Observations on Periodical Birds. 127 
formation on this obscure branch of natural 
history. 
Itis remarkable, that almostall the catalogues 
of periodical birds with which Iam acquainted, 
have been formed from observations made in 
the South of England. This circumstance is 
certainly calculated to give additional interest 
to the following tables, made in so northern 
a county as Lancashire. In forming them, 
I have ventured to deviate a little from the 
usual mode of arrangement, having separa- 
ted those birds that are irregular in the times 
of their appearance and disappearance, and 
those species also that are periodical in par- 
ticular districts only, from the regular sum- 
mer and winter birds, and have classed them 
under appropriate heads. I have, however, 
retained the wheat-ear, whinchat, and stone- 
chat among the summer birds, and the snipe 
among the winter birds; for though indivi- 
duals of the three former species frequently 
remain through the winter in the southern 
counties, and though numbers of snipes breed 
with us annually, yet the periodical appear- 
ance and disappearance ofa very large pro- 
portion of these birds cannot, I think, be 
questioned. It may be urged, that the three 
species of wagtail ought to be removed from 
among the birds that are partially periodical, 
