Popcorn is a surprisingly popular bird treat, and it is safe — as long as it is plain. The problems come entirely from what we usually put on it.
The short answer
Yes — birds can eat plain, air-popped popcorn. It is a fun, low-risk treat that many birds enjoy pecking apart. What matters is that it has nothing added: no salt, no butter, no oil, no sugar and no flavourings.
Skip the salt, butter and microwave kind
Salt is genuinely harmful to a bird's tiny kidneys, butter and oil add unhealthy fat, and microwave popcorn often contains extra salt, flavourings and chemicals you do not want your bird eating. Plain air-popped popcorn, or popcorn popped in a dry pan with nothing added, is the only kind to offer.
Popped or unpopped?
Both can work. Many birds enjoy shredding a fully popped piece, and some larger parrots like cracking open plain un-popped kernels. Hard un-popped kernels can be tough for small beaks, so for budgies and other small birds, stick to soft popped popcorn. You can even pop plain kernels yourself so you know nothing was added.