The rook is a bird heavily weighed down by myth and symbolism. They were a bird of death and misery, much like the raven. A new rookery near your house was unlucky. They staged ‘parliaments’ where they tried and sentenced their own. Plague doctors dressed in black robes with a grey peak, aping the appearance of the rook (although there is some evidence this may have been coincidental). Speak to non-birders, even some birders for that matter, and words like ‘sinister’, ‘ominous’ and even ‘ugly’ are used.
Unsurprisingly, all of this is deeply unfair. Rooks parliaments exist because they are probably the most social of UK corvids, remaining in their tight-knit rookeries all year round while others may move to a more individual existence. Such numbers are great for keeping the colony safe, but add to the sense of intimidation. Especially if you get a rookery with tens of thousands of birds.
The idea they are ugly, and that plague doctor thing, comes from the absence of feathers around the base of the pale grey bill. This gives a drawn, even skeletal appearance. But that certainly doesn’t make them ugly. In fact it is a practical adaptation that benefits hygiene when rooting around in fields, or even feeding on carrion.
They also have the most beautiful iridescent feathers, not a pure black as they can appear, more a shimmering blue-green. Also, like all the corvids, they are unusually intelligent, passing tests around tool use and even showing a rudimentary understanding of the concept of gravity.
What the rook is not connected to is the chess piece, also known as the castle. In that case, Rook comes from the Persian for ‘chariot’.