CACTUS WOODPECKER 83 



telephone poles, tree yucca and mesquite and would, more often than not, 

 chose one of these other sites by preference. But lucasmius confines itself to 

 the cardon, at least in the district we were studying, selecting a single-stalked 

 giant cactus and drilling its hole very near the top of the plant. As a result 

 the nest-cavity is rather uniformly twenty feet above ground. The entrance 

 hole is at the top of a cavity typically five inches in diameter by fifteen in 

 depth. No foreign material is brought in for a nest. The eggs lie on the chips 

 that fall in the process of excavating. 



The number of eggs in a clutch is two, three, or rarely four. The first two 

 weeks in May find almost all the San Lucas Woodpeckers at the peak of laying. 

 After the middle of the month nests with young may be expected. The parent 

 bird will ordinarily flush, especially if the cardon be tapped, but it is not very 

 nervous about its home. It is too busy with family duties to waste much 

 attention on strangers. 



The eggs are similar to those of the other subspecies. Bancroft 

 (1930) gives the average measurements of 23 eggs as 22.9 by 18.1 

 millimeters. The measurements of 10 other eggs average 21.30 by 

 16.61 millimeters ; the eggs, in this series, showing the four extremes 

 measure 24.40 by 18.70, 23.70 by 18.80, 19.50 by 16.80, and 21.43 by 

 15.42 millimeters. 



DRYOBATES SCALARIS CACTOPHILUS Oberholser 



CACTUS WOODPECKER 

 HABITS 



The ladder-backed woodpeckers are quite widely distributed in the 

 Southwestern United States and in nearly all Mexico and in British 

 Honduras, chiefly in the Lower Austral and Tropical Zones. When 

 Dr. Harry C. Oberholser (1911b) wrote his revision of this group, 

 he split the species Dryohates scalaris into 15 subspecies, 9 of which he 

 described and named as new subspecies. Only two of these sub- 

 species are found within the limits of the United States, and only 

 two in Baja California, giving us four on our Check-List. 



The name Dryohates scalaris hairdi^ which was for a long time used 

 to designate the ladder-backed woodpeckers of the United States, 

 was restricted by Oberholser to a Mexican form. He gave as the 

 characters of cactojjhUus^ "much like Dryohates scalaris eremicus, but 

 smaller, particularly the tail and bill ; lower surface lighter, laterally 

 almost always streaked with black; upper parts lighter — the black 

 bars on back and scapulars narrower; wing-quills with larger spots 

 and broader bars of white; outer long rectrices with exterior webs 

 barred throughout with black; black bars on posterior lower surface 

 narrower." 



Ridgway (1914) compares it with sy 771 pi edits, the Texas bird, as 

 "slightly larger, and with black bars on back, etc., decidedly broader." 



The cactus woodpecker ranges, according to the 1931 A. O. U. 

 Check-List, from ''central western Texas through New Mexico and 

 Arizona to extreme northeastern Lower California and southeastern 



