fame rout. This migration of the bears is particularly obferved at Manchac, on the Miffiffippi, about the latitude of 
_. Many other quadrupeds perform fimilar migrations, both in the old and in the new world. 
§. XXX. 
Nothing feems more improbable than that a clafs of animals, fuch as the greater number of birds, which are ca¬ 
pable of rapid and immenfe flights, fhould continue in a country in which the winter’s cold is generally very intenfe, 
and in which, at the fame time, the principal articles of their food are not to be procured. But I am far from deny¬ 
ing, that foine birds do pafs their winters with us, either in a torpid (late, or otherwife. Some fpecies continue with 
us pretty regularly: and individuals of many fpecies do occafionally continue with us. I have already obferved, 
that “ during our mild winters, feveral of thofe fpecies of birds which, in general, are undoubtedly migratory, 
continue the winter through in the neighbourhood of Philadelphia.”* It muff be evident, therefore, that extreme 
cold is the great caufe which compels thefe animals to retire fouth. But it is not the only caufe. A deficiency of 
their proper food is another, not much lefs extenfive. The greater number of our birds of the order of pafferes 
feed upon infeds, and the feeds and berries of vegetables. Thefe, particularly the former, are not to be procured 
in the winter-feafon, in quantity fufficient to anfwer the demands of the immenfe number of birds which vifit us at 
other feafons of the year. If our climate were more moderate than it is, and if an abundance of food were at 
all times to be procured, the number of our Refident Birds would, doubtlcfs, be much greater than it is. It is 
evident, that a failure of their food is one of the great caufes of the migrations of birds. Thus no fooner has the 
Zizania aquatica (Reed), which is one of the principal foods of the Rice-Birds, filed its feed, than thefe birds difap- 
pear, returning fouthwards.f 
S. XXXI. 
Independent on the mildnefs of the feafon, and the continuance of an abundance of their favourite kinds of food, 
individuals (and in feme inftances large flocks) of many different kinds of migratory birds pafs their winters with us. 
Dr. Darwin obferves, that ‘‘ thofe fwallows that have been hatched too late in the year to acquire their full ' 
ilrength of pinion, or that have been maimed by accident or difeafe, have been frequently found in the hollows of 
rocks on the fea coaffs, and even under water in” a torpid ftate, from which they have been revived by the warmth 
of a fire.”! I fuppofe the learned dodlor has not completely afeertained the fad:, that fuch fwallows were adually 
hatched later than others, or that they had been maimed by accident or difeafe. But it is highly probable, that the 
circumftances which he mentions are fome of the caufes which compel thefe and many other kinds of birds to pafs their 
winters in climates, and in lituations, very different from thofe in which the fpecies at large, are, at fuch times, found. 
§. XXXIL 
Birds, in migrating, often lofe themfelves, particularly, perhaps, when they get into the currents of flrong winds, 
to which they muff: fometimes be obedient. The large flight of Parakeets,§ which vifited the neighbourhood of Al¬ 
bany, in the winter of 1780, was no doubt carried thither by a flrong weflerly wind. Such wanderers, it is pro¬ 
bable, often go into a torpid flate. It is faid, that great numbers of Parakeets (I fuppofe the Pfittacus carolinenfis) 
are fometimes, in the winter-feafon, found torpid in the hollow's of trees, in North-Carolina. Admitting 
the fad, is it not likely, that thefe birds have been wanderers, like the New-York flock juft mentioned? Accidents 
of this kind are more frequent than is perhaps imagined. And I do not doubt that to fuch accidents we muft aferibe 
fome of the inftances of fwallows and other birds being found, in the winter-feafon, in a flate of hybernation. It 
will be faid, that this idea favours the notion, that birds are capable of entering into this flate according to their 
fituation. I do really fuppofe fo. Perhaps all birds, all quadrupeds, in fhort all animals, are capable of this ftate. Nor 
are vegetables exempted from it. Thofe aquatic plants which, at the approach of winter, withdraw' themfelves to the 
bottom of the w'ater, and, on the opening of the fpring, emerge from their watery bed, may be denominated Hyeer- 
Stt page Ix. §. XVI. 
f Sec the Tables. Page 8 . 
t Zoonomla, Vol. I, Sc^Jt. XVI. 
§ See Page vi. §. VII. 
