Meaning of the word "it is an ill bird that fouls its own nest" in English

What does "it is an ill bird that fouls its own nest" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

it is an ill bird that fouls its own nest

US /ɪt ɪz æn ɪl bɜːrd ðæt faʊlz ɪts oʊn nest/
UK /ɪt ɪz ən ɪl bɜːd ðæt faʊlz ɪts əʊn nest/
"it is an ill bird that fouls its own nest" picture

Idiom

it is a bad or foolish person who speaks ill of or harms their own family, home, or country

Example:
He keeps criticizing his own company in public; it is an ill bird that fouls its own nest.
Why would you tell everyone about our family problems? It is an ill bird that fouls its own nest.