PREFACE. Vll 
migration cr owing to getting mixed up with flocks of 
our own regular visitants in what has been a common 
breeding ground, and accompanying them. 
By irregular migration I mean the exceptional move- 
ments of some birds that cannot be considered as usually 
belonging in any way to the great migratorial band, and 
of others which, although they may be considered migratory, 
do not perform their journeys with the same punctuality 
as the regular migrants. 
Perhaps the best example of the first of these excep- 
tional movements may be found in that wonderful migration 
of the Sand Grouse, who, leaving their own homes on the 
plains of Tartary, migrated westward in immense numbers, 
some of them reaching as far as Ireland; some even passing 
further were probably lost in the Atlantic. Although these 
birds came from.the East the first occurrence recorded in 
these islands was at Tremadoc, in Wales, on the 9th of July, 
1859; a few others made their appearance during that year, 
but the real great immigration did not take place until the 
year 1864. In the May of that year these birds made their 
appearance in great numbers, especially in the eastern 
counties; from thence they spread themselves throughout 
the whole country. General as this migration was I cannot 
find that any of these birds made their appearance in this 
particular county, although many specimens were obtained 
in the neighbouring counties of Devon, Dorset, Wilts and 
Gloucester. A very full account of this migration is to be 
