140 Observations on Periodical Birds: 
quently and strenuously urged, as one of the 
most conclusive arguments that could be 
advanced in support of migration: but no- 
tices of this nature are extremely rare; as 
perhaps no part of the animal economy of 
the feathered tribes, has been so entirely 
neglected by natural historians, as their 
moulting. ‘That swallows, swifts, cuckoos, 
redstarts, and flycatchers, moult during their 
absence, scarcely admits of a doubt. T have 
cut feathers out of the wings and tails of 
swallows, so that I could easily distinguish 
them when flying; and I find that such fea- 
thers are never replaced while these birds 
remain with us. Great numbers of young 
swallows retire in autumn, before the exte- 
rior feathers of their tails have acquired their 
full length; yet the tail feathers of those 
birds that return in spring are always perfect 
in their growth. 'To these facts I shall add 
a few extracts from Mr. Pearson’s account of 
his experiments made for the purpose of pre- 
serving swallows alive through the winter, 
as given in Bewick’s British Birds, Vol. 1. 
p- 250—1, which are decisive as to the 
moulting of this species. The first year’s 
experiment failed, but the second attempt 
was completely successful, as Mr. Pearson 
states, that ‘the birds throve extremely 
