Position on the migratory routes

The position of lakes in global bird migration systems

As many as 140 species of birds use migratory populations to migrate to Vransko Lake. Vransko Lake is of great international importance as a resting place and feeding ground for migratory birds. The picture shows the findings of birds ringed on Vransko Lake and found outside that area, and the findings of birds ringed outside this area and found on Vransko Lake. The orange dots show the origin of the birds that use Vransko Lake, and the green areas where the birds continue their journey after the lake.

Based on this map, we can say that Vransko Lake is used by birds from all over Central, Northern and Eastern Europe. Findings of birds from Eastern Europe are the least represented on the map, but probably not because few of them cross the lake, but because very few birds are ringed in that area, a practically negligible number. Therefore, it is unknown how far to the east are the areas from which birds cross the lake.

After resting and feeding at Vransko Lake, the birds continue their migration in three main directions. The western direction bypasses the Adriatic Sea and passes through Northern Italy, and continues along the Mediterranean coast via Gibraltar to Africa. The trans-Adriatic route is used by birds that fly across the Adriatic, cross Italy and probably fly across the Mediterranean in two directions (via Southern Italy and Sicily and via Corsica and Sardinia). The southeast direction leads down the coast of the Adriatic and across the Balkans, probably further to Asia Minor and the Middle East. This direction is by far the weakest represented, it is found in that area, as well as in Eastern Europe, birds ring very little.

From the map of the findings, it is undoubtedly clear that Vransko Lake is part of a migration system that occupies Central, Northern, Eastern Europe, Southwestern and Southeastern Europe, the entire Mediterranean area, and Africa, and probably also Western Asia, and the Near and Middle East.

The number of birds migrating across Vransko Lake is very difficult to determine. Thanks to the counts during the autumn migration, and the ringing actions we have carried out in recent years (since 2001), we roughly estimate that for the autumn migration, from August to October, between 20,000 and 200,000, sometimes up to 400,000 flight tickets. Therefore, at the beginning of autumn, up to 1,000,000 birds, members of the local nesting population and the migratory population, occasionally visit the Nature Park. We cannot estimate the total number of birds that fly over the Nature Park for the entire migration, but it is certainly higher (perhaps several times) than 1,000,000.

Places of ringing and finding of birds that live on Vransko Lake. The position of Vransko Lake is marked in blue, the location of the birds from the area from which the birds come to Vransko Lake is marked in orange, and the location of the bird from the area where they leave from Vransko Lake is marked in green. The picture shows only bird finds in Europe.

(taken from „Inventarizacija i valorizacija ornitofaune Parka prirode Vransko jezero“, Department of Ornithology, HAZU, 2004.)