Interview with Marton Horvath about the conservation of the Eastern Imperial Eagle in Hungary

Date of the interview: 05 November 2009

The Eastern Imperial Eagle is one of the rarest raptors in Europe and globally vulnerable. In this interview, Marton Horvath from Birdlife Hungary (MME) talks about the current situation of this large eagle in Hungary.

Marton Horvath ringing young Eastern Imperial Eagles

Marton Horvath ringing young Eastern Imperial Eagles.
© Ivan Demeter

Markus Jais: What is the current population size for the Eastern Imperial Eagle in Hungary and how has the population developed during the last 20 years?
Marton Horvath: In 2009 the known population of Eastern Imperial Eagles consisted of 105 nesting pairs in Hungary. Most of the potential breeding habitats are covered by the intensive species-specific monitoring programme, so we estimate the real population to be between 105 and 115 breeding pairs.
Till the late 1980’s the Imperial Eagle was known to be a rare breeder of the mountainous forests in Hungary, and these pairs were foraging in the open foothills even 10-15 km from their nest sites.
In 1989 the total mountainous population was consisted of 24 nesting pairs, but surprisingly further two Imperial Eagle pairs were discovered in a completely different open agricultural habitat. Since that year this lowland population started to increase exponentially and by now 85% of the national population inhabits such lowland agricultural habitats, meanwhile the total Hungarian population became four times larger during the last 20 years.

Adult Eastern Imperial Eagle with it's freshly fledged chick

Adult Eastern Imperial Eagle with it’s freshly fledged chick.
© Andras Kovacs

Markus Jais: How many pairs were successful and how many young have fledged in 2009?
Marton Horvath: In 2009 out of the 105 nesting pairs eggs were laid at 95 pairs, chicks were hatched at 74 pairs and 70 pairs (67% of nesting pairs) were finally successful in Hungary. Altogether 132 chicks fledged, which resulted in an average breeding success of 1.39 chicks per nesting pair and 1.89 chicks per productive pair. This numbers are higher than the average of the last decade (1.15 and 1.72 respectively).

Markus Jais: What are the main threats to the Eastern Imperial Eagle in Hungary?
Marton Horvath: Between 2001 and 2009 113 full grown Imperial Eagles have been recovered dead or with serious injury in Hungary, out of which the causes of mortality could be identified in 78 cases. During the last years poisoning became the first cause of mortality, which represents 37% of the known causes. The previously first, recently second cause is electrocution, which injured 31% of the birds during the last nine years. Further causes included collision with vehicles (10%) and electric cables (3%), starving (8%), shooting (6%) and single other causes (5%).
Causes of breeding failures (i.e. mortality of eggs and chicks) could be identified in 64 cases of the 142 recorded cases between 2003 and 2009. First cause was the collapse of the nest by storms (52%), while the second was human disturbance (mostly during incubation), which composed 25% of the known failure causes. Other causes included unfertilized eggs (11%), poisoning (5%), shooting to the nest (3%), unknown mortality of parents (2%) and illegal logging (2%).

5 week old Eastern Imperial Eagle chicks

5 weeks old Eastern Imperial Eagle chicks.
© Marton Horvath

Markus Jais: Does this also affect other species, for example Saker Falcons and White-tailed Eagles?
Marton Horvath: Besides Imperial Eagles, poisoning mostly affects White-tailed Eagles out of the strictly protected species, while electrocution is among the first mortality factor of many other raptors, including the globally threatened Saker Falcon as well.

Markus Jais: What is done to reduce mortality through electrocution? Are the power lines made safe?
Marton Horvath: In the early 1990’s MME BirdLife Hungary developed a special bird protector equipment, which insulates the cross-arms of electric pylon. Till now more than 30,000 pylons have been insulated in Hungary with this method in cooperation with the Ministry of Environment and Water (MEW) and electric companies. This method proved to be efficient at the most common type of pylons, but it was not 100% safe especially for special pylon types. Therefore recently the bird friendly modifications, financed partially by the European Commission’s LIFE-Nature funds, are insulating the cables itself and not the pylons. In spite of the many efforts up till now only ca. 5-10% of the dangerous power lines have been modified to bird-friendly in the country.
In 2008 MME, MEW and electric companies signed an agreement called “Accessible Sky”, which aimed to “modify all power lines which are dangerous to birds by 2020”. MME has prepared a detailed study about the bird conservation prioritization of the medium-voltage power lines of Hungary, which revealed that based on the length of priority power lines, the estimated costs of modifications, and on the budget specified by MEW and electric companies, only the most dangerous 30% of the power lines could be modified till 2020 according to the most optimal schedule.
Therefore we believe that, although significant results have been achieved, electrocution of birds will remain a serious conservation problem in Hungary for further decades. Nevertheless the availability and proper use of financial sources could solve the problem at the most important bird habitats by 2020.

Lowland habitat of Eastern Imperial Eagles in Hungary

Lowland habitat of Eastern Imperial Eagles in Hungary.
© Marton Horvath

Markus Jais: Is there enough prey for the eagles? How does intensification of agriculture affect prey species and therefore the eagles?
Marton Horvath: The main prey species of Imperial Eagles are the brown hare, hamster and pheasant, although other 55 species have been also identified in Hungary. The populations of all three main prey species, and also of the historically important souslik, have decreased in Hungary since the 1970’s, nevertheless it has not been observed to affect significantly the reproductive success of the eagles.
All of these species are directly affected by agricultural intensification, which is (1) shrinking the most important habitats of them (i.e. bushes, shelter belts, set-aside lands and semi-natural grasslands), (2) increasing mortality caused by larger and faster machines, and (3) increasing chemical usage. Therefore the maintenance of prey populations will be one of the largest challenges of eagle conservation in Hungary in long-term, and it emphasizes the importance of collaboration with game-managers and farmers.

Markus Jais: In some countries, lack of suitable nest trees is a problem? Is this also true for Hungary? Are artificial nests built and do the eagles use them?
Marton Horvath: Yes, especially in some lowland agricultural habitats the lack of suitable (i.e. old and high) nesting trees could be a significant limitation for the species. Eagles are also building nests in suboptimal trees in otherwise good quality habitats, which increases the number of breeding failures due to storms. Here the main available nesting trees are hybrid poplars and black locust trees, which are often not old enough to have stable forks for nests. This problem also occurs in some mountainous areas, where intensive forestry work destroys especially the oldest, and therefore most suitable forest patches.
Hundreds of artificial nests have been built since the 1980s for both eagles and Saker Falcons at the Hungarian Plain, which are frequently occupied by eagles and these stably based nests are less threatened by storms. In some lowland areas the plantation of indigenous tree species (e.g. oaks and poplars) are also undertaken by national park directorates, but these actions should be much more pronounced, as this could mean the only long-term solution of the problem.

Release of rehabilitated juveline Eastern Imperial Eagle

Release of rehabilitated juvenile Eastern Imperial Eagle by Ivan Demeter.
© Marton Horvath

Markus Jais: What is MME doing for eagle conservation and how can people help?
Marton Horvath: MME is the national coordinator of Imperial Eagle monitoring and conservation since 1980, although large parts of the works are undertaken in cooperation with the relevant national park directorates (especially Bükk, Hortobágy, Körös-Maros and Aggtelek).
We have developed a system of territory coordinators, who are responsible for the regular checking of all known and potential Imperial Eagle breeding territories in Hungary. The monitoring protocol includes the localization of active nests in February-March, and afterwards the regular (usually two-weekly) check of breeding activities and number of chicks till August, when they leave the close vicinity of nest sites.
We are ringing most of the chicks in June with aluminium and coloured plastic rings (see e.g.
We accomplish direct conservation actions if we find anything which would threaten the successful breeding. E.g. we strengthen the nest if it is about to fall down, we got in contact with authorities to ban newly appearing human activities in the close vicinity of nest sites, we place back fallen chicks into the nest etc. In some cases we organized nest guarding during the most sensitive periods of the breeding. MME is also coordinating a genetic study in which we are identifying individuals and analyse the structure of our and other populations by using non-invasively collected moulted feathers.
Between 2002 and 2005 within a LIFE-Nature project we had the special opportunity to work for the conservation of the species in full time with two of my colleagues, Andras Kovacs and Ivan Demeter. In this project, we could use several new methods e.g. satellite and ground radio-tracking, nest cameras etc. We also developed a detailed guideline for the management of Imperial Eagles and their habitats laying the basis of future conservation work for Hungary (see details and downloadable publications at We located the most important temporary settlement areas of immature Imperial Eagles, which should also be handled as priority areas for the conservation of the species. During this project we also managed to hatch artificially two Imperial Eagle eggs from abandoned nests and we placed the chicks in other eagle pair’s nests, from where they fledged successfully.
Many people are sharing their data with us about the species, which is essential for effective monitoring and conservation, since nor MME staff and volunteers, neither national park rangers are able to follow all eagles in the fields. It is very important to get in contact and to gain information from local people, hunters, farmers, amateur birdwatchers etc., because even one observation could help us to improve our knowledge of the species. Such as e.g. one data of a subadult pair from March could mean a new territory, or an observation of a very “tame” bird could help us to find a poisoned eagle and to avoid further mortality. People can get in contact directly with MME or with the relevant national park directorate, but also by sharing observations at the Hungarian birding site (

Markus Jais: Is MME working with other organisations in other countries to protect the Eastern Imperial Eagle?
Marton Horvath: As the Eastern Imperial Eagles has a unified population in the Carpathian Basin, MME works in close collaboration with Slovakian colleagues (previously SVODAS, recently RPS) since the initiation of our programmes in the early 1980s. As the population increased and colonized new countries we are also sharing information with Austrian and Czech BirdLife partners, and also with North-Serbian and Romanian colleagues. MME was the co-founder in 1990 and since then the coordinator of the International Imperial Eagle Working Group (IIEWG). Up till now IIEWG held six conferences with the participation of specialists from almost all of the breeding range countries (the first five conferences were held in Hungary, while the last one was hosted by BSPB in Bulgaria in 2008). We are operating an Imperial Eagle e-mail list to promote the communication of imperial eagle specialists. The International Action Plan for the Eastern Imperial Eagle was prepared within the framework of the 4th International Imperial Eagle Conference in 1993. MME also took part in the elaboration of the Balkan (2003) and the Southern-Caucasian Action Plans (2006) for the species.
Recently the specialists of MME visited the Imperial Eagle programmes of several countries in Europe to share and gain experience for the more effective survey and conservation of the species. We organized a common expedition with UTOP in Ukraine (2006), we visited two times GCCW in Georgia (2006 and 2007), we started a species specific survey in Azerbaijan with AOS (2007-2008) and in Anatolia with DD (2007-2009), and we also visited the well-working monitoring programmes of FWFF Macedonia (2008) and BSPB in Bulgaria (2003-2009).

Markus Jais: What should the Government (and maybe the EU) do to make sure the Eastern Imperial Eagle has a future in Hungary?
Marton Horvath: The most important steps which should be done are:

  • undertake an intensive campaign to reduce significantly the intentional or accidental persecution of eagles, with a special emphasis on anti-poisoning activities;
  • modify properly the medium-voltage power lines at the most important Imperial Eagle habitats;
  • maintain old forests at mountainous habitats;
  • maintain and plant shelter belts and groups of indigenous trees at the Hungarian Plain, but avoid large scale afforestation;
  • improve the populations and habitats of hamsters, sousliks and other natural prey species, and cooperate with game-keepers in hare and pheasant management;
  • do not develop infrastructural networks, especially do not install electric power lines and wind-farms in the highest priority Imperial Eagle habitats.

Markus Jais: Can you give as a short overview of the population numbers and trends for the other eagle species that breed in Hungary, like Golden Eagle, White-tailed Eagle, Lesser Spotted Eagle and others?
Marton Horvath: Golden Eagles are localised only in the Zemplén Mountains (NE-Hungary), where constantly 4-5 pairs are breeding. The White-tailed Eagle is the most common eagle species in Hungary, which, similarly to Imperial Eagles, showed a significant increase during the last 20 years, and now the population already exceeds 200 breeding pairs. Lesser Spotted and Short-toed Eagles are relatively rare breeders mostly in the low mountains of Hungary, and both of them, after a significant decline by the 1990s, became more or less stable between 30 and 45 pairs. Booted Eagles were never numerous in the Hungarian mountains, but there was no proved breeding during the last decade, although according to scarce observations, 1-2 pairs could still exist.

Markus Jais: What was your most amazing experience with Eastern Imperial Eagles?
Marton Horvath: A few years ago I was gathering data on breeding behaviour of Imperial Eagles, for what I spent several weeks by recording the behaviour of males, females and chicks in several territories. One dawn I started to watch an eagle pair in the Bükk Mountains (NE-Hungary) from sunrise. The male and female were perching close to each other a few hundred meters away from the nest, where two chicks were waiting for the breakfast. One hour later the male started to soar up and I thought it will fly to the remote foraging areas at the foothills, but surprisingly it started to attack very aggressively the female. These attacks became more and more aggressive and sometimes even the feathers would fall out of the female, meanwhile she was giving display calls. This “abnormal” behaviour continued for approximately one hour, when I detected a third eagle appearing on the horizon with a prey in its talons. At this moment I realized that I completely misunderstood the situation, as this third eagle was the female of the given pair, while the one which was attacked, was an intruder. When the alien female observed the owner of the territory, it started to fly away quickly and the pair chased it away together. This experience about the alluring alien female and faithful male was probably the most amazing one during my fieldwork with Imperial Eagles.

Markus Jais: Marton, thank you very much for the interview.

Further Information – Conservation of Eastern Imperial Eagle in the Carpathian Basin

Hungarian Ornithological and Nature Conservation Society (MME) / Birdlife Hungary