The Importance of the Scots Pine for the Diversity of Forest Avifauna: The Augustów Forest as a Case Study

Abstract

The Scots Pine Pinus sylvestris is the most widespread tree species in forests of lowland parts of Central and Eastern Europe. In Polish forests, stands dominated by the Scots pine cover almost 60% of the forest area. We analysed the relationship between forest birds and pine trees in an extensive forest complex in north-eastern (NE) Poland. Based on the 20-year-long study, we considered the percentage of broods established on pine trees and the percentage of Scots pine in stands on grouse leks and territory. A total number of over 20 bird species are dependent on the Scots pine trees or stands to locate their nests. Among this group, 11 bird species strongly associated with pine trees were confirmed, and they located at least 90% of broods or nests on pines. The Black Woodpecker Dryocopus martius selects the Scots pine to excavate cavities. Its cavities were regularly used by some species of secondary cavity nesters. In turn, the Common Raven Corvus corax nests were occupied by selected birds of prey. The importance of Scots pine for birds increased with the age of the trees. Old Scots pine trees were chosen by birds that built large nests, placed nests in the tree top, and excavated large cavities. Populations of pine-specialized bird species may be in danger due to the possibility of the Scots pine range moving to the north, which results from global warming. The maintenance of the Scots pine with the modification of the methods of forest regeneration should be included in the Polish forestry’s strategies and plans as a critical factor for the care of the population of rare breeding bird species.