210 Lord Walden on Dr. Stoliczka^s " Ornithological 



access from the plains to the elevated tablelands north of the Hi- 

 malayas, and become a direct highway for birds migrating from 

 the north or the south of those mountains : and although, in his- 

 torical times at least, neither the nations north nor south of the 

 Himalayan barrier have ever availed themselves of these natural 

 advantages, either for warlike or commercial purposes, Dr. 

 Stoliczka almost implies that the most feasible route to or from 

 Central Asia is to be met with by following the course of the Sutlej. 

 The country of the plains extends to within the mouth of the 

 valley ; and there are still to be found the animals indigenous to 

 the low country. Higher up, but yet in the lower portions of 

 the valley, to an elevation of from 4000 to 5000 feet, many low- 

 country species of birds find thoseconditionsof food and climate 

 which become suspended in the plains during the great heat 

 and drought of summer, and the means of forming their nests 

 and rearing their young. And there also a few Central-Hima- 

 layan hill-forms occur, but diminished in variety and number of 

 species, having almost reached their western geographical limit 

 thi'ough the action and effects of an increased latitude ; while, 

 as the valley continues rising to its greatest elevation, the spe- 

 cies and genera of the Central- Asiatic fauna begin to appear, 

 increasing in number until, when the summit is gained, they 

 almost exclusively predominate. 



In short, this valley has its beginning in the Tibetan zoolo- 

 gical province, and its termination in the Indian ; is a high- 

 way for birds which pass the summer in central or northern 

 Asia and the winter in India ; is alternately a refuge for those 

 Tibetan birds which cannot endure the rigour of a Tibetan 

 winter, and for those Indian species which are unable to support 

 the great heats of summer ; and is the permanent habitation 

 of the declining Eastern- Himalayan hill-forms, and of those 

 species which are characteristic of a temperate yet unelevated 

 region in the higher latitudes of- the Old World, like Loxia, 

 Pyrrhula, Carduelis, and Garrulus, and help to connect the 

 avifauna of Europe with that of Hindustan. The meeting 

 together in the Catalogue of the Ornis of a single valley of such 

 zoo-geographical extremes as Lerwa nivicola, and Temenuchus 

 pagodarum, Carduelis canicejjs and Arachnothera magna, Monti- 



