Azara's description, under the heading _El Campestre_, probably refers to the Brazilian species, but agrees so well in every particular with the pampas Woodpecker that I cannot do better than to quote it in full. "Though this name (_Campestre_) seems inappropriate for any Woodpecker, no other better describes the present species, since it never enters forests, nor climbs on trunks to seek for insects under the bark, but finds its aliment on the open plain, running with ease on the ground, for its legs are longer than in the others. There it forcibly strikes its beak into the matted turf, where worms or insects lie concealed, and when the ant-hills are moist it breaks into them to feed on the ants or their larvæ. It also perches on trees, large or small, on the trunks or branches, whether horizontal or upright, sometimes in a clinging position and sometimes crosswise in the manner common to birds. Its voice is powerful, and its cry uttered frequently both when flying and perching. It goes with its mate or family, and is the most common species in all these countries. It lays two to four eggs, with white and highly polished shells, and breeds in holes which it excavates in old walls of mud or of unbaked brick, also in the banks of streams; and the eggs are laid on the bare floor without any lining." In Patagonia, where I have found this bird breeding in the cliffs of the Rio Negro, its habits are precisely as Azara says; but on the pampas of Buenos Ayres, where the conditions are different, there being no cliffs or old mud-walls suitable for breeding-places, the bird resorts to the big solitary ombú tree (_Pircunia dioica_), which has a very soft wood, and excavates a hole 7 to 9 inches deep, inclining upwards near the end, and terminating in a round chamber. This reversion to an ancestral habit, which (considering the modified structure of the bird) must have been lost at a very remote period in its history, is exceedingly curious. Formerly this Woodpecker was quite common on the pampas. I remember that when I was a small boy quite a colony lived in the ombú trees growing about my home; now it is nearly extinct, and one may spend years on the plains without meeting with a single example.