THE STAINS OF RUST SEEMED TO MAP BLOOD SEAS ON THE BLACK, pocked surface of Mock's Vane. A century old, it squatted on the point of an old pike that had been bolted to the outer top of the Hold's wall. Monstrous and misshapen, it had been cold-hammered into the form of a winged demon, teeth bared in a leering grin, and was tugged and buffeted in squealing protest with every gust of wind.
Gardens of the Moon by Steven Erikson, sentence No 2.
It's understood that what was meant is that the vane was protesting. But, grammatically, if the object is tugged and buffeted in squealing protest, who's in the state of protest, the object or the one who does the actions?