97 



tails become stronger and denser, suitable nesting sites can 

 be found without the employment of the stub supports, and 

 many of the nests are suspended freely in the growing vegeta- 

 tion. These nests are seldom capsized, though frequently the 

 growth of the vegetation squeezes the nest together, crowding 

 the young until they are forced to leave prematurely (Plate 

 XVII, fig. 2). By the end of the third week in May, most of 

 the vegetation in the marsh is sufficiently strong to support 

 a nest, and as a result, nests built at this season are located 

 rather indiscriminately in cat-tail, sedge, burreed, water 

 horsetail, dock, or arrow arum (Plate X, fig. 2). By the first 

 of June the cat-tails and sedges are matured, and have become 

 very dense and harsh. The Redwings now desert them for 

 the softer vegetation, such as the dock and smartweed, which 

 by this time fill most of the small ponds. A few pairs, however, 

 continue to nest in the cat-tails about the edges of ponds, 

 where it is unnecessary for them to penetrate at each visit 

 the harsh, dense tops of the vegetation above the nest. With 

 the change in nesting site during the season, there is a corre- 

 sponding change in the altitude of the nest above the water. 

 Beginning in the middle of April, the nests are located at an 

 average of eight or ten inches above the water, but by the 

 middle of June the average has risen to twenty-five inches 

 (Plate X, fig. 1). This is doubtless due to the elevation, with 

 the growth of the vegetation, of the available nesting sites. 

 There is likewise a corresponding change in nesting material 

 and workmanship. The first nests, constructed by adult birds 

 with plenty of time and material, are very neat, compact 

 structures, hke that described by Nuttall. Later nests, how- 

 ever, built by immature birds when the supply of milkweed 

 fiber has been greatly depleted and time is more limited, are 

 much less complete, not infrequently with one of the three 

 main parts eUminated. The nest shown in Plates XIV-XVI 

 is such a one, composed almost entirely of narrow strips of 

 cat-tail and sedge, without the feltUke filling and much of the 

 grass lining. In general, the materials are those which are 

 most convenient at the season and spot in which the nest is 

 being constructed, and they are utilized in so far as they can 



