First reports on the population of the lesser spotted eagle in Hungary appeared between 1978 and 1982, and based on these data, we estimate that their population was about 90 pairs during that period. By 2014 this number had decreased to below 40 pairs. The species disappeared from its former nesting sites in the lowlands, riparian habitats and also in a few hilly and mountainous areas. The reasons for its decline appear complex in Hungary. Changes in agricultural practice are suspected of being one of the main reasons which are discussed in the article. We presume that populations of prey species were also negatively affected. Decrease in undisturbed forest stands older than 100 years was probably also a significant factor affecting nesting habitats. As a marginal population, it greatly depends on the larger ones in the surrounding countries, and it is also affected by mortality during migration. Positive changes in the past four years in agricultural land use have already caused a slight increase in their numbers. Main tasks for the near future should be the establishment of a special support scheme focusing on the species’ foraging habitats.
An unexpected expansion of the Eastern Imperial Eagle (Aquila heliaca) population was observed in East Hungary from mountainous habitat into lowlands from 1989 onwards. Here the population markedly increased from 2 to 59 breeding pairs by 2006, while the mountainous population remained more or less stable with 12-17 breeding pairs. At the beginning of the expansion process the nearest neighbour distances between breeding pairs was lower in the mountains than in the lowlands, but presently they are similar, indicating a saturation process in the lowland areas, but no density dependence was revealed on breeding success. During the study period a higher ratio of non-adult pairs was observed in the lowland territories (49%) than in the mountains (22%). We found that both age and habitat influenced breeding success. We also found that age-effect was significant on success rate (i.e. the ratio of pairs that produce at least one chick), while habitat-effect was more evident on fledging success (i.e. the number of fledglings per productive pair). The overall productivity (i.e. number of fledglings per breeding pair) was affected primarily by the age of the pairs, but the interaction term of age x habitat also was significant. We suppose that better feeding possibilities (closer foraging areas and larger prey density) could explain the higher fledging success in the lowlands. We also predicted that pairs inhabiting agricultural areas in the lowlands will have a reduced success rate due to higher human disturbance, together with an age effect of the breeding pairs. Therefore adult pairs probably can habituate to disturbance even if it happens in the close vicinity of their nesting sites.
Bird conservation on electricity transmission lines has a 40-year history in Hungary. It started with the saker conservation program. The initial small-scale activities were considerably enlarged through the LIFE projects. In the first project, 301 nest boxes for sakers of a new type made of aluminium were installed on pylons of high-voltage transmission lines. In 201 3 nearly 70% of saker pairs nested in these new boxes. An estimated 1 00 000 different birds used to be killed annually on the transmission line pylons in Hungary. During the two LIFE projects about 1 4 300 pylons were made bird-safe using improved technology and materials. Nearly 800 new bird-safe crossarms of pylons are being installed in the second project, which is expected to completely eradicate the danger
The diet composition of breeding Eastern Imperial Eagles (Aquila heliaca) was analysed in Hungary between 2005 and 2017, and compared with two previously published datasets from the periods of 1982–1991 and 1992–2004. Altogether the distribution of 8543 prey items of 126 different species and 29 other taxa were analysed within a 36-years period. We found that the previously abundant Common Hamster (Cricetus cricetus) became marginal (7.42%), while European Sousliks (Spermophilus citellus) practically disappeared (0.03%) from the diet of Imperial Eagles. Small game species, like the Common Pheasant (Phasianus colchicus) and the Brown Hare (Lepus europaeus) composed a remarkable part of the diet (11.22% and 28.11% respectively), which raised some conflicts with hunters regionally and probably also contributed to the high prevalence of persecution incidents against the eagles. In parallel with the loss of traditional prey species, corvids (13.10%), pigeons (8.90%), waterbirds (6.83%), other rodents (6.71%), Roe Deers (Capreolus capreolus) (5.59%), raptors and owls (4.88%) became regularly detected prey species. The temporal changes of the main prey categories were analysed between 1998 and 2017, when the ratio of Hamster and Pheasant showed significant decrease (-27.29% and -6.38%, respectively). The ratio of Brown Hare also showed slight decrease (-3.98%), but the change was not significant. On the other hand, the ratio of corvids, waterbirds and Roe Deers within the diet showed significant increase (+18.20%, +6.25% and +5.39%, respectively). The observed flexibility in the foraging behaviour of Imperial Eagles greatly facilitate conservation efforts, as they seems to be able to utilize the most abundant prey sources, i.e. they were not depending solely from the status of any single specific prey source. However, eagles could only shift and survive in those regions, where their traditional preys decreased, if alternative species were available for them.