Cockatiel Training

My training was always simple... praise.
Most of my birds just ignored the clicker and didn't want to do anything but eat if I trained for treats.
They were just stressed and focusing on the food when I trained with treats.

Remember that cockatiels love to play with you (after all, you're a big part of their flock,) so if they're fed, they will love the interaction... it's better than sitting a stupid cage by themselves and knocking on a bell again.

They are curious and more persistent than most people I know, so have patience and they will try and figure out exactly what you want them to do.

By the way...
Yes, you have to go to work and they get left on their own. Try introducing them to different toys when you're around and make a game of it.
They might be afraid or pretend to be disinterested but check it out later... then you can rotate out the toys for variation.
If they stress on a toy for more than a couple of days, just remove it.
They will play with their toys, eat and nap... and when they hear that lock in the door, they will start yelling at the top of their lungs for you to come and play.
It will sound like they've been doing this all day.

Trust me when I say they love nap time and need about 12 hours of sleep every day.

Can't Afford Toys?
Check out this video by Madeline Franco as she shows how to make toys from household objects.
If you've had a bird for awhile, chance are that they have already started this themselves with headboards and coffee tables so you might as well give them something to focus on.

Why birds bite... the first thing anyone will tell you is that it bites out of fear.
Another reason is to defend its territory - real or perceived.
Just know that every bird bites because they also use their beak to grab onto things - like when they try to get on your finger or to get up to your shoulder.
It isn't always a hard, piercing bite. You can communicate with your bird through its biting because it can bite only slightly or maybe it wants a taste of your finger.

I have tried everything in training but the thing that works every time (and it takes a little guts) is to hold your finger in front of it and LET the bird bite you.
While it's biting you (I told you it takes guts) gently push the beak UP until the bird is uncomfortable and it will let go and turn its head away from you.

With the bird still perched on your finger, do it again. They usually get the idea that they if they hurt you, it will have unpleasant consequences.
One of my girls bit 3 times, getting softer each time until it no longer hurt. Then she knew exactly how hard she could grab onto me to perch.

CAUTION: I would not recommend this technique on larger parrots. We're not lizards. Our fingers don't grow back... at least not yet.

Here's something else to consider - your bird will think leaving you and going back to its cage is unpleasant.
So if it knows that when you take it off of your shoulder and once it gets on your finger, it can't get back on your shoulder, it can start biting to make your finger go away.
I had two that did this but I didn't put the pieces together until I had some others that did it a little differently. Those were the ones that would take my finger in their beaks and physically push it away.
Basically, they were saying, "No, thank you. I don't wish to leave you right now."
Believe me, it was absolutely adorable.

Watch this video and you can see the bird is doing what is asked of it.
Stepping up on his finger time after time... but the bird gets tired of the game and starts to make his feelings known.