FLC OF ACR MLG ACFT LANDED WITHOUT TWR CLRNC.

Narrative

THE PROBLEM AROSE OUT OF A VISUAL APCH TO 4R AT BOSTON'S LOGAN ARPT. WE WERE BEING VECTORED BY APCH CTL WHEN HE CALLED OUT TFC LNDG ON 4L (CONTRIBUTING FACTOR). THE CAPT AND I USED TCASII TO HELP TRY TO SIGHT THE TFC VISUALLY; ALL CHKLISTS WERE ACCOMPLISHED BY 1000 FT AGL. ALSO; AT 1000 FT WE SIGHTED THE TFC. AFTER THE TFC CALL BY APCH CTL THE ONLY OTHER RADIO CALL WE RECEIVED WAS CLRNC FOR THE VISUAL APCH. AT 500 FT AGL THE CAPT TURNED THE RADAR ON AFTER WE SAW BIRDS ON FINAL. THE APCH AND LNDG WERE NORMAL. WE DISCOVERED WE HAD LANDED WHILE STILL ON APCH CTL FREQ AS WE WERE CLRING RWY 4R AND MAKING THE SWITCH TO GND. WE TOLD APCH HE HAD NOT SWITCHED US TO TWR AND THEN HE SWITCHED US. WE TALKED TO TWR AND THEY MADE NO MENTION OF THE PROBLEM. AFTER WE ARRIVED AT THE GATE; THE CAPT CALLED THE BOSTON TWR SUPVR TO EXPLAIN THE SITUATION. THE TWR SUPVR SAID THAT THERE WAS NO PROBLEM AND THERE HAD BEEN NO CONFLICT. I FEEL THAT THE TA; BUSY WORKLOAD FOR THE CTLR; AND WATCHING FOR/AND AVOIDING BIRDS ON FINAL; LED TO DISTRS THAT CAUSED THE FREQ CHANGE OVERSIGHT.