As soon as spring comes back to the temperate zone, myriads
and myriads of birds which are scattered over the warmer regions
of the South come together in numberless bands, and, full of
vigour and joy, hasten northwards to rear their offspring. Each
of our hedges, each grove, each ocean cliff, and each of the
lakes and ponds with which Northern America, Northern Europe, and
Northern Asia are dotted tell us at that time of the year the
tale of what mutual aid means for the birds; what force, energy,
and protection it confers to every living being, however feeble
and defenceless it otherwise might be. Take, for instance, one of
the numberless lakes of the Russian and Siberian Steppes. Its
shores are peopled with myriads of aquatic birds, belonging to at
least a score of different species, all living in perfect
peace--all protecting one another.

"For several hundred yards from the shore the air is filled with
gulls and terns, as with snow-flakes on a winter day. Thousands
of plovers and sand-coursers run over the beach, searching their.
food, whistling, and simply enjoying life. Further on, on almost
each wave, a duck is rocking, while higher up you notice the
flocks of the Casarki ducks. Exuberant life swarms
everywhere."(1)

And here are the robbers--the strongest, the most cunning
ones, those "ideally organized for robbery." And you hear their
hungry, angry, dismal cries as for hours in succession they watch
the opportunity of snatching from this mass of living beings one
single unprotected individual. But as soon as they approach,
their presence is signalled by dozens of voluntary sentries, and
hundreds of gulls and terns set to chase the robber. Maddened by