472 NATURALIST IN CALIFORNIA. 



ou several occasions during January. The elevation of the 

 river at this point is not over 550 feet, and the whole bottom 

 land is inundated nearly every summer. The distance by 

 the course of the river from its mouth is 400 miles. 



Tlie fauna of the valley naturally partakes much of the 

 Mexican (west slope) character, and has some peculiarities. 

 It is too limited and too liable to inundation for many land 

 mammalia to flourish in it, except such as are common to the 

 neighboring deserts and mountains. A second species, at 

 present known no farther west, is the Leaf-nosed Bat (3Ia- 

 crotus CaUfornicus) from Fort Yuma. This bat, like the 

 birds, is independent of floods, and is probably migratory 

 southward in winter, like two species I obtained at Fort 

 Mojave — the Pale Bat (Antrozous pcdlidus), and a small 

 species of Vespevtilio which did not appear until March 15th, 

 thonoh the climate was warm enough for weeks before. 



On walking out with my gun I was struck with surprise 

 at the great numbers of Abert's Finch {Pipilo Abertii) 

 frequenting the grove, the flocks flitting before me like dry 

 leaves before the wind, their color exactly resembling the 

 prevailing hue of the foliage covering the ground, and now 

 densely coated with brown dust. It recalled the observation 

 I had often made as to the prevalence of this brown hue in 

 so many birds of California, of difl'ercnt genera and fami- 

 lies, but agreeing in their habit of living in low shrubbery 

 which has the same brown and dusty tint for eight or nine 

 months of the year. The loud call or alarm note of this 

 bird Avas strikingly dift'erent from the notes of its more 

 silent cousin near the coast, the P. fuscus (or crissalis), but 

 I soon noticed another strange fact, namely, that this note 

 Avas also uttered by two other very distinct birds of dissim- 

 ilar habits, the Shining Flycatcher and Gila Woodpecker 

 ( Centurus uroj)ygidlis) , both of which were abundant and 

 feeding together on the berries of the mistletoe, parasitic 

 on almost every tree. These birds Avere my first specimens, 

 together with the common Grass Finch (Pooeceies grami- 



