106 BULLETIN 135, UNITED STATES NATIONAL MUSEUM 



five are common, sets of six are frequently found, and sets of seven 

 have been reported. The shape varies from ovate, or (rarely) oval 

 to elliptical ovate, or (rarely) fusiform. The shell is smooth or slightly 

 rough. The color varies from " pale Nigara green " to " lichen green "' 

 or "pale olivine." The measurements of 50 eggs average 64.5 by 

 45.2 millimeters; the eggs showing the four extremes measure 70.4 

 by 47.6; 67.9 by 49.2; 56.9 by 42.7; and 59.2 by 42.2 millimeters. 



Young. — The period of incubation is about 28 days. Mr. Hastings 

 says that both sexes incubate. He once saw a bird with broken wing 

 feathers leave a nest and very shortly another, with perfect wings, 

 took its place. Also he has seen a great commotion around a heronry 

 early in the morning, again about 10 a. m., and at about 2 p. m., and 

 again just before dark, which he believes is due to the birds changing 

 on the nests. 



Young herons are far from attractive, either in appearance or be- 

 havior, at any age; at first they are feeble and helpless, but later on 

 they are awkward, ungainly, and pugnacious. If undisturbed, they 

 remain in the nest until as large as their parents and fully fledged; 

 but when nearly grown they are easily frightened and leave the nest 

 to climb awkwardly over the surrounding branches and perhaps fall 

 to the ground or water below, which often results in death, as their 

 parents do not seem to have sense enough to rescue or even feed 

 them. 



In the nest they are fed by both parents, at first on soft regurgitated 

 food, later on whole fresh fish. With the youngest birds the soft soup- 

 like food is passed from the bill of the parent into that of the young 

 bird; but later on the more solid food is deposited in the nest and 

 picked up by the young. The young birds usually lie quietly in the 

 nest, crouched down out of sight, between feedings; but as soon as the 

 parent is seen or heard returning (the senses of the young are very 

 keen) there is great excitement, as they stand up to clamor and wrestle 

 for their food. The old bird approaches with deliberate dignity and 

 may stand on the nest for a few minutes with her head high in the 

 air. Then with crest and plumes erected and with a pumping motion, 

 she lowers her head and one of the youngsters grabs her bill in his, 

 crosswise; the wrestling match then follows until the food passes into 

 the young bird's mouth or onto the nest. The young are usually fed 

 in rotation, but often the most aggressive youngster gets more than 

 his share. 



The young instinctively try to void their excrement by squirting 

 it over the edge of the nest, but they are not eminently successful 

 at it and the nest, the tree, and the ground under it are usually 

 completely whitewashed with their profuse ordure before they are 

 fully grown. This and the decaying fish which fall from the nests 



