«أمس الدابر» and «طائر يطير بجناحيه» might each look redundant, yet the rhetorical analyses are distinct. The former reinforces the sense of yesterday's departure; the latter helps mark which application of “bird” is meant.
ExamplePrimary rhetorical effect
أمس الدابرReinforcing an already implied feature
طائر يطير بجناحيهClarifying the intended reference and scope
Both constructions expand the phrase, but reinforcement and specification of intended meaning remain analytically distinct.