“Más vale pájaro en mano que ciento volando”(In English: “A bird in the hand is worth two in the bush“) is a Spanish saying that comes from the latin “Est avis in dextra, melior quam quattuor extra” that literally means “It’s better to have one bird in the right hand than 4 out”.
This means that it’s better to have something sure, even if humble, rather than the uncertainty of high profits.
It’s used to keep someone’s feet on the ground, when he dreams of unattainable projects that might make himself forget the simple things.