Pavlík J., Pavlik Š.: Some relationships between human impact, vegetation, and birds in urban environment. Ekológia (Bratislava), Vol. 19, No. 4, 392-408, 2000. Relationships between human impact, woody vegetation, and birds were analyzed based on 15 study plots situated within the town Zvolen (central Slovakia) using the principal component analysis and the multiple correlation analysis. Following variables characterizing the study plots have been included into the analysis: Plot size, human impact, plot age, area covered by woody vegetation, number of woody plant species, proportion of introduced and broad-leaved woody plant species, species diversity of woody plants, number of layers, vertical diversity of woody vegetation, number of bird species, relative abundance of birds, and proportion of synanthropic, cxanthropic and curythopic bird species. Based on the PCA analysis, three principal factors were extracted from the original set of variables, which correspond with the three variables - human impact, plot age and plot size. The human impact was a key factor affecting the structure of woody vegetation. There were the higher woody plant species richness and the higher proportion of introduced woody plant species due to the introduction within the study plots with man-affected woody vegetation compared to the study plots with spontaneous woody vegetation. The human impact alone did not influence the bird species richness and abundance directly, but it was manifested especially through the vegetation structure. Bird species richness and abundance were higher within the study plots with spontaneous woody vegetation. On the other hand, the study plots under the higher human impact were occupied mostly by the synanthropic and curythopic bird species. Plot size was an important factor affecting the number of both woody plant and bird species within the study plot. Plot age affected mostly the vertical structure of woody vegetation as well as the proportion of introduced/ broad-leaved woody plant species.