Do you know how old he is? Has he ever been tame or trusted a human before?
Six weeks isn’t as long as you may think. His entire life he may have been mistreated. In time he will know he is in a better place. You just have to be patient and let him come to you. Start off by learning to sprout and changing his diet. When he eats healthier , he will want treats more badly. Then he will come for them as long as you are patient.
Start off by making sure he eats seeds besides sunflower. Then remove all sunflower from his diet, they are too fatty. Buy a good seed mix that doesn’t have sunflower, almonds, flaxseed, nigerseed or peanuts. You can try hagens for parakeets , most cockatiel cage blends have sunflower. Or u can handpick them out. Save them for bonding only, two sunflowers per day. If he enjoys millet spray , remove it from his cage. If he doesn’t like millet spray, put it in the cage until he is courageous enough to try it. Once you see him enjoying it, remove it. This will be a treat and used for training and bonding.
Now the tough part. Getting him to eat vegetables/sprouts and pellets. Every time u have fresh broccoli on hand, put a stalk between two cage bars and see if he investigates it after a couple of weeks. Every time u have fresh kale, clip it from the side or top of the cage, so that big kale leaf is in his way on his favourite perch. He must wrestle with this darn kale to get it away! Maybe he will eat some too. We can hope
Try shredding up carrots, cutting broccoli tops into little green seed like florettes, finely chopping kale or any dark leafy green into small strips. Place it in his cage with some seed on top for a week. Take out his seed dish so he can investigate this dish instead. After an hour, put the original seed dish back in. Put this dish near the lowest perch, keep the healthy foods near the highest and favourite perches. After three hours, remove any wet food. After a week, remove the seed from the vegetable dish and his seed dish for one hour in the morning before he has had any food and see if he tries the new food. If he doesn’t , it’s ok u got more secrets up your sleeve. Try this for a few more days. If it doesn’t work, give him the seed back, but keep the seed out of the vegetable dish. He has had enough time to learn it can be potential food, he’s just too darn scared. It’s ok , we got another idea. In the meantime, keep trying this as much as you have fresh vegetables handy. Sometimes birds take a long time to gather courage. Months even.
Learn to sprout. Sprout his favourite seed. Sprout some Tops all in one seed mix and hagens cockatiel blend. Soaking organic seeds causes them to germinate, which makes them healthier even before you see the seed/sprout tails! You have to buy organic seeds for this to work, you can’t cheap out. You will need a stainless steel strainer, some apple cider vinegar, a metal/glass/porcelain bowl to let the strainer sit inside of. And another bowl for soaking. The strainer must not touch the bottom of the bowl. I use a strainer from Walmart and a glass bowl. Clean them well. First, place about four tablespoons of seeds into a glass bowl. Cover them with 4 times the amount of cold, fresh water. Keep this bowl away from the window. (Sunlight) soak them seeds for 10-12 hours. Pour the seeds into the strainer over the sink, rinse with cold water. Make an apple cidar vinegar solution 1:4 acv:water. Spray or soak the seeds with the mixture. Wait five minutes. Rinse throughly. The seeds should no longer smell like vinegar. If they do keep rinsing with cold water under the tap. Once they smell earthly, grass like smell they are ready to feed. Put the strainer in the bowl so the sprouts can drain. Rinse every 4-6 hours with cold water. Refrigerate overnight if u sleep longer then 8 hours so they don’t dry out. Rinse in the morning. Repeat the acv process. Rinse again. Ready to feed again. Drain. Rinse every 4-6 hours. And so on until the sprouts tails are 3/4 inch long. By then
The bird should have eaten most of them. Discard after they are this long or after three - four days.
If your sprouts ever look or smell sour or moody , discard right away. If they dry out, throw away. In my three years of sprouting , this has never happened to me, with these seed brands. Sprouting is really easy.
Now , to trick the tiel we must mix these seeds with the same seeds in dry form. Place one tablespoon of dry mix with one tablespoon of sprouted seed in burns favourite dish. Watch him try it out and see what happens. He will pick the wet sprouts. He may or may not care. If he throws it out, it’s okay. He will be throwing out a lot of seed but guess what, each time he does, he tastes it and becomes familiar with it. In time he just won’t care, it tastes very similar! Give it a couple months. By then he will start eating the sprouts, when he does, slowly lower the dry seed to sprout ratio. I haven’t heard of a fussy seed eater not eating sprouts with this method, so try to prove me wrong
persistence is key.
Remember to remove the sprout dish after three or four hours.
During the time the sprout dish /dry seed mix is in the cage, u will attempt to bribe him with food. Put a small treat dish in the cage near his favourite perch. Walk to the cage every hour the sprout dish is in there , and place one sunflower seed or millet spray bunch (ball) through the cage bars into his treat dish slowly. Watch him come up to investigate. If he eats it praise him. Now we are getting somewhere.
When he eagerly comes up to the treat dish as soon as he seess you have a treat , wait a few days then try holding the treat against the cage bars so he has to take it from u . If he doesn’t right away, look away from him and wait a minute or two then drop it in his food dish. He will come when he’s ready. Once he is on a sprout or vege diet and eats it all up, u can try holding a large branch of millet in his cage, look away, and see if he walks to the millet branch. Be patient. Wait 2-5 minutes, then try again in 1-2 hours. The best time to do this is just before u change out his sprouts for his dry seed.
As for pellets, u can just put them in a small dish with some seed for a week. Then remove the seed. U can keep pellets in the cage for two or three days as long as he doesn’t shed many feathers or poop on them. Keep the pellet dish in th cage at all times unless he loves them so much that’s all he eats. Then limit to 25% of his diet.
Once burns is more courageous and eating millet spray from ur hand, make the branch shorter every few days. Until.. it’s so short u might as well just put his favourite seed in ur hand. When he eats from ur hand, he’s starting to trust u more. In a week, attempt the step up manuvuer. Hold a millet branch with ur thumb and middle finger, away and offer your index finger as a perch. He may try very hard to get the millet without stepping up. If he does, just hold it there for two minutes. If he makes no attempt to come on ur hand, let the millet branch come a little closer to him so he has to be really close to ur hand to eat. Them manuvuer it away slowly. He will make the leap of faith when he’s ready. Do not take him out of the cage if he steps up. Let him step up and eat. Even if he just puts one foot on your finger , it is progress. This may happen for a few days to a couple of weeks before he completely steps up. Let him go back to his perch when done. In a week of him stepping up happily, attempt moving a little when he’s on ur hand in the cage. If he seems fine with it, in a week, then take him out. Put him on top of cage with a millet branch. Praise him. See what he does , let him explore if he wants to. Put a paper toy he likes up there. Or put him on a playground. After an hour , attempt to bribe him to come on ur hand for a treat. Put him in the cage. After this happens for awhile, he should be on his way to being tame. Good luck!