Well idk they’re both corvids. I’d refer to a ‘carrion crow’ as a ‘regular crow’ - black all over, feathers onto the top of the beak, flat head, about the size of a box of Kleenex. A jackdaw is pretty distinct as far as it goes, smaller, more like the size of a mango. They’re also mainly dark grey, with a darker head. Smaller beak. Jackdaws have white or pale green eyes, crows have black eyes. Jackdaws go ‘Aah Aah Aah’, crows go ‘caw caw caw’.