Which Galapagos bird uses cactus spines or twigs as tools to extract grubs?

The Galápagos bird that uses cactus spines or twigs to extract grubs is the woodpecker finch.

The woodpecker finch, Camarhynchus pallidus, uses tools to reach arthropods hidden beneath bark or inside crevices. It may pick up a twig, stick, or cactus spine and manipulate it as a probe, lever, spear, or goad. These tools allow the finch to obtain larvae that its relatively short tongue could not reach directly.

The species is one of Darwin's finches and is endemic to the Galápagos Islands. Its woodpecker-like foraging behavior probably reflects the islands' lack of native woodpeckers, although the finch is not a woodpecker and belongs to a different bird family. Researchers have also observed birds shortening or modifying tools and learning some novel tool behaviors.

Tool use is especially valuable in dry habitats and during the dry season, when food is harder to find. In some arid areas, tools help woodpecker finches obtain up to half of their prey. The main mix-up is with the New Caledonian crow, another celebrated tool user; crows are known for crafting hooked tools, while woodpecker finches are famous for using spines and twigs while foraging in the Galápagos.