(Native English speaker) Not correct as a translation of this sentence--and not, in fact, correct English. In correct English your sentence would be "Three birds seemed to be in the garden," but it is an odd sentence; it would mean that you were not sure that the birds were real, or that they were really birds. Perhaps they were a trick of the light, or you were misled in some other way. "Seem" cannot be used by itself in English (except in Shakespeare's time: viz. Hamlet: "...These indeed seem, for they are actions that a man might play....").