188 Grk “the birds of the sky” or “the birds of the heaven”; the Greek word οὐρανός (ouranos) may be translated either “sky” or “heaven,” depending on the context. The idiomatic expression “birds of the sky” refers to wild birds as opposed to domesticated fowl (cf. πετεινόν).
189 Jesus’ reply is simply this: Does the man understand the rejection he will be facing? Jesus has no home in the world (the Son of Man has no place to lay his head).

In other versions

And Jesus said to him, “Foxes have holes, and birds of the air have nests, but the Son of Man has nowhere to lay his head.”

Jesus replied, “Foxes have dens and birds have nests, but the Son of Man has no place to lay his head.”

Jesus told him, “Foxes have dens, and birds of the sky have nests, but the Son of Man has no place to lay his head.”

But Jesus replied, “Foxes have dens to live in, and birds have nests, but the Son of Man has no place even to lay his head.”

And Jesus said to him, “Foxes have dens and birds of the sky have nests, but the Son of Man has no place to lay his head.”

And Jesus said unto him, Foxes have holes, and birds of the air have nests; but the Son of man hath not where to lay his head.

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