The crow selects a forked twig, snips it so the fork forms a small hook, and trims away the surrounding material before probing crevices and dead wood for beetle larvae. The species also makes stepped, barbed tools by tearing the stiff edge of a pandanus leaf in a sequence of cuts, and it keeps favoured tools between uses rather than discarding them.
The hook is not decorative. Comparative trials show hooked tools retrieve embedded prey substantially faster than unhooked ones, which is a direct fitness-relevant payoff and helps explain why the manufacture step persists despite its cost in time.
The famous case of Betty, a captive crow that bent a straight wire into a hook, was long presented as spontaneous invention. Later observation of wild crows bending pliant twigs showed the behaviour was within the species' natural repertoire, which strengthens the species claim while weakening the specific claim about individual insight. How much of tool making is socially learned rather than developmentally canalised is still argued.