Spider plants are safe. Eucalyptus species are safe, but you might need a few to rotate outside. There are some good guides out there - when I got my budgie I just looked on Google. Check multiple lists, though, because there are some that are less correct than others. If you search you can find ones specifically for budgies, but the first ones I came across were usually for parrots or other broad groups of birds - a few even appeared to be copy-paste jobs from pet store safe plant lists (as in, for any kind of small animal in general.)
Budgies are great - I think they're one of the best pets possible. I would suggest starting your bird on fresh foods as soon as possible, and be prepared for frustration. I've had my bird Beaker for three years or so, and I only recently got him to try salad vegetables. The brand of seed mix I have him on changed their formula and he doesn't like that some certain nut is now dyed green or something, so I've been giving him an extra day between changing the seed to try to get him to try the new stuff. He still doesn't like the green seeds, but I discovered that when he's feeling hungry he'll nibble on any plant-looking thing. (Including my Paphiopedilium.) :/ Since then I've gotten him to eat various types of lettuce and shaved carrots. He takes an interest in toast and other sorts of bread, but only seems to lick them without biting.
Also, once you've got yours finger-trained, it's useful to get them comfortable being held and restrained. It's much easier to do in the dark; birdproof a small space like a bathroom or walk-in closet, and do your handling routine in the dark or with very dim light, like a shaded flashlight.
Have you seen
Victor the Budgie?
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I first found these in like 2002/2003. The "translations" have progressively become more political and religious in nature since then; I fear Victor's keeper is gradually coming unglued. But I'm utterly convinced that bird was talking, with at least the competency of a toddler.
My bird talks a little, but I'm not sure he knows about constructing sentences. He says greetings appropriate for various times of day, and can also tell me when he wants new seed or water. He knows my name, his name and nicknames, and I think he's learning pronouns. Hard to say about pronouns, since the phases he first mimicked had them before he started mixing up his own statements. When he wants attention or otherwise feels urgency, he adds emphasis to certain words. He knows the sound and significance of my alarm clock and sometimes chides me for running late. Everything he says is in a repetitive, singing/rhyming manner, though, so it's hard to determine what he's trying to say with the stuff in between the words he stresses.
I highly encourage you to talk to your bird, rather than singing or whistling to him. Chirping and whistling is much easier than talking, and if your bird learns to get your attention with those types of sounds, those are the ones he will learn to repeat. If you teach him to listen to human speech, he'll pay attention to the sounds of human speech, and you'll have a much better chance at him learning to talk. Not all birds will go as far with it as others; some are more interested in talking or learning other things than others. But at the very least, your bird will feel more a part of the group in your home if you talk to him. If you only communicate with your bird by whistling, then the sound of the flock is whistling; if you talk to him, the sound of the flock is talking, and he'll feel included when you converse with the rest of your family. My bird goes nuts when I have friends over, and even laughs when conversation gets intense. I'm not totally sure he understands laughter as a response to comedy - he screeches at things I think he finds funny - but he seems to interject with it like some sort of uncomfortable laugh track.
Haha... can you tell I'm a pet owner?
~Joe