53 



extending from Cascadilla Creek to the lake. This tract is a 

 mile wide and about four-fifths of a mile long, and covers, 

 as stated above, about 450 acres. Accordingly, in the winter 

 of 1908, such a map was roughly prepared (Plate II). Upon 

 it were located the woods, the watercourses, and the natural 

 landmarks that might be useful. For an intensive study, it 

 was decided to have a more detailed map of a portion of the 

 marsh, and in the spring of 1910 a tract was selected which 

 seemed representative, and was at the same time available 

 from the Biological Field Station.* This tract (Plate III), 

 which is delineated by the Inlet, Cascadilla Creek, and a road 

 extending through the marsh to the lighthouse, is roughly 

 triangular in outline. It is 3,750 feet in length and 1,250 

 feet in greatest width, and covers about 62 acres. With chain 

 and planetable it was accurately outlined, and the trees, 

 bushes, and other landmarks were indicated. The ponds and 

 plant societies were added by means of the planetable and a 

 series of flags, which was erected every hundred feet along 

 the lighthouse road. 



In this area each nest, as soon as discovered, was tagged 

 and marked upon the chart. Records were kept of the depth 

 of the water at the nest, the height of the nest above the water, 

 its structure, and the nature of the vegetation in which it was 

 built. Entries were made as to its progress at each observa- 

 tion. In this way, in 1910, 163 different nests were located 

 and visited from time to time. Of these, 74 were built by 

 Marsh Wrens, 51 by Red- winged Blackbirds, 10 by Virginia 

 Rails, 2 by Sora Rails, 10 others by Rails, but not finished and 

 therefore not fully identified, 8 by Swamp Sparrows, 3 by Song 

 Sparrows, and 1 by a Florida Gallinule. Many of these nests, 

 especially those of the Redwing and the Marsh Wren, were 

 never completed, and of those completed, many were de- 

 stroyed before the eggs hatched, and still others before the 

 young could leave the nest. A general summary showed that 

 of the 51 Redwings' nests carefully observed, 12 were deserted 

 before completion, in 14 the eggs were destroyed, by natural 



* The Biological Field Station of Cornell University, located in the 

 marsh near the mouth of Fall Creek; Professor J. G. Needham, Director. 



