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In the ecology of the birds this association occupies a much 

 more immediate position than the first. In its outer portion, 

 among the bulrushes, the Pied-billed Grebe finds the optimum 

 for its existence. Here, upon a floating pile of debris, it 

 deposits its eggs, and here it raises its young. In the inner 

 stretches, where the vegetation is more dense, several birds 

 are found nesting. Out into the burreed and Equisetum the 

 Redwings and Rails extend their domain, while on the inner 

 edge of the society the Marsh Wrens begin to nest and the 

 Redwings and Rails occur more abundantly. The Coot and 

 the Gallinule occasionally straggle thus far from the shelter 

 of the cat-tails for their nesting sites. None save the Grebe, 

 however, find here conditions best suited to their mode of 

 life. Aside from giving shelter for nesting sites, it provides 

 one of the best foraging grounds for most of the marsh birds, 

 not in itself, but indirectly through the insect life which it 

 supports. None of the plants of this zone — nor, in fact, any of 

 the strictly marsh plants — supply forage for the birds, so far 

 as observed. The seeds, which would be the natural food of 

 many birds, are so protected by extremely thick seed-coats, 

 as in the burreed and sedges, or by thick coatings of mucilagi- 

 nous jelly, as in the arrow arum, that they are not available. 

 The seeds that are utilized are those of plants which do not 

 belong strictly to the marsh but to its border. However, in 

 the pools and shallow water of this zone, on the leaves and in 

 the tissues of the plants, are bred the numerous insects which 

 furnish the primary food supply of most of the marsh birds 

 during at least part of the year. Beetles of the genus Donacia, 

 for instance, appear about mid-June in enormous numbers 

 on the leaves of the burreed, and furnish almost the entire 

 food supply of the Redwings at that season. 



The characteristic mammal of this habitat is the Muskrat 

 (Fiber zihethicus). Here it builds its houses, which are such 

 characteristic sights along the rush-lined shores. 



The fishes listed under the first association penetrate into 

 this habitat but do not belong strictly to it, and therefore will 

 be omitted here. 



Of the Amphibia, the adults of certain species remain in the 



