Osprey Research Articles

Human-Induced Mortality Causes Affecting a Newly Established Population of Ospreys Pandion haliaetus in Southern Iberia

Human-Induced Mortality Causes Affecting a Newly Established Population of Ospreys Pandion haliaetus in Southern Iberia

Birds of prey in the collections of the Šariš Museum in Bardejov (Slovakia)

Abstract In this study, data presented of birds of prey (Accipitriformes, Falconiformes) specimens deposited in the collection of the Šariš Museum in Bardejov (SMB), Slovakia. The work builds on previous studies highlighting the importance of the SMB museum collections, but also the importance of the museum on a global scale. In total, data of 437 individuals belonging to 22 species from 86 sites in eastern Slovakia were evaluated. Individuals were acquired in 1954–1985 (and two specimens of Buteo buteo in 1998), but mainly in 1962 (n = 63, 14.4%) and 1963 (n = 32, 7.3%). Moreover, one specimen of the Common Buzzard (B. buteo) had signs of „a dilution (isabel)” and one bird of the Western Marsh Harrier (Circus aeruginosus) had signs of „melanism“. The importance of the work also includes cataloguing, which provides important data on regional museums and their collections that can be significant not only regionally but also globally. Moreover, in the SMB collections there are also 20 specimens of 15 species of exotic Accipitriformes and Falconiformes [1 ex. – Accipiter striatus; 1 ex. – Buteo buteo; 1 ex. – B. ventralis; 1 ex. – Buteogallus gundlachii; 1 ex. – B. meridionalis; 1 ex. – Caracara plancus; 1 ex. – Elanoides forficatus; 5 ex. – Falco sparverius; 1 ex. – Geranoaetus polyosoma; 1 ex. – Gyps africanus; 1 ex. – Haliaeetus albicilla; 2 ex. – Ictinia plumbea; 1 ex. – Pandion haliaetus; 1 ex. – Rupornis magnirostris; 1 ex. – Vultur gryphus] originating mainly from Argentina and Cuba as well from Africa and Hungary.

Expanding on expansus: a new species of Scaphanocephalus from North America and the Caribbean based on molecular and morphological data.

Members of the genus Scaphanocephalus mature in accipitrids, particularly osprey, Pandion haliaetus, with metacercaria causing Black Spot Syndrome in reef fishes. In most of the world, only the type species, Scaphanocephalus expansus (Creplin, 1842) has been reported. Recent molecular studies in the Western Atlantic, Mediterranean and Persian Gulf reveal multiple species of Scaphanocephalus, but have relied on 28S rDNA, mainly from metacercariae, which limits both morphological identification and resolution of closely related species. Here we combine nuclear rDNA with mitochondrial sequences from adult worms collected in osprey across North America and the Caribbean to describe species and elucidate life cycles in Scaphanocephalus. A new species described herein can be distinguished from S. expansus based on overall body shape and size. Phylogenetic analysis of the whole mitochondrial genome of Scaphanocephalus indicates a close relationship with Cryptocotyle. We conclude that at least 3 species of Scaphanocephalus are present in the Americas and 2 others are in the Old World. Specimens in the Americas have similar or identical 28S to those in the Mediterranean and Persian Gulf, but amphi-Atlantic species are unlikely in light of divergence in cytochrome c oxidase I and the lack of amphi-Atlantic avian and fish hosts. Our results provide insight into the geographic distribution and taxonomy of a little-studied trematode recently linked to an emerging pathology in ecologically important reef fishes.

Hindlimb myology in two piscivorous raptorial birds: a quantitative comparison of the osprey and the white‐tailed sea eagle (Aves, Accipitriformes)

AbstractThe hindlimbs of Accipitriformes are vital for capturing prey. Research on hindlimb musculature has primarily focused on species preferring avian and mammalian prey, whereas piscivorous species have received limited attention. This study aims to investigate the quantitative characteristics of hindlimb muscles in two piscivorous Accipitriformes, Pandion haliaetus and Haliaeetus albicilla, to discern potential muscular features associated with their specific food preference. The mass and proportion of all hindlimb muscles in both species were assessed based on their primary function (flexion or extension). A Kruskal‐Wallis test was employed to analyze possible differences in muscle mass between species. The allometric relationships between the muscles and body mass were explored with the reduced major axis method. Additionally, a study on the architectural parameters of the primary gripping muscles in P. haliaetus was conducted, using published information from other raptorial birds for comparison. The isometric scaling relationship predominated in the majority of individual muscles helping maintain a proportional relationship relative to body mass. Both species exhibited a similar pattern in terms of quantitative muscle features, implying a preservation of muscle characteristics linked to their predatory capabilities. The largest proportion of hindlimb muscle mass was dedicated to digit flexion in accordance with the grasping abilities of birds of prey. The muscles tibialis cranialis, flexor digitorum longus and flexor hallucis longus exhibited the greatest mass, high physiological cross‐sectional area values, and long fibre, categorizing them as high‐power specialists. These muscles are crucial in the flexion movements that produce the gripping action that characterizes birds of prey. Although no statistically significant differences were detected, each species displayed slightly distinct muscular characteristics, particularly in the architectural properties of the flexor muscles controlling digits II, III, and IV. These variations seem to be associated with differences in their prey preferences.

Tweeting Trends: Unmasking the Birds of Madurai South, Tamil Nadu, India

Wetlands, acting as complex ecosystems bridging aquatic and terrestrial habitats, play a vital role in avian conservation. Despite the extensive use of bird communities in biodiversity conservation, there is a notable lacunae in baseline data, particularly for common avian species. This study aims to address this knowledge gap, providing a foundational dataset for avifauna in the wetlands of Madurai, Tamil Nadu. The survey conducted from January 2022 to December 2023 covered five wetlands: Madakulam, Thenkarai, Koothiyarkundu, Avaniyapuram, and Samanatham. A total of 151 species belonging to 55 families have been observed during the study period. The results highlight the prevalence of Passeriformes, with 51 species. Among the study sites, Samanatham recorded the highest species count, with 124 species, while Thenkarai site recorded the lowest with 82 species. Analysis of feeding guild revealed a diverse range of feeding habits, with 36% being insectivores. The analysis of relative abundance showed that 55% of the population is common (C), and concurrent analysis revealed 64% as residents and 27% being winter visitors. Notably, eight “Nearly threatened” such as Pallid Harrier Circus macrourus, Osprey Pandion haliaetus, Bar Tailed Godwit Limosa lapponica, Black Tailed Godwit Limosa limosa, Oriental Darter Anhinga melanogaster, Painted Stork Mycteria leucocephala, Spot Billed Pelican Pelecanus philippensis, Black Headed Ibis Threskiornis melanocephalus and three “Vulnerable” species, such as the River Tern Sterna aurantia, Greater Spotted Eagle Clanga clanga and Indian Spotted Eagle Clanga hastata, were observed. Throughout the study period, the months of March and April recorded the highest number of individuals across all study sites. A noticeable correlation between the abundance of microhabitats within the wetlands and the concentration of individuals was observed in the Madakulam site. In conclusion, this study serves as a critical step in addressing the dearth of baseline data for avian diversity in Madurai's wetlands. The findings contribute to the broader understanding of ecological dynamics and provide essential information for effective conservation strategies. To ensure a comprehensive approach in safeguarding the delicate balance within wetland ecosystems, ongoing monitoring will extend to environmental conditions, vegetation dynamics, other biotic resources, and potential threats to the avifauna.

Touristic activity and disturbances over Nearctic migratory birds oin the coast of Piauí State, Brazil

The migration of birds is a phenomenon that leads thousands of individuals to move between different areas for feeding and breeding, with these movements often crossing geopolitical borders. This behavior is crucial for the survival of many species. However, anthropogenic impacts are affecting the habitats of these species, contributing to the decline in bird populations. In light of this, the aim of this study was to analyze the disturbances caused by tourist activities on migratory birds visiting the estuaries of the Cardoso and Camurupim rivers on the coast of the state of Piauí and propose measures to mitigate disturbances on the birds. Samples were taken at three observation points, where changes in bird behavior in response to tourist activities were analyzed. Binoculars, a photographic camera, and a laser rangefinder were used to assist in delineating impact zones. Although various tourist activities occur in the region, the main disturbances are caused by kitesurfing and tourists walking near the feeding or resting areas of the species. Calidris minutilla, Calidris pusilla, Calidris alba, Actitis macularius, and Charadriius semipalmatus were the least sensitive species to disturbances, reacting more frequently within impact zones Z = 0-30m and Z = 30-60m, while the species Pluvialis squatarola, Numenius hudsonicus, Tringa melanoleuca, Calidris canutus, Limnodromus griseus, and Pandion haliaetus showed greater escape distances. The results of this study show that tourists walking and kitesurfing are the main activities impacting migratory birds in the region, highlighting the need for measures to mitigate such impacts. Based on the results, the creation of minimum protection zones of 160m and 200m is recommended to mitigate disturbances caused by the approach of bathers and kitesurfers.

Ospreys (Pandion haliaetus) do not exhibit strong footedness at the population level

Ospreys (Pandion haliaetus) do not exhibit strong footedness at the population level

Identifying priority mitigation areas for human–osprey conflict

AbstractRaptor nests on human‐built structures represent a significant source of conflict, as they can result in bird mortality, fires, or power outages due to falling nest materials or animals connecting with energized conductors. Power companies typically try to mitigate these conflicts to avoid service disruptions. Performing mitigation measures across all potentially problematic power infrastructure is generally not a practical solution given logistical, time, or budgetary constraints. Therefore, there is a need for quantitative, landscape‐scale tools to identify conflict risk and prioritize mitigation. We examined the influence of habitat and transmission infrastructure distribution on the potential risk of osprey (Pandion haliaetus) nesting‐infrastructure conflict in the Tennessee Valley Authority (TVA) power service area within Tennessee, Alabama, Georgia, Kentucky, Mississippi, North Carolina, and Virginia, USA, using osprey nesting and conflict records from 1990–2020. We modeled risk using a 3‐stage approach, which intersected a nesting habitat suitability model and density of infrastructure to evaluate the potential risk of conflict. Habitat suitability was greater on or near open water and closer to developed areas. Transmission line density was low (0.14 ± 0.29 lines/km2) and heterogenous across the service area with more lines within urban centers and near power facilities. Integrating habitat suitability and transmission infrastructure information revealed that very low and low‐risk areas comprised 99% of the service area. Less than 1% comprised 1,113.7 km2 of moderate and 82.2 km2 of high or very high risk, mostly concentrated along major rivers and lakes, and around urban centers. Risk was more prevalent in the northeastern portion of the service area. This work presents a top‐down approach to mitigating osprey–power infrastructure conflict, which allows for the prioritization of mitigation actions and can facilitate long‐term coexistence with this protected species.

Molecular characterization, virulence and antimicrobial and biocidal susceptibility of selected bacteria isolated from the cloaca of nestling ospreys (Pandion haliaetus) from Mono Lake, California, USA.

In the present study, the presence of the Enterobacterales, Staphylococcus spp., Mammaliicoccus spp., and Enterococcus spp. in cloacal samples of nestling ospreys (Pandion haliaetus), a fish-eating specialist, from Mono Lake, California, USA was examined by a multiphasic approach, including antimicrobial and biocide susceptibility testing, genotyping, and whole genome sequencing of selected isolates. The most commonly detected species was Escherichia coli, followed by Mammaliicoccus sciuri, Staphylococcus delphini, Enterococcus faecalis, Enterococcus faecium, Hafnia alvei, Klebsiella pneumoniae, Citrobacter braakii and single isolates of Edwardsiella tarda, Edwardsiella albertii, Klebsiella aerogenes, Plesiomonas shigelloides and Staphylococcus pseudintermedius. Multi-drug resistance (MDR) was observed in two E. coli isolates and in an Enterococcus faecium isolate. The MDR blaCTX-M-55-positive E. coli belonged to the pandemic clone ST58. The results of the present study suggest that nestling ospreys are exposed to MDR bacteria, possibly through the ingestion of contaminated fish. Ospreys may be good biosentinels for the presence of these microorganisms and antibiotic resistance in the local environment and the risk for other wildlife, livestock and humans.

Nesting Eastern Ospreys Pandion haliaetus cristatus exploiting construction-tower cranes in a populous city

Globally, Ospreys Pandion haliaetus are well known to nest on artificial structures, prompting conflicts with humans when nests are built on utility and communications infrastructure. This note describes two cases of Osprey nests that had been built on top of construction-tower cranes. Fortunately for the birds, both cases were on construction sites that were halted for other reasons. These observations raise the question whether similar scenarios on active construction sites would add to the existing span of human–Osprey conflicts, with the potentially awkward juxtaposition between the need to minimise human interference to nests and construction sites being characterised by high levels of human activity. This is especially of concern with the Osprey listed as a threatened species in some jurisdictions, such as New South Wales and South Australia.

TAXONOMIC REASSESSMENT AND MORPHOLOGICAL REDESCRIPTION OF NEMATOSTRIGEA SERPENS ANNULATA (DIGENEA: STRIGEIDAE) FROM OSPREY IN NORTH AMERICA.

Digenean trematodes in the strigeid genus Nematostrigea are parasites of various birds, most often ospreys (Pandion haliaetus). Nematostrigea currently contains 2 species, Nematostrigea serpens and Nematostigea hepatica. Nematostrigea serpens is divided into 2 subspecies: N. serpens serpens from the Palearctic and Indomalayan realms and N. serpens annulata from the Nearctic realm. In the present work, we studied the type material of N. serpens annulata and collected new specimens from an osprey in Wisconsin close to the type locality. The original description and illustration of N. serpens annulata were incomplete. Herein we provide a detailed redescription and new illustrations of N. serpens annulata on the basis of the type material as well as newly collected and sequenced specimens. Nematostrigea serpens annulata has a distinct tegumental thickening near the mid-length of the genital cone, which is absent in its congeners. Partial sequences of the large ribosomal subunit (28S) DNA and cytochrome c oxidase subunit 1 (COI) mitochondrial DNA gene sequences were generated from our specimens of N. serpens annulata. Comparisons with previously published sequences of N. serpens serpens from the Palearctic demonstrated 2.2% difference in 28S and 3.7% in COI. On the basis of morphological and molecular comparisons, we elevate N. serpens annulata to species status and recognize it as Nematostrigea annulata Dubois and Rausch, 1948.

Use of marine debris as nest material by ospreys

The use of anthropogenic debris as nest-building materials may affect nest function. We study ospreys (Pandion haliaetus) on an island with scarce vegetation and high availability of beached marine debris. We describe the anthropogenic debris in osprey nests, evaluate the factors affecting its prevalence and abundance, and test its potential effects on breeding parameters. We also quantify plastic entanglements among adults and nestlings. Of the 36 studied nests, 92 % included non-natural items, with plastic being the most frequent material (88.9 %). Nests that were bigger and closer to the coast had more anthropogenic items. The abundance of anthropogenic items in nests did not correlate with osprey breeding parameters. We recorded two live entangled adult females, which represent 3.9 % of the adult population. Monitoring the abundance of anthropogenic debris and its effects on wildlife is necessary to guarantee long-term viability of coastal wildlife.

Genetic Variability and Family Relationships in a Reintroduced Osprey (Pandion haliaetus) Population: A Field-Lab Integrated Approach

Reintroductions represent an opportunity to restore local biodiversity and reverse the effect of taxa extinction. However, they need feasibility and monitoring plans before and during their implementation to ensure concrete and lasting results. During the 20th century, the osprey (Pandion haliaetus) underwent a severe population decline in many European countries due to direct persecution and coast exploitation. In the 1960s–1970s, it was declared extinct as a breeder in Italy. In 2004, the Maremma Regional Park (Tuscany, central Italy) started a reintroduction project by capturing and releasing, from 2006 to 2010, 33 juvenile Corsican ospreys on the southern coast of Tuscany. The settlement of the first breeding pair in 2011 was the initial sign of the success of the reintroduction project, then further pairs settled from 2011 onward. A total of 81 feather or blood samples were collected for DNA extraction from both translocated (2006–2010) and newborn individuals (2011–2021). Individuals were analyzed at 16 microsatellite loci to verify any changes in genetic variability over time and to set out a protocol for the reconstruction of kinship for conservation and management purposes. We did not observe a reduction in genetic variability between the two sampling periods, although we found a slight sign of the founder effect in the reestablished population. A strong genetic differentiation was observed between this Mediterranean population and an injured osprey from a Northern European population, thus confirming the importance of considering the local genetic pool in any reintroduction project. Monogamous behavior was confirmed by family reconstruction, which allowed the identification of clear kinship relationships. Our findings indirectly inform on the genetic variability of the population during the 16-year period from the start of the project and provide useful insights for its long-term conservation.

Food supplementation increases reproductive performance of ospreys in the lower Chesapeake Bay

The Atlantic States Marine Fisheries Commission (ASMFC), the governing body responsible for managing fisheries on the U.S. East Coast, formally adopted the use of Ecological Reference Points (ERPs) for Atlantic menhaden, Brevoortia tyrannus. Scientists and stakeholders have long recognized the importance of menhaden and predators such as ospreys, Pandion haliaetus, that support the valuable ecotourism industry and hold cultural significance. Landings in the reduction fishery are at their lowest levels and menhaden is facing potential localized depletion. Mobjack Bay, located within the lower Chesapeake Bay, has been a focus of osprey research since 1970 and represents a barometer for the relationship between osprey breeding performance and the availability of their main prey, menhaden. Since local levels of menhaden abundance were not available, we conducted a supplemental menhaden feeding experiment on osprey pairs during the 2021 breeding season. Our main objective was to determine if the delivery rate of menhaden had an influence on nest success and productivity. Nest success (χ2 = 5.5, df = 1, P = 0.02) and productivity (β = 0.88, SE = 0.45, CI = 0.049, 1.825, P = 0.048) were significantly higher within the treatment group. Reproductive rates within the control group were low and unsustainable suggesting that current menhaden availability is too low to support a demographically stable osprey population. Menhaden populations should be maintained at levels that will sustain a stable osprey population in which they are able to produce 1.15 young/active nest to offset mortality.

Dynamics in spatial use by Ospreys (Pandion haliaetus) during the breeding season revealed by GPS tracking

The migratory behaviour of Ospreys (Pandion haliaetus) has been well studied using satellite telemetry, but studies on their behaviour in the breeding area are scarce. We caught and fitted 17 adult Ospreys with solar-powered GPS-enhanced satellite transmitters in northeast Germany and tracked them for up to 7 years. There was a high variation in home range size depending on sex, nesting site and breeding success. The home ranges of successfully breeding males (median 33.4 km2, 95% kernel density estimations) were significantly larger than those of females (median 4.6 km2) and varied in extent and shape between individuals. Some females made long excursions and sometimes spent the night at great distances to their nests after the juveniles had fledged but they also returned to the nesting area before they left for migration. The males’ home range areas were consistent during the breeding period. The proportion of water surfaces on the home range areas of males ranged between 9.6 and 29%. The overnight roosts were found in distances up to 7.83 km (median 980 m) for successfully breeding males and up to 105 km (median 568 m) for successfully breeding females. The correlation between overnight roost-nest distance and the corresponding home range area was significant for females but not for males. The overlap in the home ranges of individual males that occupied the same nests in different years varied between 37.3 and 54.7% of the mutual home ranges. Males partly included the same waterbodies in their home ranges, but they also visited different lakes. In the incubation and nestling phases, females are closely bound to the nest, whereas their mates can range over vast areas.

Spatial use of non-breeding sites by adult GPS-tracked Ospreys Pandion haliaetus from Germany

Recent analyses of telemetry data on Ospreys Pandion haliaetus predominantly address migratory movements, whereas studies focusing on spatial use are rare, especially concerning the African non-breeding areas. We analysed GPS telemetry data of 15 adult Ospreys breeding in northeast Germany, assigned to 37 non-breeding events at non-breeding sites in Africa and south-western Europe. We calculated seasonal home ranges and investigated daily movements as well as overnight roosts. The females arrived in Africa about one month before the males. The home ranges of males correlated with those reported for their respective breeding seasons and were similar in size to those of the females. Half of the non-breeding sites were established on rivers, 36% on the coast and 14% on lakes, with no difference between sexes. Ospreys tracked for more than one year always returned to the same non-breeding sites. Daily home-range sizes varied during the non-breeding period, with the largest home ranges found in January, in parallel with the dry season. The average number of nights per overnight roost was lowest for river habitats and was related to the overall home-range size of the individuals. We highlight the importance of non-breeding sites for the survival of populations and suggest further studies to detect and mitigate threats to migratory bird species.

First breeding records of the osprey (Pandion haliaetus) on Jeju Island, South Korea

The first breeding of osprey ( Pandion haliaetus ) on Jeju Island, South Korea, were observed in 2015, and ospreys bred on three sites. We found a total of three nests and observed that A site nest bred on successfully from 2017 to 2020. The number of eggs per clutch ranged from two to four, with a mean ± SD of 3.16 ± 0.75. The nesting period varied from 71 days to 79 days, with an average duration of 76.2 ± 3.18 days. The incubation period ranged from 34 days to 38 days, averaging 35.8 ± 1.72 days. Fledging dates ranged from July 4th to 13th. The nest tree species was Pinus thunbergii , and the average tree height was 16.2 ± 3.12 m. On average, the nest height from the ground was 14.8 ± 2.57 m. The average diameter at breast height of the nesting trees was 36.1 ± 2.02 cm. Of the total 19 eggs produced, the hatching rate was 91.4% ± 10.2%, fledgling rate was 68.6% ± 26.9%, and breeding success was 65.6% ± 25.1%. Little ecological information is available on osprey living in South Korea; therefore, this study makes a meaningful contribution to provide baseline ecological data from South Korea for this species.

Against the flow: unexpected migration movements over the open sea by inexperienced ospreys

As part of a long-term monitoring program, more than 80 Mediterranean ospreys Pandion haliaetus (both adults and juveniles) were tagged with GPS-GSM transmitters and tracked to study their spatiotemporal behaviour. Here we document the peculiar and unexpected migration movements performed by three inexperienced (juvenile/immature) individuals, who crossed the open sea “against the flow”, in the opposite direction to that foreseen for the given season. Using a combination of GPS tracking data and weather information, we found that such movements were linked to particular meteorological conditions occurring over the Mediterranean Sea during migration. Mean values of wind gust of approximately 20 km/h and moderate tailwinds seem to have mediated the onset of the movements, facilitating the flight of ospreys over water. Our findings suggest that both weather conditions (sidewinds) and the inexperience of the birds explain these long migration movements performed towards unexpected directions over the open sea. We conclude that migratory capabilities and the ability to cope with external conditions may lead inexperienced birds to perform extensive and tortuous dispersal/explotrative movements during both first autumn and spring migration.

Wind effects on the long‐distance migration of GPS‐tracked adult ospreys Pandion haliaetus from Germany

Birds that repeatedly visit distinct places along their migratory routes in consecutive years must be able to navigate to these places and respond appropriately to unfavourable wind conditions. This study analysed the migratory routes, repeatedly‐visited areas and responses to sidewinds of 15 GPS‐tracked adult ospreys Pandion haliaetus from northeast Germany migrating to their wintering sites in Africa and back. We determined stopovers and intermediate goal areas and performed repeatability estimations on timing and migratory paths in four regions. The orientation behaviour of the ospreys was analysed with regard to perpendicular wind components at each GPS point during autumn and spring migrations. Generalised linear mixed models were used to test the dependence of orientation behaviour on region and the distance to the next goal. The findings showed that ospreys demonstrate high fidelity to migratory paths in autumn and spring, as well as to the timing of migration in autumn; and sidewinds are predominantly compensated, especially when sidewinds are strong. Furthermore, during autumn migration, the proportion of compensation increases in most regions with decreasing distances to the next goal; however, during spring migration, drift behaviour was detected more often at smaller distances to the next goal than at higher distances in the regions Mediterranean and central Europe. In general, ospreys compensate for unfavourable sidewinds and utilise supporting tailwinds on their journeys to the wintering sites in Africa and back to central Europe.

Встречи крупных хищных птиц в Новосибирской области, Россия

Встречи крупных хищных птиц в Новосибирской области, Россия