288 U. S. NATIONAL MUSEUM BULLETIN 211 



Tail darker with greenish reflections. Tertials and wing coverts 

 edged with Mar's-brown." 



A complete postjuvenal molt occurs during the latter half of summer; 

 this produces a first winter plumage, in which the sexes become dis- 

 tinguishable, and which is not very different from that of the adults 

 in the fall. Dwight describes the first winter plumage of the young 

 male as "everywhere lustrous greenish black more or less veiled above 

 with Mar's-brown, below with wood-brown." The illustrations of 

 these plumages in Bird-Lore, vol. 23, No. 6, opposite p. 281, seem to 

 me to be much too highly colored. 



Ridgway (1902) adds, in a footnote, the following comment: 

 "The extent of this rusty and buffy coloring varies exceedingly in 

 different individuals, probably according to age. In some (doubtless 

 younger birds) the rusty is nearly uniform on the pileum and hindneck, 

 and forms very broad tips to the scapulars and interscapulars, while 

 the cinnamon-buffy forms a continuous broad superciliary stripe and 

 is nearly uniform over the malar region, chin and throat. Other 

 winter males (probably very old individuals) have scarcely a trace of 

 this rusty and buffy coloring, being quite like summer specimens, 

 except that the plumage is more highly glossed." 



There is apparently no prenuptial molt in either young or adult 

 birds, the spring plumage being acquired by the complete, or nearly 

 complete, wearing away of the rusty edgings. Adults have a complete 

 postnuptial molt in summer, beginning the middle of July. 



Dwight (1900) says that the first winter plumage of the female "is 

 very like the juvenal but with much Mar's-brown above chiefly on 

 the head and strongly washed below with wood -brown, these colors 

 edging slaty feathers; the lores and auriculars are dull black in contrast. 

 The first nuptial plumage is acquired by wear and later plumages vary 

 little from the first winter." 



Food. — Beal (1900) analyzed the contents of 132 stomachs of the 

 rusty blackbird, taken every month in the year except June and July, 

 and reports: 



The stomachs contained a larger proportion of animal matter (53 percent) 

 than those of any other species of American blackbirds except the bobolink. 

 This is the more remarkable in view of the fact that none were taken in the two 

 breeding months of June and July, when in all probability the food consists 

 almost exclusively of animal matter. While the birds are decidedly terrestrial 

 in their feeding habits, they do not eat many predaceous ground beetles (Cara- 

 bidae), the total consumption of these insects amounting to only 1.7 percent of 

 the whole food. Scarabaeids, the May-beetle family, form 2 percent, and in 

 April 11.7 percent. Various other families of beetles aggregate 10.1 percent, 

 largely aquatic beetles and their larvae, which, so far as known, do not have any 

 great economic importance. A few of the destructive snout-beetles (Rhyn- 

 chophora) are also included, as well as some chrysomelids and others. 



