< 140 ) 



We have thus seen tliiit tlu' Ijirds — which not only fnria tlie Imlk of the 

 inhiibitants of the Gahijiagos lshin<ls, but which are most important for zoo- 

 geograjihical considerations, since they cannot easily be distrilmted iuvohmtarily, 

 resisting as they do the winds and currents to a great extent — as well as the rest 

 of the animated nature of this group of islands, is either evidently of American 

 origin, or not opposed to it. As far as the birds arc concerned, they can all have 

 reached the (Jalapagos witliout a former land-connection. The question therefore 

 arises, are we justified to assume, on account of the presence of the tortoises, a 

 former land-connection, and the disajjpearance of vast areas of land, here as well as 

 between Africa, Aldabra. and the Masearenes ? It seems more natural to assume 

 the disappearance of a great stock of animals, the remains of which have survived, 

 through favourable circumstances and the absence of enemies — men and beasts — 

 on outlying marine islands, than to assume the disappearance, in comparatively 

 recent times (i.e., in the Eocene period or later"), of enormous land-masses. On the 

 other hand, if great islands and mountain ranges have been uplifted, others might as 

 well have — and we know they have — been submerged. Palaeontological researches 

 and many more soundings in the ocean seem to be of much importance for the solution 

 of such jiroblems. At present we can only come to the following conclusions : — 



I. The entire fauna of the Galapagos Islands derived originally from 

 America. 



II. It is uncertain whether there has ever been a land-connection between 

 the various islands and between the islands and the continent or not. 



Now to return to the ornithology of the group. There are several interesting 

 facts which should be mentioned. The absence, with few exceptions, of brightly 

 coloured species, and the prevalence of sombre forms, is striking, but can be 

 understood from the sombre aspect of the sunburnt rocks and the vegetation. A 

 peculiar feature is the quantity of birds found in the dress of immature individuals. 

 This is most apparent and has often been comnieuted on among the Geo.^pizae. It 

 is nut, however, confined to the genus Geoapi^a, but is e<iually found in the genus 

 Certhidea. Of Stila piscatrij- websteri, which breed in great numbers in white 

 plumage on Clarion Island, while greyish brown individuals are rarely seen there, 

 hundreds breed on the Galapagos Islands in a grey-brown dress, very much like 

 that of the young birds, but paler. White specimens of this t'itda are very rare 

 on the Galapagos Islands. The Anous {Anou.i atoUdus golu/xii/ciisix) resembles 

 somewhat an immature Aiioxs stolidtts having the crown somewhat darker, and 

 quite dark birds are numerous. 



The reason for this peculiarity is not known, but one might suggest that it lies 

 in some want of strength, or a somewhat arrested development. 



The great tameness of the birds has been mentioned by most visitors to these 

 islands. We find the same on other oceanic uninhabited islands, most of all 

 on Laysan, where it is quite stupendous.* 



With regard to the affinities between the fauna of the various islands, we find 

 that the birds of those islands which are nearer to each other are generally much 

 more allied or identical, while the more distant islands have many less forms in 

 common. This of course applies almost only to the land birds. In many cases 

 Narburough, Albemarle, James, Jervis, Duncan, Indefatigable and Barrington have 

 the same forms, in others at least James, Jervis, Duncan, and Indefatigable. The 



* K't, SchauiDsland, Drei Monate auf thier KoralUnimel, and Rotbscliild, Avifauna of Linjsan, I'art 



