YELLOW-HEADED BLACKBIRD 107 



and out among the upright supports. Of course, there is great varia- 

 tion in placing each individual shred, but the resultant nieshwork of 

 fibers forms a wonderfully strong and compact basket. When the 

 female has disposed of all the loose material on the rim, she tugs at 

 any loose ends in sight, especially on the outside of the nest. She 

 reaches far over the edge and pulls such strands over the rim, if 

 possible, and thrusts tbem into the inside of the wall." 



For shaping the inside of the nest, she "supports herself by her head 

 and tail on the rim and stamps her feet alternately in rapid succession 

 on the bottom and sides of the cup. The nest is usually so wet that 

 the stamping can be beard several meters away. After a few seconds 

 she rises and settles down at a slightly different angle and duplicates 

 the performance. This procedure may be repeated a number of times 

 in quick succession. * * * 



"After the outer wall is high enough the female adds material to the 

 inner side of the wall and in the bottom in order to make the cavity the 

 right size and shape. This may be called the inner cup. She does 

 not loop the strands around the supports but drops each load directly 

 in front of her as she enters the nest. Her breast is then applied to 

 this newly brought material while she stamps her feet in the manner 

 already described, thus making the nest compact, and the inside 

 smooth, round, and of the correct diameter. The general appearance 

 of the inner wall when finished is different from the outer wall. The 

 direction of nearly every strand is in an arc, parallel to the circum- 

 ference, and the brim is generally smooth and on a horizontal plane. 



"A final stage of construction that is by no means universal is the 

 addition of some fine, dry grasses which serve as a lining. When 

 present they are usually confined to the wall and often only imme- 

 diately below the rim on the inside, thus constricting the opening." 



Ira N. Gabriclson (1914), writing of a Nebraska swamp, says: 

 "The Yellow-headed Blackbirds were by far the most abundant breed- 

 ing form of the swamp. In the part examined there were probably 

 several hundred nests; in the remaining half of the swamp the number 

 is only a matter of conjecture. The nests which we examined were 

 practically identical in location, being built in the wild rice growing 

 some distance from the shore. They were woven in basket shape 

 about three or more stems from eighteen inches to two and one-half 

 feet above the water. The water in the region of the nests was about 

 hip deep and they seemed to be confined to a belt of this depth around 

 the part of the swamp studied." 



Eggs. — The yellow-headed blackbird lays from three to five eggs 

 to a full set, most commonly four, and only very rarely five. Of 504 

 nests examined by Amraann (MS.), only 8 contained 5 eggs, while 

 282 held 4, and 110 sets consisted of 3 eggs. 



