FEEDING HABITS FOOD RESOURCES 



PHYTOPLANKTON 



ZOOPLANKTON 



PLANKTONIC ^^^ >. NEKTONIC CRUSTACEANS 



FISH EGGS AND LARVAE 



LARGE FISHES 



NEKTONIC 



DETRITUS, ALGAE 



POLYCHAETES 



DEMERSAL AND ^ ^\ MOLLUSCS 



SEMIDEMERSAL 



SMALL FISHES, SQUID 

 CRUSTACEANS 



Figure 5-25. Feeding habits of estuarine fishes. 



invertebrates and vertebrates of the strand line (the supratidal zone where a 

 community develops on the macroalgae that washes ashore) . Shorebirds eat 

 mostly intertidal mudflat invertebrates (i.e., oligochaete and polychaete 

 worms, amphipods, and the Baltic clam), squid, other invertebrates, finfish, 

 zooplankton, and strand line invertebrates. Wading birds prey on reptiles, 

 amphibians, finfish, insects, benthic invertebrates, birds, small mammals and 

 some plant materials. Waterfowl feed mostly on benthic and other 

 invertebrates, fish, and plant material. Brant are important herbivores, 

 feeding on intertidal and subtidal algae (e.g., Ulva ) , vascular plants (e.g., 

 eelgrass), and the invertebrate fauna associated with these communities. 

 Ospreys are primarily fish eaters. Bald eagles in coastal Maine feed mostly 

 on fish, waterfowl, and seabirds. 



Islands in estuaries are used for nesting (e.g., bald eagles, ospreys, wading 

 birds, gulls, eiders, and double-crested cormorants), rearing young (e.g., 

 bald eagles, ospreys, eiders, black duck, common and roseate terns, laughing 

 gulls, and wading birds), moulting (e.g., eiders and Bonapartes gulls), 

 roosting (most groups), wintering (e.g., bald eagles, black ducks, mallards, 

 Canada geese, seaducks, purple sandpipers, gulls, loons, grebes, kittiwakes, 

 and great cormorants), and as migratory stopover areas (e.g., shorebirds, 

 brant, geese, dabbling ducks, peregrine falcon, bald eagles, ospreys, diving 

 ducks, Bonaparte's gulls, and ring-billed gulls). 



5-45 



10-80 



