ON THE OCCURRENCE OF AMERICAN BIRDS IN EUROPE. 459 
ON THE OCCURRENCE OF AMERICAN BIRDS IN EUROPE. 
BY H- GATKE, OF HELIGOLAND. 
(From the Proceedings of the Zoological Society of London. 1860.) 
The route by which American birds proceed to Europe is, as Yarrell 
justly terms it, “an interesting problem, of difficult solution.’ For 
years this solution has occupied my attention, and although I have 
myself always been convinced that such of these entirely American 
birds as occasionally visit Europe do reach us by a passage across the 
Atlantic, this remains a mere opinion, carrying no weight if unsup- 
ported by facts, or by at least sufficient argument to make good the 
question at issue. 
The mere comparative review of the occasional visitors among the 
birds of Great Britain and of Germany will lead to the conclusion 
that the route of American birds to Europe must needs be a voyage 
across the Atlantic, for almost all the additions to the birds of Europe, 
of species purely American, have been obtained in Great Britain— 
which could not have been the case if they had proceeded in any 
other than an eastern direction—whilst the additions by Germany, 
furnished to the European Ornis, consist nearly entirely of birds 
belonging to Asia. 
However striking the result of such a comparative review may be, 
one question will always present itself, namely :—Whether it be pos- 
sible for a bird to sustain an uninterrupted flight sufficient to carry 
it across the wide expanse of the Atlantic. I am convinced that this 
is possible, and shall endeavour to prove such possibility. 
This purpose necessitates a measure for the rate of locomotion of 
a bird through the atmosphere. For a long time I vainly endeavoured 
to obtain reliable data upon which to found an estimation of the rate 
of flight of birds—when at last I hit upon a passage in Yarrell’s 
‘British Birds,” ii. p. 295, where, speaking of the Carrier Pigeon, he 
‘mentions the fact of one of these birds having performed a flight of 
150 miles in an hour and a half: it was on the 24th of June, 1833 ; 
the Pigeon flew from Rouen to Ghent ; sixteen others flew the same 
distance in two hours and a half. 
Wonderful as this instance of swiftness of the flight of a bird may 
appear, it certainly is still surpassed by birds when on their periodical 
Vou. VI. 21 
