In 2010, an attempt was made to quantify bird species breeding in the Opava Mts. and their foothill (c. 135 km2, including c. 40 km2 [31%] of forests). The area is situated in the extreme south of Opole Silesia, SSW Poland. For most non-passerine species, total counts were made for the whole area (distribution of their breeding pairs is shown on maps), while for most passerine species, semi-quantitative studies were conducted. A total of 116 breeding and two probably breeding bird species were recorded. Changes in breeding avifauna of the area during the years 1880-2010 are also analysed based on literature search. A total of 134 breeding bird species were recorded over the 130 years. During the years 1990-2010, decreae in numbers has been evidenced for the following species: