TWILIGHT AND DAWN 139 
the starry dark. On clear calm evenings the soft 
swoosh, the soft roar of their flight, lasted for 
hours. 
With the faintest break of dawn the callings and 
wailings and howlings and caterwaulings that 
had troubled the island began to lessen, and very 
quickly to cease. Birds, called to dry land by dusk, 
were now summoned oceanwards by returning 
light. The wet peat sweated them. Dazed with 
the darkness of their long imprisonment, brushing 
clumsily against the petty obstacles in their 
paths, in thousands they rolled like giant drops, 
or trickled like thin streams from the bare sides 
of the islands. 
In the hour of departure, even whilst still on 
land, to many of them their first thought was of 
their wings. The pinions that so well deserved 
care were from time to time stretched aloft, the 
bird pausing in its progress to the cliff edge and 
vibrating the tips with the rapid tremor notice- 
able in newly hatched moths. To the last, Petrel - 
as indifferent to fellow Petrel as stone to neigh- 
bouring stone, these grey ghosts of the grey dawn 
paused or followed one another in silent uncon- 
cern to the rocky bluffs. There, from projecting 
juts worn smooth by centuries of use, they fell 
into the air rather than flew away, one reaching 
the sea by a long glissade, then resting a while 
on the heaving deck; another dropping to sea- 
