Milvus Migrans Research Articles

Inter-individual differences in foveal shape in a scavenging raptor, the black kite Milvus migrans

Birds, and especially raptors, are believed to forage mainly using visual cues. Indeed, raptors (scavengers and predators) have the highest visual acuity known to date. However, scavengers and predators differ in their visual systems such as in their foveal configuration. While the function of the foveal shape remains unknown, individual variation has never been quantified in birds. In this study, we examined whether foveal shape differs among individuals in relation to eye size, sex, age, eye (left or right) and genetic proximity in a scavenging raptor, the black kite Milvus migrans. We assessed foveal shape in 47 individuals using spectral domain optical coherence tomography (OCT) and geometric morphometric analysis. We found that foveal depth was significantly related to eye size. While foveal width also increased with eye size, it was strongly related to age; younger individuals had a wider fovea with a more pronounced rim. We found no relationship between foveal shape and genetic proximity, suggesting that foveal shape is not a hereditary trait. Our study revealed that the shape of the fovea is directly linked to eye size and that the physical structure of the fovea may develop during the entire life of black kites.

The gateway to Africa: What determines sea crossing performance of a migratory soaring bird at the Strait of Gibraltar?

Large bodies of water represent major obstacles for the migration of soaring birds because thermal updrafts are absent or weak over water. Soaring birds are known to time their water crossings with favourable weather conditions and there are records of birds falling into the water and drowning in large numbers. However, it is still unclear how environmental factors, individual traits and trajectory choices affect their water crossing performance, this being important to understand the fitness consequences of water barriers for this group of birds. We addressed this problem using the black kite Milvus migrans as model species at a major migration bottleneck, the Strait of Gibraltar. We recorded high-resolution GPS and triaxial accelerometer data for 73 birds while crossing the Strait of Gibraltar, allowing the determination of sea crossing duration, length, altitude, speed and tortuosity, the flapping behaviour of birds and their failed crossing attempts. These parameters were modelled against wind speed and direction, time of the day, solar irradiance (proxy of thermal uplift), starting altitude and distance to Morocco, and age and sex of birds. We found that sea crossing performance of black kites is driven by their age, the wind conditions, the starting altitude and distance to Morocco. Young birds made longer sea crossings and reached lower altitude above the sea than adults. Crosswinds promoted longer sea crossings, with birds reaching lower altitudes and with higher flapping effort. Birds starting at lower altitudes were more likely to quit or made higher flapping effort to complete the crossing. The location where birds started the sea crossings impacted crossing distance and duration. We present evidence that explains why migrating soaring birds accumulate at sea passages during adverse weather conditions. Strong crosswinds during sea crossings force birds to extended flap-powered flight at low altitude, which may increase their chances of falling in the water. We also showed that juvenile birds assume more risks than adults. Finally, the way in which birds start the sea crossing is crucial for their success, particularly the starting altitude, which dictates how far birds can reach with reduced flapping effort.

Analysis of temporal patterns in animal movement networks

Abstract Understanding how animal movements change across space and time is a fundamental question in ecology. While classical analyses of trajectories give insightful descriptors of spatial patterns, a satisfying method for assessing the temporal succession of such patterns is lacking. Network analyses are increasingly used to capture properties of complex animal trajectories in simple graphical metrics. Here, building on this approach, we introduce a method that incorporates time into movement network analyses based on temporal sequences of network motifs. We illustrate our method using four example trajectories (bumblebee, black kite, roe deer, wolf) collected with different technologies (harmonic radar, platform terminal transmitter, global positioning system). First, we transformed each trajectory into a spatial network by defining the animal's coordinates as nodes and movements in between as edges. Second, we extracted temporal sequences of network motifs from each movement network and compared the resulting behavioural profiles to topological features of the original trajectory. Finally, we compared each sequence of motifs with simulated Brownian and Lévy random motions to statistically determine differences between trajectories and classical movement models. Our analysis of the temporal sequences of network motifs in individual movement networks revealed successions of spatial patterns corresponding to changes in behavioural modes that can be attributed to specific spatio‐temporal events of each animal trajectory. Future applications of our method to multi‐layered movement and social network analysis yield considerable promises for extending the study of complex movement patterns at the population level.

Population Dynamics and Distribution Patterns of Diurnal Raptors in Northeastern Algeria: Seasonal Variation and Some Nesting Characteristics

Abstract Providing a live data monitoring of raptor abundances and spatial localization of their most important nesting areas is very helpful in building a strong future study and applying a sound strategy for effective safeguarding of these emblematic species. Using geographic information system (GIS) and global positioning system (GPS) techniques, we investigated spatial patterns of raptors distribution in the northeastern areas of Algeria during two consecutive breeding seasons (2014 and 2015). The total area sampled (31,000 km2) host diverse raptor species (14 species), among them, the threatened species Egyptian vulture (Neophron percnopterus; 108 individuals and 19 active nests) and red-footed falcon (Falco vespertinus; 12individuals). The value of the region is attested by the presence of an abundant population of nesting black kite (Milvus migrans; 337 individuals). The large-scale spatial analyses of the studied region illustrate certain similarities in nesting habitat selection among raptors. Almost all species (90% of 209 nests detected) preferred to nest within multispecies assemblages (20 raptor assemblages found) and occupied altitudinal rocky cliffs across the inland region (semi-arid zones) rather than coastal region (sub-humid zones). Among all raptor species, exclusively, the common kestrel (Falco tinnunculus) is relatively synanthropic, because it was found to breed within cities (tolerate human activities). The raptor community in the coastal versus inland regions differed by 14%. The latter area seems to be more preferred in nest building, probably consequence of their semi-arid bioclimatic and landscapes characteristics, where high elevations and grasslands forming mosaics with Oak, Alpine, and Cedar forests are patchily distributed. The study is a first mapping database of important nesting sites dispatched across the northeastern areas of Algeria, and it can be effectively used in future complementary researches that aim to elucidate environmental factors that affect raptors life cycle.

Diurnal raptors of West Africa woodland-farmland mosaics: Data from walking-transects in eastern Guinea-Bissau

Guinea-Bissau is a small country in West Africa, which in spite of its rich biodiversity and the high proportion of protected areas remains under-surveyed in relation to most animal groups, including raptors. The first scientific articles about raptors were only very recently issued. Here, we report raptor occurrence data from eastern Guinea-Bissau. Raptors were surveyed in the dry season along transects walked around 21 villages in a rural woodland-farmland mosaic landscape. The raptor assemblage is composed of 25 species of which the hooded vulture, the lizard buzzard and the African harrier-hawk were the species more often encountered, followed by the African white-backed vulture. The palm-nut vulture, black kite, brown snake-eagle, grasshopper buzzard, African hawk-eagle, grey kestrel and lanner falcon were secondary, although not uncommon species. The remaining species were seldom recorded. The study complements previous knowledge on this bird group, specifically in the central-eastern part of the country, and reaffirms the international relevance of Guinea-Bissau for the conservation of the hooded and African white-backed vultures.

Гибель птиц на ЛЭП в Хакасии (Россия) в 2020 году

The article represents results of inspection of power lines for bird casualty in the Minusinsk Hollow, Khakassia, Russia in 2020. Previous inspection was done in the region in 2011 thus our work reveals changes in bird casualty over the last 10 years. The bird mortality on power lines of medium voltage remains remarkably high – mean value for the breeding season is 8.21 ind. per 1 km of line. The most dangerous lines are the ones on concrete poles with pin insulators located in open habitats away from human settlements. Lines of this type attract vast abundance of birds with high species diversity including high percentage of birds of prey and owls. Short lines protruding in the open terrain and parts of lines running through hilly landscapes are of extreme danger. Electrocuted birds are mostly represented by Corvids (66%). Raptors made 28% from the total, represented mostly by the common species such as Kestrel (Falco tinnunculus) – 17.7% and Black Kite (Milvus migrans) – 6.5%, that is character for the forest-steppe zone of Russia. Total damage done to nature by 111.5 km of surveyed power lines was accounted for 18 100 000 Rub (about €204 000 or $243 770). The overall damage which could be caused by the power network of Khakassia was estimated as 64 171 440 Rub per year (that is equal to €723 310 or $864 246). This involves death of more than 3 252 birds per year in one small republic. The damage caused by one electricity pole calculated by the actual results of inspection was 10 485.6 Rub, that is at least 10 time higher that the cost of a set of bird-protection devices for a pole. At the end of the article, we gave our recommendations for minimizing the damage.

A New Approach to Assessment of Bird Carcass Removal (Scavenging) Time on Wind Farm in Egypt

Abstract Wind farms developing rapidly in order to meet the high demand for energy from green sources. However, the impact of wind farm operation on the environment still needs to be established. The risk to wild birds is drawing the attention of stakeholders and bird conservation organizations. Carcass search is the main method used to assess the impact of wind farm operation on wild birds of various systematic groups and sizes. Assessment of the overall risk that wind farms pose to birds depends primarily on accurate calculation of carcass removal times and the detection ability of the searcher. Most studies have assessed the carcass removal time using pet bird species, pigeons, or various local birds. In Egypt, all studies conducted in operating wind farms up to 2016 had used chickens to assess the carcass removal time and in this way to the estimate the total number of bird fatalities within wind farms. The use of birds killed by a wind farm in carcass removal trials provides the actual time of carcass disappearance, in contrast with the use of other bird species. The removal times of carcasses of parakeets, quails, partridges and chickens were shorter than those of carcasses of White Stork, White Pelican, Honey Buzzard, Black Kites and eagles used in the current study and in another study in Australia. The results of the present study indicate that carcasses of birds killed within the studied wind farm remain for two to three months, while the carcasses of other in species other localities remain no more than 1 to 15 days, which unquestionably influences the calculation of total fatalities and leads to overestimation of the overall risk that wind farms for birds.

When and where mortality occurs throughout the annual cycle changes with age in a migratory bird: individual vs population implications

The annual cycle of most animals is structured into discrete stages, such as breeding, migration and dispersal. While there is growing appreciation of the importance of different stages of an organism’s annual cycle for its fitness and population dynamics, almost nothing is known about if and how such seasonal effects can change through a species lifespan. Here, we take advantage of the opportunity offered by a long-term satellite/GPS-tracking study and a reliable method of remote death-detection to show that certain stages of both the annual and life cycle of a migratory long-lived raptor, the Black kite Milvus migrans, may represent sensitive bottlenecks for survival. In particular, migratory journeys caused bursts of concentrated-mortality throughout life, but the relative importance of stage-specific survival changed with age. On the other hand, the balance between short-stages of high mortality and long-stages of low mortality made population-growth similarly dependent on all portions of the annual cycle. Our results illustrate how the population dynamics of migratory organisms can be inextricably linked to ecological pressures balanced over multiple stages of the annual cycle and thus multiple areas of the globe, suggesting the frequent need for challenging conservation strategies targeting all portions of a species year-round range.

Movement Patterns of the Black Kite (Milvus migrans) During Spring Migration over Rift Valley/Red Sea Flyway, Gulf of Suez, Egypt

The aim of this study to follow up on the spring migration of the black kite (Milvus migrans) before crossing from the west bank of the Gulf of Suez opposite the South Sinai region, Egypt. Daily observations were carried out over the period 22 February - 12 May 2019, where 7,004 individuals (968 records) of BK were recorded. Most BK flight direction observed (46% NW and 17% SE) had a reversed direction of spring migration, which need to soar to gain height, and then return over and around the study area at higher altitudes to be able to cross the water barrier easily. The observed behavior of black kites is regularly shown in the study area despite long-term irregular weather conditions during the Spring, most of BK 66% were recorded during the prevailing northwardly wind. whereas, more than 43% of BK were recorded in low wind speeds, representing about 43% of all records, while less than 3% of birds recorded in high wind speeds, representing less than 6% of records.

Natal dispersal of black kites from Slovakia

Three black kite (Milvus migrans migrans) pulli (siblings, BK1, BK2, and BK3) from the same nest in eastern Slovakia were tagged with telemetry (GPS/GSM) loggers on 1 July 2016. BK1 (female), BK2 (male) and BK3 (female) occupied post-fledging areas until 12 August 2016 when they began to migrate southeast. BK1 wintered in Libya, returned to Turkey in the summer, then wintered in Israel. After spending the winter there, it returned to Europe, looped the Baltic Sea and stayed in western Russia throughout the summer. During the autumn, it passed Ukraine and travelled along the Black Sea and wintered in Syria then it moved again to Europe. It used 18 temporary settlement areas (TSA) during its journey until 12 June 2019 when it was roadkilled in Norway. BK2 migrated to the northern tip of the Red Sea and crossed the sea where positions of the bird spatiotemporally coincided with a position of transcontinental cargo ship. It is expected that the bird died whilst on the cargo ship and its body was passively carried on-board and discarded on the west coast of the Red Sea. BK3 reached the northern outpost of the Red Sea in Saudi Arabia. It then continued southeast along the east coast of the Red Sea to Yemen and crossed the Strait of Bab-el-Mandeb to Africa. It wintered mainly in Sudan, Southern Sudan and Uganda, then returned along the west coast of the Red Sea and the east coast of the Mediterranean Sea arriving to the Turkey/Syria border area. Only two TSA were revealed on its route. The migration behaviour among these floaters during natal dispersal was substantially different and covered surprisingly large parts of Europe and North and East Africa.

Accounting for differential migration strategies between age groups to monitor raptor population dynamics in the eastern Black Sea flyway

Migration counts can offer a cost‐effective method for monitoring the state of migrant raptor populations. However, differential migration strategies between inexperienced juveniles and experienced non‐juveniles are rarely accounted for when inferring population trends from raptor migration counts. Since 2011, the Batumi Raptor Count (BRC) monitors the autumn migration of more than 1 million raptors along the eastern Black Sea coast in the Republic of Georgia. We also systematically sampled age information to assess differential migration timing between age groups and estimate age‐specific linear trends in abundance between 2011 and 2018 for eight focal species. In so doing we aimed (1) to reassess the global relevance of BRC counts for each species and the potential for monitoring abundance of juveniles and non‐juveniles, and (2) to identify demographic changes underlying recent trends in overall abundance. We found that the mean annual passage of non‐juveniles at Batumi represents at least 1% of the estimated global breeding population of five study species. As expected, counts of juveniles were more variable than counts of non‐juveniles. Yet despite our short monitoring period our models had sufficient statistical power to detect changes in abundance of 10%/year or less for at least one age group in all species except Pallid Harrier Circus macrourus. Our results indicate stable abundance and demography for half of the study species. We also found strong and significant increases in the abundance of Black Kites Milvis migrans and Short‐toed Eagles Circaetus gallicus that were primarily due to increasing numbers of non‐juveniles. By contrast, juvenile Montagu's Harriers Circus pygargus and Booted Eagles Hieraaetus pennatus significantly decreased in abundance. The first decade of BRC surveys offers an important benchmark for monitoring raptor populations using the eastern African–Palearctic flyway in the 21st century. We discuss possible causes of the observed trends and hope our work will stimulate demographic monitoring at migration count sites.

Plasmid-Mediated mcr-1 Colistin Resistance in Escherichia coli from a Black Kite in Russia.

The gene mcr-1 conferring resistance to last-line antibiotic colistin has been reported globally. Here, we describe the first detection of plasmid-mediated colistin resistance in Russian wildlife, an isolate of Escherichia coli sequence type 2280 from a black kite (Milvus migrans) scavenging raptor. Whole-genome sequencing and plasmid transferability experiments revealed that mcr-1.1 was located on conjugative IncI2 plasmid pDR164 (59891 bp). Migratory black kites may contribute to the global spread of mobile colistin resistance.

Stick supply to nests by cliff-nesting raptors as an evolutionary load of past tree-nesting

The supply of sticks to cliff nests by many European raptors has been explained only as a functional means of decreasing ectoparasite loads in nests and for signalling nest occupancy. We provide here a historical explanation of this behaviour as we consider it represents an evolutionary load of formerly tree-nesting species. Basically, from this perspective, facultative tree/cliff-nesting species reproduce the nests they used to build originally on top of trees, but on cliffs. Facultative species (likely evolved in forested areas) that supply their cliff nests with sticks include Pandion haliaetus, Haliaetus albicilla, Milvus migrans, Circaetus gallicus, Buteo buteo, Aquila fasciata, A. pennata, A. chrysaetos, A. heliaca, Gypaetus barbatus Gyps fulvus and Neophron percnopterus. On the contrary, the only Falco species that solely nests in cliffs (F. eleonorae)) and does not supply its nests with sticks and should be considered a true cliff-nester, likely evolved in non-forested areas. All other Falco species that do not supply their cliff nests with sticks but can make use of tree nests made by other non-raptorial species, should also be considered as true cliff-nesters, likely evolved in more forested areas or times. Milvus milvus, Elanus caeruleus, Accipiter nisus, A. gentilis, Pernis apivorus, Aquila adalberti, A. clanga, A. pomarina and Aegypius monachus are true tree nesters, likely evolved in forested areas, which did not evolve the plasticity to nest directly on cliffs.

Nest characteristics and breeding success of Black Kites (Milvus migrans migrans) in the High Plateau (Algeria)

The breeding ecology of the Black Kite Milvus migrans migrans in Algeria was first studied in 2014 and 2015 on Tarf Mountain in the semi-arid High Plateaus region. The nearest-neighbour nest distance was found to range from 130 to 550 m for colonial pairs and from 1,730 to 2,390 m for the solitary ones. All 12 monitored nests were placed on cliffs at different heights ranging from 149 to 155 m. The mean egg laying period was 15 days, and the mean clutch size was 2.83 ± 0.31 and 3 ± 00 eggs per nest in 2014 and 2015, respectively. The mean hatching success was 83% and that of fledging 75%. Only 2 nests were predated. Our results disagree with those of the previous studies that were carried out mainly in the Mediterranean basin and Asia, differing in such nest characteristics as the nearest - neighbour nest distance, cliff and nesting heights, egg laying period and hatching success. Otherwise, no consistent differences in clutch size and fledging success were revealed. Finally, we determined that Black Kites tend to build their nest on the eastern side of cliffs. However, our analysis showed no effect of nest placement on breeding parameters and success.

Frequent detection of anticoagulant rodenticides in raptors sampled in Taiwan reflects government rodent control policy

Anticoagulant rodenticides (ARs) are known to cause extensive secondary exposure in top predators in Europe and North America, but there remains a paucity of data in Asia. In this study, we collected 221 liver samples from 21 raptor species in Taiwan between 2010 and 2018. Most birds were recovered from rescue organizations, but some free-ranging individuals were obtained from bird-strike prevention measures at airports. ARs were detected in 10 species and more than half of the total samples. Common rodent-eating Black-winged Kites (Elanus caeruleus) had the highest prevalence (89.2%) and highest average sum concentration (0.211 ± 0.219 mg/kg), which was similar between free-ranging birds at airports and injured birds from rescue organizations. Scavenging Black Kites (Milvus migrans) and snake-eating Crested Serpent-eagles (Spilornis cheela) had the second highest prevalence or sum concentration, respectively. Seven different AR compounds were detected, of which brodifacoum was the most common and had the highest average concentration, followed by flocoumafen and bromadiolone. The frequency of occurrence in the three most numerous species (Black-winged Kite, Crested Goshawk [Accipiter trivirgatus], and Collared Scops-owl [Otus lettia]) was significantly higher in autumn than summer, which is consistent with the timing of the Taiwanese government's supply of free ARs to farmers. Regional differences in the detection of individual compounds also tended to reflect differences in human population density and use patterns (in agriculture or urban-dominated environments). Clinical poisoning was confirmed in Black Kites with sum concentrations as low as 0.026 mg/kg; however, further study of interspecific differences in AR sensitivity and potential population effects are needed. In addition, continued monitoring remains important given the Taiwanese government has modified their farmland rodent control policy to gradually reduce free AR supplies since 2015.

Czarne sezony. Czarne latawce. O dziecięcych bibliotekach w gettach

The article Black Seasons. Black Kites. About the Children’s Reading in Ghettos is devoted to the Holocaust seen and lived from the perspective of children. The author is interested in book collections of those who survived the war and later became writers (U. Orlev, A. Frankel, and M. Głowiński), and those stories that thematise children’s reading in ghettos (D. Combrzyńska-Nogala, M. Szczygielski). Joanna Roszak shows which books became for the children readers a matrix imposed on reality, which met the needs of a library therapy, helped children to cope with the emotional challenges of ghetto existence, and which enabled integration and identification processes. Moreover, the authoress presents which books triggered the escapist interpretation and finally which found an extension in the stories and essays created after the war. The title of the paper refers to The Black Seasons [Czarne sezony] by Michał Głowiński, and to a line from Czesław Miłosz’s Campo di Fiori.

Effect of piscivorous and omnivorous colonial birds’ activity on structure, abundance and diversity of soil free-living nematodes. Preliminary results from a study of the impact of avifauna on soil biota in Israel’s Mediterranean Coastal Plain

Abstract The soil biota, including soil microorganisms and free-living nematodes, was investigated in the nesting and roosting habitats of the following piscivorous and omnivorous colonial birds: black kite (Milvus migrans), great cormorant (Phalacrocorax carbo), black-crowned night heron (Nycticorax nycticorax) and little egret (Egretta garzetta), in Israel’s Mediterranean region. Abiotic variables, abundance, trophic structure, sex ratio and genus diversity of soil free-living nematodes, and total abundance of bacteria and fungi, were measured during the hottest period of 2016. The impact of the birds’ activity on the soil biota was most notable in the upper soil layer and weaker in the lower soil layer. Soil properties such as alkalinity (pH) and conductivity, along with contents of ammonium, nitrate and phosphorus were found to be among the main drivers influencing prey–predator relationships in the observed soil habitat by altering the predation success of soil free-living nematodes. The observed nematode species were affected by the birds’ nesting and roosting activity, as reflected by an increasing proportion of common nematodes and the disappearance of rare species in the colonial birds’ habitats. The applied ecological indices showed that the different species of colonial birds can have different (stimulatory or inhibitory) impacts on the abundance and diversity of the soil biota, affecting the structure of soil free-living nematodes at the generic, trophic and sexual levels. Moreover, the soil ecosystem in the area of bird activity had a less complex food web, but with higher concentrations of nutrients than the uninhabited control area.

Endangered bird mortality by gunshots: still a current problem

This study analysed the illegal shootings of threatened species through information compiled from rehabilitation centres in Spain. Our objective was to assess whether this cause of mortality has reduced or increased over time and to verify if gunshots could be causing a decline of especially vulnerable species. We also aimed to identify the monthly distribution of gunshots, and whether they corresponded to hunting periods. A total of 67 not hunting species were shot, 58 species classified as “Least Concern”, six species as “Near Threatened”, two species as “Vulnerable” and one specie as “Endangered” according the IUCN red List. Across the whole set of species, as well as among “Least Concern”, there has been a decrease in the number of specimens shot over the years. However, for species “Near Threatened”, “Vulnerable” and “Endangered”, a maintained trend over time was observed. More gunshots on threatened species occurred during hunting periods, but gunshots occurred during all months of the year. One of the periods with more gunshots, in August and September, is caused by the shooting of trans-Saharan migratory species, such as the Montagu’s Harrier, the Hobby, the Booted Eagle and the Black Kite. Another peak in gunshots occurs between October and January, and particularly affects sedentary and wintering species. The most frequently shot species have shown decreasing population trends, although there is fragmentary information to obtain accurate data. Gunshots remain a serious problem for threatened species in relation to its population and it is important to reduce this cause of no natural mortality.

A mixed pair of black and red kites in Ukraine, including DNA analysis of hybrid offspring

Red kite (Milvus milvus) is a European raptor. Kites of the nominal subspecies Milvus migrans migrans (hereafter called black kites) breed in the Western Palearctic and in Central Asia. Due to the extremely short period since their divergence, black and red kites can successfully hybridize. A mixed pair of black kite female and red kite male was observed during breeding seasons 2017 and 2018 in Poltva, Ukraine (i.e., in the easternmost part of red kites’ breeding territory). This pair produced three and three young in 2017 and 2018, respectively. DNA of the three young from 2018 was analyzed regarding their mitochondrial CytB haplotype and nuclear Myc gene alleles. All three young had a common black kite CytB haplotype. Myc alleles combinations suggest that the male parent could be not a pure red kite and could have a black kite among its ancestors. All three young from 2018 were presumed predated on or close to the nest by goshawk (Accipiter gentilis).

A kite Milvus migrans migrans/lineatus in Ukraine

A kite designated Milvus migrans migrans/lineatus was observed and photographed near the village of Zhornyska in Yavorivskyi District, Lviv Region, Ukraine several times between 10 and 17 May 2018. This is the first well documented observation in Ukraine of a kite presumably originated from a large hybrid zone between black kites Milvus migrans migrans and black-eared kites Milvus migrans lineatus. Its occurrence in Ukraine possibly coincides with spreading of both a breeding area of black-eared kites and of a hybridization zone between black kites and black-eared kites from Western Siberia to the west.