24 THE ARCHITECTURE OF BIRDS. 
their watery way; or the buoy that warns them of 
the sunken rocks below, as this harmless wanderer, 
whose manner informs them of the approach of the 
storm, and thereby enables them to prepare for it.” 
The petrels are nocturnal birds. When, therefore, 
they are seen flying about and feeding by day, the 
fact appears to indicate that they have been driven 
from their usual quarters by a storm; and hence, 
perhaps, arose the association of the bird with the 
tempest. Though the petrels venture to wing their 
way over the wide ocean as fearlessly as our swal- 
lows do over a millpond, they are not, therefore, 
the less sensible to danger; and, as if feelingly aware 
of their own weakness, they make all haste to the 
nearest shelter. When they cannot then find an 
island or a rock to shield them from the blast, they 
fly towards the first ship they can descry, crowd into 
her wake, and even close under the stern, heedless, 
it would appear, of the rushing surge, so that they 
can keep the vessel between them and the unbro- 
ken sweep of the wind. It isnot to be wondered at, 
in such cases, that their low wailing note of weet, 
weet, should add something supernatural to the roar 
of the waves and whistling of the wind, and infuse 
an ominous dread into minds prone to superstition. 
The popular opinion among sailors, that the pe- 
trels carry their eggs under their wings in order to 
hatch them, is no less unfounded than the fancy of 
their causing storms; it is, indeed, physically impos- 
sible. Onthe contrary, the petrels have been ascer- 
tained to breed on rocky shores, in numerous com- 
munities, like the bank-swallow, making their nests 
in the holes and cavities of the rocks above the sea, 
returning to feed their young only during the night, 
with the superabundant oily food from their stom- 
achs. The quantity of this oily matter is so con- 
siderable, that, in the Faro Isles, they use petrels 
for candles, with no other preparation than drawing 
a wick through the body of the birds from the mouth 
