508 U. S. NATIONAL MUSEUM BULLETIN 211 



In the Valley of the lower Colorado River, Grinnell (1914b) found 

 this tanager "strictly confined to the willow association. Not one 

 bird was seen even so far from this association as the mesquite belt." 

 And in New Mexico, it is reported by Mrs. Bailey (1928) as frequenting 

 the cottonwoods along the rivers and in canyons. Referring to 

 Brewster County, Tex., Van Tyne and Sutton (1937) record Cooper's 

 tanager as a common nesting species "where there are cottonwood, 

 mesquite, or willow trees. It is apparently not so fond of oaks, 

 although singing males were noted more than once in oak woods in 

 lower parts of the Chisos Mountains." * * * 



"On May 13 * * * Sutton observed an adult male that was singing 

 and displaying before a parti-colored young male which also was 

 singing fervently. In display, the adult male spread its wings and 

 tail and stuck its bill straight up." 



Nesting. — Van Tyne and Sutton (1937) found two nests of 

 Cooper's tanager in Brewster County: "On May 11a nest with four 

 fresh eggs and the female parent were collected at Castalon. The 

 nest was about fifteen feet from the ground close against the trunk of 

 a slender willow that stood not far from the Rio Grande. On May 29 

 a nest and four eggs were found on the Combs ranch, thirteen miles 

 south of Marathon. This nest was built on a horizontal willow bough, 

 about twenty feet above a stagnant pool along the Maravillas." 



A New Mexico nest, reported by Mrs. Bailey (1928), "was found by 

 Mr. Ligon in the top branches of a walnut tree growing in a canyon 

 bed. Its one egg was eaten and the nest destroyed by a Woodhouse 

 Jay." 



The Arizona nest, referred to above, was taken by Frank C. Willard 

 on June 9, 1922, near Fairbank in the San Pedro Valley. It was 

 placed in the extreme top of a large willow, 35 feet from the ground. 

 The nest was made of grass and green weed stems, with a lining of 

 fine grass. 



Eggs. — The four eggs in the normal set for Cooper's tanager are 

 apparently indistinguishable from the eggs of the summer tanager. 



The measurements of 38 eggs average 23.3 by 17.4 millimeters; the 

 eggs showing the four extremes measure 25.4 by 18.3, 22.9 by 18.8, 

 21.8 by 17.4, and 22.4 by 16.3 millimeters. 



Food. — Evidently, Cooper's tanager is quite as fond of honey 

 bees as is its eastern relative. In a letter to Herbert Brandt, H. E. 

 Weisner, who operates a large apiary near Tucson, Ariz., complains of 

 the damage done to his bees by this and the western tanager. He 

 writes as follows: "It was several years before I realized the fact that 

 their food in the areas about my apiaries consisted almost entirely of 

 bees, and worker bees at that. Or, I had better say parts of bees, 



