NORTH AMERICAN MARSH BIRDS 191 



form and appearance of the bird went through a marvelous change. 

 In short flights this heron may retain the elongated pose of the neck, 

 but in longer ones it folds up and retracts that member. 



When walking about, especially if it knows it is watched, the green 

 heron nervously twitches its tail downwards and erects and depresses 

 its crest. It is also able to remain perfectly still, especially when on 

 the watch for game. A common posture assumed on the margin of 

 a pond or sand flats at low tide is with the back and neck horizontal 

 and the tarsi so nearly flat on the ground that the body is close to 

 the same. The bird under these circumstances is easily mistaken for 

 a log of wood. In this position it waits patiently, ready to pounce 

 on the little fish that swim its way and it rarely misses its aim. At 

 other times it approaches stealthily, putting down each foot with care 

 and secures its prey with a quick stroke. That this stroke must be 

 quick and accurate is evident when we consider the natm'e of some 

 of its food, frogs, fish, and grasshoppers. 



That green herons in some cases jimip or even dive into the water 

 after their prey, is shown in the following account by Samuel H. 

 Barker (1901) who saw an individual plunge from a plank after fish 

 into a pond 3 to 6 feet deep. 



Although he missed his aim, the effort was well meant and, to judge by appear- 

 ances, not the first of its kind. Turning about in the water, he rose from it with 

 little difficulty and with a few flaps was back on the plank. ♦ * * That this 

 one instance of an individual green heron plunging into deep water after food 

 proves such to be a natural habit of the species can hardly be said. I would add, 

 however, that further study of the feeding habits of the green heron, with a view 

 to settling this question, convinces me that a quite usual method of fishing is for 

 it to watch from a stand a few inches above the water and from there to jump 

 quickly down upon its prey. 



W. Sprague Brooks (1923) watched a green heron walking stealth- 

 ily along the stone rim of the Public Garden pond in Boston. 



After a while it turned cautiously until facing the water, toes at the rim of the 

 stone, its neck stretched out at full length, and suddenly, as a swinamer in a race 

 plunges from the marble rim of a tank, it plunged into the water, completely sub- 

 merged, came to the surface with a goldfish which it immediately swallowed, and 

 raising its wings, flew back, only a matter of two wing strokes, to the stone bor- 

 der. Twice I watched it do this. 



The note commonl}^ emitted by this bird as it flies from the intruder 

 can, perhaps, best be represented by the syllables yeu-ah. It gener- 

 ally resembles very closely the sound made by blowing a blade of 

 grass stretched tightly between the thumbs side by side. When 

 much startled the green heron croaks hoarsely but soon returns to 

 the usual peu-ah. Sometimes, especially about the nesting tree, it 

 may be heard to give a short caekle or cluck. Early one morning, 

 when I was lying concealed in a grove of trees, a green heron alighted 



