It's an ill bird that fouls its own nest

It's an ill bird that fouls its own nest.

Prov. Only a foolish or dishonorable person would bring dishonor to his or her self or his or her surroundings.; Only a bad person would ruin the place where he or she lives. (See also foul one's own nest.) I don't like my new neighbor. Not only does he never mow his lawn, he covers it with all kinds of trash. It's an ill bird that fouls its own nest.
See also: bird, foul, ill, nest