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



Food. — The food of the rufous-crowned sparrow apparently varies 

 considerably according to season and locaUty — ^depending largely on 

 its availability and condition. Probably the young are fed largely or 

 wholly on insects and insect larvae, as in A. r. eremoeca (Nice, 1929), 

 though no data are available. Later the food varies greatly. Patrick 

 J. Gould took stomachs with about 80 percent animal matter on 

 Oct. 23 and Nov. 4, 1960; but others he examined November 12 and 

 February 13 and 17 held 95 to 100 percent plant material, aside, of 

 course, from the inevitable gravel. 



The above data suggest a simple seasonal change of diet, but the 

 stomachs of Mexican specimens, kindly examined for me by Leonila 

 Vdsquez and others of the Instituto de Biologia, Universidad Nacional 

 Aut6noma de Mexico, do not bear this out. The above-mentioned 

 female of May 15, 1959 and another of Oct. 4, 1961 had eaten largely 

 seeds; while a male from arid southwestern Oaxaca (May 7, 1962) was 

 feeding mostly on insects. 



The plant material ingested was largely small, unidentified seeds. 

 But the November 12 female (an adult from the Graham or Pinaleno 

 Mountains, Ariz.) held "95+ percent short lengths of fresh grass 

 stems" (P. J. Gould, MS.); and the February 17 female had eaten 

 "many tender plant shoots and a lot of unidentifiable bulk" besides, 

 of course, seeds. Animals eaten include arthropods of many kinds, 

 mostly small beetles and orthopterans; CoccineUidae and grass- 

 hoppers are the only important groups identified. Others ingested 

 occasionally were spiders, ants, mosquito, Anthomyiid fly, cock- 

 roach, mantis, wasp, aphid, leafhopper, and an adult butterfly or moth. 



Behavior. — When we make occasional visits to its haunts, the 

 rufous-crowned sparrow seems almost a will-o'-the-wisp. It flushes 

 from the roadside or low brush and dives into the grass, Agave mats, 

 or rocks, never to reappear. Only singing males or anxious parents 

 let us really see them. But when accustomed to man, they evidently 

 lose this shyness. Living among them, W. E. D. Scott (1887) found 

 them "quite tame and familiar, coming to feed on grain and crumbs 

 daily about my house." 



Aiken (1937) writes: 



If I am walking near where one is feeding in the grass it mounts upon a log or 

 the under branches of a tree to see what is going on, where he remains silent and 

 motionless except [for] perhaps a jerking of the taU. If excited he hops around 

 uneasily with the taU raised at an angle of 45 degrees and if frightened it dives 

 in the long grass. It is almost useless to pursue them after they are once 

 aroused. * * * I sometimes find them among the thick low bushes of the creek 

 bottom, but think they have only resorted to such places for water or food. 



Nowadays they seldom have to get up into trees to see above the 

 pitiful remnants of grass. 



