NORTHERN FLICKER 273 



sparrow and red-headed woodpecker eggs in freshly excavated quarters 

 with one or more eggs of the Flicker are not uncommon, and upon 

 investigation the latter proved to be the aggrieved party in every 

 instance." He also tells of a flicker that laid an egg in a mourning 

 dove's nest. 



The eggs of the flicker are pure lustrous white, with a brilliant 

 gloss; the shell is translucent, and, when fresh, the yolk shows 

 through it, suffusing the egg with a delicate pinkish glow, which is 

 very beautiful. 



The shape is quite variable, but the majority are ovate; some are 

 short-ovate or elliptical-ovate, some nearly oval, and some rarely 

 somewhat pointed. The measurements of 57 eggs average 26.85 by 

 20.58 millimeters; the eggs showing the four extremes measure 

 30.48 by 22.86, 28.19 by 24.38, 24.45' by 21.34, and 27.68 by 19.05 

 millimeters. 



Young. — The period of incubation of the flicker has been said to 

 be from 14 to 16 days. Miss Sherman's (1910) careful observations 

 on marked eggs, laid on known dates, indicate a shorter period. 

 From some former nests she had learned "that sometimes the eggs 

 hatched in nine days, but more frequently in ten days after the laying 

 of the last eggJ^ In these cases, incubation may have begun before 

 the set was complete, or the eggs may have received some heat from 

 tlie body of the male, for she said that, in at least one case, "while the 

 eggs were being laid, and before incubation began the male roosted 

 in the box with the eggs." According to a later observation, "the 

 exact time for incubation had been twelve days, three hours and 

 fifty-two minutes. The seventh egg hatched four hours later making 

 its period of incubation eleven days and eight hours nearly." After 

 another similar experience with the hatching of nine marked eggs, 

 which extended over a period from 5:40 a.m. one day until 10:48 

 a.m. the next day, she says : "Eoughly speaking, then, the time that 

 our Flickers take for incubation is from eleven to twelve days." 



Her observations showed that the duties of incubation are shared 

 by both sexes, that the male usually incubates during the night, but 

 "by day the duties of incubation seem to be shared about equally 

 between the two birds, who are close sitters, the eggs seldom being 

 found alone. Of the length of the sittings no adequate record has 

 been kept, but those lasting from one hour and a half to two hours 

 have been noted." 



Miss Sherman (1910) noted that "the usual time for depositing the 

 eggs in the nest appears to be the hour between five and six o'clock 

 in the morning," though in one case an egg was laid between 11 a.m. 

 and 4 p. m. 



