by the active and inquisitive, and by those that reside much in 
the country. 
Eoreign systematics are, I observe, much too vague in their 
specific differences ; which are almost universally constituted 
by one or two particular marks, the rest of the description 
