Volume 26 (2018): Issue 1 (June 2018)

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.

This study investigated the dietary niche of the Barn Owl (Tyto alba) in an intensively farmed landscape, based on pellet samples from 12 nesting pairs containing 25 animal taxa and 1,994 prey items after the breeding season in 2016. Based on land use categories of the buffer area around each nest, three landscape types (agricultural, mosaic, urban) were considered, to analyse the diet composition and food-niche parameters. Niche breadth was calculated at the local and landscape level. Small mammals were the most frequent in the diet than other prey in each of the landscape types. The Common Vole (Microtus arvalis), considered to be an important agricultural pest was the most numerous prey in all landscape groups. The trophic niche of Barn Owl varied between 0.69 – 0.86 at the local level, and the overall value of niche breadth was significantly higher in the urban than in the other two landscape types. Our results showed that the increase of Common Vole frequency lead to a decrease in niche breadth; significantly negative relationship was detected between these parameters. Despite differences in niche breadth, similarly high niche overlaps were detected by the randomisation test in the three landscapes. Our results suggest that the diet composition of Barn Owls, mainly their food-niche pattern, reflected prey availability in the comparison of the studied landscapes, which pointed out that it is necessary to examine the dietary difference of Barn Owls at the finer scale of land use.

Owls (Strigiformes) are small to large birds, mostly solitary and nocturnal predators. They can be found all around the Earth except Antarctica and some remote islands. The species differ in size, diet and habitat, which led to different morphological adaptations of the skull. The main differences are in the orbital and the otical region, which are connected to the visual and hearing capabilities. The aim of the recent study is to increase our knowledge of the relationship between skull shape and foraging habits and tried to find those characters that are related to diet. A geometric morphometric approach was used to analyse two-dimensional cranial landmarks. We used principal component (PC) analyses on measurements that may be related to visual and hearing abilities. The PCs are resulted in the robusticity of the skull and the asymmetry of the otical region. There are differences in position and shape of postorbital processes (POP) and tympanic wings (TW). Species with symmetrical skull shape are basically crepuscular or diurnal predators and species with more asymmetrical skulls are mostly nocturnal hunters and have better hearing capabilities.

Population of the Eagle Owl (Bubo bubo) has been increasing in Europe including Hungary. The species occupy new habitats beside its ancient territories including quarries and buildings. This may result in conflicting conservation and economic interests in active quarries. Because eagle owls are strictly protected in Hungary, human activities around known nest sites require environmental permits. We aimed to obtain information on Eagle Owl behaviour in an operating quarry by tracking an adult female to base a future species-specific guideline to issue environmental permits for mining in quarries. We used a combined GPS-GSM and VHF telemetry. We found that the tracked female did not breed in the study year but remained in her home range during the study period. By studying her seasonal and daily patterns of movements, we found that she was not disturbed by regular human activities under the nesting cliff, but she was more sensitive to unexpected non-regular disturbance. Based on the satellite-tracking data, this specimen used an approximately 18 km² home range during the study period.

The breeding strategies of the White Stork changed drastically during the past decades: a decreasing number of individuals nest on traditional nest sites – trees, roofs, chimneys, whereas electricity poles are increasingly selected. Here we analysed long-term breeding data of White Storks breeding in six Hungarian counties to detect patterns in nest site preferences in Hungary. According to our results, the shift to preference for electricity poles was shown at the same rate in every county, independently from the proportion of original nest sites. After 2000, although electricity poles dominated everywhere, the proportion of nest on poles without platform increased, despite the abundance of available empty platforms. To explain this pattern, we propose that White Storks show a preference for viewpoints, thus choosing to breed as near as possible to optimal habitats, regardless of nest site types. Therefore, conservation measures concerning the nest sites of this species should include preliminary habitat analysis.

We investigated relationships among bustard presence data as response as well as properties of habitat patches such as shape, size, type of land use and landscape connectivity in 2015, employing bustard occurrence data in Körös-Maros National Park (KMNP hereafter). Additionally, we aimed to present a geometrical approach of habitat choice in animals, focusing on geometric properties rather than vegetation structure. Here we applied landscape metrics approach, providing landscape classification by analysing spatial patterns in potentially important landscape objects, disregarding linear constructions. Our findings show insignificant differences between shape metrics of selected and non-selected habitat patches, in line with previous studies concluding that bustards choose habitats based on habitat type classes rather than on geometric properties. Further, our results indicate that the original habitats of the study species, adapted to extensive, open steppes, became strongly fragmented, resulting in the absence of large contiguous areas. Within the study area, landscape connectivity values represent optimal habitat conditions, probably as a result of highly patchy structure of the landscape and relatively small nearest neighbour distances of habitat patches. Thus, our findings also indicate that Great Bustards adapted to modified landscape structures. Our landscape analytical approach provides a methodological framework which can be applied on habitat selection tactics in a number of species of key conservation importance.

Based on data available so far, it seems that Common Moorhens (Gallinula chloropus) rarely, but regularly lay one or more eggs in the nests of Common Little Bittern (Ixobrychus minutus). Three such incidents from Hungary are hereby added to the cases known to date. However, Common Moorhens do not only lay eggs in other species’ nests, but also in the nests of conspecifics, while other species may also parasitise the nest of Common Moorhens. The present study summarises these aspects.

The author describes the presence of the oldest extinct diurnal birds of prey species in the world and fossilized representatives of different families, as well as the presence of recent species in the Carpathian Basin among fossilized remains. In case of ospreys, one of the oldest known materials is classified as a new extinct species named Pandion pannonicus. The text is supplemented by a plate and a size chart.

Ornithological studies often rely on long-term bird ringing data sets as sources of information. However, basic descriptive statistics of raw data are rarely provided. In order to fill this gap, here we present the sixth item of a series of exploratory analyses of migration timing and body size measurements of the most frequent passerine species at a ringing station located in Central Hungary (1984–2017). First, we give a concise description of foreign ring recoveries of the European Robin in relation to Hungary. We then shift focus to data of 40,128 ringed and 11,231 recaptured individuals with 24,056 recaptures (several years recaptures in 313 individuals) derived from the ringing station, where birds have been trapped, handled and ringed with standardized methodology since 1984. Timing is described through annual and daily capture and recapture frequencies and their descriptive statistics. We show annual mean arrival dates within the study period and present the cumulative distributions of first captures with stopover durations. We present the distributions of wing, third primary, tail length and body mass, and the annual means of these variables. Furthermore, we show the distributions of individual fat and muscle scores, and the distributions of body mass within each fat score category.We distinguish the spring and autumn migratory periods and age groups (i.e. juveniles and adults). Our aim is to provide a comprehensive overview of the analysed variables. However, we do not aim to interpret the obtained results, merely to draw attention to interesting patterns that may be worth exploring in detail. Data used here are available upon request for further analyses.

Ornithological studies often rely on long-term bird ringing data sets as sources of information. However, basic descriptive statistics of raw data are rarely provided. In order to fill this gap, here we present the seventh item of a series of exploratory analyses of migration timing and body size measurements of the most frequent Passerine species at a ringing station located in Central Hungary (1984–2017). First, we give a concise description of foreign ring recoveries of the Thrush Nightingale in relation to Hungary. We then shift focus to data of 1138 ringed and 547 recaptured individuals with 1557 recaptures (several years recaptures in 76 individuals) derived from the ringing station, where birds have been trapped, handled and ringed with standardized methodology since 1984. Timing is described through annual and daily capture and recapture frequencies and their descriptive statistics. We show annual mean arrival dates within the study period and present the cumulative distributions of first captures with stopover durations. We present the distributions of wing, third primary, tail length and body mass, and the annual means of these variables. Furthermore, we show the distributions of individual fat and muscle scores, and the distributions of body mass within each fat score category. We present data only for the autumn migratory period since there were only 27 spring captures in the study period. We distinguish the age groups (i.e. juveniles and adults) in the analyses. Our aim is to provide a comprehensive overview of the analysed variables. However, we do not aim to interpret the obtained results, merely to draw attention to interesting patterns that may be worth exploring in detail. Data used here are available upon request for further analyses.