The nests of the large birds – eagles and black storks are impressive in their size and weight. The longest lasting nests can reach even 1 tonne of weight. Such nests can be supproted only by old and strong trees with strong branches. If a nest is build in a stable jab of old pine or oak tree and birds add new materials to it on a regular basis, the longevity of the nest can reach tenths of years. However, usualy the life of nests is shorter. If the nest has grown to be very large and heavy and there have been prolonged raining and snowing that have added humidty to the nest, it can fall off and soon turn into a pile of branches and turf on the ground. Besides natural causes also forestry is affecting the safety of nests and undistrubed nesting. The project “Conservation Arrangements for Lesser Spotted Eagle in Latvia” has found out that one tenth of all inventored nests are endagered by forestry.
One of a well tested methods in nature conservation for increasing the longevity of nests is setting up of artificial platforms. Therefore the experts of Latvian Fund for Nature each year will build 10 to 15 artificial nests for Lesser spotted eagles in the state forests of Latvia.
Ornithologist and eagle expert Jānis Ķuze explains that the artificial nest is built in a tree that has been evaluated as suitable for Lesser spotted eagle. Such a tree has strong branches and is vital and also old enough. The location matters, too. The tree has to be close to the edge of the forest as Lesser spotted eagles are typically living close to forest edges and feeding grounds. If possible, spruces or birch trees are chosen for artificial nests are these are the trees that would be preferred by the birds themselves. If there had been a nest historically – even better. The experience shows that articial nests build shortly after falling of the natural nests are most likely to be inhibited. There are several methods for building the neests, and the choice of construction depends on the form of tree. It can look very natural and be a copy of a nest built by eagles, but it can also be just a platform – a frame for the nest. Eagles, black storks and Euroasian Eagleowls are quite glad to occupy these constructions and they can be even more stable and durable than the nests built by birds themselves. Construction of one artificial nest requires two days work of two people, but, if the job is done well, a nest can last more than 20 years.
Latvia is a very significant territory for Lesser spotted eagles as almost half of EU population lives here. Installation of articial nests is one of the many nature conservation activities that helps the population of Lesser spotted eagles.