When a bird squawks, it makes a loud harsh noise.
e.g. I threw pebbles at the hens, and that made them jump and squawk.
If a person squawks, they complain loudly, often in a high-pitched, harsh tone.
e.g. Mr Arbor squawked that the deal was a double-cross...
e.g. 'Wait for me!' Melanie squawked. 'I'm not staying here alone.'