Could be, birds like peppers. You have some ambitious birds, they usually for Hawaiian chilies they are easier to get and swallow. They usually don't bother my larger peppers until they turn red and softer to break apart.
There are only a couple of things that work. 1. build a cage to go over the peppers to keep the birds out
2. Need a cage or frame and cover it with bird netting.
3. Grow Hawaiian peppers and papaya. They will go after them before anything else every time.
I don't grow as much Hawaiian peppers anymore, they are always capped. I grow super chili instead. They look and taste like Hawaiian peppers only they are a little bigger. The bulbuls will still go after them but they usually don't cap the tree.