Upon its release, radio is claiming Taylor Swift's "Mine" as its own.

Rushed to iTunes Wednesday (Aug. 4), "Mine," the first single from Swift's forthcoming album "Speak Now," registered 321 plays on 134 pop and country stations in its first day of availability, according to Nielsen BDS. The spins translated to an audience of 3.1 million listeners.

Country KFRG (K-FROG)/Riverside, Calif. led all stations with 10 plays Wednesday. KHOP (@95-1)/Modesto, Calif. topped all pop outlets with nine first-day plays, followed at the format by KIIS (102.7)/Los Angeles with eight plays.

Second-day airplay swelled yesterday, with "Mine" logging 522 plays on 180 pop and country stations and 5.4 million audience impressions.

After two days at radio, "Mine" is already the week's 26th-most-heard title on the Hot Country Songs building chart and No. 44 on the all-format Hot 100 Airplay building survey. (The weekly Hot Country Songs chart reflects airplay Monday through Sunday. Hot 100 Airplay runs on a Wednesday through Tuesday tracking week).

"We instantly got it and started playing it every hour," says KIIS assistant program director/music director Julie Pilat of "Mine."

"With her last album ("Fearless"), some people were surprised that we would play a country artist on a pop station. As soon as this single dropped, however, there wasn't a question, except listeners calling in and asking, 'When can I buy this?!'

"The passion for Taylor's music seems as strong as ever. If all the awards and album sales last album weren't enough, the audience reaction is proof that she's an official pop superstar."

Industry prognosticators estimate that "Mine" will sell approximately 350,000 first-week downloads. Swift's best debut sales week came courtesy of "Today Was a Fairytale," which opened this February with 325,000. She posted her highest sales frame when "Love Story" shifted 360,000 downloads in the post-Christmas week of 2008.

With its hefty out-of-the-box airplay to be combined with its projected first-week digital sales, "Mine" could manage a debut as high as in the top three on next week's Billboard Hot 100, to be released on billboard.biz next Thursday (Aug. 12).

Additional reporting by Silvio Pietroluongo