Figure 1. Great Barnstable Marsh, Cape Cod, Massachusetts, with the typical 

 meandering tidal creeks and the barrier beach in the background. Photo by J.M. 

 Teal, Woods Hole Oceanographic Institution. 



relatively few kinds of insects occur 

 here, those species present can be very 

 abundant, as illustrated by the annoying 

 mosquitoes and greenhead flies. Snails, 

 crabs, amphipods, mussels, and, at high 

 tide, small fishes are present in large 

 numbers. Wading birds are often 

 conspicuous feeders on the fish and 

 invertebrates; rails, wrens, and other 

 less conspicuous birds are also common. 

 Canada geese may feed on the leaves of 

 Spartina and, in winter, snow geese may 

 dig fbT rhizomes. Small mammals, mink, 

 otters, and raccoons come onto the low 

 marsh to feed on grasses, invertebrates, 

 and small fishes. Raccoons sometimes 

 build nests in the high grass to wait out 

 the high tide. 



There are conspicuous seasonal 

 changes in the salt marshes. In the 

 north, winter typically brings a thick ice 



cover that is moved by the higher tides. 

 Occasionally, ice frozen firmly to the 

 underlying marsh rips a chunk of marsh up 

 when rising with the tide and leaves it 

 lying on the marsh surface. These 

 ice-rafted chunks interrupt the otherwise 

 dead, frozen, level surface. Though birds 

 may rest on the marsh in winter, in 

 general, there is little activity. 



Spring warming comes slowly: the 

 regular inundation by the more slowly 

 warming ocean waters delays the greening 

 of the marsh in relation to the 

 neighboring uplands. The mud surface is 

 first to color as it is warmed by the sun 

 at low tide and algae grow quickly enough 

 to take advantage of the brief warm 

 intervals between tides. When in early 

 summer the marsh turns bright green with 

 grass, the algal color fades, robbed of 

 the necessary light by shading of the 



