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We studied various aspects regarding migration behavior of the Common Buzzard for two subspecies (B. b. buteo and B. b. vulpinus) transiting the region which overlaps with the Western Black Sea Corridor. Using vantage points set across Dobruja we managed to count 2,662 individuals. We highlighted the seasonal and diurnal peak passage, flight directions and height of flight for each season. Our results suggest that 57% of the counted individuals belongs to long-distance migrant Steppe Buzzard - B. b. vulpinus. The peek passage period in autumn migration was reached between the 26th of September to the 6th of October, while for the spring migration peek passage remained uncertain. The main autumn passage direction was from N to S, and NNW to SSE but also from NE to SW. For spring passage the main direction was from S to N but also from ESE to WNW. Flight height during autumn migration was mostly at high altitude while in spring migration was more evenly distributed. The most significant activity was recorded in the second time period, between 10:01 and 13:00 (43%). [ABSTRACT FROM AUTHOR]

Telemetric studies have provided ample information on threatened raptors, but still little is known about space use and dispersal of common species. Here I describe the home range and breeding dispersal of a GPS-tracked adult male common buzzard, studied in south-eastern Estonia in 2014-16. This buzzard's home range covered 8.3 km2 (kernel 95% estimate) with the core range being 2.1 km2 (kernel 50%). The home range increased in the course of the breeding season but decreased again before migration. Surprisingly, the nests in the two successive breeding years were located in the opposite margins of the home range, 1.7 km from each other. [ABSTRACT FROM AUTHOR]

Most forest ecosystems contain a diverse community of top-level predators. How these predator species interact, and how their interactions influence their spatial distribution is still poorly understood. Here we studied interactions among top predators in a guild of diurnal forest raptors in order to test the hypothesis that predation among competing predators (intraguild predation) significantly affects the spatial distribution of predator species, causing subordinate species to nest farther away from the dominant ones. The study analyzed a guild in southwestern Europe comprising three raptor species. For 8 years we studied the spatial distribution of used nests, breeding phenology, intraguild predation, territory occupancy, and nest-builder species and subsequent nest-user species. The subordinate species (sparrowhawk Accipiter nisus) nested farther away from the dominant species (goshawk A. gentilis), which preyed on sparrowhawks but not on buzzards Buteo buteo, and closer to buzzards, with which sparrowhawks do not share many common prey. This presumably reflects an effort to seek protection from goshawks. This potential positive effect of buzzards on sparrowhawks may be reciprocal, because buzzards benefit from old sparrowhawk nests, which buzzards used as a base for their nests, and from used sparrowhawk nests, from which buzzards stole prey. Buzzards occasionally occupied old goshawk nests. These results support our initial hypothesis that interspecific interactions within the raptor guild influence the spatial distribution of predator species in forest ecosystems, with intraguild predation as a key driver. We discuss several mechanisms that may promote the coexistence of subordinate and dominant predators and the spatial assembly of this raptor guild: spatial refuges, different breeding phenology, spatial avoidance, low territory occupancy between neighboring nesting territories, nest concealment and protection, and diet segregation. [ABSTRACT FROM AUTHOR]

The Common Buzzards Buteo buteo 'lanzarotae' from Fuerteventura, in the Canary Islands, are distinctive. This taxon resembles Long-legged Buzzard B.rufmus but also shows some plumage traits consistent with Common Buzzard B.buteo. We describe the plumage of 'lanzarotae', and highlight features that separate it from Common Buzzards in the western Canary Islands and from 'North African Long-legged Buzzard' B. r. cirtensis. We suggest that the appearance of 'lanzarotae'may be the product of a past hybridisation event and also that currently accepted records of Long-legged Buzzard in the Canary Islands are in fact 'lanzarotae'. [ABSTRACT FROM AUTHOR]

Winters have become warmer under the impact of climate change, which has modified the phenology as well as the distribution ranges of birds. The African Long-legged Buzzard Buteo rufinus cirtensis has recently colonized Europe via the Strait of Gibraltar. We aim to explain the native distribution of this species and to predict favourable areas in newly colonized parts of Europe using geospatial modelling to identify the most influential factors in this process. We applied the favourability function, a generalized linear model describing environmental favourability, for the presence/absence of breeding areas in northern Morocco and the southern Iberian Peninsula, according to a set of variables describing climate, topography, human activity, vegetation and purely spatial trends. A model was built using some known breeding sites in northern Morocco, and was used to forecast future suitable breeding areas in Europe. A second model was built with the available data for northern Morocco and Europe to explain the current distribution of breeding sites. Both models were assessed according to discrimination, calibration and parsimony criteria, and the influence of each factor was analysed using variation partitioning. We conclude that the Iberian Peninsula could provide new suitable areas for the species and facilitate its northward expansion. This result, together with the increasing number of records available, suggests that this species could soon spread throughout Europe. Steady temperatures and abundant but seasonally distributed precipitation showed the strongest predictive power in the models. This indicates a close relationship between the species' distribution and climate in the study area, and suggests that this species finds its most favourable environments in the Mediterranean biome. Topography and vegetation, specifically cliffs and woods near hunting zones, point to a fine-scale habitat selection for breeding. As the case of the African Long-legged Buzzard is not a unique event, our results may be useful to determine whether a northward expansion of the Mediterranean biome could be followed by distribution shifts of bird species that have so far been restricted to Africa. [ABSTRACT FROM AUTHOR]

The evolution and maintenance of conspicuous phenotypic polymorphisms has challenged evolutionary ecologists for centuries. Polymorphisms in pleiotropic cascades or genetic linkage may lead to correlations of life history traits such as immunity, parasite infection levels, pigmentation and lifetime reproductive success. The common buzzard Buteo buteo is a bird of prey occurring in several plumage morphs, which differ in pigmentation and in the prevalence, infection intensity and clone composition of their most common blood parasite, as well as in ectoparasite infestation levels. Buzzard morphs are heritable and exhibit a heterozygote advantage where intermediates have higher lifetime reproductive success (LRS). We explored the hypothesis that the differences in pigmentation also correspond to differences in immunity. We hence compared an inducible adaptive and an innate constitutive immune response between the buzzard plumage morphs. The increase of specific anti-tetanus antibodies after vaccination was explained by the morph of the nestling's mother and was highest in offspring of intermediate mothers. Additionally, nestlings with higher humoral response were less infected with blood parasites and, if infected, harboured a lower genetic diversity of these parasites. The phytohaemagglutinin-induced skin swelling, a complex of cellular inflammatory responses, was lowest in intermediate nestlings. The higher LRS of intermediate buzzards suggests that the cellular immunity is an inferior fitness determinant compared to humoral immunity. The strength of immune responses was not linear along the melanisation gradient, indicating that there is most likely no simple genetic correlation between immune responses and plumage morphs. [ABSTRACT FROM AUTHOR]

Some parasites exploit many host species, while others are confined to only a few. Despite decades of study, the mechanisms that determine parasite host specificity remain poorly understood. We investigated host specificity in New Zealand's largest endemic moth, Aenetus virescens (Lepidoptera: Hepialidae), which as larvae excavate tunnels into tree trunks and feed on host tree sap. We sampled host use in 2213 trees belonging to 24 tree species in three sites on the North island of New Zealand to test whether (1) larvae preferentially use particular tree species rather than the most abundant, (2) larvae preferentially use tree species with high nutrient rewards (Phloem turnover and sugar content), and (3) larvae preferentially use tree species with reduced defences (wood density and bark thickness). Overall, 180 individual trees from 15 species were used by larvae. However, results indicated larvae preferentially used particular tree species rather than the most abundant. In particular, larvae preferentially used Aristotelia serrata and Carpodetus serratus, despite being rare at each site. Larvae did not preferentially use tree species with high nutrient rewards nor low wood density. Instead, we found a significant negative relationship between the number of trees per species used by larvae and bark thickness. Overall results indicate bark thickness may be the primary mechanism driving host specificity for A. virescens. [ABSTRACT FROM AUTHOR]

Trace elements are chemical contaminants spread in the environment by anthropogenic activities and threaten wildlife and human health. Many studies have investigated this contamination in apex raptors as sentinel birds. However, there is limited data for long-term biomonitoring of multiple trace elements in raptors. In the present study, we measured the concentrations of 14 essential and non-essential trace elements in the livers of the common buzzard (But eo buteo) collected in the United Kingdom from 2001 to 2019 and investigated whether concentrations have changed during this period. In addition, we estimated the importance of selected variables for modelling element accumulations in tissues. Except for cadmium, hepatic concentrations of harmful elements in most buzzards were lower than the biological significance level of each element. Hepatic concentrations of certain elements, including lead, cadmium, and arsenic, varied markedly seasonally within years. Their peak was in late winter and trough in late summer, except copper which showed an opposite seasonal pattern. In addition, lead in the liver consistently increased over time, whereas strontium showed a decreasing trend. Hepatic concentrations of cadmium, mercury, and chromium increased with age, whereas selenium and chromium were influenced by sex. Hepatic concentrations of arsenic and chromium also differed between different regions. Overall, our samples showed a low risk of harmful effects of most elements compared to the thresholds reported in the literature. Seasonal fluctuation was an important descriptor of exposure, which might be related to the diet of the buzzard, the ecology of their prey, and human activities such as the use of lead shot for hunting. However, elucidating reasons for these observed trends needs further examination, and biomonitoring studies exploring the effects of variables such as age, sex, and seasonality are required. [Display omitted] • Liver Pb, Cd, As, Se, Cu, and Co fluctuated seasonally within a year. • Fluctuation peak was in late winter and trough in late summer, except for Cu. • Liver Pb increased over the monitoring period. • Body and liver weights were negatively correlated with liver essential elements. • Relative importance of variables for predictive models of metal burden was estimated. [ABSTRACT FROM AUTHOR]

Potential indicators of the relative health of an ecological area are top predators, such as raptors. The reestablishment of a raptor population is usually considered a sign of a recovering habitat with reduced human disturbance. On Cyprus, we studied the reproductive biology of Long-legged Buzzard, Buteo rufinus , in the years 2005–2007, and collected data on population size till 2012. The clutch size for all three years was an average of 2.7 ± 0.6 eggs per breeding attempt. Nestling survival was high and of 76 chicks that hatched 68 (89.5%) fledged the nest. The overall breeding success during three years, i.e., total number of young fledged (68) from the number of eggs laid (106), of the Long-legged Buzzard population in Cyprus was 64.2%. The population strongly increased over the study period, and the information on breeding ecology of the Long-legged Buzzard are the first for this part of the Mediterranean Basin, and indicate that the population is doing well. [ABSTRACT FROM AUTHOR]

We examined common buzzard (Buteo buteo) feeding patterns in landscapes with different habitat structure in Belarus. A total of 561 pellets and prey remains were sampled in 1998-2012 from which 1065 prey and other food items were identified. Effects of habitat structure on buzzard diet composition were investigated using correlation analysis. The most abundant group in buzzards' diets were small rodents (49-80% of the biomass consumed), followed by other mammals and birds. Reptiles, anurans, fish and invertebrates constituted the rest. Proportions of all food items varied greatly between landscapes. The mean-weighted body mass of vertebrate prey hunted by common buzzards in different landscapes ranged from 107 to 244 g, constituting on average 180 g. Among small rodents, voles of the genus Microtus were hunted selectively. The food niche breadth was directly proportional to the amount of forest habitat. With increasing amount of forest habitat, the proportion of Microtus voles in buzzards' diets decreased and the proportions of other food items grew. These findings confirm the majority of previous results indicating feeding opportunism of the common buzzard. Our investigation enables better understanding of predator-prey interactions and the prey choice of the common buzzard in Belarus. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are anthropogenic chemicals that have been globally distributed. Biological time series data suggest variation in temporal PFAS concentrations due to regulations and the phase-out of multiple PFAS analytes. Nonetheless, biomonitoring temporal trends of PFAS concentrations in raptors has only been done sporadically in Europe at a national scale. In the present study, we examined the concentrations of 28 PFAS in livers of common buzzard (Buteo buteo) collected in Belgium in the period 2000–2005 and in 2021. Despite the regulations and phase-out, the ΣPFAS concentrations remained similar in the livers over the past 20 years. However, over time the abundance of perfluorooctane sulfonate (PFOS), dominant in livers collected in 2000–2005, to the ΣPFAS concentration decreased from 46% to 27%, whereas the abundance of perfluorotetradecanoic acid (PFTeDA), dominant in 2021, increased from 19% to 43%. The PFOS concentrations in the present study did not exceed the Toxicity Reference Values (TRVs), which were determined in liver on the characteristics of an avian top predator. The absence of temporal changes in PFAS concentrations is hypothesized to be due to a lagged response in environmental concentrations compared to atmospheric concentrations. • Most PFAS concentrations in common buzzard liver samples were similar over the past 20 years. • PFDoDA and PFTeDA concentrations have increased since the early 2000s. • The relative abundance of PFPeS and PFOS decreased while that of PFDoDA and PFTeDA increased. • Regulations and the phase-out of some PFAS seemed to have little effects on their levels. • Accumulated PFOS concentrations are unlikely to cause toxic effects. [ABSTRACT FROM AUTHOR]

Distinct numerical responses of predators to fluctuations in the abundance of their prey are often observed in northern regions but occur more rarely in temperate latitudes. This statement is, however, mostly based on observations of breeding populations, while in some predators, for example in raptors, numerous non-breeding floaters can occur. I estimated the breeding density and reproductive performance (nest survey) as well as the density of entire population (transects with distance sampling) of the common buzzard Buteo buteo in western Poland (52°N) in the years 2005-2014 to test the hypotheses that in temperate latitudes: (1) the breeding population of these birds does not show any numerical response, understood as annual changes in their abundance; (2) its reproductive success, however, changes with the abundance of main prey, the common vole Microtus arvalis; and (3) hence the entire buzzard population (including potential immature floaters) present in a given area during the nesting period responds numerically with some time delay. The reproductive success of buzzards was positively correlated with their prey abundance. Contrary to my predictions, however, the breeding population of buzzards showed a slight numerical response with a 3-year lag and the entire population tracked vole fluctuations without any time delay. The immediate numerical response of the entire buzzard population was probably caused by large-scale movements of floaters. Such rapid numerical responses of some predators may contribute to the relative stability of prey populations in temperate latitudes compared to northern regions. [ABSTRACT FROM AUTHOR]

This study was aimed to evaluate the status of total oxidant, antioxidant capacity and DNA damage caused by gunshot for wild falcons. Wounded and debilitated buzzards (buteo family) (n=20) were examined having different types of injuries caused by gunshot and other minor accidents. Buzzards were divided in to two groups, having gunshot wounds (n=10) and other kept as control group (n=10) which were having mild injuries and debilitated condition due to minor accidents. Total oxidant (TOS) and total antioxidant status (TAS) levels were determined using Rel Assay Diagnostic kit and DNA damage was determined by comet assay. There was significant (P < 0.05) increase in TOS and total DNA damage while non-significant (P > 0.05) difference was in TAS was observed in gunshot wounded falcons as compared to control group. Oxidative stress has recently been examined together with DNA damage in mammals. However this combined evaluation has never been found in wild raptors in previous literature. Therefore, this study is known to be the first report for TAS- TOS and DNA damage for wild gunshoted falcons. [ABSTRACT FROM AUTHOR]

Applications for licences to kill buzzards in order to prevent serious damage to the viability of pheasant shoots were regarded by Natural England, the licensing authority, as sufficiently novel to require direction from the Department for the Environment, Food and Rural Affairs (Defra), the government department responsible for the licensing provisions in the Wildlife & Countryside Act and their implementation in accordance with the EU Birds Directive. Defra declined to issue a specific policy for raptors and instructed Natural England to apply the general policy. The court found that Natural England had not done this but had, in effect, applied a hidden policy to refuse such applications. Natural England’s decision to refuse to grant licences was quashed on the grounds of reliance on an undisclosed policy, taking account unlawfully of public opinion, unreasonableness and failing to deal with the option of licensing live trapping of birds. Ouseley J also found that the case was covered by the Aarhus Convention because it related to an environmental matter. The fact that the case was about a refusal to grant a licence and therefore amounted to a challenge seeking to cause harm was irrelevant. [ABSTRACT FROM AUTHOR]