782 U.S. NATIONAL MUSEUM BULLETIN 237 i'art 2 



nests are attached to vertical stems of grass and herbs from 6 to 20 

 inches above the ground; these lack the roof of arching vegetation. 



Usually the nest is a deep cup, though Hyde (1939) found one that 

 was merely a shallow open saucer and poorly concealed. The nest cup 

 measures about 2 inches in inside diameter, 3 inches in outside diam- 

 eter, and has a depth of 1 to 2 inches. The nest is made of coarse 

 grasses and dead weed leaves and lined with finer grasses and some- 

 times with hair. 



Nest material is gathered near the nest site, within 50 feet of one 

 nest Hyde watched. The nest building is done chiefly if not entirely 

 by the female. Hyde reports (1939) the male of one pair sang softly 

 nearby while the female was at work; when she stopped working he 

 became more vociferous. The male of a pair observed by J. T. 

 Southard (pers. comm.) was seen carrying blades of grass twice while 

 the female worked at nest building. Hyde watched one female 

 bring nesting material from 9 :08 to 9 :50 a.m. at the rate of once every 

 3.3 minutes; she spent 0.7 of a minute arranging it at the nest before 

 leaving for more supplies. 



Nest building activity seems to be most intense during early morn- 

 ing, but may occur throughout the day until dusk. The nest is built 

 in 4 to 5 days. Hyde reports that one pair, after its nest was de- 

 stroyed, chose a new site and completed a new nest in 5 to 6 days. 



Eggs. — Henslow's sparrow usually lays from 3 to 5 eggs. They 

 are ovate and slightly glossy. The ground is creamy white or pale 

 greenish white, with speckles, spots, and occasional large blotches of 

 reddish bro\vns such as "russet," "hazel," "auburn," "Rood's brown," 

 and "tawny," with undermarkings of "light purplish gray" or "light 

 neutral gray." The eggs of this species are not so heavily marked as 

 those of the sharp-tailed or seaside sparrows, but resemble more the 

 pattern of those of the grasshopper sparrow. The spottings are con- 

 centrated toward the large end where they often form a ^\Teath. 

 The spots may be either sharp and distinct or dull and clouded. 

 The measurements of 55 eggs average 18.3 by 14.1 millimeters; the 

 eggs showing the four extremes measure S0.3 by 15.2, 16.7 by 13.8, 

 and 18.8 by 13.0 millimeters. 



The finding of many nests with eggs in Michigan in July and of 

 four eggs laid in one nest between August 12 and 16, and of young 

 still in the nest in Wisconsin in September suggests that some pairs 

 may be double-brooded. 



Young. — Incubation is entirely by the female. While she incubates 

 the male sings from various perches nearby. She has been observed 

 to respond to his singing by twittering softly from the nest. Hyde 

 (1939) determined that incubation starts with the laying of the last 

 or the next to last egg and takes about 1 1 days. 



