NORTHERN PILEATED WOODPECIvER 179 



lector whose experience was chiefly in Centre County, to the effect 

 that "May 10 is the standard date for a full clutch of eggs." 



Records of nests are at hand from Maine, New Hampshire, New 

 York, Pennsylvania, Ohio, and Wisconsin. Tlie total body of data, 

 however, is small; and it is not possible to discover what the difference 

 may be in mean nesting date from south to north within the region 

 covered. There is a record from Maine, for instance (Morrell, 1901), 

 of a set of eggs found to be heavily incubated as early as May 13. 



Eggs. — The eggs are white, Avith a gleaming smoothness and trans- 

 lucence of shell. They rest at the bottom of the cavity, on the bare 

 bed of finely splintered wood. Three eggs often complete the set, 

 but more commonly four. Of 17 recorded sets, 4 are sets of three, and 

 13 are sets of four. Some of the earlier writers (Wilson, for instance, 

 1811) said the number of eggs might be five or even six; but no specific 

 record of so large a number has been found. The eggs are of ovate 

 outline. 



The measurements of 51 eggs average 33.16 by 25.21 millimeters; 

 the eggs showing the four extremes measure 38.2 by 27.1, 30.2 by 

 25.2, and 33.05 by 23.75 millimeters. 



There are cases on record in which a pair of these birds, robbed 

 of their eggs, have laid again (and in the same cavity) ; with this 

 qualification, there is but a single brood in a season. 



Young. — In a particular instance, which I take to be typical, of 

 a nesting (in northern Fulton County, Pa.) I found the male to 

 be no less attentive than the female to the duties of incubation and 

 nurture. In one respect, indeed, the male seemed to be the more 

 attentive, for on both of the two occasions when I had opportunity 

 to observe — once shortly before, the other shortly after the hatch- 

 ing of the eggs — it was the male bird who at sunset retired within 

 the hole and who at sunrise the following morning . appeared from 

 within. And I mention this the more confidently since I find chance 

 confirmation in the narrative of another observer, Morrell (1901), 

 and since like observations have been made upon other species of 

 woodpeckers — upon the flicker, for instance, and upon the ivory- 

 billed woodpecker (Allen, 1937). 



Wlien incubation was in progress I found the parent birds to be 

 relieving one another at intervals of about two hours; and a week 

 later, when the young were still small, they were coming in with 

 food and replacing one another at intervals of approximately one 

 hour. It may have been accidental, and yet it seemed to me note- 

 worthy, that the routine of hourly visits was broken when the 

 female returned after an absence of 10 minutes to afford the male 

 freedom for 40 minutes before he returned to retire within the 

 cavity for the night. 



