Reintroduction of ural owl

This project's goal is returning Ural owl, which is a rare species of an owl to Šumava. This species of owl disappeared there at the beginning of the century. Birds released into the wild are bred in the Hluboká Zoo and other zoos and other breeding facilities.

Ing. Bohuslav Kloubec (CHKO Třeboňsko management)

RNDr. Roman Kössl (Zoo Hluboká)


Who participates on this project (info until 2010):

Management CHKO Třeboňsko, Třeboň (project management)
Management NP and CHKO Šumava, Vimperk (releasing, terrain research)
Vojenské lesy a statky ČR, Horní Planá (releasing)
Zoo Bojnice, Slovensko (catching breedable birds from the nature)
Zoo Hluboká (breeding management, breeding - 4 pairs of owl, releasing)
Podkrušnohorský Zoopark Chomutov (breeding - 2 pairs of owl)
Stanice ochrany fauny, Pavlov (breeding - 3 pairs of owl)
Přírodovědecká stanice, Horažďovice (breeding - 3 pairs)
Zoo Děčín (breeding since 2006 - 2 pairs)
Zoo Praha (breeding since 2007 - 1 pair)
Záchranná stanice Kladno (breeding since 2009 - 1 pair)


Project description:

1. History of the occurrence of the ural owl in Šumava

The ural owl belongs to the original species of owl in Šumava. Certain differences in the habit even led to the description of the unique Šumava form of Strix schumavensis (HEYROVSKÝ, 1851). At the turn of the 19th and 20th centuries, the white-eared owl regularly occurred on the Czech and German sides of the Šumava Mountains and in its foothills. It was one of the westernmost occurrences in the spread of the owl in the western Palearctic. It nested here especially in mixed forest stands and its number there could reach at least several dozen pairs. The area between Vimperk, Volary and Nová Pec was one of the most frequent areas of occurrence. Since the beginning of our century, a decrease in the number of ural owls has been recorded, the latest data on nesting are available from the 1920s, and since the end of the 1930s the ural owl has been considered an extinct species on both sides of the Šumava.

The cause of a very significant decrease or disappearance of the Šumava ural owl population is difficult to define retrospectively. Available data suggest that it may be a combination of intense bombardment with some adverse circumstances of living conditions (decline of mixed and deciduous forests of primeval character, strong population size fluctuations due to possible climatic fluctuations and gradations of small mammals, genetic isolation of a small population) . The ural owl is a conspicuous and tame owl, often activating in broad daylight, which is highly aggressive in the vicinity of its nest. It can therefore be assumed that with the then large number of inhabitants of Šumava and the possibilities of essentially free liquidation of damage causing animals, it was the persecution of humans that had a decisive influence on the disappearance of the owl. At present, the reintroduction of the ural owl in Šumava can be considered promising, because the risk of direct liquidation of the ural owl is minimal. As a critically endangered species, it is legally protected and the possibility of illegal shooting is unlikely in recent years due to a generally more favorable relationship with birds of prey and owls in particular.

From the 1930s to the 1970s, several observations of the ural owl were recorded in Šumava. These are probably accidental flights from places of permanent expansion, several hundred kilometers away from Šumava, but the possibility of survival of a very limited original Šumava population cannot be ruled out. Occasional occurrences of ural owls on the Czech side of the Šumava from the 1980s and 1990s can be attributed mainly to the discharge in the Bavarian National Park. The project of reintroduction of the ural owl on the Bavarian side of the Šumava was started in the early 1970s and can now be considered relatively successful, as in recent years several pairs have successfully nested in the wild that have formed from released individuals. At the beginning, however, the project did not meet two of the basic conditions, namely a sufficient number of initial parental pairs (only 9 specimens formed the basis for breeding, so that less than 200 chicks produce unwanted inbreeding) and their origin (most birds come from different zoos and some belong to an inappropriate subspecies from northern Europe). So far, this German reintroduction program has been carried out to a lesser extent (an average of 8 young per year have been released) and so far there is no permanent larger and reproducible ural owl population on the Bavarian side of the Šumava Mountains. It is therefore highly desirable to eliminate all of the above adverse factors by significantly enhancing the genetically appropriate population. It can be assumed that the project of reintroduction of the ural owl on the Czech side of the Šumava should meet all these requirements.

From the 1920s until the beginning of the 21st century, the ural owl did not nest in Bohemia. In Moravia, a small isolated nesting population was formed in the Beskydy Mountains in the 1980s. This is probably a consequence of the gradual spread of the ural owl westward from the Slovak Republic, where there is currently a large stabilized population. At present, the ural owl is widespread mainly in the mountain forests of Central Europe (the Carpathians, some mountain areas of the former Yugoslavia and the easternmost areas of the Alps). In all cases, it is a Central European subspecies (Strix uralensis macroura WOLF, 1810), which is isolated from the main area of distribution of this species in a large area of the taiga zone of the Palearctic.

Based on current knowledge about the food of the ural owl (smaller mammal species predominate, birds, amphibians and insects are less represented) and with current knowledge about populations of small mammals and birds and predators in Šumava, it can be assumed that the return of this larger predator to Šumava biocenoses will not have any competitors. When considering the justification of reintroduction and its effects, the fact that the owl is one of those predators whose abundance and reproductive strategy is very much dependent on sufficiency or surplus cannot be overlooked. Due to its trophic strategy (wide food spectrum, hunting during the day and night, winter wanderings), in the current conditions of the Šumava, there is no danger that it will suffer in the period of lower population of small mammals. The ural owl with a severe lack of food wouldn't compensate it with the trophic specialisation.


2. Securing animals for reintroduction

The limiting factor for initiating successful reintroduction was securing of a sufficient amount of breeding material. From the genetic and economic point of view, the use of the Central European subspecies from the Slovak Republic proved to be the most suitable for reintroduction. The population of the ural owl is large in this area and the collection of a certain number of individuals can in no way affect the size and quality of the population. Considering that the estimated 500 Slovak pairs of owls will produce min. 500 and in favorable years more than 1500 cubs, then, for example, the planned 5-10 cubs taken per year represents a negligible part of the hatched individuals. During the collection, the principle is observed that only one of the youngest cubs is taken from a nest of two or more cubs  which usually dies due to lack of food. It is therefore clear that the effect of sampling on the total number of all hatched cubs is practically zero and in no case can it affect this population in any way. Nesting and its success in the East Slovak population of the ural owl are supported by the production and installation of nesting boxes, which are often used for nesting and the number of cubs in them reaches even higher values ​​than in other methods of nesting.

The breeding of ural owls is based on a number of published data and experience with the breeding of ural owls in the Bavarian National Park. For the compilation of breeding pairs, it is necessary to use a combination of a larger number of individuals from the free population in different places in Slovakia as a basis. In the case of these imported pieces, sex is performed by the endoscopic method in the autumn, followed by the formation of couples. These are then located in several permanent breeding facilities with a sufficient personnel and material base (Ohrada Zoo near Hluboká n. Vlt., Horažďovice Science Station, Pavlov Fauna Protection Station, Chomutov Zoo, later Děčín Zoo and Prague Zoo). In them, owls regularly nest and raise cubs which are used for release into the wild or for assembling other breeding pairs. Based on current experience with proper feeding, one parent pair raises an average of about two cubs per year, with the number of young usually increasing with the age of the parents. It was therefore assumed that with the planned permanent breeding of 6-10 nesting pairs and the annual import of 5-10 cubs from the Slovak Republic, it would be possible to release up to 150-200 specimens in Šumava by 2005. This number, together with approximately the same number of released individuals in the Bavarian National Park and in combination with the planned release of owls in Austria, can be considered sufficient for the emergence of a permanent reproducible population in the Šumava region.


3. Releasing ural owls

Ural owls in releasing aviary

The actual release of the ural owl into the wild is based primarily on the proven methodology in the Bavarian National Park. Breeding pairs are located in discharge facilities, more spacious aviaries, built in Šumava in suitable habitats or their immediate vicinity. In a suitable period, usually at the end of July, parental pairs with cubs from permanent breeding facilities are placed in these release aviaries 1-2 months before the release of the cubs (longer-term or permanent breeding of nesting pairs in release aviaries has so far proved unsuitable for financial and organizational reasons) . Sometimes cubs couples or even Slovak cubs from the wild are added to parent pairs with cubs. After release, the cubs move around these aviaries and are in visual and vocal contact with their parents, which is very important for good adaptation into the wild. During this time, the cubs are fed, but gradually begin to hunt for food on their own and in a few weeks leave the immediate vicinity of the aviary. We assume that in the future, in some cases, chicks with a parent pair will be released from these aviaries, which will allow even more natural development of chicks in contact with parents and a longer time spent together after leaving the nest. A nesting pair released in this way is likely to have a strong nesting connection to the place of release in subsequent years (older birds usually do not move as far after release as young birds, which can move tens of kilometers during the first winter. However, the number of nesting pairs released in this way will depend on the number of individuals who will be suitable for this purpose. severely handicapped by nature and may tend to attack humans to an increased extent.

The cubs are released in the Šumava National Park in places of historical occurrence of the ural owl. There were originally three, currently two discharge facilities (in the vicinity of České Žleby, Stožka and Rejštejn). Later, two aviaries were added to the territory of Boletice managed by VLS Horní Planá. When choosing the location of discharge facilities, preference was given to forest stands, close in their species, age and spatial composition to natural forests (in given conditions mainly mixed stands of primeval character with a predominance of beech) in combination with open areas with sufficient food. At the same time, these are places with the recent occurrence of other individuals of the ural owl not originating from this project.

Suitable nesting boxes were gradually installed in the discharge areas, although nesting can be expected in other ways as well (old predator nests, in tree breaks, on the ground, etc.). All released individuals were circled and labeled with microarrays. Radios have been installed in almost half of the specimens since 2000, with the help of which it was possible to obtain important information about the movement of birds after release into the wild for a period of up to one year. In principle, it can be stated that the whole reintroduction is designed with maximum regard for the most natural breeding and release of bred individuals with the reduction of stressful situations to a minimum.

Due to the considerable dispersion of young after release, a gradually expanding, but very difficult to predict occurrence was expected in the entire Šumava region. Long-term accumulation of more individuals in the same locality was not expected, and the total density will probably not reach higher values in the future due to the large area of the Pošumaví. Simultaneously with the planting, field evaluation of changes in the number of ural owls, control of the occupancy of booths and other potential nesting sites, evaluation of prey supply and food composition of ural owls and other activities took place in model areas.

Since the start of the project in 1991, 31 cubs and 3 adult handicapped individuals from the Slovak Republic have been imported so far, and 124 cubs have been bred in our zoos (of which 54 in the Ohrada Zoo), in 1995-2010 107 individuals were released into the wild (of which 37 bred in Zoo Ohrada). This successfully completed the first phase of the project, which aimed to unite a team of collaborators, provide a suitable background for the project, gather genetically suitable individuals and begin their reproduction, verify methods of breeding and release of young into the wild. The whole project can already be described as successful, because already in 1998 and 1999 on the Czech side of the Šumava after more than 70 years the nesting of the ural owl in the wild was proved again, near the places of its release, other released individuals are regularly observed on several other places suitable for nesting, and nesting was eventually recorded repeatedly in the following years. On the Czech side, a relatively large (approximately 15–20 pair) reproductive population was created. It can therefore be assumed that, assuming the continuation of the reintroduction program and the consistent protection of the owl in the wild, there is a real hope for increasing the number and stabilization of the Šumava nesting population of this owl.


4. Many thanks to our partners

The whole project could not start and run successfully without the help of many organizations and individuals. The Faculty of Forestry of the Technical University in Zvolen (Ing. Rudolf Kropil, CSc.), Bojnice Zoo and Mgr. Stefan Danko, RNDr. Pavol Kanuch, RNDr. Štefan Pčola and MUDr. Ladislav Šimák. The support of the nature protection authorities of the Slovak Republic (especially the Ministry of the Environment of the Slovak Republic) has always been helpful. Ing. Jaroslav Cerveny, CSc. It is necessary to ensure its own breeding, which until now provides and largely pays for its costs Zoo Hluboká (in the beginning was RNDr. Vladimír Holas, Petr Bednář and others), Science Station in Horažďovice (Karel Průcha), Station for Fauna Protection in Pavlov (RNDr. Aleš Toman with co-workers) and the Zoo in Chomutov (MVDr. Martin Ptáček etc.), later the cooperation started with the Děčín Zoo and the Prague Zoo. The work and costs associated with the release into the wild are guaranteed by the Šumava National Park and Protected Landscape Area Administration (RNDr. Luděk Bufka, employees of LS České Žleby, Stožec and Rejštejn) and cooperation with the Bavarian Forest National Park (Dr. Wolfgang Scherzinger) has always been significant. The organization of the entire reintroduction project is provided by the Třeboňsko Protected Landscape Area Administration (Ing. Bohuslav Kloubec). Part of the financial costs is also covered by the Ministry of the Environment of the Czech Republic, the Agency for Nature and Landscape Protection of the Czech Republic and the Administration of Protected Landscape Areas of the Czech Republic.


View ural owl in Zoo Hluboká