WESTERN WHITE-WINGED DOVE 431 



Eggs. — The white-winged dove lays two eggs, very seldom three 

 or only one. Frequently one egg proves to be infertile, resulting 

 in the rearing of only one young. The eggs are elliptical oval or oval 

 in shape, and the shell is smooth but not glossy. Fresh eggs, even 

 after being blown, are often a rich, creamy buff, but this color 

 varies greatly, and many eggs are pale creamy white or nearly pure 

 white; the whitest eggs are probably those that have been incubated 

 longest. The color fades very soon, sometimes within a few days, 

 after the eggs are blown. The measurements of 42 eggs average 31.1 

 by 23.3 millimeters; the eggs showing the four extremes measure 

 34 by 24, 27.5 by 21.5, and 33.5 by 21 millimeters. 



Young. — The period of incubation, according to Major Bendire 

 (1892), is about 18 days, in which "the male relieves the female 

 somewhat in these duties, but does not assist to any great extent; 

 he, however, assiduously helps to care for the young." Apparently 

 only one brood is raised in a season in the northern part of its 

 range, but farther south in Mexico two or more broods may be raised 

 during a longer breeding season. 



Doctor Wetmore (1920) writes: 



I was of the opinion that males did not aid in incubation, but this I was 

 unable to ascertain with certainty. Occasionally I saw both parents perched 

 on the sides of a nest that contained young, but all birds that were definitely 

 identified while engaged in incubating were females. Each mate chose a 

 perch near the nest site, usually from ten to thirty feet away, and remained 

 there on guard while the female was sitting, save for the times required to 

 secure food. Such perches were selected in situations that were well shaded 

 from the direct rays of the sun during the heat of the day, and when not 

 occupied could be readily located by the collection of ordure, often con- 

 siderable in quantity, on the ground beneath. 



The young birds were fed by regurgitation and at the age of four days 

 received solid food in the form of undigested seeds, in addition to the usual 

 diet of " pigeon's milk." Fledglings left the nest when between three and 

 four weeks old, as nearly as I could ascertain. The first young bird able to fly 

 was noted on June 12, and by June 15 birds of this age were fairly common. 

 These young were still dependent upon their parents for food, and though 

 able to fly well were undeveloped and small. On first leaving the nest they 

 perched about in the mesquites, always seeking shade, but in a few days 

 were often found on the ground, preferably where the soil was sandy. There 

 they walked about in the thin shade of the mesquites, examining bits of sticks 

 and other refuse curiously, often testing such fragments with their bills, or 

 rested quietly, squatting on the earth. In many instances it was found that 

 they were heavily infested with small ticks against whose attacks they seemed 

 inexperienced. No ill results from the presence of these parasites were noted 

 and older birds were free from them. 



Plumages. — He says further: 



Young White-winged Doves when first hatched were well covered with long, 

 straggling down, that in color was dull white slightly tinged with buff. This 

 natal down was replaced by secondary feather growth so rapidly that it had 



