Just outside Juodkrantė on the way towards Nida, yet before the steep Avino Hill, in the old forest is another – Garnių (Heron) Hill. It got its name from the nearby located heron and cormorant colonies. This is one of the largest colonies of these birds in Europe. According to the data for the year 2000, 582 gray heron and 1361 cormorant pairs nested here.
It is hardly possible to answer the question when the herons moved to the neighborhood of Juodkrantė? In the middle of the nineteenth century they were common part of everyday life. It is safe to assert that these birds lived here in seventeenth century or even earlier.
What prompted herons to move their nesting from the northern districts of Juodkrantė to the southern? Historical sources tell of their struggle with an aggressive entrant - cormorants. Cormorants (Phalacrocorax carbo L. Carbo or CORMORANO), otherwise known as sea raven "corvus marinus", appeared in Juodkrantė in 1803. They settled near herons and started taking over their nests. Gradually, herons were pushed to the periphery. They started migrating south of Juodkrantė. Another 10 years led to two separate colonies of herons and cormorants in the southern and northern outskirts of Juodkrantė.
The fight of cormorants and herons
O.Glagau also describes the strange cormorants and herons mutual fight, won by the cormorants and for some time supplanting the grey herons.
Cormorants moved their colony to the south near the herons. This time, herons and cormorants relationship was intervened by man. In the light of local forester’s recommendations and local fishermen's complaints, the Prussian government allowed the eradication of black strangers.
Until 1978, great cormorants have been very rare guests to Lithuanian coast and the Curonian Lagoon. Subsequently, only single birds might have been spotted in these areas from time to time, mostly in the spring and autumn migration periods.
The other Cormorants wave reached Juodkrantė in 1974-1978. Non-breeding birds have been observed in various places of the lagoon during various seasons. Soon, black birds settled next to the herons.
Gradually, herons have been forced to cede a large part of their nesting places to the invaders, and in 1995 the lowest content of nesting herons was recorded.
Now side by side there are two - the heron and cormorant colonies. According to year 2000 accounting data 500 pairs of gray heron and 2000 cormorant pairs nest here. First cormorants began nesting in 1989, the abundance curve is increasing and when stabilized, or what will be the consequences of their competition is still to be seen. Herons and cormorants are protected by law right now, so the artificial reduction of their numbers is out of question.
Currently, cormorants are quite common birds, and their abundance in the lagoon is increasing. The local fishermen and foresters are not satisfied with damage caused by those birds.
Prepared by: Gediminas Gražulevičius and Dainius Elertas (Curonian Spit National Park)