250 ANIMAL LIFE IX THE YO SEMITE 



In one part of the colonj- there are many hop-sage bushes about 3 feet 

 high and 3 or 4 feet in diameter. These grow close to the g:round, and the 

 strong wind which continually sweeps the island blows the molted white 

 body feathers of the parent gulls against these bushes until each bush has 

 at its base a feathery white windrow often six inches thick. When alarmed, 

 the gray downy young gulls rush headlong into these windrows and do 

 not stop until they are entirely hidden. The larger young, in dusky juvenal 

 plumiige, are not so fortunate. They cannot hide their whole bodies in 

 the windrows, and their stubby black tails remain projecting out beyond 

 the drifted feathers in a very grotesque manner. Six youngsters were 

 pulled out of one windrow and there were still other, smaller chicks hidden 

 in the mass. Holes in the rocks were also favorite shelters and places of 

 concealment for the small young; often a chick would shade its head in a 

 small cavity while its body remained out in the broiling heat of the sun. 



When disturbed, the larger young headed for the beach, jumping and 

 tumbling over the rocks faster than a man could walk. When they reached 

 the ten-foot bank which borders the waters of the lake they did not hesitate, 

 but plunged over the edge. Once in the water they seemed perfectly at 

 home and swam about, 100 yards offshore, where they were herded into 

 'rafts' by the parents and prevented from going farther out. (See pi. 41r.) 

 As soon as the intruder retired, the young turned back toward the beach. 

 Once, when a party of a dozen juvenile gulls started down the slope toward 

 the water, they loosened a veritable avalanche of small rocks. Gulls and 

 rocks were pretty well mixed by the time the water was reached and it 

 seemed as though some of the birds would certainly be killed; but they 

 all swam away apparently unharmed. 



The young gulls when first hatched eat bits of eggshell, but soon their 

 diet consists exclusively of brine shrimps. Birds 3 or 4 days old had, we 

 found, a considerable number of these crustaceans in their stomachs. When 

 handled, the first thing a young gull does is to throw up quantities of brine 

 shrimps; and the adults, flj'ing overhead, show their displeasure at the 

 disturbance of the young by pouring down similar disgorgements. When 

 undisturbed the adults stand on guard at the nest site. The young play 

 around in the vicinity, but seem always to return to the nest site for 

 feeding. The larger young frequently climb up on the tops of the rocks 

 to await the return of the parents. 



The old birds often visit fresh-water lakes in the vicinity to feed on the 

 huge frog tadpoles which there abound. An adult bird captured near 

 Williams Butte on June 23, 1916, disgorged several of these large tadpoles. 



