8 BULLETIN 396^ U. S. DEPARTMENT OF AGRICULTURE. 



divided into 92 acres of plowed land, 27 acres of hay land, 3 acres 

 of woodland, 34 acres of improved meadow and pasture land, and 

 the remainder, 85 acres, of wild, treeless, native prairie. The average 

 bird life per acre on such land is naturally much less than on the 

 part of the farm selected for the enumeration. How much less, the 

 data in hand are not sufficient to determine. Anyone who has ridden 

 over the native prairie knows how seldom birds are seen, and an at- 

 tempt was made at Sisseton, S. Dak., to obtain a numerical state- 

 ment of this scarcity. On a tract of 40 acres of prairie pasture land 

 adjoining the Sisseton town site, but having better than average con- 

 ditions, in that a stream of water, bordered with brush, crossed the 

 tract, the following were found nesting: Killdeer, 2 pairs; prairie 

 horned lark, 3 ; Sennett nighthawk, 2 ; lark bunting, 2 ; and meadow- 

 lark, 3 ; a total of 12 pairs on 40 acres, or at the rate of 30 pairs to 100 

 acres, as compared with the 125 pairs to 100 acres of the farm land. 

 Some suggestive figures in this connection come from Onaga, Kans., 

 where a tract of 80 acres of native pasture, crossed by a creek with 

 a narrow fringe of native timber and occupied at one end by a small 

 cornfield, supported a population of 31 pairs of native birds of 22 

 species, or in the proportion of about 40 pairs to 100 acres. The ad- 

 joining 40 acres, containing the farm home, a 5-acre orchard, and 6 

 acres of groves, was the summer home of the same number of kinds 

 of birds represented by 49 pairs, or at the rate of 122 pairs to 100 

 acres. 



REPORTS FROM THE ROCKY MOUNTAIN STATES. 



The foregoing records from the Plains region are from the part 

 east of the one hundredth meridian, where the average annual rain- 

 fall is more than 20 inches and where crops are raised successfully 

 without irrigation. To the west, as the rainfall diminishes, the 

 native bird population on the open prairie decreases until in some 

 of the more desolate sections it almost disappears. 



A little west of the one hundredth meridian, near Hobbs, N. Mex., 

 in the extreme southeastern corner of the State, one tract of 80 

 acres, all native pasture except a 20-acre field of milo maize, had a 

 bird population of 22 pairs representing 9 species; a neighboring 

 80 acres, with only 10 acres in milo maize, showed 17 pairs of 8 

 species; while in the same township still a third 80 acres, none of 

 which had ever been disturbed by the plow, was supporting only 13 

 pairs of 5 species, notwithstanding each of these equal areas con- 

 tained a set of farm buildings with windmill and tank. The average 

 of these three counts is 17 pairs to 80 acres, or 21 pairs to each 100 

 acres. 



Still farther west, in the irrigated district of western Colorado, t^yo 

 reports have been contributed showing the effect of irrigation on the 

 density of bird life. The first area consisted of 320 acres of irrigated 



