226 
Yellow-Headed Blackbird 
site and returns year after year^ even when the surroundings undergo 
great and uncongenial changes, deserting it only with the drying up of 
the marsh. The Yellowhead is very closely restricted to its special nest- 
ing haunts, and as the members of each colony go in the spring directly 
to their particular rendezvous, and wander but a little 
^oyal to surrounding country until after the com- 
pletion of the breeding period, they are easily over- 
looked if their nesting sloughs are not numerous or their homes be not 
actually invaded. 
In the northward movement in spring the vanguard of the Y’ellow- 
heads that are to breed in Canada reach the international boundary 
about May 1, the males preceding the females by a few days. In Minne- 
sota, where the writer’s entire experience with this bird has been gained, 
stragglers enter the southern part of the State about the middle of April, 
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 growth of 
quill-reeds (Phragmiies) that fills or encircles many of the sloughs and 
shallow lakes of the prairie and semi-prairie parts of the State. Occa- 
sionally 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. 
A Denizen Nest-building is usually begun in central Minnesota 
of the Reeds about the middle of May and continues until well into 
June. It seems probable, however, that only one brood is raised in a 
season, the 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 breed- 
ing season furnish the data for the following summary of the chief fea- 
tures of the nesting of the Yellowhead : 
The female builds the nest and incubates the eggs without any assist- 
ance by the male. 
The male assists in the care of the young, but only to a limited ex- 
tent and chiefly after they leave the nest. 
The body of the nest is constructed of wet material collected from 
the water near by. This is wov-en about the stems 
of the reeds, two or three feet above the water, and 
its drying and contracting fixes the nest securely in 
position, as is well shown in the illustration on page 225. 
The lining consists of pieces of broad, dry reed-leaves, and often the 
rim of the nest is finished with the fine branches of the plume-like 
fruiting-tops of the reeds, forming a sort of canopy over the somewhat 
constricted entrance. 
Structure 
of the Nest 
* For fuller details, see The Auk, xxvi, 1909, pp. 371-389, 10 plates, 24 photographs. 
