C 435 
I. 0/ Birds c/" Paffage, by Mr. Mark Catesby, 
F. R. S. 
Read at a Meetiagf T"i h E Places whereto Birds of 
March j R °i y 7467. Ciety ’ X Paffage retreat when they take 
their Leave of us, are firft of 
all to be inquired after ; and then it will be proper 
to examine by what Road, and in what Manner 
they convey themfelves to fuch Places wherefoever 
fituated on our Globe. 
The Reports of their lying torpid in Caverns and 
hollow Trees, and of their refting in the fame State 
at the Bottom of deep Waters, are fo ill attefted, and 
abfurd in themfelves, that the bare Mention of them 
is more than they deferve. Of much the like Stamp 
is a late broach'd Hypothefis, which fends them above 
our Atmofphere for a Paffage to their Retreat ; which 
to me feems as remote from Reafon, as the Ethereal 
Region is from the Aereal ; through which laft Re- 
gion I cannot conceive any Obftruftion to their Paf- 
fage, when, by the Approach of our Winter, they 
find a Want of Food, and at the fame time are di- 
rected, by Inftind, to refort to fome other Parts of 
the Globe, where they may find a frefh Supply. 
For the Want of Food feems to be the chief if not 
the only Reafon of their Migration. And tho' Tit* 
mice and other fmall Birds abide here the whole 
Winter, and fubfift on Infers, which they find tor- 
pid, or in a State of Mutation, in the Crevices of 
the Barks of Trees, and other their Winter-Receffes, 
yet moft Birds of Paffage, having tender Bills, are 
L 1 1 incapacitated 
