1.  bird of passage(n = noun.person) roamer, rover, wanderer - someone who leads a wandering unsettled life;
is a kind of traveler, traveller
has particulars: nomad, drifter, floater, vagabond, vagrant

2.  bird of passage(n = noun.animal) - any bird that migrates seasonally;
is a kind of bird

N  traveler, wayfarer, voyager, itinerant, passenger, commuter, tourist, excursionist, explorer, adventurer, mountaineer, hiker, backpacker, Alpine Club, peregrinator, wanderer, rover, straggler, rambler, bird of passage, gadabout, gadling, vagrant, scatterling, landloper, waifs and estrays, wastrel, foundling, loafer, tramp, tramper, vagabond, nomad, Bohemian, gypsy, Arab, Wandering Jew, Hadji, pilgrim, palmer, peripatetic, somnambulist, emigrant, fugitive, refugee, beach comber, booly, globegirdler, globetrotter, vagrant, hobo, night walker, sleep walker, noctambulist, runabout, straphanger, swagman, swagsman, trecker, trekker, zingano, zingaro, runner, courier, Mercury, Iris, Ariel, comet, pedestrian, walker, foot passenger, cyclist, wheelman, rider, horseman, equestrian, cavalier, jockey, roughrider, trainer, breaker, driver, coachman, whip, Jehu, charioteer, postilion, postboy, carter, wagoner, drayman, cabman, cabdriver, voiturier, vetturino, condottiere, engine driver, stoker, fireman, guard, chauffeur, conductor, engineer, gharry-wallah, gari-wala, hackman, syce, truckman, on the road.

adjutant bird, air passage, anseriform bird, ant bird, apodiform bird, aquatic bird, baby bird, baltimore bird, bird, bird cage, bird cherry, bird cherry tree, bird dog, bird family, bird fancier, bird feed, bird feeder, bird food, bird genus, bird louse, bird nest, bird of jove, bird of juno, bird of minerva, bird of night, bird of paradise, bird of prey, bird parker, bird pepper, bird sanctuary, bird shot, bird vetch, bird watcher, boatswain bird, bower bird, butcher bird, canary bird, caprimulgiform bird, carinate bird, cedar bird, chipping bird, coastal diving bird, cockyoly, bird, columbiform bird, common bird cherry, coraciiform bird, corvine bird, crocodile bird, cuculiform bird, early bird, elephant bird, european bird cherry, flightless bird, flying bird, frigate bird, gallinaceous bird, gallows bird, game bird, gooney bird, huia bird, humming bird, indigo bird, inland passage, inside passage, jail bird, limicoline bird, lyre bird, mallee bird, man-of-war bird, mino bird, mocking bird, mound bird, musical passage, myna bird, mynah bird, myrtle bird, night bird, nonpasserine bird, northwest passage, oceanic bird, oscine bird, passage, passeriform bird, peabody bird, pelagic bird, perching bird, phoebe bird, piciform bird, policeman bird, purple passage, queer bird, quetzal bird, raptorial bird, rare bird, ratite bird, rifleman bird, rite of passage, satin bird, scrub bird, sea bird, secretary bird, sedge bird, shore bird, tropic bird, tyrant bird, umbrella bird, wading bird, water bird, wheatsel bird, whidah bird, whydah bird, widow bird, windward passage, yard bird, young bird