252 BULLETIN 17 4, UNITED STATES NATIONAL MUSEUM 



Referring to the nesting habits of this woodpecker in the vicinity 

 of the Gila River, in Arizona, Mr. Gilman (1915) writes: 



Nesting sites in this locality are restricted to giant cactus {Cereus gigan- 

 teus), Cottonwood and willow, as they are the only suitable material for a 

 nest excavation. More nests are found in the giant cactus, as these plants 

 are more numerous than the others, and more "peckable," though the willows 

 and cottonwoods along the river and the canals are well patronized when suf- 

 ficiently decayed. Of the nests I examined I should say that fifty per cent 

 were in the cactus, and the rest equally divided between the other trees 

 mentioned. * * * 



As to the size of the holes in the cactus as compared with those in cotton- 

 wood and willow, I found no appreciable difference. I expected the holes in 

 the cactus to average a little larger owing to possible greater ease in excavating 

 but the difference was too slight to be sure of in measuring. Of eighteen holes 

 measured, the average diameter was 1.95 inches; the largest was 2.25 inches 

 and the smallest 1.87 inches. The deepest hole was 16 inches, with the en- 

 trance 2 inches in diameter. The shallowest one was 9 inches, with entrance a 

 little less than 2 inches in diameter. The average depth of holes measured 

 was a little more than 12 inches. Many of the holes were not exactly circular, 

 there being a difference of from % to nearly % inch between the long and 

 short diameter if it be allowable to use the term in that way. Usually the nest 

 hole runs straight in for a short distance before turning downward, the distance 

 seemingly depending on the texture of the wood. In one case the hole went 

 straight back for nine inches before turning downward. It was in a big 

 Cottonwood stump, and the bird excavated horizontally until decayed wood 

 was reached, when the hole turned downward. This was an extreme case, 

 as the depth horizontally is usually about three inches. In the giant cactus 

 it varies according to the diameter of the trunk, the smaller the trunk the 

 less distance before turning downward. * * * 



The same nest hole is used more than one season, both in cactus and other 

 locations. In 1913 I found a nest in a big Cottonwood stump containing young. 

 The next year it had young again, and I cut into it to measure the hole and 

 count them. 



Frank C. Willard (1912) says: "I think it is their habit to dig 

 fresh holes after raising their brood of yonng. These fresh holes 

 are not occupied that year but are made use of the next year when 

 the sap has had a chance to dry and form the hard lining which 

 coats the inside of all the cavities. I have found but one fresh hole 

 occupied as a nest." Bendire (1895) also says that "most of their 

 nesting sites are used for several years in succession ; in fact, I doubt 

 very much if a freshly excavated hole in a giant cactus is fit to nest 

 in the same season. Both sexes assist in excavating the nesting site." 



In the heavily incrusted nest cavity in a giant cactus, the eggs 

 lie on the bare, hard floor of the nest, there being no chips to furnish 

 a soft bed. 



In addition to the trees mentioned above, the Gila woodpecker has 

 been found nesting more rarely in oaks and palo-verdes. 



Eggs. — ^The Gila woodpecker lays three to five eggs, three or four 

 being much oftener found than five. The eggs are pure white and 



