History of storks - nest weight - reintroduction in Alsace,... Since its creation in 1976, NaturOparC's aim has been to preserve biodiversity. Its first conservation campaign, completed in 2015, targeted the white stork, whose population was endangered with only 2 wild pairs in 1982. The team studied the causes of the species' disappearance, and embarked on captive breeding, which proved a resounding success. Today, no fewer than 950 pairs live in Alsace. Look up during your excursions through the villages of Alsace! You may catch a glimpse of one of them in the many nests on the roofs of Alsatian houses. Their nests can be up to 1.50 m in circumference and weigh up to 500 kg, or even a ton in some cases!