TREE SPARROW 1153 



distinct dark shafts on the crown feathers are first-year females, A 

 wider crown usually indicates a male, a narrow crown a female. 

 Male birds frequently show a loose flecking of buff over the whole 

 crown, which in the female tends to be more heavily concentrated 

 toward the center. The distinct dark shafts in the center crown 

 feathers, though not invariable, are characteristic of first-year females. 

 Operators of banding stations interested in sexing their tree sparrows 

 should refer to the original article (Heydweillcr, 193G) which gives 

 measurements, a sketch of four typical crown patterns, and further 

 details. 



The western form, Spizella arborea ochracea, was recognized as a 

 distinct subspecies by William Brewster in 1881. In describing it, he 

 (Brewster 1882) remarks: 



"The ground color of the back is decidedly paler than the eastern 

 examples, bringing out the dark streaks in sharper contrast, which is 

 heightened by the absence of their usual chestnut edging; ash of 

 throat and sides of head is much fainter, in many places replaced by 

 brownish fulvous; the imderparts, especially the sides and abdomen, 

 are more strongly ochraceous; and the broad ashy crown patch gives 

 the head a very different appearance." 



The types of ochracea are now in the Harvard College Museum of 

 Comparative Zoology: co-types from Fort Walla Walla, Washmgton, 

 collected by Captain C. E. Bendire, male — Nov. 8, 1881; female — 

 Dec. 13, 1881. 



Food. — ^Beal (1897) found that a single tree sparrow eats about 

 one-fourth ounce of seeds per day. Estimating conservatively that 

 ten birds per square mile spend an average of 200 days in Iowa, then 

 this species alone destroys 875 tons of weed seed annually. This 

 figure, he thought, could without exaggeration be multiphed by four. 

 In the stomach of an individual bu-d he recorded 700 seeds of pigeon 

 grass. A specimen I collected at Ithaca, N.Y., contained 982 seeds 

 in the crop alone, with another 200 in a crushed mass in the stomach. 



During its stay in the United States, the tree sparrow subsists almost 

 entirely on weed and grass seed (Judd, 1901), with 98 percent seed 

 food, about 2 percent animal matter, and an insignificant quantity of 

 fruit. This species difi^ers from associated fringilhds in the large 

 proportion of grass seed it eats, which makes up fully 50 percent of its 

 vegetable diet. Panicums, pigeon grass, and allied grasses seem to be 

 preferred, after which ragweed, lamb's quarters, and the polygonums 

 comprise another 40 percent, with the remainmg 10 percent a variety 

 of seeds, berries, buds, catkins, flowers, and waste grain. 



Animal food found by Judd consisted chiefly of weevils and other 

 beetles, groimd beetles, rose beetles, wasp-hke insects, ants, cater- 

 pillars, bugs, grasshoppers, and spiders. Knight (1908) adds flies, 



