Bird colonies affect all elements of inhabited ecosystems, such as the soil, floristic composition and phytocoenosis structure, including the lichen biota. To date, the few papers focusing on changes in the composition of lichen vegetation caused by bird colonies are concerned with saxicolous ornithocoprophilous communities. The aim of this study was to define the impact of the grey heron in two breeding colonies on epiphytic lichens on Scots pines presently inhabited by birds, as well as those recently abandoned. Analysis of the lichen biota showed that the species composition and number of lichens were significantly modified in the functioning colony and the post-colony areas when compared with the control plots never inhabited by grey heron. Within the functioning and post-colony areas, mainly species with a wide ecological amplitude and those characteristic of fertile habitats dominated, while acidophilous and ubiquitous taxa occurred in the control plots. Multivariate analyses (for species abundance and ecological characteristics) showed that lichens growing within the functioning colony and post-colony areas differed significantly from those in the control area in their habitat requirements, as they demanded nutrient-rich, low or moderately moist and deacidified bark. Within the control plots, lichens preferring a relatively acidic and slightly nitrified substratum occurred. The direct impact of bird excrement and the fertilized bark could cause significant modifications in qualitative and quantitative species composition compared to the epiphytic lichen biota usually occurring on Scots pines. Key words: corticolous lichens, eutrophication, heronry, Wirth’s indicators.