INTRODUCTION. View 
less to say that through their kind assistance in revising the 
details now presented to the reader, a greater accuracy has 
been ensured than could possibly have been the case had the 
author relied solely upon his own efforts. 
The results which follow from a consideration of these 
details are both curious and instructive. 
When the late Mr. Yarrell, in 1856, published the third 
edition of his ‘ History of British Birds, he enumerated 352 
species which he considered had more or less claim to be in- 
cluded in the British list. Since that time no less than 47 
others have been added*, so that the total number of species 
at present recognized as occurring in Great Britain should be 
399; but leaving out four of those noticed by Yarrell—viz. 
Cygnus olor, a domesticated species, Uria ringvia (p. 74) 
and Larus capistratus (p. 175), which are mere varieties, and 
Alca impennis, now believed to be extinct—the corrected total 
arrived at is 395. 
Of these, in round numbers, 130 are Residents, 100 Perio- 
dical Migrants, and 30 Annual Visitants, the remainder being 
Rare and Accidental Visitants. And here it may be well, in 
order to avoid future misunderstanding, to define the terms 
which have just been employed. 
As Resrpents are included those species which rear their 
* These are:—-Falco islandicus, Astur atricapillus, Milvus migrans, 
Buteo lineatus, Nyctale acadica, Lanius minor, Muscicapa parva, Vireo- 
sylvia olivacea, Turdus atrigularis, T. sibiricus, Salicaria palustris, 8. 
aquatica, Regulus calendula, Motacilla cinereocapilla, Anthus spinoletta, 
A. campestris, A. cervinus, A. ludovicianus, Alauda calandra, A. sibirica, 
Emberiza pusilla, E. rustica, E. melanocephala, Fringilla serinus, Carpo- 
dacus erythrinus, Sturnella magna, Picus medius, P. villosus, P. pubescens, 
P. auratus, Cuculus erythrophthalmus, Hirundo bicolor, Cypselus cauda- 
cutus, Caprimulgus ruficollis, Syrrhaptes paradoxus, Aigialitis vociferus, 
Totanus solitarius, Gallinago wilsoni, Grus virgo, G. pavonina, Crex 
carolina, Cygnus americanus, C. buccinator, Anser albatus, Sterna velox, 
Larus ichthyaétus, and Larus melanocephalus. 
