The big owls (Bubo bubo) are on the list of protected species of animals, plants and mushrooms of the Republic of Lithuania. The main causes of the decline are deforestation and other work during reproduction. Birds are susceptible to disturbance. Boars and other predators are often destroyed by boars and other predators. The project is currently in a favourable situation for a significant reduction in the wild boar population due to swine fever. There is also a decrease in the population of small predators due to the itch mite. The project is aimed at increasing the population of the great owls by breeding, adapting and releasing juveniles into nature, as well as follow-up observations on released offspring. The objective will be achieved through the breeding of pairs of grand marriages (by artificial incubation and rearing of juveniles where necessary). The Lithuanian Zoo together with its partner Ecosystem Protection Centre will breed the pairs of marriages it owns, adapt all the planned releases in selected release areas, half of the large offspring will be equipped with transmitters and will monitor the movement of the released pups, the places of stay and the habitats where the birds are staying.