Mar., 1913 NESTING OF THE PRAIRIE FALCON 59 gone down from above xvould have meant some risk, as well as an accompani- ment of blinding dust, so "Kelly" made a detour and attacked from below. By dint of carving steps with a hammer he succeeded at last in clutching the dan- gling rope-end, and so reached the coveted shelf. The Falcon meanwhile made the great amphitheater resound with malediction, and charged about in a fashion to make the beholder dizzy as he watched her passage across the fluted background. Her anger made our visit memorable, but it failed to arouse her mate, who was doubtless off hunting in the basin country. Though slow to take alarm, the Falcon once roused from the nest becomes very wary. It was doubly fortunate, therefore, that the bird photographed in one accompanying picture could be approached under cover, and suddenly con- fronted from a convenient spur just opposite. To reach this nest our intrepid guide, Dean Brown, went down hand over hand the full length of a x4o-foot Fig. 12. A TYPICAL NESTING CLIFF. X INDICATES POSITION OF CLIMBER . rope.' A bird who knows sfie is under surveillance will never resume a position on the eggs; but she will intersperse her nervous and often distant excursions by prolonged rests on some favorite perch or commanding knob. And this she is the more ready to do if the observer himself remains quiet. A resumption of hostil- ities sends her off on the instant to screak and .soar or tower and stoop. In about half the cases noted the male bird, who was in no instance the sit- ter, responded to the summons of his mate and joined in the outcry. He was quite as loud, but not quite so persistent in denunciation as the female; and I could not detect any difference in the notes as between the sexs, such as exists in the case of the American Peregrine (Falco peregrinus anatum). The assaults of an angry Falcon are really dangerous. Even when the ear- liest efforts are discouraged by a show of stick or stones, it is decidedly discon- certing to feel the rush of air from a passing falcon-wing upon your hatless
