The small bird referred to as “txarraskala” in Zumaia and its vicinity, of the species Serinus serinus, is a member of the finch family (Fringillidae Passeriformes). It has acquired numerous names in Basque, which can be broadly categorized into two groups: those related to its song, such as txirribirri, txirriskala, or ziringarro; and those associated with its feeding habits, like arbitxori or nabazitxori.

An ornithologist, in his 1918 catalog, also recorded the name “txoriberde” for this bird, which is known as “verdecillo” in Spanish.

The males of this bird typically display a prominent yellow breast, especially during spring. They possess a short, broad beak, well-suited for their granivorous diet, although they also consume insects and fruits occasionally. They are primarily found in environments with small groves and fields, as well as in farmsteads and rural areas. Its song is cheerful and chirping, a light and penetrating trill.