306 BULLETIN 16 7, UNITED STATES NATIONAL MUSEUM 



fessor W. W. Cooke computes that "32 prairie dogs consume as much grass as 

 one sheep, and 256 prairie dogs as much as one cow." 



Throughout tlie month of April, and for two days in May, allowing an aver- 

 age of three prairie dogs per diem, we get a total of 96 prairie dogs up to the 

 time that the eaglets are hatched. Subsequently, 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 captui'ing a prairie dog floats leisurely above the "town" at a medium height 

 on motionless wings. Preliminary inspection of the hunting ground is accom- 

 plished in wide circles or long sweeps, perhaps two or three miles each way, 

 so as not to unduly alarm the game. Passing over at long intervals, the bird 

 scans the dog town and judges of the prospect for a successful stoop. The 

 "dogs" are of course immediately on the alert, but can only see their enemy for 

 a short time on account of the high surrounding pine hills, and, indeed, most 

 "dog towns" are too extensive for the denizens at one end to notice an eagle 

 passing over at the other. Moreover, an unsuccessful eagle will keep on the 

 wing for several hours, and it is almost certain that the hungry prairie dogs 

 will relax their vigilance at last. When the eagle considers that a favorable 

 chance has arrived it sinks lower, so as to bring the distance between itself 

 and the animals to something like 75 or 100 yards. Should the latter still 

 remain above ground, the royal bird suddenly folds its wings, and, with 

 meteoric rush, falls head first towards the astounded prairie dogs. These 

 scamper for their holes, but about three yards from the ground the eagle 

 spreads its wings and, swiftly following the intended victim, darts out a cruel 

 foot to grasp it. If the attack fails, as sometimes happens, the eagle mounts 

 in a slow, reluctant manner which plainly reveals its disappointment. 



This bold bird sometimes "catches a Tartar." Albert Lano (1922) 

 had one brought to him that had attacked a porcupine ; "it was liter- 

 ally covered underneath with quills. In fact there were a number of 

 quills in the roof of its mouth. The body was much emaciated and 

 many of the quills liad penetrated deep into the flesh causing pus to 

 form." 



These eagles have often been known to attack foxes caught in traps, 

 but the following spirited encounter, described by Mr. Gordon (1915) 

 is unique: 



The eagle was devouring the carcass of a blue hare when a fox sprang from 

 the surrounding heather and seized the great bird by the wing. A well-con- 

 tested struggle ensued in which the eagle made a desperate attempt to defend 

 itself with its claws and succeeded in extricating itself from its enemy's grasp, 

 but before it had time to escape Reynard seized it by the breast and seemed 

 more determined than ever. The eagle made another attempt to overpower its 

 antagonist by striking with its wings, but that would not compel the aggressor 

 to quit its hold. At last the eagle succeeded in raising the fox from the 

 ground, and for a few minutes Reynard was suspended by his own jaws be- 

 tween heaven and earth. Although now placed in an unfavorable position for 

 lighting his courage did not forsake him, as he firmly kept his hold and seemed 

 to make several attempts to bring the eagle down, but he soon found the strong 

 wings of the eagle were capable of raising him, and that there was no way of 



