Rivers constitute natural ecological corridors that allow plants and animals to move and occupy new territories, thus enabling them to exchange genes between distant populations. In 2002, in the north-west part of Wrocław, on 256.6 km of the Odra river course a construction of Millenium Bridge has been started. The building and utilisation of that bridge may cause undesirable changes in the natural environment of the river and adjacent areas. The most negative effects of roads connected with exploatation of the road network include: 1) animal road mortaility on the resulting from collisions with vehicles, 2) changes in animal behaviour, 3) changes in the chemical and physical environment due to the accumulation of chemical substances and 4) spreading of alien species of flora and fauna. The paper presents the results of quantitative studies on breeding bird fauna in the Odra embankment within the Millenium Bridge construction site, in the first two years of construction. The studies on birds were conducted using the transect method, on three sections of the embankment. In spite of intensive construction works that removed a part of high vegetation, no big changes were documented in breeding communities of birds living in the Odra embankment. In the second year of study in the whole area a 9% decrease in the number of species (from 45 to 41) and about 6% decrease in breeding pairs (from 120 to 113) were found.

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