Var.: Не сули бычка, а дай стакан (чашку) молочка
Cf: An acre of performance is worth the whole world of promise (Am.). A bird in the hand is worth two in the bush (Am., Br.). A bird in the sack is worth two on the wing (Am.). A feather in the hand is better than a bird in the air (Am., Br.). A gift in the hand is better than two promises (Am., Br.). A gift is better than a promise (Am.). One acre of performance is worth twenty of the Land of Promise (Br.). One bird in the cage is worth two in the bush (Am.). One bird in the net is better than a hundred flying (Br.). ne dollar in your hand beats the promise of two in somebody else's (Am.)Русско-английский словарь пословиц и поговорок. Академик.ру. 2013.