Eggs.--The flicker is notorious as a prolific egg layer, but under ordinary circumstances, when not disturbed, the average set consists of six to eight eggs. Incubated sets of as few as three or four have been found, sets of nine and ten are not very rare, and as many as 17 have been found in a nest at one time; the large numbers may be products of two females. Mr. Burns (1900) records the contents of 169 sets of the northern flicker as 11 sets of four, 16 sets of five, 35 sets of six, 34 sets of seven, 38 sets of eight, 17 sets of nine, 13 sets of ten, 3 sets of twelve, and one each of thirteen and fourteen. Major Bendire (1895) states that Steward Ogilby, of Staten Island, N.Y., reports "finding a brood of not less than nineteen young Flickers in one nest, all alive and apparently in good condition."
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.
Patchylou - here's some answers to the question you brought up:
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 egg." In these cases, incubation may have begun before the set was complete, or the eggs may have received some heat from the 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: "Roughly speaking, then, the time that our Flickers take for incubation is from eleven to twelve days."
The information above is from this great website about Northern Flickers :
http://home.bluemarble.net/~pqn/ch11-20/flicker.html
