260 SEA-BIRDS 



seems to vary considerably, with a minimum of 21 days. The new- 

 born chick is covered with a long soft down with fine hair-like tips, 

 and is protectively coloured: the background of the down is some 

 shade of buff, marked and streaked with patterns of black and brown. 

 Terns will lay a second clutch if the first one is lost, or abandoned by 

 a shift of the whole colony, and a third if a second is freshly taken. 

 Black terns in North America lay three clutches (of 3, i, i) if con- 

 tinuously robbed. Little terns in South California are said to raise 

 two broods in a season. 



The Marples record that the greatest anxiety of the adult at hatch- 

 ing time is to remove the egg-shell as soon as the young bird is free, 

 and to carry the shell off and drop it at a distance ; they argue that 

 the female does this instinctively, but by so doing she "removes, one 

 after the other, the evidence of the birth of her offspring, and this 

 was presumably to protect them from danger, for the presence of the 

 shells would draw attention to the nests." 



Young terns have a peculiar shrill chittering, squealing or whistling 

 note, which they use until they are well on the wing. They are brooded 

 in the nest for the first two or three days by the female, the male 

 feeding both his mate and his chicks during this period. Both parents 

 feed the chicks subsequently, bringing in sand-eels — among the princi- 

 pal food of the Atlantic sea- terns. When one parent is feeding the chicks 

 the other often appears to mount guard, driving away neighbours 

 which approach too near. When handing over a fish to its mate or 

 chick, the adult always places it head first in the other's bill. It is 

 never dropped, except occasionally, on the ground. If it does fall 

 to the ground the adult may pick it up again, but the chick seems 

 incapable of doing this, and many fish will be found lying about on 

 the ground in a ternery, with the young terns, oblivious of this food 

 at their feet, calling hungrily to be fed. Young terns will swallow 

 fish of greater length than their own bodies, and will gulp uncomfort- 

 ably for a long time with the tail hanging from the mouth while the 

 head is being digested in the stomach. The old tern thrusts the fish 

 only sufficiently far into the mouth of the young tern for the throat 

 muscles to grip it. On hot days the adult may provide shade for the 

 chicks by partly opening its wings, but for short periods. Chicks not 

 provided with shade have been known to die from heat upon sand 

 (Austin, 1932b). 



In some cold stormy summers there is great mortality among 

 young terns, due to lack of food and to the dangers from drifting sand 



