258 THE COMMUNITIES OF BIRDS. 
The negro has not yet invented the door; his hut remains open. 
Against the nocturnal forays of wild beasts, he obstructs the entrance 
with thorns. 
Nor does the bird know how to close his nest. What shall be 
its defence? A great and terrible question. 
He makes the entry narrow and tortuous. If he selects a natural 
nest, as the wryneck does, in the hollow of a tree, he contracts the 
opening by skilful masonry. Many, like the pine-pine, build a double 
nest in two apartments: the mother sits in the alcove ; in the vesti- 
bule watches the father, an attentive sentinel, to repulse invasion. 
What enemies has he to fear! Serpents, men or apes, squirrels! 
And what do I say? The birds themselves! This people, too, has 
its robbers. His neighbours sometimes assist a feeble bird to recover 
his property, to expel by force the unjust usurper. Naturalists assure 
us that the rooks (a kind of crow) carry further the spirit of justice. 
They do not pardon a young couple who, to complete their establish- 
ment the sooner, rob the materials—“ the movables’”—of another nest. 
They assemble in a troop of eight or ten to rend in fragments the 
nest of the criminals, and completely destroy that house of theft. And 
punished thieves are driven afar, and forced to begin all over again. 
