92 LIFE HISTORIES OF NORTH AMERICAN BIRDS. 



Incubation lasts from three to four weeks. The male does .not assist in 

 this duty, but keeps to himself. The young leave the nest as soon as hatched, 

 and are cared for by the female alone. Their food at first consists almost, if 

 not entirely, of insects, and when grasshoppers are plenty, as they frequently 

 are in the northern parts of their breeding range, they subsist almost exclu- 

 sively on them. Later they frequent the grain fields and feed on the different 

 cereals as well as other small seeds and berries. The female is much devoted 

 to her young, and will act similarly to the Ruffed Grouse in trying to attract 

 the attention of the intruder to herself and away from the chicks, which hide 

 quickly in the grass at the first intimation of danger which the parent may 

 give. 



By the latter part of August most of the broods are well grown and able 

 to care for themselves. Two or three coveys pack together then, and later in 

 the fall packs numbering fully five hundred and more may be seen where these 

 birds are common. 



The eggs of the Prairie Hen, as previously stated, number on an average 

 from eleven to fourteen to a set, and if the first clutch is destroyed, which is 

 unfortunately too often the case, a second and smaller set is laid. The color of 

 the eggs varies from pale cream to vinaceous and olive buff, as well as light 

 brown and clay color. Scarcely two sets are alike in this respect. 



The majority of the eggs of this species in the U. S. National Museum 

 collection, are faintly but regularly spotted with fine pin points of reddish 

 brown, in some instances scarcely perceptible to the naked eye. In a few sets 

 in the series the markings show plainly, but none are larger than a No. 6 shot, 

 and but few that size. The spots are pretty regular in size, and well defined, 

 even when very small. 



The eggs are ovate; a few short-ovate in shape. The average size is 43 

 by 32.5 millimetres. The largest egg in one hundred and two specimens meas- 

 ures 46 by 34, the smallest 40 by 30 millimetres. A 'runt egg of this species 

 in the collection measures but 18 by 15 millimetres. 



The type-. specimen (No. 3103), from a set of eleven eggs (PI. 2, Fig. 18), 

 was collected by J. W. Tolman, near Winnebago, Illinois, May, 1860. No. 

 14517, from a set of sixteen eggs (PI. 2, Fig. 19), was collected by G. and C. 

 Blackburn, in Buchanan County, Iowa, May 22, 1868. This is the heaviest 

 marked set in the series. No. 21102, from a set of eleven (PI. 2, Fig. 20), 

 collected for myself by Capt. B. F. Goss, Pewaukee, Wisconsin, May 20, 1876, 

 is one of the darkest sets in the series. 



