220 BULLETIN 146, UNITED STATES NATIONAL MUSEUM 



the male semipalmated plover, and he says that " the males did a 

 large part of the incubation and that it was the males that were the 

 most fearless in the face of danger when caring for their young." 



P. B. Philipp (1925), on the other hand, studying the nesting bird 

 in the Magdalens, writes : " I judge that the female does most of the 

 incubating, three birds shot off the nest being of this sex." H. S. 

 Swarth also sustains the side of the female, for he writes: "With 

 binoculars it is often possible to distinguish the sexes of the plovers, 

 and it could be seen that it was the male who tired first in such efforts 

 [shamming injury] to deflect danger from the nest. Even when he 

 withdrew entirely, the female continued her protests until we were 

 well out of her territory." Dr. L. B. Bishop (1900), however, recon- 

 ciles both points of view, for he says : " Bare pectoral spaces showed 

 that both sexes assisted in incubation." 



The young leave the nest and run after the parents almost as soon 

 as they are hatched. Bishop (1900) in the Yukon River region 

 found an egg that was already pipped. He says: "I removed the 

 young bird from the shell, and within half an hour the down was 

 almost dry, the eyes were open, and it could hop about on its ' knees.' " 



Dr. W. H. Osgood (1909) reports the following observation by 

 N. Hollister on a doAvny young of this species: "Although it was 

 perfectly able to run about as fast as the adults, it at once lay flat 

 to the ground when approached, with head extended foreward in the 

 sand, making it very difficult to see, so closely did it match the ground 

 in color." 



The actions of the parent incubating the eggs when a human 

 intruder appears is well told by H. S. Swarth in a communication, 

 as follows : 



The breeding bird skulked from the nest at the first appearance of an in- 

 truder, and, after performing an unobtrusive retreat to a distant point, launched 

 out in conspicuous protest at the trespass. The call notes served to summon 

 the mate, and sometimes even another pair of birds, all hovering about overhead 

 or racing close by over the sand. A liquid call note, not particularly loud, was 

 uttered constantly, and both birds of a pair would go through the form of 

 pretended injury, dragging themselves over the sand with drooping wings and 

 spread tail. 



In another case — 



A bird was flushed, as it had been many times before, at a point 300 yards 

 or more above the water line, and I sat down quietly to watch her from the 

 shelter of a scrubby willow. She flew to a distance, but returned in a few 

 minutes, to run aimlessly iibout over the gravel nearby. Gradually she drew 

 away, running over and between logs and other drift, her manner changing 

 from one of noisy protest to furtive withdrawal behind any available cover. 

 Finally, about 20 minutes after I began to watch, she settled down on the 

 gravel, as it developed, upon the eggs. 



