The short answer for a plate-stealing conure
A sun conure should never eat avocado, chocolate, caffeine, alcohol, apple seeds, or the pits of peaches, plums, cherries, and similar stone fruit. Onion, garlic, heavily salted snacks, fried food, and sugary people food also belong on the banned list. Sun conures are bold, social eaters who learn quickly that whatever you are holding must be interesting, so the risk is less about what you deliberately serve and more about what a determined orange-and-yellow bird talks you out of at the table.
Why these particular foods harm a conure
Avocado contains a compound that birds handle very poorly, and even a small amount can be dangerous for a bird of a sun conure's size. Chocolate and caffeine stimulate a bird's heart and nervous system far more strongly than they do a person's, which is why a sip of coffee or a corner of a chocolate bar is not a harmless treat. Alcohol is similarly risky for a lightweight bird with a fast metabolism. Apple seeds and stone-fruit pits carry compounds that are unsafe when chewed open, and a conure's powerful beak is built to crack exactly those kinds of things.
Onion and garlic can irritate and damage a bird's system in amounts a person would consider seasoning. Salt is another quiet problem: a few salty chips deliver far more sodium than a small parrot needs, and fried or sugary foods crowd out nutrition while encouraging the picky, seed-and-snack habits conures slide into easily.
Making your kitchen conure-proof
Treat mealtimes as a management problem, not a willpower contest. If your sun conure is out while you eat, give him his own small dish of safe chopped vegetables and a piece of fruit on his play stand, away from your plate, so joining the meal does not mean raiding it. Keep coffee cups, wine glasses, and bowls of guacamole or salsa behind the bird, not in front of him, and wipe up crumbs of chocolate cake or dropped chips before he spots them on the floor.
Brief everyone in the house, including guests who find a begging conure charming. The classic accident is a visitor offering a chip, a sip of soda, or a bit of avocado toast because the bird asked so sweetly. A written list on the cage or fridge stops that conversation before it starts.
What to do if your conure eats something unsafe
Act quickly and do not wait for symptoms to settle the question. Note what he ate, roughly how much, and when, and remove the rest of the food so he cannot go back for more. A bird that becomes unusually quiet, fluffed, unsteady, reluctant to eat, or breathes with effort after eating a suspect food needs an avian veterinarian promptly — call the vet or an emergency clinic for guidance right away rather than watching overnight.
If he only mouthed a safe-but-unwise food, such as a plain salty cracker, offer fresh water and his normal diet, watch him through the day, and tighten the setup that let it happen.
Building the safe list everyone actually uses
Write down what your sun conure can have just as clearly as what he cannot: his formulated staple, the vegetables he reliably eats, the fruits you rotate as treats, and the foods banned above. When a sitter or family member can see both lists together, they stop guessing and stop improvising with leftovers. Review the list whenever his diet changes, and keep unsafe people food stored where an out-of-cage conure cannot land on it and help himself.
With KinsLe, Care Teams turns that two-sided list into assigned feeding duties on your sun conure's profile, so the person chopping his vegetables each morning works from the same banned-foods note you wrote.