58 Zoology of Colorado 



by Roddy to devour eight English sparrows and a mouse in one 

 day. One flicker stomach contained 5,040 ants and two others 

 contained about 3,000 each. One quail stomach contained 10,000 

 pigweed seeds, another contained 5,000 pigeon-grass seeds." It 

 can readily be seen from the above why most birds must fly, and 

 many migrate. No sedentary animal could expect to find the 

 amount of food required. The birds resemble mankind, in that 

 their wants have multiplied with their power of supplying them. 

 But also like mankind, they are sometimes penalized for their 

 progress, and when unusual circumstances occur they may be 

 unable to meet them successfully.* In exceptionally hard winters, 

 or after sudden storms, we have a fellow feeling for the birds, and 

 are glad to mitigate their distress by gifts of food. The bird 

 population of any region necessarily changes with the plants, 

 insects and rodents. Thus man's influence, directly and in- 

 directly, controls the abundance or even presence of many birds. 

 One of the most interesting studies to be made today in Colorado 

 concerns the immigration of alien plants and insects, and the 

 effect of these on the birds. The practise of irrigation is chang- 

 ing the face of the country, and this affects nearly all forms of life. 

 The full investigation of these matters is urgently needed at the 

 present time, because after a series of years it will be too late. 



Fossil birds are very rare in Colorado, though feathers are 

 not uncommon in the Florissant Miocene and Roan Mountain 

 Eocene.** Two species, a plover and a supposed finch have been 

 described from the Florissant shales. Marsh described a sup- 

 posed fossil turkey, Meleagris antique from the White River 

 Oligocene of Colorado, but Shufeldt considers the material too 

 imperfect for determination. Shufeldt, more recently (1915) de- 

 scribed a cormorant, Phalacrocorax mediterraneus, from the White 

 River Oligocene at Gerry's Ranch, Colorado. The specimen, 

 part of a carpo-metacarpus, was found by G. B. Grinnell. 



It is not practicable within the limits of the present work, 

 to describe or refer to all the Colorado birds. The following 



*One such "circumstance" is the Washington Monument at Washington, D. C. The 

 migratory birds, flying at great speed at a height sufficient tc clear all ordinary obstacles, dash 

 themselves against this structure in the night, and perish in great numbers. Our posterity, 

 with more tender conscience in these matters, will probably remove the building, and substitute 

 something much more beautiful and entirely harmless. 



**R. W. Shufeldt, Fossil Feathers and Some Heretofore Undescribed Fossil Birds. Journal 

 of Geology, Oct.-Nov. 1913. In this paper Shufeldt describes a fossil bird Hebe schucherti, from 

 the Green River Shales of Wyoming. It appears to be related to a group at present known 

 from South America. This should be looked for in the Green River beds of Colorado. 



