ON THE MIGRATION OF BIRDS. 3 
appearance and disappearance, and those species also 
which are periodical in particular districts only, from 
the regular summer and winter birds, and have classed 
them under appropriate heads. I have, however, 
retained the Stonechat and Pied Wagtail among the 
suinmer birds, and the Snipe and Wild Duck among 
the winter birds; for though individuals of the first 
two species frequently remain through the winter in 
the southern counties, and though considerable num- 
bers of Snipes and Wild Ducks breed with us annually, 
yet the periodical appearance and disappearance of a 
very large proportion of these birds cannot, I think, 
be questioned. Many of the larger species of aquatic 
birds included in the Tables are rarely seen in the 
vicinity of Manchester, except during severe frosts or 
after violent storms of wind; of course their appear- 
ance is uncertain, and their stay is generally short. 
The remarks consist chiefly of details of such cir- 
cumstances relative to the migration of birds as have 
fallen under my own observation, and of conclusions 
drawn from them and from an attentive consideration 
of the facts recorded by others. 
TABLES OF THE VARIOUS SPECIES OF PERIODICAL 
BIRDS OBSERVED IN THE NEIGHBOURHOOD OF 
MANCHESTER. 
The Periodical Birds may, with propriety, be ar- 
ranged under four distinct heads :— 
B2 
