ORNITHOLOGICAL CLUB. 35 



several instances I found the nests floating in two and a half to 

 three feet of water without the least sign of floating rushes in the 

 vicinity ; in fact, there were no rushes or anything else except fine 

 swamp gi-ass growing anywhere near, and of this the nests were 

 built." 



As already stated, they build in this section (vicinity of Minne- 

 apolis) in the latter part of May or early in June, usually placing 

 the nest in a prairie slough or marsh bordering an open pond. The 

 material used in the construction is short bits of grass and reeds 

 disposed in such a manner that a neat, but loose structure is 

 formed. Occasionally greater skill is displayed, longer material 

 being used, which is slightly interwoven, so that the nest may even 

 be i-emovcd alone without injuring it. These frail structures are 

 sometimes found upon floating masses of decayed debris, and when 

 so situated it is necessary, with but few exceptions, to detach a por- 

 tion of this underlying bed in order to remove the nest intact. But 

 they are oftener placed upon the tops of small mounds of partially 

 decayed vegetable matter. These n^ounds, undoubtedly made by 

 the Terns as foundations for their nests, are seven or eight inches 

 in diameter, and rise one or two inches above the surface of the 

 water. They are placed over beds of live moss, and are partly sup- 

 ported by the water and partly by the moss below. It takes but a 

 slight motion of the water to rock them, and they would undoubt- 

 edly often go adrift Avere they not generally protected by the grass 

 growing around them. To obtain the nest in good condition the 

 hand may be inserted beneath the pile and the whole lifted up. 



The average external diameter of the nest of this Tern is aboul 

 five inches ; internal diametei', three inches ; while the depth varies 

 from a slight depression to three fourths of an inch or more. The 

 eggs are either two or three in number, perhaps oftener three than 

 two. Their ground-color varies from deep brown to greenish white. 

 The markings consist of blotches, dots, etc., of various shades of 

 brown. On some specimens there are a few, and on others numer- 

 ous, obscure pale spots in the shell. Frequently the markings are 

 nearly equally distributed over the entire surface of the e^^, but 

 usually are aggregated to form a wreath around the larger end. So 

 far as my observations have extended, all the eggs taken from one 

 nest have about the same ground-color and character of marking. 

 The average measurement of fifteen eggs before me is 1.35 inches 

 in length by .98 inches in width. 



