One crow sorrow?

Ever been followed, literally, by a bird? On this evening's stroll a crow picked me for a partner. Paced itself to swoop a little ahead, perching in the wires till I caught up, letting me pass only to swoop to the next nearby perch, all at eerily regular intervals. A perfectly straight line, following my path along a fairly busy road. Not so much as the crow flies but as the human ambles. Wings so close to my head I could feel their draft. After ten minutes or so it ditched me as unexpectedly as it had begun to tail me, flying back the way we'd come. Weird. A harbinger of what?