LESSER TERN. 309 



very extensive. This Tern makes no nest, not even 

 scratching a hollow for the reception of the eggs, but 

 laying them, not on the fine sand, but on the slips. of 

 rough shingle, where the bold character of their mark- 

 ings harmonizes so closely with the ground that their 

 discovery is difficult. The birds become noisy and fly 

 anxiously about overhead when their nesting-ground 

 is invaded, but show less concern for their treasures 

 than the other Terns invariably do. 



RANGE OF EGG COLOURATION AND MEASUREMENT: 

 The eggs of the Lesser Tern are from two to four in 

 number. On two separate occasions I have seen 

 clutches of the latter, but three is the average number. 

 They vary from buff to grayish-brown in ground colour, 

 spotted and blotched with dark brown and yellowish- 

 brown, and with underlying markings of gray. They 

 run through every variation that characterizes the eggs 

 of the two preceding species, and may perhaps be best 

 described as resembling those of the Common Tern in 

 ground colour, and those of the Arctic Tern in the bold 

 nature of the markings. Average measurement, 1*25 

 inch in length, by '95 inch in breadth. Incubation, per- 

 formed by both sexes, is said by Tiedemann to last 

 from fourteen to sixteen days, but this probably is an 

 error, the period most likely being the same as that of 

 the preceding species. 



DIAGNOSTIC CHARACTERS : The eggs of the Lesser 

 Tern may be at once distinguished by their small size, 

 elliptical shape, and the bold character of their markings. 



