All nests examined upon this occasion [an occasion when he found half a dozen nests] were of uniform gourd-like shape, with the sides very smoothly and evenly chiselled. They averaged about fourteen inches in depth by five in diameter at the widest point, while the diameter of the exterior hole varied from 1.25 to 1.60 inches. So small, indeed, was this entrance in proportion to the size of the bird, that in many cases they were obliged to struggle violently for several seconds in either going out or in. The nests in most instances were very easily discovered, as the bird was almost always in the immediate vicinity, and if the tree was approached would fly to the hole and utter a few low calls, which would bring out its sitting mate, when both would pass to and from the spot, emitting notes of anxiety and alarm. The bird not employed in incubation has also a peculiar habit of clinging to the trunk just below the hole, in a perfectly motionless and strikingly pensive attitude, apparently looking in, though from the conformation of the interior it would be impossible for it to see its mate or eggs. In this position it will remain without moving for many minutes at a time. Henry Mousley (1916) states that the bird “often nests year after year in the same tree (but not necessarily in the same hole) the favourite ones here [Hatley, Quebec] being elm, poplar, and butternut. * * * Of two nests examined the average dimensions are as follows, viz.: entrance hole 1⅜ inches in diameter, extreme depth 10¾ inches, and width 2⅞ inches.” Philipp and Bowdish (1917) say of the nesting site in New Brunswick: “The favorite situation was the dead heart of a live poplar, most often on the bank of a stream, and facing same, but some nests were in totally dead trees, of different kinds. They ranged from eight to forty feet from ground.” Bendire (1895) says that the birds “are devoted parents, and when incubation is somewhat advanced, or the young have been recently hatched, the bird on the nest is loath to leave it, and will sometimes allow itself to be captured rather than to desert its treasures.” _Eggs._--[AUTHOR’S NOTE: The yellow-bellied sapsucker lays four to seven eggs to a set, though five or six eggs are more commonly found. They vary from ovate to elliptical-ovate and sometimes to elliptical-oval. The shell is smooth and either dull or moderately glossy. They are pure white, like all woodpeckers’ eggs. The measurements of 52 eggs average 22.44 by 16.92 millimeters; the eggs showing the four extremes measure =24.9= by 17.0, 23.8 by =18.0=, =20.57= by 16.26, and 22.1 by =15.5= millimeters.] _Young._--As in the case of most nestling birds reared in a hole in a tree, little is known of the young sapsuckers while they are in the nest.