Here's why a cat might meow when seeing a bird:
* Excitement/Alertness: A cat might meow to alert their human to the presence of the bird. This could be a call to action, encouraging their human to chase the bird or perhaps to join them in watching it.
* Frustration: If the cat wants to catch the bird but can't reach it, they might meow out of frustration or disappointment.
* Hunting Instincts: The sight of a bird triggers their natural hunting instincts. The meow could be a way to focus their attention on the bird and prepare for a potential chase.
It's important to note that meowing is a complex form of communication for cats, and we don't always understand all the nuances of their meows. While they might seem to meow differently when seeing birds, it's likely just a different combination of their typical vocalizations.