20 BULLETIN 170, UNITED STATES NATIONAL MUSEUM 



effort than simply walking to it and picking up the eggs, while others 

 are placed under an 'overhang' of rock at such dizzy heights that we 

 simply wished them good luck. In Washington they are, as a rule, 

 less than sixty feet above the ground, forty feet being perhaps a fair 

 average." In most cases the shelves or crevices used are natural, 

 but in the soft material of dirt banks the birds may excavate a hollow 

 of their own. Where they have a choice of sites falcons place their 

 nests in recesses, or "pot-holes", varying from a few inches to several 

 feet in width and penetrating into the walls from a foot to as much as 

 5 feet. Generally there is a projection above, protecting the nest. 

 Although the species, as the name indicates, is prairie-loving, falcons 

 are sometimes found where the mountains are quite heavily wooded. 

 On the other hand, they do not nest on cliffs over the ocean as the 

 duck hawks sometimes do. As a rule there is no nesting material 

 whatever, the eggs being laid on clear sand or gravel, or amid bones, 

 bits of fur, and feathers. Although falcons often use ravens' nests 

 that are placed in niches in the rocks, they less often make use of 

 ones placed on rock pinnacles, but Sclater (1912) says of Colorado 

 birds: "Dille found a nest on the top of a chimney of sandstone in 

 some buttes in the north of Weld county, on May 5th; it was an 

 immense pile of rubbish, with skeletons and dead animals scattered 

 round. * * * Gale took four eggs of this species from an old eagle's 

 nest on April 24th, in a cliff on the Little Thompson River, the situa- 

 tion was about fifty feet from the bottom, and thirty feet from the 

 top of the cliff, * * * another nest in a similar position on the 

 St. Vrain." There is only one well-authenticated record of a falcon 

 nest in a tree, even on the prairies, where cliffs are rare. Goss (1891) 

 says: "At Marysville, Mo., [was] a nest in a tree, thirty-five feet from 

 the ground; notes fail to show whether the nest was in the forks of 

 the branches or in a hole in the tree, but doubtless in the latter." 

 Since that record no further instances of tree-nesting have come to 

 light. Mr. Bent noted a nest in a cliff at the top of a rocky hill in 

 the Mojave Desert, San Bernardino County, Calif., saying: "When 

 we yelled or clapped our hands the bird flew out from a little shelf 

 on the side of a vertical crevice in the rocks. The eggs were in the 

 remains of an old nest of a raven which had crumbled almost to dust, 

 only a few pieces of sticks remaining, the eggs lying on the dirt in the 

 center. Later, while I was at the nest the female made several 

 close swoops at me within ten or fifteen feet; she was flying and cack- 

 ling all the time." Generally these swoops are vicious in appearance 

 and very trying to the collector's nerves, but almost always the falcon 

 will, when within a few feet of the intruder, suddenly swerve to one 

 side or the other. She does not have quite the nerve required for 

 an actual attack, but Mr. Dawson (1923) says: 



