Abstract In this study, we investigated the Eurasian eagle owl (Bubo bubo) breeding in lowland forests in the trans-border area between western Slovakia, eastern Austria, and southern Moravia. The research provides new information on the reuse of nests by eagle owls and presents initial insights into population density and trends of eagle owls in the March-Thaya floodplains. Our 19-year monitoring has shown that the eagle owl has become a widespread breeder over the study area, with an increasing population trend. A total of 151 breeding attempts by eagle owls have been identified, occupying 82 natural nests (originally built by at least nine species of birds) and 12 artificial nests. With an average of 6.2 active nests per 100 km2 and a maximum of 17 active nests found in 2021 (~10.6 pairs per 100 km2), our findings represent one of the highest eagle owl breeding densities found, especially in comparison with core populations nesting in the mountains (the Carpathians, north-eastern Alps and the Bohemian Massif). Regarding the dynamics of nest reuse, our results reveal that only a third of nests used by eagle owls were reused by other raptors or storks (Ciconia sp.). Almost 50% of the natural nests in which eagle owl bred, subsequently disintegrated after the owlets had fledged. Lastly, black stork (Ciconia nigra) nests re-used by eagle owls were twice as likely to have disintegrated after the owlets had fledged than nests built by other bird species. Our results suggest that black stork nests in the March and Thaya floodplain forests are most susceptible to destruction.

Abstract Raptors have been successfully used to disperse and often control flocks of pest birds. However, the question that has not been resolved is, “If the raptor kills a small number of the target flock, does this improve the efficiency of control?” This mini-review examines the few research reports that have been published that can shed light on this question.

Abstract The diet of the endemic Cyprus scops owl (Otus cyprius) was studied for the first time during the breeding season 2021 in 7 nesting sites from 6 sampling locations using the pellet analysis (n = 65 pellets). Insects, mostly Orthoptera and Coleoptera, comprised the bulk of the owl diet (87% abundance, 31% biomass), whereas small mammals and reptiles were important in terms of biomass, with 41% and 24%, respectively. Birds were the lowest prey order, with 0.6% abundance and 3.6% biomass. The most essential insects were grasshoppers (Acrididae) (17%) and scarab beetles (Scarabaeidae) (6%). From vertebrate prey, Mus spp. (23.7%), Mediterranean house gecko (Hemidactylus turcicus) (8%), Cyprus spiny mice (Acomys nesiotes) (8%), juvenile black rats (Rattus rattus) (7%), and Cyprus agamas (Laudakia cypriaca) (5%) stand out as % biomass. Predation on a bat species (Pipistrellus sp.) by scops owl was documented for the first time in Cyprus. The estimated prey biomass ranged from 0.1 – 25 grams, averaging 2.1 g.

Abstract Wildlife rehabilitators treat thousands of raptors yearly, providing an opportunity to better understand species’ biology, the changing environment, and the dangers raptors encounter in the wild. However, that data is siloed within individual facilities, making it challenging to understand the wider impact of rehabilitation and the dangers raptors face. Data were collected from 50 facilities across the state of Florida, United States of America, from 2009 to early 2023, representing 54,574 patients of 39 species. Patient intake at these facilities doubled between 2010 and 2020 over a relatively stable number of facilities (average = 31.5/year) with an average release rate of 36.6% (range 31.7 – 41.5%). Release rates varied significantly from 21% to 57% between species with over 100 recorded patients. Comparing release rates with the “cause for admission” provided a more nuanced understanding of what was affecting raptor patients and their release rates. Trauma was the most common cause of admission (40.2%) and has been relatively consistent year over year. For those patients with more specific identification attributes, 65% were male, 50% were adults, and patients spent an average of 16.6 days in care. The data provided in this study has the potential to make fundamental changes to raptor rehabilitation policies and encourage more collaboration between rehabilitators and researchers for the betterment of the patients in care.

Abstract The annual survival rate of adult raptors is an important parameter in population dynamics and is needed to derive measures for population stability and conservation management. Here we studied adult European honey buzzards (Pernis apivorus), a migratory land bird, using satellite telemetry throughout the year for up to three years. We used the Kaplan-Meier method of survival estimation in combination with the distribution density function for survival. This function describes the number of survivors N as a function of time t, based on the survival rate SR. This probabilistic extension of the Kaplan-Meier estimator results in a simple method that does not require a commercial statistical program to extract survival rates from event time analysis. It can be applied to analysing any event-time data, not only telemetry results but also ring recoveries, as demonstrated using European honey buzzards as an example. The average adult survival rate in our study, based on permanent satellite telemetry monitoring, was 0.44/year (linear correlation factor f = 0.99). This implies an adult mortality rate of 0.56 per year. It seems that particularly unfavourable weather conditions during the crossing of the Sahara and the Mediterranean led to this high mortality rate of our birds during migration from 2001 to 2011, but is likely to vary greatly from year to year. However, the loss rate in the wintering area was also high, at one third of the birds. More honey buzzards need to be tracked throughout the year to assess factors affecting survival and threats to populations adequately.

Abstract The Eurasian eagle-owl (Bubo bubo) has adapted to hunt local fauna that are subject to the influence of human agricultural activities. In the sparse forests, marshes and lakes of the mountainous regions of central Norway, the eagle-owl’s diet is dominated by small mammals and gallinaceous birds, but the common frog Rana temporaria features more frequently in regions near the fjords, with various species of seabirds predominating on some islands. The eagle-owls, breeding in several protected regions of the Czech Republic, hunting in agricultural areas small mammals and game animals in addition to waterbirds nesting by fishponds. In Slovakia, the majority of the eagle-owl population nests on the edges of mountain valleys. In the past, they hunted small mammals and amphibians on pastureland located deep in the mountains, but they have adapted to hunting larger prey in more intensively farmed valleys. Predominantly in the eastern part of Turkey, the diet of Eurasian eagle-owl hunting on natural mountain steppes has been studied, where mammals of the family Cricetidae dominate. In the arid conditions of the southern countries of Syria, Jordan and Israel, mammals of the Gerbillinae sub-family predominated in addition to a higher proportion of birds. In the more variable areas of Iran, eagle-owl diets feature a wide range of indigenous mammals and birds, with different species represented in several territories. Studies from the edges of the Fergana Valley in southern Kyrgyzstan found differences in the diets of eagle-owls living at lower elevations and those living higher in the mountains, while birds were the predominant prey in the Kalek site. Smaller samples of eagle-owl diets were also collected in the Altai Mountains of Mongolia, the Barguzinsky Mountains to the east of Lake Baikal and the Vaida Mountain on Sakhalin Island. The results presented in this study can also contribute to our knowledge about the fauna of the above-mentioned regions.

Abstract The laying of two clutches in a single breeding season can increase the fitness of the parent birds and stabilise a population. Our study analysed the rate of second-breeding attempts in the common kestrel (Falco tinnunculus) population in the Czech Republic. In the research, a total of 8,049 common kestrel nests were checked between 1979 and 2019. Of the 1,197 breeding events recorded during the study period in Moravia, 1,184 cases were first clutches and 13 cases (1.1%) were second breeding attempts. In Bohemia, a total of 6,852 breeding events were observed during the same study period, of which 6,811 were first clutches, 32 cases were late breeding attempts and 9 cases (0.1%) were second clutches. Second breeding events occurred only rarely, mainly during population outbreaks of prey species. During the mass outbreak of the common vole (Microtus arvalis) population in the Czech Republic in 2019, 5 (5.2%) of the 97 studied common kestrel pairs nested for the second time in Moravia; in Bohemia, second clutches were recorded in 3 (8.1%) of the 37 studied pairs. The second breeding attempts were recorded at an altitude of 272 ± 123 m (mean ± SD, range 179–560 m, n = 22) and commenced between 24 June and 25 July (29 June on average, n = 5). The range of the time gap between the first and the second clutch was 54 to 92 days (70.8 ± 16.3 days, n = 5). The second clutches consisted of an average of 4.1 ± 0.9 eggs (range 3–6, n = 12), with an average of 3.7 ± 0.9 fledglings in each successful breeding pair (range 2–5, n = 11) and 2.6 ± 1.9 fledglings for each initiated breeding attempt (range 0–5, n = 16).

Abstract Bird crime is a serious problem in many countries around the world. This study focuses on the situation in Slovakia, summarising data on bird crime in the country between 2016 and 2022. Over the course of that period, 92 cases were recorded in 27 districts involving 33 animal species. At least 249 protected birds and 78 mammals fell victim to illegal activities, and 61 poisoned baits were discovered. Social value is the monetary value which state institutions use to quantify the damage incurred to wildlife. Slovak law determines whether an illegal act is an offence or a criminal act based on the value of the incurred damage. The total social value of all of the protected animals as a result of illegal activities was estimated at € 696,250. Intentional poisoning, typically using carbofuran, was the most common of illegal act identified in the recorded cases, followed by shooting and trapping. An analysis of the recorded cases of bird crime was also used to assess the risk in each of Slovakia’s districts in relation to landscape structure variables. The percentage share of arable land was found to be a reliable predictor of bird crime, regardless of whether the birds had been poisoned or shot. These findings can help to develop better preventive inspections to detect bird crime incidents. We also recommended several management measures to help tackle bird crime more quickly and effectively.

Abstract The Iraqi Organization for Conservation of Nature (IOCN) continuously conducts field surveys targeting key biodiversity areas within Iraq to discover the environmental conditions with more focus on the threatened species and their habitats. Two new bird species for Iraq were recorded during two of the ongoing field surveys conducted by IOCN, namely in the Khour Az-Zubair tidal mudflats in September 2022 and the Al-Najaf Desert in February 2023. Among the considerable list of the birds (and other fauna species) that have been observed, two bird species have been considered quite important: Amur falcon (Falco amurensis) and lappet-faced (or Arabian) vulture, Torgos tracheliotos negevensis]. Both of these observations have been carefully described and documented. Referring to the literature on the avifauna of Iraq, none of these bird species have already been considered Iraqi species and, subsequently, have been added to the list of avifauna of Iraq.

Abstract Using global position system (GPS) technology, we tracked an adult female greater spotted eagle (Clanga clanga) on its wintering grounds in the Sudan-South Sudan borderland during 2005–2015. There were 10 909 GPS locations for this bird in the non-breeding range. Throughout the study, the eagle showed fidelity to its wintering grounds. The non-breeding season coincided with the dry season. The median arrival date was 11 October (n = 10). The median departure date (n = 10) was 4 March, and was less variable than the arrival date. The 95% kernel density estimate (KDE) for all years was 33 838 km2, and the 50% KDE encompassed 6 585 km2. The wintering range was split between two areas, west and east, with the eagle typically arriving in the western area, where it stayed for some time. It then moved about 330 km to the eastern area, where it would remain for a few weeks before departing for Europe in the spring. In both the western and eastern subareas, the annual home ranges overlapped to a variable extent (14–99%). The high degree of fidelity to the wintering grounds shown by this bird was mirrored by the behaviours of two other adult greater spotted eagles that we tracked (using >1 tracking devices) for 15 years that wintered in South Sudan and Turkey. The number of greater spotted eagles that winter in Africa is a matter of speculation, although virtually all individuals are likely to pass through a narrow corridor near Suez, Egypt. Collectively, these tracking data and the findings of other studies suggest that greater spotted eagles from the western parts of the European breeding range often move to Africa. Further, the Sudd wetlands in South Sudan are important for greater spotted eagles and other rare bird species during the non-breeding season.