1908 ^] Cameron, The Golden Eagle in Montana. 255 



paper on 'The Prairie Dog of The Great Phiins,' ^ by Dr. C. 

 Hart Merriam, quickly to reahze what an unmitigated pest this 

 animal becomes, and how rapidly its to^\ais spread. As quoted 

 therein, Professor W. W. Cooke computes that "32 prairie dogs 

 consume as much grass as one sheep, and 256 prairie dogs as much 

 as one cow." Therefore, whenever eagles, hawks, and owls prey 

 upon these ravagers "they should be protected and encouraged," 

 as recommended in Dr. Merriam's bulletin above mentioned. 

 Only the most energetic measures saved a thirty-acre field of oats 

 belonging to Messrs. Archdale brothers (whose ranch joins that 

 of Mr. Price) from being destroyed by prairie dogs. Despite the 

 liberal use of bisulphide of carbon inside the burrows, combined 

 with frequent shooting of the animals outside, the total estimated 

 summer kill was about 1200 — • a number not quite double that 

 credited to the Golden Eagles during the nesting season alone.' 

 A hungry eagle will eat two prairie dogs for a meal, but allowance 

 must be made for the fact that females during incubation consume 

 half of what they require at other times. Relying both on what 

 I have myself seen at the eyrie, and upon the observations of others, 

 I have compiled the following statistics. 



Throughout the month of April, and for two days in May, allow- 

 ing an average of three prairie dogs per diem, we get a total of 9G 

 prairie dogs up to the time that the eaglets are hatched. Subse- 

 quently, until the young birds forage for themselves (about Aug. 

 1), if we allow only six of the rodents a day, the total is obtained of 

 540 prairie dogs for seventy-four days sustenance of four eagles. 

 Thus we have a grand total of 636 prairie dogs during four months 

 for one pair of eagles, which is probably well within the mark.^ 

 An eagle intent on capturing a prairie dog floats leisurely above 

 the 'town' at a medium height on motionless wings. Preliminary 

 inspection of the hunting-ground is accomplished in wide circles 

 or long sweeps, perhaps two or three miles each way, so as not 

 unduly to alarm the game. Passing over at long intervals, the 



1 Yearbook U. S. Dept. of Agriculture, 1901, pp. 257-270. 



2 Besides those suffocated, large numbers of prairie dogs were driven by the bisul- 

 phide fumes to migrate, and were observed on their travels by Messrs. Archdale. 



3 In an interesting article on the Golden Eagle, Mr. William L. Finley estimates 

 that the family of California Eagles observed by him consumed 540 ground squirrels 

 in three months. (Condor, Vol. VIII, 1906, p. 10.) 



