Establishing a contact call

My GCC screams for me when ever I leave the room, she will settle after about 30 seconds, but during that half a minute she sounds so upset. I had read here about establishing a contact call. Something she will mimic and I'll mimic back. But I was wondering how to go about doing that. I've got a short whistle I've started using when i'm out of the room. My fiancee says when i do the whistle, Lizzy stops what she's doing and looks interested. Is there something else I should be doing? She hasn't mimicked the whistle yet (the only thing she's learned here is my cough from when i had the flu haha). What else can I do to help establish this contact call?

Other info: We've already started clicker training, but as of now she's terrified of the stick i'm using for target training, so I'm trying to get her used to it - putting treats on the end of it, setting it near her during meals etc. She's gotten better, but runs away when i touch it. Work in progress, but i'm moving at her pace.

Does she make any other noises while you're out of the room that would make an acceptable call? You can reinforce those by returning the sound.

My GCC has learned that making the sound "weeee" is the best way to get my attention when I'm out of the room. I started out by ignoring the screaming and once she got quiet for a moment, I would make the sound. Of course, this usually made her scream again, so I went back to ignoring her and we'd start the process over.

Also, when she took a break from the calling and made any noise that sounded even remotely like what I was looking for (basically anything other than the screaming), I would respond to it. Eventually she figured out which noises were better for getting my attention.

Hope this helps.

Doesn't matter what it is, just do the same thing consistently every time. Let the bird associate the noise with you...

Once she quiets down I can hear her make small chirps and that's when I'll whistle back to her. I'm not too good at mimicking bird noises lol. I've only had for for about two weeks now so she's still getting used to everything too.

We're trying to establish our call to Verde as well right now. Hubby can't whistle or roll "r's" haha so we're finding a sound we can both do haha