74 THE SECOND BOOK OF BIRDS 
martin has a good deal of sense. One of these 
birds built in a box under a window, fixed so 
that the owner could open it and take out eggs. 
He took out several, one at a time, and at last he 
took out one of the birds. 
The mate of the stolen bird went off and in 
a few days came back with another mate. The 
box was too good to give up, so both the birds 
went to work to make it safe against the nest 
robber. They built up a wall of mud before the 
too handy back door. The egg thief could not 
get in without breaking down the wall, and he 
was ashamed to do that. So the birds kept their 
pleasant home, and reared their family there. 
