46 Tin: Wilson Bulletin — No. 55. 



The habits of the partly fledged young, before they are capa- 

 ble of flight, lend color to the supposition that these color pat- 

 terns are protective in nature. 



I could discover no evidence, however, to prove that the 

 young birds are conscious of the protective nature of their 

 color patterns. The downy young usually squatted and 

 "froze" when the parent uttered the alarm cry, and the partly 

 fledged young usually ran to hide — invariably trying to crawl 

 under something. 



The streakiness of the doui^aHi downy young harmonizes 

 with the shadows which the grass overhanging the nest cast. 

 After they leave the nest they are difficult to see beneath it, 

 because the colors and pattern of the downy plumage harmon- 

 ize well with the grass and shadows. The blotchiness of the 

 Itirnndo downy young harmonizes with the rubble of the beach 

 and, while there is more contrast with the grass in which some 

 are found than with the downy young of dougaUi, there is yet 

 harmony enough to miake the young bird inconspicuous while 

 it is still. 



The juvenile hintndo hides, or tries to hide, like the Ostrich 

 — by thrusting its head beneath the grass cover. Its head is 

 nearly black with a light colored frontlet, while the barring 

 of the rest of the upper parts with tawny and dusky or black 

 harmonize with the grass beneath which the head is thrust. 

 Persons who had not studied the terns in their nesting places 

 w^ere unable to see the young when so placed. Under broad 

 leaved plants these young were readily seen after the leaves 

 had been parted. The juvenile doiii^alli pushes himself com- 

 pletely beneath the grass or leafy retreat. When the cover- 

 ing is partly removed his peculiar pattern of barring and 

 mottling makes him inconspicuous. His habit of moving 

 toward deeper cover when his hiding place is disturbed betrays 

 him. 



The pure black crown, pure white under parts, and clear 

 "gull blue" upper parts of both of these terns in adult plum- 

 age is well known. If there be any protective coloration in 

 the adult pattern it nuist be while the birds are a-wing, for 

 they are conspicuous objects when a-light. 



