Take not a swallow under your roof, he only pays his visit in the spring, but when winter, the time of difficulty and hardships, approaches, he is gone. Entertain no one as a friend who seeks only his own advantage by the intimacy he solicits. The proverb is also supposed to intimate that we should not admit chatterers to a familiarity with us, who will be sure to divulge whatsoever they may see or hear in our houses. «Percontatorem fugito, nam garrulus idem est». The swallow only comes, it is said, for his own purpose, and having produced and brought up its young, leaves us, without making any beneficial return for the entertainment it has received. Though it is probable that by devouring myriads of insects, which would have destroyed our fruit, they pay us abundantly for the subsistence afforded them.
Fuente: Erasmo, 2 (21).