160 THE NATURAL HISTORY OF SELBORNE. 
squab, naked chicks (or young); on the 8th of July I repeated 
the same inquiry, and found that they had made very little 
progress towards the fledged state, but were still naked and 
helpless. From whence we may conclude that birds whose 
way of life keeps them perpetually on the wing would not be 
able to quit their nest till the end of the month. Swallows 
and martins, that have numerous families, are continually feed- 
ing them every two or three minutes; while swifts, that have 
but two young to maintain, are much at their leisure, and do 
not attend on their nest for hours together. 
Sometimes they pursue and strike at hawks that come in 
their way; but not with that vehemence and fury that swallows 
express on the same occasion. ‘They are out all day long in 
wet days, feeding about, and disregarding still rain: from 
whence two things may be gathered; first, that many insects 
abide high in the air, even in rain; and next, that the feathers 
of these birds must be well preened to resist so much wet. 
Windy, and particularly windy weather with heavy showers, 
they dislike; and on such days withdraw, and are ‘scarce ever 
seen. 
There is a circumstance respecting the color of swifts which 
seems not to be unworthy of our attention. When they arrive 
in the spring they are all over of a glossy, dark soot-color, 
except their chins, which are white; but, by being all day long 
in the sun and air, they become quite weather-beaten and 
bleached before they depart, and yet they return glossy again 
in the spring. Now, if they pursue the sun into-lower lati- 
tudes, as some suppose, in order to enjoy a perpetual summer, 
why do they not return bleached? Do they not rather per- 
haps retire to rest for a season, and at that juncture moult and 
change their feathers, since all other birds are known to moult 
soon after the season of breeding. ; 
Swifts are very anomalous in many particulars, dissenting 
from all their congeners not only in the number of their young, 
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