categories of foraging tactics are stand 

 or stalk feeding, disturb and chase feed- 

 ing, and aerial and deep water feeding. 

 VJithin each of these major categories, 

 there are several variations. The stand 

 and wait feeding behavior is the most 

 typical and is common to all species of 

 herons (Allen 1962). 



Depending on the habitat, which in- 

 cludes prey density, predator density, 

 water depth, and plant cover, species use 

 their own unique hunting tactics (Kushlan 

 1976). In his study of heron feeding in 

 southern New Jersey, Willard (1977) sum- 

 marized the foraging behaviors of many of 

 the herons seen in New England. He found 

 that great blue herons and common egrets 

 hunt in deeper water than the smaller 

 species. Great blue herons used stand 

 and wait and slow wading techniques to the 

 same extent. Active pursuit was rare, 

 probably related to the large and highly 

 mobile fish species in the diet. Great 

 egrets also used slow wading techniques 

 but their pace was faster than the great 

 blue herons, and when feeding in flocks, 

 they used the stand and wait technique. 

 Snowy egrets showed the greatest variety 

 of feeding behaviors and of habitat selec- 

 tion. They were the only species to fre- 

 quent exposed mud flats where they would 

 take large polychaetes. Slow wading was 

 the nost frequent hunting technique, but 

 foot stirring and active pursuit were also 

 common. The foot stirring behavior re- 

 sulted in a larger portion of benthic 

 crustaceans in the snowy egret's diet. 

 The Louisiana herons also relied on active 

 pursuit, but the most common feeding 

 behavior was to crouch and strike hori- 

 zontal to the water's surface. This was 

 the only species in which slow wading was 

 not the preferred technique. Little blue 

 herons commonly waded slowly and peered 

 around banks and vegetation. The green 

 heron and black-crowned night heron were 

 not studied by Willard (1977). Both these 

 species can be commonly seen crouched 

 overlooking the water's surface where they 

 wait motionless for prey to wander by. 



5.5 WATERFOWL AND DIVING BIRDS 



This group is composed of a wide 

 variety of families, including the loons 



(Gaviidae), grebes (Podicipedidae), cormo- 

 rants (Phalacrocoracidae), and the ducks, 

 geese, and swans (Anatidae). The majority 

 are migrants, present in New England only 

 during spring and fall, or they are winter 

 residents. Exceptions are the double- 

 crested cormorant, common loon, gadwall, 

 wood duck, and red-breasted merganser that 

 breed in some areas of New England and the 

 pied-billed grebe, Canada goose, black 

 duck, mallard, and mute swan that are 

 year-round residents. With only a few 

 exceptions (the geese, swan, and dabbling 

 ducks), all these birds dive for their 

 food which is usually fish, molluscs, or 

 crustaceans. Although many species are 

 capable of dives to great depths (over 

 70 m or 230 ft for the common loon), most 

 forage in shallower water, usually less 

 than 10 m (33 ft) deep. Some have become 

 extremely well-adapted to an aquatic 

 existence, can barely walk on land, and 

 can only take off from the water. 



Two species of loons (common loon and 

 red-throated loon) are often found along 

 the New England coast during the winter. 

 Although they do not concentrate their 

 foraging on tidal flats, at high tide, 

 they may be seen over these shallow areas 

 diving for fish. Common loons are soli- 

 tary, even during migrations, and occur 

 singly or in pairs, while the red-throated 

 loons accumulate in large flocks, particu- 

 larly during migrations (Terres 1980). 

 Because the loons require up to several 

 hundred meters of water "runway" to become 

 airborn, when approached, they will dive 

 rather than fly as a means of escape. 



Grebes, like the loons, may use tidal 

 flats at high tide as one of several of 

 their feeding areas. They are extremely 

 well-adapted for their primarily aquatic 

 existence where they feed, sleep, court, 

 and carry their chicks on their backs in 

 the water. Of the three species seen along 

 the New England coast, the horned and red- 

 necked grebes breed in Canada but winter 

 in coastal New England. The pied-billed 

 grebe breeds throughout New England and 

 winters as far north as Massachusetts. 

 Their diets consist of small fish and 

 crustaceans. 



Cormorants are related to pelicans 

 and feed almost entirely on fish that they 



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