THE SEA BIRD LOCKLEY 345 



since the burrow, after all, is the only point on the island that has 

 ever attracted them. They went off to sea and certainly would not 

 appear on the island again until the following spring. Probably, 

 in their winter quarters at sea they would soon be plunged deep in 

 their molt, which takes place in the autumn. We can surmise, if 

 we like, that the physiological state immediately preceding the molt 

 has something to do with this, to us, rather unnatural desertion of 

 the tender nestling. 



And yet if it seems unnatural, it is at least not improvident. At 

 this age the chick is so fat that it could scarcely waddle to the sea. 

 If it did so and plunged over the cliffs it would drop like a pound of 

 butter and go to pieces on the rocks below. 



The chick has never been out of its burrow yet. Since its parents 

 vanished, the matchsticks which we have placed at the entrance to 

 the burrow have remained upright. (We used matchsticks a great 

 deal in these experiments to enable us to prove whether a burrow 

 had been visited by night, for of course it was impossible for us to 

 remain watching every night personally.) After about 6 days the 

 fledgling is beginning to thin down, and probably feeling hungry 

 and cramped it now comes out of its burrow for an hour or two each 

 dark night. It not only proves this exit by pushing over our match- 

 sticks, but it leaves additional evidence in a trail of the natural 

 down which it has lately molted. These deserted chicks, sitting 

 outside their homes at night, are a regular, if rather pathetic, feature 

 of the island on dark nights in August and September. In the open 

 air they can try their wings at last. They flap their wings a great 

 deal, but do not move from near the entrance to the burrow, into 

 which they retire before dawn. After a week of this fasting and a 

 week of this combined fasting and exercising, the fledgling is fully 

 feathered and has very little down visible. It takes off for the sea 

 at night, blundering along on all fours, using wings and legs and 

 beak to scramble over rough ground, for it cannot fly yet. When 

 it reaches the cliffs, over it goes and flaps down on a long plane to 

 avoid the rocks below. 



Once in the sea the young bird is safe. We have taken shearwaters 

 at this stage and put them in the sea by day. How thirsty they 

 are — I wonder if thirst may not be for them an important factor in 

 drawing them to the sea, the sound of which they must hear before 

 they leave the nest? At any rate their first action is to drink, then 

 to wash, then suddenly they discover that they can dive. They half 

 open their wings so that the quills remain partly spread, like a half- 

 opened fan, and with these strong paddles they swim under water 

 with the agility of penguins. They come up for air, and dive again, 

 and so gradually work off to sea, making haste to leave behind the 



