PRAIRIE FALCON 39 



female Prairie Falcon near Chino, California. My attention was 

 drawn to this bird, which was sitting in a large branching willow, 

 by the actions of some Red-winged Blackbirds (Agelaius phoeniceus 

 neutralis) that were sitting about in the same tree with the falcon. 

 Several of their number kept persistently flying at the falcon, who 

 apparently cared little for their actions, as she sat quietly until I 

 approached." 



With other raptors the contacts observed have largely been fighting 

 ones. Brooks (1909) says that "a male Peale Falcon incessantly 

 badgered the female Prairie Falcon of a pair nesting near, with a 

 series of splendid stoops." Of a nesting site known to have been used 

 previously to 1901 by prairie falcons, Cohen (1903) writes: "In 1901, 

 March 30, the site was tenanted by a pair of duck hawks * * *. 

 It is probable that no pair of duck hawks, or even prairie falcons dwell 

 within a few miles of each other's domain owing to mutual antago- 

 nism * * *. In 1902 we did not arrive at the prairie falcon nest 

 until April 15, so as to allow the usurping duck hawks ample time 

 to pay the rent, and found things vice-versa once more." Grinnell, 

 Dixon, and Linsdale (1930) record that "a great horned owl was 

 trapped at Eagle Lake on October 19, 1923. A Prairie Falcon 

 that discovered the owl in the trap swooped and struck at the bird 

 repeatedly." 



One strange enemy with which the prairie falcons could ill contend 

 was the open tar pits in California. The bones of the victims have 

 been collected and reported upon by Dr. Loye Miller. He says there 

 were great numbers of prairie falcons, duck hawks, and an extinct 

 falcon caught at the McKittrick pool, but not so many at the Rancho 

 La Brea now within the western limits of Los Angeles. 



We so rarely get any items on the parasitic enemies of birds that 

 the following is particularly welcome. Ellsworth D. Lumley writes 

 of a prairie falcon taken in the act of killing a chicken: "I found its 

 stomach contained a pocket gopher, but more interesting than this 

 I found its entire viscera filled with long white roundworms. These 

 were wound through the mesentery, intestines, cardiac muscles, 

 even into the lungs and trachea. The insides of the bird looked 

 almost as if they had been sewed together with white thread." These 

 worms have since been identified as Serratospiculum tendo by Dr. John 

 E. Guberelet, of the University of Washington, who further adds that 

 these parasites are not uncommon in hawks in various parts of the 

 world. 



Winter. — According to Decker and Bowles (1930), these birds change 

 their diet from rabbits to birds in winter. The stomachs of the birds 

 mentioned in the previous paragraph all contained the remains of 

 western meadowlarks. Cameron (1907) says the Montana prairie 

 falcon is a "relentless persecutor of the Sharp-tailed Grouse. I have 



