The implication of this expression is “not enough” -one wishes it were more. If sparrows could cry, their tears would be tiny. Sparrows are commonly found throughout Japan and often represent ordinary people in Japanese folktales.
A: Kyuuryoo agatta n da tte?
B: Iya, honno sukoshi.
A: Sonna koto nai daroo.
B: Agatta koto wa agatta kedo sa, honno suzume no namida de nee.
A: I hear you got a pay raise. Is it true?
B: Well…just a little.
A: You expect me to believe that?
B: OK, I got a pay raise, but it’s such a small amount.