In the Basque Country (N Spain) the black woodpecker Dryocopus martius (L., 1758) was virtually unrecorded until the late 1990’s, but since then the number of observations has increased sharply. To determine the current distribution of the species, extensive, standardized field surveys of suitable forest patches in the province of Álava were performed during the 2011 early breeding season. The presence of the species was recorded in 16 UTM 100 km2 squares. Furthermore, reliable observations were collected during the 2003 to 2011 breeding seasons in another 23 UTM 100 km2 squares, adjacent to the study area, where the black woodpecker had gone undetected in the last published breeding atlas for the period 1998-2002. This range increase implies that the two, formerly separate populations in Spain (Pyrenees and Cantabrian Mountains) have currently coalesced into a continuous distribution, highlighting the relevance of the study area in the expansion of forest species between the two great mountain ranges of northern Iberia. Forest biomass growth and ageing of stands due to a reduction in felling operations over the last few decades have probably allowed the colonization of previously vacant localities.