Cherries are a sweet summer treat that birds can enjoy, but they come with an important safety rule: the flesh is fine, but the stone inside is toxic.
The short answer
Yes — birds can eat cherry flesh, but never the pit. The juicy flesh is a safe, sweet treat, but the stone (pit) contains compounds that release cyanide, exactly like apple seeds and other stone-fruit pits. The pit must always be removed.
Why the pit is dangerous
Cherry stones, along with peach, plum and apricot pits, contain amygdalin, which releases cyanide when crushed. Because birds are small, this is a genuine danger, so a bird should never have access to the pit or be able to crack one open.
How to feed cherries
Wash the cherry, remove the stem and pit completely, and offer a small piece of the flesh. Both sweet and sour cherries are fine once the pit is out. Keep it a treat, as cherries are sugary, and give a small amount a couple of times a week.