Sex identification comparison of barn owls (Tyto alba javanica) using morphological features and molecular-based methods

Sexing of barn owls, Tyto alba javanica, using morphological traits has not been accurate enough due to ambiguous sexual dimorphism between sexes. This has been one of the major problems for the management of barn owls worldwide, especially for translocation and captive-breeding programs. In order to increase the success rate of sexing the barn owl, we compared the results of a molecular sexing method to six morphological traits for sexing the owls: the shape and colour of the facial disc, the colour of the throat area, the tail plumage, the colour of their tarsus, the back plumage, and the frequency of spotting on the chest and underside of the wings. The result of our comparison showed that sex identification using morphological traits had an accuracy of only 72.7%. Three of our samples were identified as females using morphological traits, but molecular sexing determined that these samples were males. We also used our results to determine the best morphological traits for sexing barn owls, and concluded that the best traits for morphological sexing are the frequency of spotting on the chest and underparts of barn owls (accuracy of 81.8%), as well as colour of the owls’ facial disc and throat area (accuracy of 63.6%).

Collision between a migrating lesser spotted eagle (Clanga pomarina) and an aircraft as detailed by fine-scale GSM-GPS telemetry data

We tracked a breeding adult female lesser spotted eagle (Clanga pomarina) from Germany using GPS technology, and provide details of her collision with a small aircraft at Rzeszów (SE Poland) during April 2016, when she was migrating towards her breeding territory. The ultimate fate of the bird was not established until the tag was found by chance and the data were recovered. Bird strikes are a global problem with sometimes lethal consequences for animals and people. This account highlights the way technology allows us to closely monitor events during bird migration, and document human-raptor interactions. The collision illustrates how food availability might affect bird-strike risk, and indicates that removing animal carcasses from the vicinity of airports could reduce that risk. We discuss the data in relation to risks faced by lesser spotted eagles (and other soaring birds) of collision with aircraft, especially along flyways during migration seasons.

Diet of boreal owl (Aegolius funereus) in lowlands of north-eastern Poland

Although studies on many owl species diets are common, there are only scarce data on the diet of the boreal owl from the lowlands of Eastern Europe. We have therefore studied its diet in one of the most important Polish population areas, the Knyszyńska Forest (north-eastern Poland). Pellets were gathered between February and June in 2006, 2012–2016 from tree hollows and the ground underneath. Altogether 178 pellets and six sets of pellet fragments were collected from 19 different sites. Eight mammal and eight bird species were identified among the 213 prey items found in the gathered material. Small mammals dominated, both in prey number (88.3%) and biomass (85.1%). Bank vole proved to be the main prey (over 40% of prey numbers), while Microtus voles (27.3%), small passerine birds (11.7%) and shrews (7.5%) were important alternative prey. Diet range proved to be similar to other sites in Europe.

Size of home range of Tengmalm’s owl (Aegolius funereus) males during breeding season assessed by radio-telemetry in the Jizera Mountains, Czechia

Animal home ranges are typically characterized by their size, shape and a given time interval and can be affected by many different biotic and abiotic factors. Understanding of animal movements and assessing the size of their home ranges are essential topics in ecology and necessary for effective species protection, especially concerning birds of prey. Using radio-telemetry (VHF; 2.1 g tail-mounted tags) we studied the movements of two Tengmalm’s owl (Aegolius funereus) males during the breeding season 2008 in a mountain area of Central Europe (the Czech Republic, the Jizera Mountains: 50˚ 50’ N, 15˚ 16’ E). We determined their average nocturnal hunting and diurnal roosting home range sizes. The mean hunting home range size calculated according to the 90% fixed kernel density estimator was 251.1 ± 43.2 ha (± SD). The mean roosting home range size calculated according to the 100% minimum convex polygon method was 57.9 ± 15.8 ha (± SD). The sizes of hunting home ranges during breeding in this study coincide with those previously reported by other studies focusing on Tengmalm’s owl males. However, we found the roosting home ranges were smaller in size compared to those previously reported. This result was most probably connected with different habitat structure in our study area, which was severally damaged by air-pollution in the past, thus probably offering fewer suitable hiding-places, for instance from predators. We found the roosting locations were concentrated in the oldest and densest Norway spruce forest patches. We emphasize that these parts of forest stands require the highest possible protection in our study area.

On the diet of owls (Strigiformes) in Jordan

Between 2005 and 2015 I undertook eight trips to Jordan during which I collected pellets from seven owl species. In them 14,203 food items were identified. Mammals (Mammalia, 46 species, 37.9% of prey items) formed the most numerous component, invertebrates (Evertebrata) made up 33.4%, birds (Aves, 25.4%) were represented with at least 104 species, reptiles (Reptilia) came to 3.2%, and two species of amphibian were identified (Amphibia, 0.2%). Pharoah eagle owls (Bubo ascalaphus) and Byzantine eagle owls (Bubo bubo interpositus) primarily hunt larger mammals and birds, although Agamidae and Scorpiones were also represented more frequently among B. ascalaphus. Mammals predominated among tawny owls (Strix aluco wilkonskii) (Mammalia, 58.9%), mainly the eastern rock mouse (Apodemus mystacinus) (24.9%). For wintering long-eared owls Asio otus otus the most important food was small birds (Aves, 78.3%), especially house sparrows (Passer domesticus), Fringillidae and Sylviidae. For barn owls (Tyto alba erlangeri) the principal prey was small mammals (83.1%), mainly mice (Mus sp.), Günther’s vole (Microtus guentheri), grey hamster (Cricetulus migratorius) and shrews (Soricidae). Hume’s tawny owl (Strix butleri) pellets contained mostly invertebrates (58.9%) and lizards, and their most frequent mammal prey were Wagner’s gerbil (Gerbillus dasyurus) and spiny mice (Acomys sp.). There was an even higher propostion of invertebrates (86.4%) among lilith owlets (Athene lilith). In addition to the insect orders Coleoptera, Orthoptera and Hymenoptera, remains of Scorpiones and Solifugae were also frequently found. The summarized results from individual owl species are compared with those gathered by the author in the surrounding Middle Eastern countries: Israel, Syria, Lebanon and Egypt.

Trend in an isolated population of the red-footed falcon (Falco vespertinus) at the edge of its breeding range (south-western Slovakia)

The population of the red-footed falcon in Slovakia inhabits the north-western edge of the species' breeding range. This breeding population is relatively small and came near to extinction during the population decline of this species in central Europe in recent decades. Thanks to increasing numbers of breeding pairs in Hungary, the Slovak population began to grow again. Moreover, some differences in breeding biology associated with breeding in nest boxes were found. Here we describe the dependence of the small isolated breeding population in Slovakia on the core population in the more eastern parts of the Carpathian Basin, and the impact of supporting activities (nest boxes) on this raptor species in Slovakia.

Agricultural utilisation and potential suitability of the Sysľovské polia Special Protection Area (south-western Slovakia) landscape in relation to the habitat requirements of the red-footed falcon (Falco vespertinus)

Intensification of land use in an agricultural landscape significantly affects biodiversity also in protected areas. This can be observed in the Sysľovské polia Special Protection Area in relation to the occurrence of the red-footed falcon (Falco vespertinus). The objective of this study was to evaluate the landscape structure and suitability of agrotechnical procedures for the habitat demands of this species in the course of the period from 2004 until 2017. The utilisation was assessed on the basis of four landscape elements representation in 1949 and 2017. The next step was analysis of landscape patches. The aim was to quantify the diversity and the spatial structure of the landscape mosaic using Shannon’s Diversity Index and Evenness Index as well as Simpson’s Diversity Index and Evenness Index and spatial pattern analysis in the Fragstats software programme. Assessment of crop suitability was carried out according to the following criteria: representation of positive/negative agricultural crops, diversity of crops in crop rotation, and (non-)observance of crop rotation. It was found that the agricultural landscape use did not change significantly. The study area has been used as an intensively-farmed agricultural landscape for a long time. The landscape elements have remained almost identical, with dominance of arable land. Differences emerged in the analysis of the micropatches, which are represented by natural hedgerows consisting of various species of trees, shrubs and grasses. The results show a decrease in the diversity of patches and changes in the structure of the landscape patches, which may be important in terms of the preservation of the habitat of fauna which form an important part of the F vespertinus diet. On the basis of the evaluation of the suitability of agricultural crop growing, we found that there were some areas showing negative values in all the criteria, and thus they require changes in the crop rotation focusing on increasing positive crop diversity and the share of grassland.

Common wintering of black kites (Milvus migrans migrans) in Greece, and new data on their wintering elsewhere in Europe

Black kites of the nominal subspecies Milvus migrans migrans breed in the Western Palearctic and in Central Asia, while the European population is relatively small. The birds winter mostly in sub-Saharan Africa. Until 2000 winter observations of black kites were rare in Greece, and also within the tri-point border area of Austria, the Czech Republic and Slovakia. At that time regular wintering of black kites started there. These data and evidence from recent local literature as well as from a number of unpublished data obtained throughout European countries and reviewed in this paper corroborate the impression that numbers of black kites wintering in Europe and the whole Mediterranean area including Turkey are increasing. The reasons considered are climate warming in the area and some negative changes in sub-Saharan Africa in the traditional wintering grounds of black kites. Notes about the wintering of black/red kite hybrids are also added.

Review and summary of red-footed falcon (Falco vespertinus) observations during migration periods in Slovakia

The red-footed falcon (Falco vespertinus) migrates throughout the territory of Slovakia regularly, though it rarely breeds here. In the present paper we have reviewed and summarised its observations between the years 1905–2016, focusing on the spring and autumn migration periods and its occurrence outside the breeding season. In total, we have gathered the data on 799 observations of 3,717 individuals. Considering the unsystematic data collection, the data should be taken with caution and may rather serve for information purposes only. However, they provide useful basic items of information regarding the species’ seasonal dynamics in Slovakia and its phenology, and document the evident increase in the number of individuals observed since 2014.

Foraging opportunism and feeding frequency in the red-footed falcon (Falco vespertinus) in Slovakia: case study from 2017

Foraging opportunism and feeding frequency are less studied parameters of behaviour in insectivorous falcons, many of which are endangered bird species. In this short study, prey composition and feeding frequency of red-footed falcon (Falco vespertinus) nestlings were studied using the method of camera recordings during seven days in July 2017 in southwestern Slovakia. Camera recording analyses of 2–3 chicks (14–26 days old) in three nests revealed a significant preference for insects (97%, n = 305 prey items), of which the Italian locust (Calliptamus italicus) was highly predominant (54%). We also found very high average chick feeding frequency (9.9 feedings per hour, n = 29 hours 22 min of regular observations), whereby the females fed their young ones more frequently (64.9%, n = 305 feedings) than the males (35.1%). Analyses of food composition in adverse weather conditions showed that unfavourable weather had a negative effect on chick feeding frequency, and in rainy weather the males fed significantly less than the females.