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July, 1915 WOODPECKERS OF THE ARIZONA LOWLANDS 161 feet from the ground, and in Saguaros from eleven to twenty-five or thirty feet. April is the month for Flicker nesting, as nineteen of the twenty-seven oc- cupied nests were noted during that month. Eleven contained eggs, and eight had young. Of eight nests found in May, four had eggs and four contained young. April 11 was the earliest date for a complete set, and April 19 date of first young found. May 17 was the latest date of ne?t with eggs. The number of eggs in a set varies, and it is hard to determine just what constitutes the average set. The number of infertile eggs seems to be quite large, and unless the nest is investigated before hatching or soon after, the count of young is not a correct indication of the number of eggs laid. In two cases I have seen one and two infertile eggs in a set before hatching, and a visit shortly afterwards showed the young all right but no sign of the infertile eggs. The eggs that fail to hatch are often broken, as the nest odor would in- dicate; at times they must be removed bodily as no odor or shells are in evi- dence. Occasionally an infertile egg is seen in the nest when the young are about ready to leave, showing in such cases neither accident nor removal. Of the twenty-seven nests examined, eight had five eggs, or young plus eggs, to Fig. 59. YousG GILDED FLICI?ERS AT BASE OF SAGUARO. make count of five for the set; eleven had four eggs or young, or young plus eggs; six nests contained three eggs or three young; and two nests had two young each. In no case did I find five young in a nest, and from the fact that infertile eggs were found with three and four young in a nest, it may be in- ferred that in many of the nests containing two, three or four young, more eggs had been laid. In no nest did I find more than five eggs, and I conclude that the set is from three to five eggs. From the data mentioned it would seem the average number in a set was 3.92 but deducting the two nests containing two young each, the average would be slightly more than four, which I believe somewhere near right. The entrance to the nest holes varies much, as may be seen from the fig- ures given. The smallest entrance measured 2? inches and the largest 4? inches. The shallowest hole was ten inches, and the deepest eighteen inches. The average diameter of entrance to thirty-six holes measured was 3.28 inches, and average depth of same holes was 12.75 inches. The entrance to the eigh- teen inch hole was three and one-half inches in diameter, and while the ratio is not constant, the shallower holes tend to have smaller entrances, and the