Eurasian eagle owl diet reveals new records of threatened giant bush-crickets

Bird diets provide a real treasure for research into the distribution and conservation of their prey, conclude scientists after studying the Eurasian Eagle Owl in southeastern Bulgaria. In their paper, published in the open-access, peer-reviewed journal Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa”, they report the frequent presence of the threatened Big-Bellied Glandular Bush-Cricket, and conclude that studies on the Eurasian Eagle Owl could be used to identify biodiversity-rich areas in need of protection.

Male specimen of the Big-Bellied Glandular Bush-Cricket (Bradyporus macrogaster)
Photo by Dragan Chobanov

Bird diets provide a real treasure for research into the distribution and conservation of their prey, such as overlooked and rare bush-cricket species, point out scientists after studying the diet of the Eurasian Eagle Owl (Bubo bubo) in southeastern Bulgaria.

In their paper, published in the open-access, peer-reviewed journal Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa”, Dr Dragan Chobanov (Institute of Biodiversity and Ecosystem Research, Bulgaria) and Dr Boyan Milchev (University of Forestry, Bulgaria) report the frequent presence of the threatened with extinction Big-Bellied Glandular Bush-Cricket (Bradyporus macrogaster) in the diet of Eurasian Eagle Owls, and conclude that the predatory bird could be used to identify biodiversity-rich areas in need of protection.

While the Balkan Peninsula has already been recognised as the area with the highest diversity of orthopterans (grasshoppers, crickets and bush-crickets) in Europe and one of the generally most biologically diverse areas in the whole Palearctic realm, it is also home to a worrying number of threatened species. Additionally, a thorough and updated country assessment of the conservation status of the orthopterans found in Bulgaria is currently lacking. This is why the Bulgarian team undertook a study on the biodiversity of these insects by analysing food remains from pellets of Eurasian Eagle Owls, collected from 53 breeding sites in southeastern Bulgaria.

As a result, the scientists reported three species of bush crickets that have become a significant part of the diet of the studied predatory birds. Curiously enough, all three species are rare or threatened in Bulgaria. The case of the Big-Bellied Glandular Bush-Cricket is of special concern, as it is a species threatened by extinction. Meanwhile, the local decline in mammals and birds that weigh between 0.2 and 1.9 kg, which are in fact the preferred prey for the Eurasian Eagle Owl, has led the highly opportunistic predator to increasingly seek large insects for food. The researchers even suspect that there might be more overlooked species attracting the owls.

Taking into account the hereby reported interconnected inferences of conservation concern, as well as the vulnerability of the Big-Bellied Glandular Bush-Cricket, a species with a crucial role in the food chain, the scientists call for the newly provided data to prompt the designation of a new Natura 2000 site. Additionally, due to the species’ requirements for habitats of low disturbance and high vegetation diversity, and its large size and easy location via singing males, they point out that it makes a suitable indicator for habitat quality and species community health.

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Original source:

Chobanov D, Milchev B (2020) Orthopterans (Insecta: Orthoptera) of conservation value in the Eurasian Eagle Owl Bubo bubo food in Bulgaria. Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa” 63(2): 161-167. https://doi.org/10.3897/travaux.63.e53867

Special issue: Natura 2000 appropriate assessment and derogation procedure

The focus is on the case-law of the European Court of Justice and the German Federal Administrative Court

With over 27,500 sites, Natura 2000 is the greatest nature conservation network in the world. It covers more than 18 percent of the land area in the European Union and around 395,000 km2 of its marine territory.

Projects and plans within those sites or in their vicinity require an appropriate assessment to ensure that they will not have a significant impact on the integrity of a Natura 2000 site, according to Article 6(3) of the Habitats Directive 92/43/EEC. The Natura 2000 appropriate assessment is the central statutory instrument for the protection of the network, in addition to the general prohibition of deterioration.

An assessment must take place prior to the authorisation and implementation of a project or a plan. As a result of the European Court of Justice (ECJ) having maximised the effectiveness of the assessment by a stringent legal interpretation, a project or a plan must be rejected by the competent authorities if there is any remaining reasonable scientific doubt that it might adversely affect the integrity of the site.

Nevertheless, in accordance with the European principle of proportionality, the Habitats Directive does not intend to ban all human activity in Natura 2000 sites. This is the reason why, on the one hand, only significant adverse impacts on the integrity of a Natura 2000 site are relevant and, on the other, according to Article 6(4) Habitats Directive, a derogating authorisation is possible in favour of public interests.

However, numerous questions, which are relevant in practice, have so far only been considered by national courts. A special issue recently published with the open access journal Nature Conservation features a comprehensive review of the relevant case-law of the German Federal Administrative Court (BVerwG), which has thoroughly dealt with the Natura 2000 regime in a long series of judgements.

The author, Dr. Stefan Möckel of the Helmholtz-Centre for Environmental Research GmbH, Germany, is a long standing specialist in European and German nature conservation law. Within the four articles comprising the issue, he analyses the scope, procedural steps and requirements of the appropriate assessment and the derogation procedure. He also comments on the interpretations and practical solutions found by the ECJ and the BVerwG.

The first article explains the main steps and demands of the appropriate assessment. Questions on the scope of the terms “project” and “plan”, as well as determining significant impacts are discussed in greater detail in the second and third article. The fourth paper explores the requirements needed for a derogation to be approved.

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Original source:

Möckel S (2017) The European ecological network “Natura 2000” and the appropriate assessment for projects and plans under Article 6(3) of the Habitats Directive. In: Möckel S (Ed.) Natura 2000 appropriate assessment and derogation procedure – legal requirements in the light of European and German case-law. Nature Conservation 23: 1-29. https://doi.org/10.3897/natureconservation.23.13599

Möckel S (2017) The terms “project” and “plan” in the Natura 2000 appropriate assessment. In: Möckel S (Ed.) Natura 2000 appropriate assessment and derogation procedure – legal requirements in the light of European and German case-law. Nature Conservation 23: 31-56. https://doi.org/10.3897/natureconservation.23.13601

Möckel S (2017) The assessment of significant effects on the integrity of “Natura 2000” sites under Article 6(2) and 6(3) of the Habitats Directive. In: Möckel S (Ed.) Natura 2000 appropriate assessment and derogation procedure – legal requirements in the light of European and German case-law. Nature Conservation 23: 57-85. https://doi.org/10.3897/natureconservation.23.13602

Möckel S (2017) The European ecological network “Natura 2000” and its derogation procedure to ensure compatibility with competing public interests. In: Möckel S (Ed.) Natura 2000 appropriate assessment and derogation procedure – legal requirements in the light of European and German case-law. Nature Conservation 23: 87-116. https://doi.org/10.3897/natureconservation.23.13603