The Three-toed Woodpecker(Picoides tridactylus) is a character species of subalpine spruce forests. It is about the size of a blackbird and has black and white patterned plumage and the wings are uniformly dark in color. The head plate of the male shines bright yellow, while on the other hand the female has a silver-gray crest .

A distinctive feature of this woodpecker species is the presence of only three toes, with two pointing forward and one pointing backward.

As habitat the woodpecker claims subalpine coniferous and mixed forests with old trees and dead wood. The Three-toed Woodpecker feeds on larvae and pupae of beetles, especially those of the bark beetle. In order for the Three-toed Woodpecker to find enough food, there must be many dying, diseased and dead trees in its territory. A study in the Swiss Alps showed that a threshold of about 20 m³ (equivalent to a filling volume of 3 children's swimming pools with a diameter of 3.6 m) of standing deadwood per ha (equivalent to about 1.4 soccer fields) must be reached for this species to ensure its survival (Bütler and Schlaepfer 2004).

To get its food, the Three-toed Woodpecker removes pieces of bark with its beak. It often works on middle and lower trunk sections, rotting snags, or fallen wood lying on the ground. From spring to September, the Three-toed Woodpecker "rings" spruce logs. This means that he hacks rows of holes in their bark with his beak in order to reach the tree sap.