The Yellow-Headed Blackbird 251 



about Ihe middle of Ai)ril, but it is not until the very last of that month or 

 early in May that they become numerous. 



In this region they breed almost exclusively in the dense 

 Nesting growth of quill-reeds {Phragmites) that fills or encircles many 



of the sloughs and shallow lakes of the prairie and semi-prairie 

 portions of the state. Occasionally spring freshets or other disturbances may 

 drive them to place their nests among bulrushes {Scirpus) in upland sloughs 

 or more rarely still, in willows and bushes adjacent to open water. Nest- 

 building is usually begun in central Minnesota about the middle of May and 

 continues until well into June. The writer has found young birds near Min- 

 neapolis hatched as early as May 28, and has watched the building of nests at 

 Heron Lake in southwestern Minnesota as late as June 20, when many young 

 were already awing. It seems probable, however, that only one brood is raised 

 in a season, this great variation in the nesting-time being explainable by the 

 depredations of various small animals which devour the eggs and young, and 

 by severe elemental disturbances. 



The examination of many hundreds of nests over a long period of time 

 and a detailed study of a single colony* throughout the entire breeding season 

 furnish the data for the following summary of the chief features of the 

 nesting of the Yellow-head : 



The female builds the nest and incubates the eggs without any assistance 

 from the male. 



The male assists in the care of the young, but only to a limited extent and 

 chiefly after they leave the nest. 



The body of the nest is constructed of wet material collected from the 

 water nearby. This is woven about the stems of the reeds, two or three feet 

 above the water, and its drying and contracting fixes the nest securely in 

 position. 



Thelining consists of pieces of broad, dry reed-leaves, the rim of the nest 

 being often finished of^ with the fine branches of the plume-like fruiting tops 

 of the reeds, forming a sort of canopy over the somewhat constricted entrance. 



The typical finished nest is a firm, inverted, cone-shaped basket-like affair, 

 suspended among the rigid stems of last year's reeds, only exceptionally among 

 new growth. The height is usually eight to ten inches, rarely only four or 

 as much as twelve inches. 



A skillful, industrious bird will build one of these large, beautifully woven 

 and lined nests all complete in two to four days. When it is considered that a 

 single bird has not only to collect but skillfully to manipulate all this large 

 mass of material, it is a surprising matter to see these bulky nests spring up 

 almost over night. 



The eggs in a set are three to five, usually four. They are laid one each 

 day, the first egg one to five days after the completion of the nest, depending 



*For fuller details, see 'Auk.'^XXV'I, 1909, pp. 371-389, 10 plates, 24 photographs. 



