<abstract xmlns="http://www.w3.org/1999/xhtml">

The northern hawk owl is a real irruptive species that respond to irregular changes in the food supply. When prey levels are adequate, it breeds and winters within northern forests. Decreased prey availability can start winter invasions, the timing and magnitude of which are the subject of this study. Mainly the citizen data were extracted from the national bird websites to obtain data on the number of northern hawk owls observed in 2010–22. This paper demonstrates that through citizen data large amounts of information can be collected over wide areas, entire Europe in this case.
From Finland to Poland and Czechia the invasions years were very similar, 2013–14, 2017–18 and 2021–22 but in Sweden and Norway three clear irruption years were a year or two before. In Denmark, the clear invasions years were 2013–14, 2016–17 and 2019–20 but Poland, peak years were not at all as clear as in the other countries. The invasions started earliest in Finland in September and peaked in November. In Estonia and Latvia peaks occurred from November to January. In Poland, irruption peaked a month later in December but continued until April like in Finland, Estonia and Latvia.
The origin of the irrupting owls in the region has been debated. In Norway, authors are convinced that owls originate from Fennoscandia but this paper indicates that mass invasions have to originate from northern Russia. However, only in Denmark there was one Russian northern hawk owl ring recovery.
Further ring recoveries and preferably GPS tagging and satellite tracking of the northern hawk owls are awaited to have a better picture of invasion movements and future conservation needs.
</abstract>

Department of Ecology and Anthropology, Institute of Biology

Department of Avian Biology and Ecology, Faculty of Biology

The northern hawk owl <italic>Surnia ulula</italic> invasions in Europe

<abstract xmlns="http://www.w3.org/1999/xhtml">

In territorial raptors, breeding performance and foraging behaviour are affected by territory characteristics as the abundance and availability of different prey species varies between habitats. In this study, we examined the diet of two White-tailed Eagle pairs, occupying neighbouring territories in two adjacent inland lakes in Northern Greece. We assess the diet composition of the species in the southernmost part of its European range and evaluate any intraspecific differences in the diet that may reflect resource and/or niche partitioning between territories. We found that birds and specifically waterbirds comprise the largest and quantitatively most important part of the White-tailed Eagle´s diet, with fish being the second most important prey group that was only found in the nest remains from one territory. There was high diet overlap between the two territories and when considering only avian prey our results suggest that the species predates on heavier (and the most common) waterbird species. A main factor that could be driving differences in the abundance and availability of different prey species between territories could be lake physiography, as our results point to a segregation and a subsequent resource partitioning between territories, with each pair utilizing an adjacent lake and its associated habitats. Competition and territoriality therefore seem to be important intraspecific interactions that along with prey availability could promote changes in territory size and ultimately affect individual fitness.
</abstract>

Department of Biological Applications and Technology

Diet composition of White-tailed Eagles inhabiting two adjacent inland lakes in Northern Greece

<abstract xmlns="http://www.w3.org/1999/xhtml">

The paper describes the observation in Belarus of an adult greater spotted eagle breeding female pale morph “fulvescens”, which retained the same light colour of plumage for five successive years. The data on the presence of pale morph adult birds in the collections of some zoo museums is also analysed.
</abstract>

Greater spotted eagles (<italic>Clanga clanga</italic>) pale morph “fulvescens” breeding during five consecutive years

<abstract xmlns="http://www.w3.org/1999/xhtml">

The nest building and courtship behaviours of the golden eagle are poorly represented in the scientific literature. The paper reports on the first detailed description of building a new nest by a pair of golden eagles. Reciprocal pendulum flight by the pair as part of a pre-breeding courtship display is described for the first time. The “mock attack” between the members of the pair is confirmed to serve the courtship function.
</abstract>

A first detailed description of building a new nest and new data on the courtship behaviour of golden eagle

<abstract xmlns="http://www.w3.org/1999/xhtml">

Using global position system (GPS) technology, we tracked an adult female greater spotted eagle (<italic>Clanga clanga</italic>) 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.
</abstract>

Department of Game Management and Forest Protection

Ranging behaviour of an adult female greater spotted eagle (<italic>Clanga clanga</italic>) wintering in Sudan for 10 years, as revealed by satellite telemetry

<abstract xmlns="http://www.w3.org/1999/xhtml">

As inhabitants of cavities, some owl species benefit from natural processes, different tree compositions and higher volumes of dead wood. We assumed that protected areas would have a positive impact on the owl community. We compared the abundance of calling owls on 22 lines in managed versus protected forests. Here, we recorded the acoustic communication of owls. The composition of the owl community did not differ between areas. However, we found the impact of forest landscape integrity index and altitude on the diversity of owls. Forests in protected areas probably need time to develop natural and heterogeneous habitat structures. The conservation priority should be to increase the integrity of the forests. Our results also confirmed that managed forests can have a high diversity of owls.
</abstract>

Owls’ responses to forest conservation in the Alps

<abstract xmlns="http://www.w3.org/1999/xhtml">

Beak deformities may be permanent or temporary and are caused by various factors. Despite its vast geographical area in India, there has been little research on beak deformities in wild birds, and few cases have been reported. In the present study, we described, as far as we know, the first known report of a beak deformity in the Egyptian vulture (<italic>Neophron percnopterus percnopterus</italic>) worldwide. On 6 January 2014, the first author (HP) recorded the Egyptian vulture with a heavily deformed bill on the garbage dump in Jorbeed, Bikaner, Rajasthan, India. The causes of the bill abnormality in this individual are unknown, but our record increases the knowledge of the presence of development deformities in Egyptian vultures. We highlight the importance of photographs as a valuable tool for documenting bird beak deformities. In conclusion, we encourage other researchers to report the records of beak deformities, which is necessary for a better understanding of this phenomenon and its insights into the ecological and physiological implications of this condition considerably affecting bird survival.
</abstract>

Department of Zoology and Wildlife Biology

Bill deformities in Egyptian vulture (<italic>Neophron percnopterus percnopterus</italic>): a noteworthy record from Rajasthan, India

AHEAD OF PRINT

Volume 18 (2024): Issue 1 (March 2024)

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Volume 8 (2014): Issue 2014 (January 2014) Proceedings from VII. International Conference on the Conservation of the Eastern Imperial Eagle, Bratislava, Slovakia, 2013

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Raptor Journal

 Journal for science, research and conservation on birds of prey and owls. Raptor Journal (formerly known as Slovak Raptor Journal) is issued generally annually and publishes original papers, reviews, short notes and other articles focusing on birds of prey and owls. All articles are published in English.   Why read  The readers can find information about all aspects of the life of raptors and owls – habitat requirements and selection, foraging ecology and diet preferences, breeding biology and nest success, postbreeding movements and migration, threats and protection, population statuses and trends etc.   Why submit   The journal has no article publication charges.  No regional limitation – journal published papers from Europe, Asia and both Americas in last years.  Fair and fast peer review.  All accepted manuscripts are published as “online first” before completing the issue.  All published articles are visible and accessible in full version.   Archiving  Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.  Plagiarism Policy  The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. 

Raptor Journal

Volume 17 (2023): Issue 1 (June 2023)

The northern hawk owl Surnia ulula invasions in Europe

Diet composition of White-tailed Eagles inhabiting two adjacent inland lakes in Northern Greece

Greater spotted eagles (Clanga clanga) pale morph “fulvescens” breeding during five consecutive years

A first detailed description of building a new nest and new data on the courtship behaviour of golden eagle

Ranging behaviour of an adult female greater spotted eagle (Clanga clanga) wintering in Sudan for 10 years, as revealed by satellite telemetry

Owls’ responses to forest conservation in the Alps

Bill deformities in Egyptian vulture (Neophron percnopterus percnopterus): a noteworthy record from Rajasthan, India

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