4U 



INSULAR FLORAS AND FAUNAS WITH 



[Ch. XLI. 



observer informs ns that tlie s^Decies are most nnmerous in the 

 easternmost islands, and that the nnmber diminishes rapidly 



those lying farther west, showing that the 



examine 



wearied and hungry voyagers drop down on the first land 

 they discern. It is only by this frequent arrival of new- 



comer 



and continental fauna, the tendency to variation and in- 

 definite divergence being checked in the manner explained 

 at p. 321, by the absorption of the insular into the conti- 

 nental types, with which they are continually crossed. There 

 are no American birds in the Azores, which cannot be entirely 

 explained by the greater distance of that continent, because 

 no less than sixty species are known to have crossed the 

 Atlantic as stragglers, and to have reached the British Islands. 



m 



Sim 



ously in the right direction, are indispensable to enable birds 

 to colonise remote islands. 



The Bermudas, which are 700 

 America, are stocked with species all belonging to that conti- 

 nent. Of three European stragglers mentioned by Baird, two 



miles from 



coasts of 



common 



Greenland, and may 



come 



north, Newfoundland having served as an intermediate 

 halting-place ; and the third, our common sky-lark, a rare and 

 occasional visitor, is so often carried in ships to America, that 

 it may perhaps sometimes escape from a cage, and alight on 

 the first land which presents itself. 



The number of days for which land-birds can fast would 

 more than suffice for their flight from Europe or even from 

 America to the Azores. Mr. Bartlett informs me that a, par- 

 tridge sent from the London Zoological Gardens to the 

 country remained accidentally in the box in which it was 

 enclosed for five days without food or water ; when discovered, 

 it was alive, and being fed was soon restored to its usual 

 vigour. 



The avifauna of the volcanic archipelago of the Galapagos 

 presents in some respects a contrast to that of the Atlantic 

 islands ; for althoug^h the distance from the nearest mainland 

 is scarcely more than half that which separates the Azores 

 from Europe, four-fifths of the land-birds are of species found 



