Dreads and panics

   

Gulls and terns are closely related.

They seem to fly like embodied spirits clad in grey and white,

though some have black hoods,

and some have black on their wings.

The long-winged, long-tailed terns

are altogether more volatile and dainty

and less aggressive than the larger and heavier-built gull tribe.

Terns, even when undisturbed by man,

will rise up suddenly from their breeding ground 

and leave it deserted for a while as they float together in the sky,

moving silently and in a compact cloud over the sea. 

These movements have been called 'dreads' and 'panics',
but it is obvious that fear is not always the impelling motive.

Whatever the cause, the result is inimical to the survival

of the species, as the nesting ground is left exposed

to the attentions of predatory neighbours.

  

Collective flight in birds often appears to be so instantaneous

that some writers have suggested it is governed by a form of

thought-transference taking place over the air-waves

or vibrations of which we know little or nothing.

Taken from

   

King Penguins Birds of the Sea by R.M.Lockley.