70 PACIFIC COAST AVIFAUNA No. 9 



will take possession of a grain field, building their light, basket-like structures 

 amid the swaying wheat or barley stalks, from six inches to two feet above the 

 ground. 



Not infrequently this species departs from the usual customs that have been 

 followed for so long, and nests in treetops. One such colony found May 25, 

 1906, was occupying some willows along a canal, one nest was fully thirty i-eet 

 from the ground and resembled a kingbird's home, except that several long 

 streamers of dry tule strips were left dangling and swaying in the breeze, mak- 

 ing the nest very conspicuous. That this site was chosen from preference and 

 not from necessity was clearly evident, as there was a growth of tules all along 

 the edge of the canal, and a half section of wheat adjoining. Another colony 

 chose nesting sites among the thick foliage of a long row of fig trees, the nests 

 being situated from twelve to twenty feet above the ground. In driving along 

 the road after the leaves had fallen from the trees 1 counted eighteen nests in a 

 short section of the row. Almost under these trees was a small ditch in which 

 water stood nearly all summer, and which was partly concealed by willows, tules, 

 and sedges ; but perhaps the close proximity of a schoolhouse had taught the 

 birds to elevate their nests and conceal them as well. 



Nests of the Bicolored Blackbird are well- woven, light but substantial, struc- 

 tures, composed of dry grass .stems and tule stalks, plastered with mud and lined 

 with finer dry grass. In probably ninety percent of the nests examined four 

 eggs con'stituted the set. Sometimes, especially late in the season, sets of three 

 are deposited, but out of hundreds of nests that have come under my notice I 

 have yet to find a set of five eggs. Probably two or more broods are raised in ? 

 season, as a nesting colony seems to be in a continual state of operation for about 

 three months in the year and nests with incomplete sets of fresh eggs are fre- 

 quently found within a few feet of others that hold large young birds. 



Throughout the winter these blackbirds rove about the valley seeking feed- 

 ing grounds, often congregating in large numbers in fields that are being cleared 

 of weeds, or following a string of plows, along with a host of Brewer Black- 

 birds. 



Farmers regard this bird with considerable disfavor on account of its fond- 

 ness for newly planted grain, and because of its attacks upon ripening Kaffir, or 

 Egyptian, corn. In districts where large fields of alfalfa are under irrigation 

 these birds are of much service in destroying various bugs and worms. 



TRTCor.oRED Blackbird. Agelaius tricolor (Audubon). 



Tricolored Blackbirds, although occurring commonly in the Fresno district, 

 are much more local in distribution than any of our other blackbirds ; and while 

 they scatter out over the greater part of the lowlands of the valley during the 

 winter months, they appear to be confined to certain favorable sections when the 

 breeding season is at hand. It is not unusual to find a few of this species as- 

 sociating 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. 



During the month of March great hordes of Tricolored Blackbirds fly north- 

 ward in what is evidently a local migration. Every morning, from daylight until 

 after sunrise, they pass over at frequent intervals : sometimes half a dozen birds 



