The lower part of the floodplain area of the Morava river at the Slovak-Austrian frontier was till 1990 closed for the public and from the ornithological viewpoint it is most valuable part of the 107.5 river km long Slovak reach of the river. This part of the alluvium (from the 0 km at the confluence of the Morava and the Danube up to the confluence of the Morava and Dyje) on the area of 9050.4 ha includes a complex of floodplain forests, dead arms, marshes, natural and semi-natural wet meadows being almost unknown in Slovakia. During our investigation in the lower part of the alluvium we found 201 bird species, i.e. 92.62 % from the total amount of species found on the alluvium of the whole Slovak reach of the Morava river. 111 of them were nesting birds. Most species were found in floodplain forests (86) with the highest part of nesting birds (83.7 %), less on meadows (84), and dead arms and marshes (82). A most conserved biotopes are on an interleveeal area (3527 ha). We can find here also a larger part (1672 ha) of the whole area (2329 ha) of wet meadows. From the ornithological viewpoint this biotope is one of the most endangered ones in Slovakia. Except from suitable nesting conditions for rare nesting birds it offers rich supply of food for bird populations on the left-side (Slovak) and right-side (Austrian) areas of the alluvium. It is important mainly for birds of prey, white stork (Ciconia ciconia) and common heron (Ardea cinerea) nesting in colonies in the WWF reserve. A comparison of qualitative-quantitative representation of birds on the monitoring plots in the floodplain forests of the alluvium of the Morava, Danube and Little Danube reflects the difference in species composition of vegetation in floodplain forests. Since 1993 the whole alluvium of the Morava has been a selected Slovak area protected by the Ramsar Convention.