624 U.S. NATIONAL MUSEUM BULLETIN 23 7 part 2 



while the female continues to feed in perfect security without even 

 glancing up. 



Nesting. — The following extreme dates of nesting about Tucson, 

 Ariz., encompass a remarkably long nesting season. Marshall saw a 

 pair feeding young out of the nest on Mar. 31, 1958. A. R. Phillips 

 writes, "My latest nest was in a wash at Wilmot Road, Tucson, 5 

 feet up in a cholla cactus. It had three eggs on Aug. 28, 1939, small 

 young on September 1, young stUl there September 6, empty and 

 clean on September 12." The normal number of successful nestings 

 by any one pair at Tucson is not Icnown, but one pair had success- 

 fully fledged two broods by May 21 in 1958. Both parents had been 

 color-banded the previous winter. The schedule of their two nestings 

 was as follows: stationary juveniles out of nest on March 31, clutch 

 of four eggs in second nest at least from April 15 to 23, young in this 

 nest on April 30, older juveniles following parents from May 21 at 

 least until June 20. As both parents were tending the fully grown 

 young in May and June, we must conclude they had not yet started 

 a third nest, though another 10 weeks stUl remained of the potential 

 nesting season. July and August nests could be new attempts after 

 repeated failures, or even first attempts by young of the previous 

 year that matured or paired late. 



The solidly constructed nest is generally placed against the main 

 trunk of a small tree or tall bush where it is supported by strong 

 branches and well shaded and hidden by fohage or twigs of the tree. 

 Nests have been found around Tucson on the north, shaded side of 

 cholla cacti, mesquites, elderberries, and hackberries at heights from 

 3 to 12 feet. In the spring of 1958, young were successfully reared 

 before the trees holding their nests had leafed-out. The female 

 canyon towhee is a close sitter. She flushes only when approached 

 to within 2 or 3 feet, and then silently and inconspicuously. 



The buUc of a nest collected and analyzed at Tucson was con- 

 structed of small twigs, dry composite stems and heads, crucifer 

 stems and inflorescences, leaves of grasses, leafy ends of stems, and 

 large hollow herbaceous stems. It was lined with elm leaves, 

 small shredded hollow herbaceous stems, fine strips of bark, leafy 

 ends of herbaceous stems, and finally with exceedingly fine stems and 

 spikelets of grasses and with animal hair. C. E. Bendire (1890) 

 gives bYi inches across and 3}^ inches in height for outside measure- 

 ments with 3 inches across and 2 inches in depth for inner dimensions. 

 Brewster (1882a) differs slightly with 5 inches across outside, 2 inches 

 in height, 2 inches across inside, and \% inches in depth. 



F. C. Willard (1923) lists some unusual nesting sites. One pair 

 built inside a porch in a robin-like situation. Also listed are the 

 tops of Cottonwood trees and honeysuckle vines. H. Brandt (1951) 



