184 BULLETIN 142, UNITED STATES NATIONAL MUSEUM 



artifice or delay ; in fact, often within two or three minutes. The above pro- 

 cedure is not an invariable practice, as one female I knew would flush directly 

 from the nest to begin her tactics only when there was danger of the nest 

 being actually trodden upon. 



Eggs. — The four eggs usually laid by the white-rumped sand- 

 piper are ovate pyriform in shape ; all that I have seen are uniform 

 in shape and have characteristic colors and markings. One of the 

 two sets in the United States National Museum has a " deep olive 

 buff " ground color, and the eggs are heavily blotched about the 

 larger end, sparingly spotted elsewhere with " wood brown," " warm 

 sepia," and "benzo brown," and with a few underlying spots of 

 various shades of "brownish drab"; an egg from this set is well 

 figured by Frank Poynting (1895). The other set differs from this 

 one in having the ground color lighter, " olive buff," and the spots 

 finer, more scrawly, and lighter in color; the underlying drab mark- 

 ings are also more numerous. 



There is also a set of four eggs in the Thayer collection, taken with 

 the parent bird by Alfred H. Anderson on Taylor Island, Victoria 

 Land, July 7, 1919. These eggs are much like the egg figured by 

 Mr. Poynting, except that in one or two of the eggs the ground 

 color is more greenish. 



One of the three sets taken by J. Dewey Soper on Baffin Island 

 looks much like a miniature set of long-billed curlew's eggs. In 

 three of the eggs the ground color is "mignonette green," covered 

 with small spots, more thickly at the larger end, of "bister" and 

 " snuff brown " ; the other has a " deep lichen, green " ground color 

 and is irregularly blotched near the larger end, finely speckled else- 

 where with "bister " and " brownish drab." 



The measurements of 34 eggs average 33.7 by 24 millimeters; the 

 eggs showing the four extremes measure 36.1 by 23.6, 34.2 by 27.7, 

 31.5 by 23.5, and 35 by 22.8 millimeters. 



Young. — Mr. Soper's notes on the young are as follows : 



The first juveniles, about a day old, were seen and collected on July 11. 

 They were exceedingly active, a good example of precocial young. These were 

 ashy below, buffy above, with black markings, and the down over the lower 

 back and rump tipped with small spots of white. This species is much more 

 demonstrative and less artful in the concealment of young than Baird's sand- 

 piper. The adults come within a few feet of the intruder, and by their 

 action advertise much more clearly the position of the young. The parent birds 

 keep up a continual fine twittering cry of alarm, the female louder and more 

 pronounced. The male comes on the scene only at intervals with a mouse- 

 like squeaking note. The young are adepts in the art of concealment, " freez- 

 ing" flat to the ground with warning notes from the adults. They will lie in 

 this fashion as though dead until actually picked up in the hand. "When 

 they realize the game is up they then become wild and frantically struggle 

 to escape. When allowed to do so they will run rapidly away and either 

 hide again or attempt to reach the mother bird, whose frantic cries come 

 from but a few yards away. 



