186 U. S. NATIONAL MUSEUM BULLETIN 211 



caterpillars and various sorts of insects in various stages of growth, and probably 

 the harm done to the grain is more than offset by the good work of destroying 

 injurious pests of the insect world. 



Nuttall wrote to Audubon (1842) that tricolored redwings were 

 seen in the suburbs of Santa Barbara, feeding "almost exclusively on 

 the maggots or larvae of the blow-flies, which are generated in the 

 offal of the cattle constantly killed around the town for the sake of 

 the hides." 



Economic status. — As can be seen from the above statements, the 

 economic status of the tricolored redwing is not as bad as it has been 

 painted. Examination of stomachs has shown that a surprisingly 

 small amount of grain is consumed, which is largely offset by the 

 immense numbers of injurious insects eaten. Where the birds are 

 especially abundant, however, hordes of them may be seen flying to 

 and from the fields of barley, rice, and other grains, leaving many 

 stripped heads of ripening grain on the stalks, resulting in considerable 

 losses, especially in fields near the large breeding colonies. 



Behavior. — The outstanding characteristic of the tiicolored red- 

 wing is its highly gregarious behavior at all times, the density of its 

 nesting colonies, the immensity of its flocks, and its social habits. 

 Dawson (1923) puts it very aptly as follows: "Agelaius tricolor is 

 intensely gregarious, more so perhaps than any other American bird. 

 Every major act of its life is performed in close association with its 

 fellows. Not only does it roost, or ravage grain fields, or foregather 

 for nesting, in hundreds and thousands, but the very day of its nesting 

 is agreed upon in concert. In continuous procession the individuals 

 of a colony repair to a field agreed upon in quest of building material ; 

 and when the babies are clamoring the loudest for food, the deploying 

 foragers join their nearest fellows aud return to the swamps by platoons 

 and voilej^s, rather than as individuals." 



And Grinnell and Storer (1924) remark: "Zealous guarding of the 

 nesting precincts, which is so marked a trait in the behavior of the 

 male Red-wing, is not practiced by the Tri-color. There is not the need 

 for each and every male to remain at the nest while the female is 

 absent; the nests are located so very close together that there are 

 always enough adult birds about the colony to sound an alarm should 

 an enemy appear. It would seem as though the Tri-colored Blackbirds 

 had attained to a more successfully communal stage of development in 

 their domestic affairs than have the Bi-colored Red-winged Black- 

 birds." 



Tyler (1913) says that— 



It is not unusual to find a few of this species associating with the large flocks of 

 mixed blackbirds that are so often seen in winter, but for the most part the 

 Tricolors seek no company aside from that of their own kind. 



