Earlier today I actually tried to play some recordings of outside nighttime noise while doing my best impression of a green treefrog call (not TOO loud, of course lol) I could've sworn his throat sac was drooping and enlarging a little bit. I might try again (but with recorded frog calls) tonight. I think he may wait until all the TVs in the house are turned off and it is silent to call. He must feel more calm in those quiet conditions. Thanks for your help