Xx INTRODUCTION. 
and, indeed, it may be said that the only two species which 
attract attention as coming repeatedly from the African con- 
tinent both belong to this order. A single African web- 
footed bird, the Spur-winged Goose (P. gambensis), has been 
recorded to have been met with at large in this country on 
four different occasions, although it has been supposed by 
some that these specimens may have escaped from a state of 
semidomestication upon some ornamental waters. 
But while speculating upon the isolated occurrences of a 
few African birds in this country, at intervals perhaps of 
several years, it should be borne in mind that half the sum- 
mer migrants which visit us annually and rear their young 
here, such as the Hirundines, Sylvia atricapilla, S. hortensis, 
S. cinerea, Salicaria phragmitis, S. strepera, and others, spend 
a considerable portion of their existence during the winter 
mouths in some part of Africa. 
The question therefore is not one of possibility, but of 
design; and this strikes us the more forcibly when reviewing 
the large number of species (above forty) which have come 
to us, or are supposed to have come to us, from America. 
These are :—Astur atricapillus (8), N. furcatus (5), Buteo 
lineatus (1, doubtfully), Scops asio (2, doubtfully), N. acadica 
(1, doubtfully), Vireosylvia olivacea (1), Regulus calendula (1), 
Anthus ludovicianus (9, doubtfully), Lowia leucoptera (4), 
Ageleus pheniceus (9), Sturnella magna (8), Picus villosus (2), 
P. pubescens (1), P. auratus (1), Cuculus americanus (5), C. 
erythrophthalmus (1), Ceryle alcyon (2), Hirundo purpurea (2, 
doubtfully), H. bicolor (1), Columba migratoria (5)*, Ortyxe 
virginianus (introduced), Aigialitis vociferus, Totanus flavipes 
(3), 7. solitarius (1), Actiturus bartramius (4), Tringites ru- 
fescens (15), Tringoides macularius (16), Tringa maculata (16) 
* Four only are noticed at p. 128; but Thompson mentions another 
(Nat. Hist. Ivel. (Birds) vol. ili. p. 445), as procured near Tralee in 1848. 
