was perfectly smooth at the entrance hole, but on either side, slightly above, were the bases of two large branches that could not have given the opening any protection from the weather. The opening in the maple faced north, two of those in the oaks east, and one west. Audubon states: “The birds pay great regard to the particular situation of the tree and the inclination of the trunk; first, because they prefer retirement, and, again, because they are anxious to secure the aperture against the access of water during beating rains. To prevent such a calamity the hole is generally dug immediately under the juncture of a large branch with the trunk.” None of the nests examined by us showed this desire for protection from rain, and the chips at the bottom of the cavity were perfectly dry, though we had had some very heavy rains shortly before they were examined. Audubon further states: “The average diameter of the different nests which I examined was about 7 inches within, although the entrance, which is perfectly round, is only just large enough to admit the bird.” Beyer (1900) says: “The entrance measures exactly 4½ inches in height and 3⅞ inches in width,” and McIlhenny (Bendire, 1895) gives the measurements of a typical hole as “oval and measures 4⅛ by 5¾ inches,” and Scott (1888) as “3½ inches wide and 4½ inches high.” The corresponding measurements of the nests of Pileated Woodpeckers are given by Bendire (1895) as follows: “The entrance measures from 3 to 3½ inches in diameter, and it often goes 5 inches straight into the trunk before it is worked downward.” The additional one to two inches in diameter of the nest hole should be kept in mind when searching for reasons why the Ivorybill has proven less successful than the Pileated Woodpecker in its struggle for existence. Thompson (1885) states: “The depth of the hole varies from three to seven feet, as a rule, but I found one that was nearly nine feet deep and another that was less than two.” He also claims that they are always jug-shaped at the lower end.