156 BULLETIN 203, UNITED STATES NATIONAL MUSEUM 



in a tree close by. After a few trips with material the female would 

 fly into the tree where he was and let him feed her. This is the only 

 time I have observed nest building going on and the male not following 

 the female in her flights." In his description of the nest, he says: 

 "It is supported by ten small live twigs from the size of a pencil down, 

 all growing from a branch about five eighths of an inch in diameter. 

 It is composed outwardly of moss and pine bud hulls with plant down 

 scattered thruout. The proportion of this latter increases until the 

 the lining is reacht where it forms a felt like a hummingbird's nest. 

 This lining is supplemented with a few very fine rootlets." 



He gives an interesting account of his attempts to locate another 

 nest in "a short-leaf pine whose branches were weighted down with 

 masses of twigs and cones." He worked from ten in the morning until 

 three in the afternoon, following the birds about, climbing the sus- 

 pected tree several times and cutting off many twigs, before he finally 

 found the nest. "The tree was not a very large one and I had shaken 

 every branch and jarred them with my foot, but until I practically 

 toucht the nest she had stayed on." 



While I was in Arizona with Willard he collected for me on May 30 

 a beautiful nest of the olive warbler, with four fresh eggs. It was 

 taken at an altitude of 8,500 feet on the Huachuca Mountains and was 

 built in a clump of mistletoe near the tip of a branch of a sugar pine 

 about 20 feet out from the trunk and 55 feet from the ground. Its 

 construction was similar to those described previously (pi. 23). The 

 loftiest nest that he ever found was 70 feet from the ground in a pine. 



The nest built by the Arizona olive warbler is beautiful, and quite 

 different from that of any other species of its group. A typical nest 

 (in the Thayer collection in Cambridge) is made mainly of a brown 

 lichen or moss mixed with other lichens and mosses, bud scales, flower 

 scales, and some plant down, reinforced with fine yellowish rootlets. 

 All these are compactly worked into and supported by the living 

 needles of the yellow pine in which the nest was built. The lining 

 consists of plant down and finer strands of the same yellowish rootlets. 

 It measures 3% by 3 inches in outside diameter and 2i/2 in height; 

 the inner cavity is about 2 inches in diameter and l^^ inches in depth. 



Eggs. — Three or four distinctive eggs seem to constitute the full 

 set for the northern olive warbler. These are ovate to short ovate 

 and have a very slight lustre. They are grayish or bluish white, or 

 even very pale blue, liberally speckled, spotted and blotched with 

 "dark olive-gray," "dark grayish olive," "drab," "olive-brown," or 

 "dark brownish drab." These are interspersed with undertones of 

 "mouse gray," "deep mouse gray," or "Quaker drab." On some eggs 

 the spots are sharp and distinct, while on others the olive, brown, and 

 drab markings are clouded into the undertones. The spottings are 



