Search Results (181)

Raptors, being at top of the food chain, serve as important models to study the impact of changing climate, as they are more vulnerable due to their unique ecology. They are vulnerable to extinction, with 52% species declining population and 18% are threatened globally. The effect of climate change on raptors is poorly studied in the Eastern Himalayan region. The present study offers a complete investigation of climate change effects on the raptors in the northeast region of the Eastern Himalayas, employing ensemble species distribution modeling. The future predictions were employed to model the climate change across two socioeconomic pathways (SSP) i.e. SSP245 and SSP585 for the periods 2041–2060 and 2061–2080. Specifically, five algorithms were employed for the ensemble model, viz. boosted regression tree (BRT), generalized linear model (GLM), multivariate adaptive regression splines (MARS), maximum entropy (MaxEnt) and random forest (RF). The study highlights worrying results, as only 10.5% area of the NE region is presently suitable for Falco severus, 11.4% for the critically endangered Gyps tenuirostris, and a mere 6.9% area is presently suitable for the endangered Haliaeetus leucoryphus. The most influential covariates were precipitation of the driest quarter, precipitation of the wettest month, and temperature seasonality. Future projection revealed reduction of 33–41% in suitable habitats for F. severus, G. tenuirostris is expected to lose 53–96% of its suitable habitats, and H. leucoryphus has lost nearly 94–99% of its suitable habitats. Such decline indicates apparent habitat fragmentation, with shrinking habitat patches. Full article

To address the difficulty of extracting thermal bending failure and centerline horizontal displacement fault feature signals when judging the operating status of cement rotary kilns, we propose a method for extracting fault features based on improved secretary bird optimization algorithm (ISBOA) and variational modal decomposition (VMD). First, a strategy of randomly consuming prey with inertial weights is proposed to enhance the randomness of search results and avoid local optima. Then, the whale algorithm’s encirclement strategy is introduced into the secretary bird’s camouflage strategy to coordinate the capabilities of local search and global exploration. Finally, ISBOA demonstrated superior performance to other optimization algorithms in VMD parameter selection, achieving a 75% improvement in convergence speed compared to pre-optimization. Through validation with experimental and simulation data, this method demonstrates good feasibility. By decomposing actual signals and comparing the mean energy of their characteristic signals, the severity of thermal bending faults in the cylinder and centerline horizontal displacement faults in cement rotary kilns is diagnosed. Verified against actual measurement results, the accuracy reached 96.7%. Full article

This study presents preliminary data on the diet composition of reintroduced Lesser Kestrels (Falco naumanni) in two restored colonies in Bulgaria—near Stara Zagora and in the Sakar Mountains at Levka village—based on pellet analysis. A total of 103 and 48 identifiable prey items (occurrences in the pellets) were recovered from the respective sites. Insects (particularly Coleoptera) dominated the diet at both colonies, but some differences were observed in the occurrence of vertebrate prey. Birds (Aves) were the second most common category in Stara Zagora, while small mammals (Mammalia) were more prevalent in Sakar. Annelids were detected only in Stara Zagora, and millipedes (Diplopoda) only in Sakar. Synthetic materials were found in pellets from Stara Zagora, suggesting plastic ingestion. Levins’ index indicated similar niche breadths (1.915 vs. 2.008), and Pianka’s index showed a high dietary overlap (0.981), pointing to broadly similar trophic preferences despite local prey availability. Full article

Anti-predator behaviour in birds is required by day and night but has barely been studied at night. For prey which detect predators visually, low light levels may diminish detection or monitoring of approaching threats. We conducted standardised approaches to Silver Gulls (Chroicocephalus novaehollandiae) by day and night along an urban foreshore in Melbourne, Australia, measuring light levels (Lux) experienced by the gull, Flight-initiation Distance (FID; the distance at which escape is initiated), and Starting Distance (the initial distance between the observer and the bird). We fitted models reflecting different conceptual possibilities for the relationship between Lux and FID. Support existed for a model with a stepwise effect of light on FID. Longer FIDs (i.e., earlier escape) in darker conditions suggest that gulls can detect an approaching threat in darkness at least as well as by day, but the tolerance of closer approaches may be diminished in dull and dark conditions, perhaps due to difficulty in monitoring an approaching threat and/or because nighttime represents a time of greater predator risk. Starting Distance was positively related to FID, a result commonly reported for many taxa by day. Full article

Rodent damage significantly affects agriculture around the world. Rodenticides can sometimes control pests, but they are costly, may cause secondary poisoning to nontarget wildlife, and can become less efficient over time due to bait shyness and resistance. Using wildlife as biological pest control agents, particularly barn owls (Tyto spp.), has been suggested as an alternative. Barn owl nest boxes and hunting perches have been added to increase predator pressure, yet few studies have examined their effectiveness. We conducted a field study in forty-five 10 × 10 m² plots to compare three treatments (biological pest control by adding hunting perches, 1080 rodenticide, and control) on rodent (vole) activity and crop health (alfalfa, Medicago sativa) using unmanned aerial system (UAS) remote sensing and ground surveys. Additionally, we used 24/7 video cameras and a machine learning (YOLOv5) object detection algorithm to determine whether hunting perches increase the presence of diurnal and nocturnal raptors. Rodent activity increased during the study and did not vary among the treatments across all three treatment groups, indicating that neither the biological pest control nor the rodenticides prevented the rodent population from increasing. Moreover, the vegetation indices clearly showed that the alfalfa has become increasingly damaged over time, due to the rising damage caused by rodents. There were significantly more raptors in plots with hunting perches than in control plots and those treated with rodenticides. Specifically, barn owls and diurnal raptors (mainly black-shouldered kites) spent 97.92% more time on hunting perch plots than rodenticide plots and 97.61% more time on hunting perch plots than control plots. The number of barn owls was positively related to vole activity, indicating a bottom-up process, while the number of black-shouldered kites was unrelated to vole activity. Even though hunting perches effectively increased the presence and activity of diurnal and nocturnal raptors, rodent populations increased. Future research should investigate whether hunting perches can increase raptor populations and improve crop health in crops beyond alfalfa, which is known to be particularly challenging to control for voles. Full article

The Set Coverage Problem (SCP) is an important combinatorial optimization problem known to be NP-complete. The use of metaheuristics to solve the SCP includes different algorithms. In particular, binarization techniques have been explored to adapt metaheuristics designed for continuous optimization problems to the binary domain of the SCP. In this work, we present a new approach to solve the SCP based on the Secretary Bird Optimization Algorithm (SBOA). This algorithm is inspired by the natural behavior of the secretary bird, known for its ability to hunt prey and evade predators in its environment. Since the SBOA was originally designed for optimization problems in continuous space and the SCP is a binary problem, this paper proposes the implementation of several binarization techniques to adapt the algorithm to the discrete domain. These techniques include eight transfer functions and five different discretization methods. Taken together, these combinations create multiple SBOA adaptations that effectively balance exploration and exploitation, promoting an adequate distribution in the search space. Experimental results applied to the SCP together with its variant Unicost SCP and compared to Grey Wolf Optimizer and Particle Swarm Optimization suggest that the binary version of SBOA is a robust algorithm capable of producing high quality solutions with low computational cost. Given the promising results obtained, it is proposed as future work to focus on complex and large-scale problems as well as to optimize their performance in terms of time and accuracy. Full article

The griffon vulture (Gyps fulvus fulvus) is a scavenger species that plays a vital ecological role in carrion removal. Successful survival and reproduction in captive and wildlife conditions require optimal physical status and plumage integrity. Nutritional and environmental factors, systemic diseases, and various etiological agents can influence feather alterations. Although frequently documented in captive psittacine species, feather abnormalities are extremely rare in wild birds. Since 2020, two free-living griffon vultures in northeastern Italy have been found in poor physical condition, unable to fly due to partial feather loss and malformation of remiges and rectrices. Histopathologic examination of follicles and peri-follicular tissue revealed atrophy, keratin replacement, vasculitis, and calamus dystrophy with lymphohistiocytic perivasculitis. Immunohistochemical and ultrastructural analysis identified the presence of virus-like particles in epithelial and inflammatory cells. Although virome analysis did not confirm the presence of this virus in pooled affected samples, this study provides the first report of an emerging plumage disorder in free-ranging griffon vultures, which requires further characterization. Full article

The non-traditional companion animal (NTCA) sector, particularly involving avian species, has significantly expanded in Italy, raising concerns over the spread of infectious diseases. These animals can harbor various pathogens and act as reservoirs, posing risks to native wildlife through legal or illegal trade, escapes, or intentional releases. However, the epidemiology of avian pathogens in NTCAs remains poorly understood and is typically investigated only in symptomatic individuals. In the present study, cloacal and choanal cleft swabs were collected from 319 ornamental and raptor birds across 19 families, pooled and tested for beak and feather disease virus (BFDV), avian polyomavirus (APV-1), psittacid herpesvirus 1 (PsHV-1), and avian metapneumovirus (aMPV). BFDV and APV-1 were detected in 13.79% and 2.19% of birds, respectively, with five co-infections. No cases of PsHV-1 or aMPV were found. Both viruses showed a higher prevalence than in previous Italian and most of international studies, with several non-psittacine species, including birds of prey, testing positive—some for the first time. Mixed-species settings and participation in public exhibitions were proven as significant infection risk factors. The study highlights the growing relevance of BFDV and APV-1 in non-commercial birds and recommends improved biosecurity and preventive screening to reduce disease spread and safeguard animal health. Full article

Background/Objectives: Increasing levels of antimicrobial resistance (AMR) have recently been observed at the human–domestic animal–wildlife interface. Wild birds have been identified as carriers of antimicrobial-resistant bacteria and serve as excellent biomarkers for epidemiological studies. This study assessed the current AMR presence in Eastern Spain’s commensal Escherichia coli isolated from free-ranging Bonelli’s eagles (Aquila fasciata). Methods: Nestlings and their nests were intensively sampled between 2022 and 2024 to determine their AMR profile and characterize E. coli. AMR testing was conducted using the broth microdilution method, following the European Committee on Antimicrobial Susceptibility Testing guidelines. Additionally, the presence of eaeA (intimin gene) and stx-1 and stx-2 (shiga toxins) was analyzed by real-time PCR to classify E. coli strains into enteropathogenic (EPEC) and Shiga-toxigenic (STEC) pathotypes. Results: Of all E. coli isolates, 41.7% were resistant to at least one antimicrobial, and 30% were multidrug-resistant. Only two strains were classified as EPEC and none as STEC. The highest resistance rates were observed for amoxicillin and tetracycline (19.6% each). Alarmingly, resistance to colistin and meropenem, last-resort antibiotics in human medicine, was also detected. Conclusions: Although the mechanisms of resistance acquisition remain unclear, transmission is likely to occur through the food chain, with synanthropic prey acting as intermediary vectors. These results highlight the role of Bonelli’s eagles as essential sentinels of environmental AMR dissemination, even in remote ecosystems. Strengthening One Health-based surveillance is necessary to address AMR’s ecological and public health risks in wildlife. Full article

How humans perceive and interact with other animal species is critical in enhancing conservation initiatives. The study recorded and analyzed people’s knowledge and perceptions of birds of prey and their interactions in three rural communities in Paraíba, Brazil. The data were collected by face-to-face interviews using semi-structured questionnaires. One hundred ninety-one people were interviewed, and 19 species were recorded. Based on the answers to the questionnaires, the species are considered omens of climatic/ecological and supernatural events. They are important in the maintenance of ecosystems (predation of rodents and snakes and feeding on dead animals). However, most birds of prey are killed because they cause damage by preying upon domestic animals or for being associated with bad omens. The diversity of information listed here shows the need for complex and interdisciplinary studies to understand the human dimensions of knowledge and relationships between people and birds, contributing to species conservation and encouraging coexistence between people and birds of prey. Full article

The ability of terrestrial isopods (Crustacea: Isopoda: Oniscidea) to protect themselves effectively from predation by birds has never been tested. They are equipped with glands producing chemical substances; moreover, some species show conspicuous coloration, which might suffice as an aposematic signal. We evaluated the palatability of isopods to birds. We tested the responses of Parus major captured in the wild (and thus possessing some experience with common native isopod species) to the following isopod species: Porcellio scaber (native, inconspicuous), Oniscus asellus (native, moderately conspicuous), Armadillo officinalis (non-native, moderately conspicuous), Armadillidium versicolor (native, conspicuous), and Armadillidium gestroi (non-native, conspicuous). We compared bird responses to isopods with reactions to the Blaptica dubia, an edible roach very similar to isopods in size and appearance. Isopods were better protected from bird attacks than roaches; however, their color pattern did not affect the level of protection. Birds were able to differentiate isopods from the roach; in experiments, where we presented isopod and roach individuals together, the birds hesitated longer in attacking and observed both prey items for a longer time. Non-native species either profited from the generalization of the protection of native isopods or from neophobia. Some isopods elicited significantly more discomfort behavior in birds, suggesting differences in the chemical protection among the tested species. Full article

The grey-headed woodpecker (Picus canus) (GHW) is one of the least-studied European woodpeckers, listed in Annex I of the Birds Directive. We examined the key environmental characteristics that determine the possibility of GHW occurrence in vast forests in northeast Poland. Woodpeckers were inventoried in spring on 54 study plots (4 km²) covering 20% of the forest area. Active territories were detected and mapped using the playback experiment of territorial voices and drumming. The generalized linear model GLM, random forest RF, and Boosting were used for modeling. GLM was used to indicate the most critical factors affecting the abundance of GHW. The number of territories in a single study plot ranged from 0 to 3; the most frequent were areas without woodpeckers. The probability of the nesting of the GHW was increasing at plots with watercourses, a bigger share of mixed forest area, and a proportion of stands over 120 years old. The calculation for all 400 quadrats allowed us to estimate the population size at approximately 180–200 breeding pairs. The overall density of GHW in the study area was assessed at 0.13/km², while at the optimal quadrats, it increased to about 0.75/km². Preference for watercourses was linked to alders growing along water banks. Near the water, there are often small meadows where the GHW can prey on ants. In turn, old-growth forests above 120 years old increased the probability of the presence of the GHW. There are more dead and dying trees in older forests, which are the ones the GHW chooses to excavate cavities. To effectively protect the habitats of the GHW, it is necessary to maintain a larger area of stands over 120 years old, mainly on wet sites. Full article

Pododermatitis (bumblefoot) occurs commonly in birds of prey and owls and shows species-specific differences in its prevalence, especially between falcons and hawks. The development of the disease is particularly associated with circulatory disorders of the feet. To compare the blood vessel supply of the foot sole, especially the metatarsal foot pad, macroscopic dissections including intravascular injection of latex, contrast µCT scans with barium sulphate, corrosion casts (epoxy resin), and histological examinations of the skin were performed in eight avian species. The main supplying artery of the metatarsal pad, the pulvinar artery, originated from the medial digital artery of the first toe. This main pulvinar artery showed a rather vertical course towards the sole surface, subsequently encircling the metatarsal pad like a basket in falcons and owls, whereas a rather horizontal straight course was observed in northern goshawks and common buzzards. Organized fat tissue was present in the subcutis as the basis for the metatarsal pad only in falcons and owls. The dermis of the metatarsal pad showed a well-developed papillary layer and prominent dermal and subdermal vascular networks in all species examined. The observed differences were discussed regarding both the species-specific prevalence and the etiology of bumblefoot. Full article

The Eurasian eagle-owl (Bubo bubo) is a large, generalist predator widely distributed across Eurasia, including mainland Greece, where it occupies a broad range of habitats. Its diet is known to consist primarily of mammals and birds, with reptiles occasionally included. However, to date, chameleons have not been documented among its prey. Here, we report the first confirmed case of B. bubo preying on an African chameleon (Chamaeleo africanus) in the western Peloponnese of southern Greece—a region where the two species occur in limited sympatry. C. africanus, native to North Africa and introduced to Greece since antiquity, is a diurnal, slow-moving, arboreal lizard with highly cryptic behavior and specialized anti-predator strategies. Despite these traits, our observation highlights its potential vulnerability to nocturnal avian predators. This rare predation event offers novel insights into the trophic ecology of B. bubo and raises important considerations for the conservation of C. africanus, a species listed as Critically Endangered in Greece and increasingly threatened by habitat loss, illegal collection, and road traffic collisions. Full article

Urbanization changes the environment through physical constructions, disturbances, and altered resource availability. These modifications influence both prey and predator assemblages. Several studies have indicated that hole-nesting birds outnumber ground nesters in cities. Differential nest predation can be one reason behind this observation. We conducted a multi-year artificial nest predation experiment along an urban gradient by using artificial ground nests and nestboxes in Rovaniemi, Finland. Because visually searching avian predators dominate in cities, we predicted that nest predation of ground nests will increase with urbanization, whereas nests in holes will be better protected than ground nests. Ground nest predation increased with urbanization, being lowest in forest and rural areas, intermediate in suburban area and highest in urban area. However, there was no year-effects on artificial ground nest predation, suggesting that even a single-year results of artificial nest predation experiment can be reliable. In the city, ground nest predation was greater than nestbox predation. In forests, nestbox predation was greater than ground nest predation. Among ground nests, predation was greater in the city than in forests. Among nestboxes, predation was greater in forest than in urban or suburban habitats. Only the ground nest predation was greater in managed than in un-managed parks. Ground nest predation decreased with tree cover and increased with the patch area. No variables were entered in the models of the nestboxes. The results indicated that ground nesters might avoid urban areas as nesting sites. We assume that visually searching avian predators benefit from the lack of covering vegetation in city parks. However, because most avian nest predators, like corvids, are not effective nest predators of hole-nesting birds, urban areas are safe nesting areas for hole-nesters. The results suggest that nest predation is one important factor that could explain, why hole-nesting bird species outnumbered ground-nesting species in cities. The result give support for the hypothesis that nest predation pressure can modify urban bird assemblage structure. Full article