On the way to Nida, just outside of Juodkrantė and before reaching the peak of the steep Avinas Hill, there is another hill in the ancient woods, called the Garniai Hill (the Hill of Herons). It has been named after a nearby colony of grey herons and great cormorants. It is one of the largest colonies of such birds in the whole Europe. It is hardly possible to answer the question when herons settled in the surroundings of Juodkrantė. In the middle of the 19th c., they were a usual attribute of daily life. It can be rightfully claimed that these long-legged birds lived here in the 17th c. and maybe even earlier. What has made herons move their nesting places from the northern areas of Juodkrantė to the southern ones? Historical sources tell about their fight with the aggressive newcomer, i.e. the cormorant. Cormorants (Phalacrocorax carbo L. or Carbo cormoranus), also called sea ravens (corvus marinus), appeared in Juodkrantė in 1803. They settled next to the herons and started taking over their nesting places. Gradually, herons were forced to live in the periphery. They started migrating closer to Juodkrantė. Ten years later, two separate colonies of herons and cormorants formed in the southern and northern parts of the outskirts of Juodkrantė. Yet, up to 1978, great cormorants were very rare guests to the Lithuanian coast and in the Curonian Lagoon. Another big wave of cormorants reached Juodkrantė between 1974 and 1978. Non-breeding birds were spotted in various places of the lagoon and in different seasons. Soon, the black birds settled near herons. Little by little, herons had to give up the largest part of their nesting places to the intruders, while in 1995 the smallest ever amount of nesting herons was recorded.
Now, two colonies, one of herons and one of cormorants, exist next to each other. According to the data of 2021, 3,135 couples of great cormorants and 228 couples of grey herons nested in the colony. It has been several years since the number of pairs of nesting cormorants has been around 3,000 and that of herons - around 200. The population of cormorants has been regulated. It is one of the largest and longest-known colonies in Lithuania. In the first half of February, the first cormorants reach the Curonian Spit. Later, grey herons come. By the end of March, the colony comes back to life.