When water bodies began to be cleared due to the ever-increasing urbanisation in Slovene Istria as well as in the Mediterranean in general, the Sečovlje salt-pans began to gain, through years, on their significance as a bird sanctuary. A great role in this respect has also been played by the abandoned salt-making in the southern half of the pans. The salters indeed stopped gathering salt there, but they still maintained the levees, regulated the water level in salt basins and thus conserved the different natural living environments. An important role has also been played by the processes of natural forces, which formed a series of similar but different enough environments, which have been eventually inhabited by birds with different dietary and breeding demands. Seawater, which runs deep into the pans through salt-pan channels, brings to the basins large amounts of food that can be easily reached by birds in the shallow basins of the abandoned part of the pans. These are primarily planktonic organisms, tiny invertebrates, and fry. In springtime the pans, which are a widened boundary between the land and the sea as far as birds are concerned, become an important nest-site for numerous birds. 
For at least two bird species this is their only nest-site in Slovenia, but there are also several local breeders, which are otherwise known to nest only at a couple of other sites within the country.
 The Sečovlje salt-pans play, however, even more important role in the wintering and migration of birds. As they are situated on the Mediterranean coast with its characteristic sub-Mediterranean climate and mild winters, they are highly inviting for numerous winter residents from northerly regions and at the same time constitute the natural habitat, which is truly unique at the national level. The overwintering and migrating bird species are here most numerous as far as the Slovene coast and Slovenia in general are concerned.