The Old Lake has a special value in maintaining ecological diversity of this region, this role is
outstandingly unique within a city. The extended site is one of the few major stopover sites for
migratory birds in Transdanubia (Hungary west of the River Danube). Thereby, it is essential to
maintain these migrants in the region. It is the only other site apart from lake Fertő where the
endangered Lesser White-fronted Goose annually occurs. For list of all internationally designated
bird species, see Criterion 2. It is also one of the three sites in Hungary where Senecio umbrosus
occurs, and the only site in northern Transdanubia for Ludwigia palustris.
Criterion 4. Lakes by Tata is a key staging site for large numbers of waterfowl (especially Anser
fabalis, Anser albifrons), in a critical period during migration, particularly in autumn. The site is
necessary for their survival as there are only a few other sites in the region (Northern
Transdanubia) which are suitable for migrant goose populations. The site also holds
representative populations of numerous rare species of fauna (see Section 22.).
Criterion 5.
Lakes by Tata are valuable habitats for migratory birds, especially for waterfowls during the
autumn and spring time. Regularly more than 25 000 waterfowl spend their night on the Old lake
in November – early December (this is the peak time of Anser species and Anas platyrhynchos, as
well as Larus ridibundus). These migratory birds roost and feed here.