Observations on Periodical Birds. 141 
well; they sung their song through the win- 
ter, and soon after Christmas began to moult, 
which they got through without any difficulty, 
and lived three or four years, regularly 
moulting every year at the usual time. On 
the renewal of their feathers it appeared that 
their tails were forked exactly the same as in 
those birds which return here in the spring, 
and in every respect their appearance was 
the same. These birds were exhibited to the 
Society for promoting Natural History, on 
the 14th day of February, 1786, at the time 
they were in adeep moult, during a severe 
frost, when the snow was on the ground.” 
The account is concluded by Mr. Pearson in 
the following words. “Jan. 20, 1797.—I 
have now in my house, No. 21, Great New- 
port-street, Long Acre, four swallows in 
moult, in as perfect health as any birds ever 
appeared to bein when moulting.”” The plu- 
mage of swifts, from exposure to the sun 
and air, loses that deep soot colour which it 
always has on their arrival, and becomes 
gradually paler till they withdraw. This 
circumstance has not escaped the observation 
of Mr. White. (See his Hist. Sel., p. 183.) 
The plumage of young cuckoos, redstarts, 
and flycatchers, is very different from that of 
adults. Young cuckoos have the upper parts 
