Academic literature on the topic 'Diurnal raptors'

AbstractDiurnal raptors may be highly sensitive to anthropogenic disturbances. We evaluated the diversity and abundance of diurnal raptors at an Atlantic Forest–cerrado transition zone in relation to two habitat types (forest fragments and open habitats) and to urbanization, comparing natural open and forested habitats with corresponding habitats within a large urban area. We sampled 80 points, 20 in each of four habitats (semi-natural and urban forests, semi-natural and urban open areas), during 12 months. Diurnal raptors recorded (21 species) included only three out of 10 species with some level of threat in the region. Forested habitats had more species (17) than open habitats (12). Urban areas had only 14 (67%) species, whereas semi-natural areas had all 21 species. Diurnal raptors were as abundant in urban areas as in semi-natural areas in spite of a loss in species richness in urban areas. A re-analysis without Caracara plancus showed that urban areas had a lower mean number of individuals per point than semi-natural areas. Overall species richness usually fluctuated from 14 to 16 species, being slightly higher between January and May than in other months. Overall abundance of diurnal raptors was much higher during summer than during winter. Local extinction may have already occurred for some species of diurnal raptors in the region and will probably shortly include several others. At least C. plancus, a habitat generalist, requires further studies and eventually management actions, since it is able to reach high population numbers in urbanized areas. Furthermore, highly sensitive species that were not recorded require further investigation regarding their conservation status.ResumoRaptores diurnos podem ser altamente sensíveis a perturbações antropogênicas. Avaliamos a diversidade e a abundância de raptores diurnos em uma região de transição entre Floresta Atlântica e Cerrado em relação a dois tipos de hábitats (fragmentos florestais e hábitats abertos) e è urbanização, comparando hábitats abertos e florestais aos hábitats correspondentes dentro de uma área urbana. Amostramos 80 pontos, 20 em cada um dos quatro hábitats (florestas semi-naturais e urbanas, áreas abertas semi-naturais e urbanas) durante 12 meses. Entre os raptores diurnos registrados (21 espécies) estão apenas três das 10 espécies com algum nível de ameaça na região. Mais espécies foram registradas nos hábitats florestados (17) do que nos hábitats abertos (12). Apenas 14 (67 %) espécies foram registradas nas áreas urbanas, enquanto as 21 espécies foram registradas nas áreas semi-naturais. Os raptores diurnos foram igualmente abundantes nas áreas urbanas e nas áreas semi-naturais independentemente da perda de espécies nas áreas urbanas. Uma nova análise sem Caracara plancus mostrou que as áreas urbanas tiveram um menor número médio de indivíduos por ponto do que as áreas semi-naturais. A riqueza total de espécies foi de 14 e 16 espécies, em geral, sendo um pouco mais alta entre janeiro e maio do que nos outros meses. A abundância total de raptores diurnos foi muito maior durante o verão do que no inverno. Algumas espécies de raptores diurnos já podem estar localmente extintas na região, o que ainda pode ocorrer para várias outras espécies em breve. Pelo menos C. plancus, uma espécie generalista de hábitat, necessita de mais estudos e eventualmente ações de manejo uma vez que pode atingir grandes tamanhos populacionais em áreas urbanizadas. Além disso, espécies altamente sensíveis que não foram registradas necessitam de mais investigações sobre seus status de conservação.

Infection patterns of parasites, including their prevalence, diversity and host specificity, can be impacted by many biological and environmental factors, but no study has focused on the circadian rhythms of vertebrate hosts, which may affect susceptibilities and encounter rates between hosts and vectors and further shape host-parasite associations. In this study, we focused on avian haemosporidians, a classical model in studies of host-parasite associations, and investigated the infection patterns in rescued raptors brought to the Beijing Raptor Rescue Center during 2007–2020. We first assessed the association between prevalence and host biotic traits; haemosporidian prevalence was higher in the nocturnal raptors than in the diurnal raptors, and the prevalence of Haemoproteus and Leucocytozoon in the nocturnal raptors was significantly higher than that in the diurnal raptors. Furthermore, we analysed the phylogenetic relationship and host-parasite network-level differences of haemosporidian parasites in diurnal and nocturnal raptors, and demonstrated that the lineages infecting the diurnal and nocturnal raptors were not clearly separated, but the nocturnal lifestyle led to a more specialized host-parasite network structure. These variations in host-parasite associations may be driven by different susceptibilities of the hosts and the diversity or abundance of vectors during the day and night. Our study provides new insight into host-parasite associations shaped by circadian rhythm and calls for more studies on the underlying mechanisms of parasite infection.

Abstract The status and distribution of diurnal raptor bird species were analysed in the south-eastern part of Turkey based on studies and records between 1994 and 2014. Our information about raptor species is very limited in the south-eastern Anatolia Region. The study showed that of 42 diurnal raptor species listed in Turkey, 37 of these species were found in the studied region; 9 of them are certainly, 4 probably and 1 possibly breeding in the area - according to the breeding criteria of the EBCC - while 17 of them were transitory migrating or wintering birds for the region, and the breeding/migratory status of 6 is unknown. Habitats lost and fragmentation related to agricultural intensification together with pesticide applications are the main hazards threatening wildlife including raptors in the region. So as to increase knowledge on raptors in south-eastern Anatolia and evaluate their populations, a coordinated education and research program is essential.

Abstract In Finland, population monitoring for both diurnal and nocturnal raptors has been almost entirely based on fieldwork carried out by voluntary raptor ringers. Responsible organisations include the Finnish Museum of Natural History, with economic support for administration from the Ministry of Environment, “Metsahallitus” (former National Board of Forestry) and WWF Finland. Since the early 1970s, numbers and productivity of four endangered species, the White-tailed Eagle Haliaeetus albicilla, Golden Eagle Aquila chrysaetos, Osprey Pandion haliaetus and Peregrine Falcon Falco peregrinus have been monitored by country-wide Comprehensive Surveys, with the aim of checking all known nest sites of these species every year. The Gyrfalcon F. rusticolus was included in this group in the late 1990s. Data for monitoring the populations of the other raptor species have been gathered by the Raptor Grid and Raptor Questionnaire projects. The Raptor Grid project produces annual population indices, which are calculated from the data collected from 10 × 10 km study plots (n = ca. 130/year) and quite well reflect the annual population fluctuations and longterm trends of seven common species of diurnal and six species of nocturnal raptors breeding in the southern part of Finland. For the rest of the species, which are either rare all over Finland or breed mostly in the north, outside the good coverage of the distribution of Raptor Grid study plots, conclusions on population changes are based on the total numbers of occupied territories and active nests reported annually by the Raptor Questionnaires

Abstract Despite the key role of raptors (including birds of prey Falconiformes and owls Strigiformes) in ecosystems and their sensitivity to environmental change, a well coordinated, Europe-wide monitoring of raptors is lacking. EURAPMON, a Research Networking Programme of the European Science Foundation, was launched with the aim of establishing a sustainable Europewide network for monitoring of raptors. An overview of current monitoring schemes for raptor populations in 28 European countries, as reported by EURAPMON National Coordinators at the workshop in Murcia (Spain) in 2012, showed existing monitoring schemes to be limited to a restricted number of species (mostly diurnal and rare raptor species). The most widely monitored species are the Golden Eagle Aquila chrysaetos amongst diurnal raptors and the Eagle Owl Bubo bubo amongst owls. Broad coverage of a species range across Europe is reached only for restricted-range species. The key driver for monitoring, which is mostly coordinated by NGOs, is conservation, and the main end users are governmental institutions. International collaboration in the field of monitoring of raptors is mainly regional and not yet pan-European in scale. The involvement of volunteers in raptor monitoring was perceived as the main strength of many schemes, but insufficient manpower and a focus on rare species were recognised as the main weaknesses across Europe as a whole. Among priorities identified for the future development of monitoring schemes are: improvements to national coordination; support to increase the number of volunteers; and assurances of stable funding. Further analysis of EURAPMON questionnaires will identify knowledge gaps, which will steer good practice guidance on survey methodologies; the need for the latter was identified as the main benefit that National Coordinators expect to gain from international networking

SummaryHabitat loss and fragmentation, especially due to agriculture expansion, pose the main threats to biodiversity conservation. While some species are able to survive and proliferate in human-modified habitats (winner species), others are highly dependent on well-preserved habitats, being more vulnerable to extinction (losers). Many raptors can be considered loser species due to their high trophic position, large home ranges, and low reproductive rates. Consequently, this group is frequently used to reflect the environmental quality of habitats and the biodiversity status of communities. Here we describe the diurnal raptor assemblages found in shaded-cocoa agroforests (cabrucas) of Southern Bahia, Brazil, and the determinants of raptor occupancy in this system. We systematically surveyed diurnal raptors in 16cabrucasites using complementary sampling methods – active search, playback, and point-count – and modeled species occupancy using covariates related to vegetation structure, landscape, management intensity, and biological traits (body mass, trophic level, and diet specialisation). We found a high number of species (at least 18) as able to usecabrucasand a negative relationship between species occupancy and the degree of diet specialisation. Thus, our results suggest thatcabrucashave a high potential to mitigate the effects of forest loss and fragmentation on diurnal raptors, but this system alone may not support complete assemblages of this group. It highlights the need for the maintenance of forest remnants in the landscapes to increase species diversity at a regional scale and to assure the conservation of this group in Southern Bahian Atlantic Forest.

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.

Abstract Since 1990, nature conservation NGOs are the main players in the running of nation-wide research and monitoring schemes for raptors in Bulgaria. Among them, the Bulgarian Society for the Protection of Birds (BSPB) and Green Balkans are most active, covering the most threatened diurnal raptors in the country. The key species covered by comprehensive monitoring schemes are the Imperial Eagle Aquila heliaca, White-tailed Eagle Haliaeetus albicilla, Egyptian Vulture Neophron percnopterus, Griffon Vulture Gyps fulvus, Black Vulture Aegypius monachus, Saker Falcon Falco cherrug and Red-footed Falcon F. vespertinus. Information on their distribution, numbers, breeding success, productivity, diet, movements etc. is gathered on annual basis. The Buzzard Buteo buteo and Kestrel F. tinnunculus are also regularly monitored at the national level by the Common Bird Monitoring scheme. Distribution of all raptor species has been studied for the purpose of the Atlas of Breeding Birds in Bulgaria. The contemporary satellite telemetry methods revealed important aspects of movements and threats to eagles and vultures from Bulgaria within the country and abroad. Main threats for the raptors in Bulgaria are related to habitat loss, unnatural mortality and disturbance. The main gaps in raptor monitoring in Bulgaria are related to the lack of coverage of most of the diurnal species and owls. There is a strong national and international cooperation in conjunction with the work concerning Imperial Eagle, Egyptian and Griffon Vultures. However, further enhancement of cooperation on other raptor species and issues such as lobbying for implementation of raptor-friendly agricultural practices and enhancement of various economic sectors are needed

Diets and food-niche metrics of nesting raptors were studied in the eastern deciduous forest biome of northern New Jersey, southeastern New York, and northwestern Connecticut. Raptor diets were determined from 2506 prey individuals recovered from prey remains and pellets collected from nest sites of a community consisting of five hawk and four owl species. Food-niche overlaps were higher on average in the hawk guild (0.422) than in the owl guild (0.342), correlating with increased species packing and decreased body size differences in the hawk guild. Differences in activity times (diurnal versus nocturnal) did not result in reduced food-niche overlap between diurnal and nocturnal raptors. The lack of interference-type competition probably allowed greater exploitative-type competition but was offset by nearly exclusive use of certain prey types by several raptor species. Thus, temporal niche differences ultimately did aid in the resource partitioning of food between hawks and owls. Overall, the forest raptor community displayed significant food-niche overdispersion, with 35 of 36 food-niche overlap values below the 0.6 "competition" threshold. This result would be expected in a community structured by competition.