LIFE HISTOKIES OF NORTH AMERICAN GUULS AND TERNS. 275 



portions of its range. But Mr. W. Lee Chambers (1908), in speaking 

 of a protected colony in southern California, says : 



I should say that fully 75 per cent of the birds in this colony raised two or 

 three broods. 



Probably in warm climates, where the breeding season is more 

 prolonged, second broods are more often raised. 



Eggs. — The eggs of the least tern are good examples of protective 

 coloration, for they match their surroundings remarkably well and 

 can hardly be distinguished from mottled pebbles. The usual 

 ground color varies from deep rich " cartridge buff " to very " pale 

 olive buff," or to a color between " pale olive buff " and white. This 

 is more or less unevenly sprinkled with small spots, and sometimes 

 with a few large spots or blotches of dark shades of brown, such as 

 "Mars brown," "sepia," or "mummy brown." Most eggs show 

 some spots and many, particularly of the lighter types, show large 

 underlying blotches of " Rood's lavender " or other shades of " laven- 

 der gray." Some eggs show very handsome patterns of bold dark 

 markings over lighter shades. The shape varies from ovate to short 

 ovate and the shell is thin and lusterless. The measurements of 63 

 eggs, in the United States National Museum, average 31 by 23.5 

 millimeters; the eggs showing the four extremes measure 37 by 24, 

 28.5 by 23 and 29.5 by 22 millimeters. 



Young. — ^The period of incubation is said to be from 14 to 16 days. 

 The young remain in the nest for a few days, but soon begin to 

 develop powers of locomotion. They realize the value of the hiding 

 pose and are well aware of their protective coloration ; they lie pros- 

 trate on the sand, where they are nearly invisible, until almost 

 touched, when they start up and run away with astonishing rapidity. 

 When once started they seldom attempt to hide again and are very 

 difficult to catch. 



Mr. Edward H. Forbush has sent me the following interesting ob- 

 servations on the behavior of the young : 



Near me were two little young, just hatched and their down hardly dry, yet 

 they were able to run about a little. Near by were several other youngsters. 

 As I lay there propped up on my elbows, awaiting the return of the mother 

 birds, several of them flitted back and forth, and soon their cheeping cries 

 changed to a musical metallic "pidink," which has something of the tinkling 

 quality of the bobolink's note. Soon the mother of the two nearest little ones 

 alighted, and, running to her charges, settled easily upon them, shading them 

 from the hot sun's rays. Then she turned her gaze upward and called softly 

 in reply to the tender notes of the male, which circled overhead. Soon he 

 alighted and took the mother's place in shading the young, while she flew away, 

 perhaps to fish and bathe. Soon she returned with a little sand eel, which 

 she gave to one of the tiny ones, who ran to her for it. Then she flew again, 

 descended into the sea and returned to her charges which the male relinquished 



