THE LITTLE FLYCATCHER. 309 



one of the most compactly built ones, measures 3J inches in outer diameter by 

 4 inches in depth; the inner cup is 2 inches wide by 2 inches deep. In some 

 specimens the outer walls are fully an inch thick. 



The Little Flycatcher occasionally builds a double nest. Dr. Clinton T. 

 Cooke writes me: "On June 20, 1891, I found a nest on Hammer's Island, in 

 the Willamette River. It was situated in a willow crotch, about 4 feet from the 

 ground; contained no eggs and presented nothing abnormal to view. I was 

 prevented from making a second visit to the nest until July 6, when I supposed 

 it would contain either young or badly incubated eggs. I was much surprised, 

 however, to find that it looked abnormally deep outside. The cavity was about 

 the usual depth, but from the bottom to the margin of this the nest measured 

 about 5 inches, and resembled an inverted cone, presenting no irregularities from 

 apex to base. It contained four fresh eggs. On examining it more closely I 

 saw it was a two-storied nest, one neatly built upon the other. The lower one 

 also contained four eggs, the contents of which were too dry to be removed, and 

 which evidently had been abandoned for some inexplicable cause." 



The number of eggs to a set varies from two to four, usually three or four; 

 sets of the latter number are oftener found in the more northern parts of its 

 range than the smaller number ; and an egg is deposited daily. Only one brood 

 is raised in a season, and incubation lasts about twelve days; the young are 

 fed on insects of various kinds, and remain in the nest about two weeks. The 

 return migration to their winter homes usually begins in the more northern 

 portions of their range about, the first week in September, and none winter 

 within om- borders. 



The eggs are usually ovate in shape ; the shell is strong and without luster. 

 The ground color varies from a pale creamy white to pale bufi", and this is 

 moderately spotted with vinaceous rufous and ferruginous. The markings are 

 principally confined to the larger end of the egg, and vary from small rounded 

 dots to larger irregular blotches among the finer ones. In some specimens the 

 ground color might be called dead white. 



The average measurement of one hundred and twenty-nine eggs in the 

 United States National Museum collection is 17.86 by 13.39 millimetres, or 

 about 0.70 by 0.53 inch. The largest egg of the series measures 19.56 by 

 13.97 millimetres, or 0.77 by 0.55 inch; the smallest, 15.49 by 12.70 millimetres, 

 or 0.61 by 0.50 inch. 



The type specimens, Nos. 25228 and 25229 (PI. 2, Figs. 28 and 29), both 

 taken from sets of four eggs which were collected by Dr. Clinton T. Cooke, 

 near Salem, Oregon, on June 22 and July 2, 1891, are selected to show the 

 extremes in coloration and markings, and were presented for tliat purpose. 



