| modelling hen harrier dynamics to inform human-wildlife conflict resolution: a spatially-realistic, individual-based approach. | individual-based models have gained popularity in ecology, and enable simultaneous incorporation of spatial explicitness and population dynamic processes to understand spatio-temporal patterns of populations. we introduce an individual-based model for understanding and predicting spatial hen harrier (circus cyaneus) population dynamics in great britain. the model uses a landscape with habitat, prey and game management indices. the hen harrier population was initialised according to empirical cen ... | 2014 | 25405860 |
| genetic characterization of oropharyngeal trichomonad isolates from wild birds indicates that genotype is associated with host species, diet and presence of pathognomonic lesions. | oropharyngeal trichomonad isolates of wild birds from spain were studied. a total of 1688 samples (1214 of predator birds and 474 of prey species) from wildlife recovery centres and scientific bird-ringing campaigns were analysed from 2011 to 2013. the overall infection prevalence was 20.3% (11.4% in predator birds and 43.3% in prey species). pathognomonic lesions were present in 26% of the infected birds (57.3% in predator birds and 4.9% in prey species). the most commonly parasitized species w ... | 2014 | 25262786 |
| permanent genetic resources added to molecular ecology resources database 1 june 2011-31 july 2011. | this article documents the addition of 112 microsatellite marker loci and 24 pairs of single nucleotide polymorphism (snp) sequencing primers to the molecular ecology resources database. loci were developed for the following species: agelaius phoeniceus, austrolittorina cincta, circus cyaneus, circus macrourus, circus pygargus, cryptocoryne × purpurea ridl. nothovar. purpurea, mya arenaria, patagioenas squamosa, prochilodus mariae, scylla serrata and scytalopus speluncae. these loci were cross-t ... | 2011 | 21951598 |
| lead in the tissues of terrestrial raptors in southern ontario, canada, 1995-2001. | terrestrial raptors which feed on upland hunted game species may increase their risk to lead exposure and lead poisoning by ingesting lead shot found in the tissues of prey. lead exposure in 225 individuals of nineteen species of terrestrial raptors, collected as carcasses in southern ontario from 1995-2001, was examined through the analysis of bone, liver and kidney tissues. in this study, one red-tailed hawk contained liver lead concentrations and exhibited signs consistent with lead poisoning ... | 2008 | 18063010 |
| sensitivity to assumptions in models of generalist predation on a cyclic prey. | ecological theory predicts that generalist predators should damp or suppress long-term periodic fluctuations (cycles) in their prey populations and depress their average densities. however, the magnitude of these impacts is likely to vary depending on the availability of alternative prey species and the nature of ecological mechanisms driving the prey cycles. these multispecies effects can be modeled explicitly if parameterized functions relating prey consumption to prey abundance, and realistic ... | 2007 | 18027760 |
| habitat loss and raptor predation: disentangling long- and short-term causes of red grouse declines. | the number of red grouse (lagopus lagopus scoticus) shot in the uk has declined by 50% during the 20th century this decline has coincided with reductions in the area of suitable habitat and recoveries in the populations of some avian predators. here we use long-term records of shooting bags and a large-scale manipulation of raptor density to disentangle the effects of habitat loss and raptor predation on grouse populations. the numbers of grouse harvested on the eskdale half of langholm moor in ... | 2000 | 10821608 |
| occurrence of leucocytozoon and haemoproteus (apicomplexa, haemosporina) in falconiformes and strigiformes of italy. | blood smears from falconiformes (91 birds of 10 species) and strigiformes (23 birds of 5 species) captured in italy, were examined for haematozoa. leucocytozoon were found in falco tinnuculus, buteo buteo, circus cyaneus, circus pygargus, accipiter nisus from falconiformes and in strix aluco, from strigiformes. haemoproteus were found in falco tinnuculus and strix aluco; this latter species harbored mixed infections leucocytozoon-haemoproteus. prevalences were 20.80% in falconiformes and 21.74% ... | 1984 | 6431891 |
| normal fasting plasma glucose levels in some birds of prey. | blood samples taken from five great horned owls (bubo virginianus), eight red-tailed hawks (buteo jamaicensis), four marsh hawks (circus cyaneus), two prairie falcons (falco mexicanus), five golden eagles (aquila chrysaetos), and five white leghorn chickens (gallus domesticus) that had been fasted for 24 h were used to determine plasma levels of glucose by the glucose oxidase method. the mean plasma glucose levels were: great horned owls 374.6 mg/100 ml, red-tailed hawks 346.5 mg/00 ml, marsh ha ... | 1978 | 739587 |
| the relative importance of prey availability and intruder pressure in feeding territory size regulation by harriers, circus cyaneus. | the relative importance of prey availability and intruder pressure in the regulation of harrier (circus cyaneus) territory size was investigated over two years using analytical methods chosen to permit comparison with myers et al. (1979) study of sanderlings (calidris alba). relationships between territory area and two variables, prey type (mice; large, medium, and small birds) and intruder type (conspecific neighbors, conspecific floaters, and heterospecific floaters), and the consistency of th ... | 1987 | 28312003 |
| lead in hawks, falcons and owls downstream from a mining site on the coeur d'alene river, idaho. | mining and smelting at kellogg-smelterville, idaho, resulted in high concentrations of lead in coeur d'alene (cda) river sediments and the floodplain downstream, where american kestrels (falco sparverius), northern harriers (circus cyaneus), red-tailed hawks (buteo jamaicensis), great horned owls (bubo virginianus), and western screech-owls (otus kennicotti) nested. nestling american kestrels contained significantly higher (p=0.0012) blood lead concentrations along the cda river (0.24 µg/g, wet ... | 1994 | 24221348 |
| effects of military training activities on shrub-steppe raptors in southwestern idaho, usa. | / between 1991 and 1994, we assessed relative abundance, nesting success, and distribution of ferruginous hawks (buteo regalis), northern harriers (circus cyaneus), burrowing owls (athene cunicularia), and short-eared owls (asio flammeus) inside and outside a military training site in the snake river birds of prey national conservation area, southwestern idaho. the orchard training area is used primarily for armored vehicle training and artillery firing by the idaho army national guard. relative ... | 1999 | 9950702 |
| fatal epicarditis in a hen harrier (circus cyaneus) a red-listed bird of high conservation concern in britain associated with cyathostoma species and escherichia coli infection. | | 2013 | 24145504 |
| respiratory nematodiases in raptors in quebec. | this is a retrospective study on wild raptors submitted to the université de montréal (quebec, canada) from 1989 to 1996. cyathostoma spp. (nematoda: syngamidae) adults and/or eggs were found in air sacs, lungs, bronchi, and trachea of 12 raptors (falconiformes and strigiformes) from quebec, canada, belonging to eight different species, five of which are first host records for this parasite: barred owl (strix varia), snowy owl (nyctea scandiaca), northern harrier (circus cyaneus), northern gosha ... | 1999 | 10231766 |
| female begging calls reflect nutritional need of nestlings in the hen harrier circus cyaneus. | most birds exhibit bi-parental care with both sexes providing food for their young. nestling signal food needs through begging. however, for some species, males rarely visit the nest, so have limited opportunity for gaining information directly from the chicks. instead, females beg when males deliver food. we tested whether this calling signalled nutritional need and specifically the needs of the female (breeder need hypothesis) or that of their chicks (offspring need hypothesis). | 2017 | 28629327 |
| fine-scale genetic structure in a high dispersal capacity raptor, the montagu's harrier (circus pygargus), revealed by a set of novel microsatellite loci. | the montagu's harrier (circus pygargus) is a semi-colonial raptor species widely but patchily distributed across the palearctic region with recorded cases of philopatry and presence of extra-pair copulation. in order to assess montagu's harrier spatial genetic structure and contemporary gene flow, we developed 16 new microsatellite markers using 454 pyrosequencing. genotypes of 117 chicks sampled in a 200 × 300 km farmland area in central western france were analyzed to characterize genetic poly ... | 2019 | 30671744 |
| a molecular phylogeny of the harriers (circus, accipitridae) indicate the role of long distance dispersal and migration in diversification. | the monophyly of the raptorial circus genus (harriers) has never been in question, but the specific status of many, often vulnerable island endemic, taxa remains uncertain. here we utilise one mitochondrial and three nuclear loci from all currently recognised circus taxa (species and subspecies) to infer a robust phylogeny, to estimate the divergence date and to reconstruct the biogeographic origins of the circus group. our phylogeny supports both the monophyly of circus and polyphyly of the gen ... | 2015 | 25701771 |
| the landscape of fear as an emergent property of heterogeneity: contrasting patterns of predation risk in grassland ecosystems. | the likelihood of encountering a predator influences prey behavior and spatial distribution such that non-consumptive effects can outweigh the influence of direct predation. prey species are thought to filter information on perceived predator encounter rates in physical landscapes into a landscape of fear defined by spatially explicit heterogeneity in predation risk. the presence of multiple predators using different hunting strategies further complicates navigation through a landscape of fear a ... | 2017 | 28690807 |
| feather mercury concentrations in north american raptors sampled at migration monitoring stations. | we assessed total mercury (thg) concentrations in breast feathers of diurnal north american raptors collected at migration monitoring stations. for 9 species in the pacific flyway, we found species and age influenced feather thg concentrations whereas sex did not. feather thg concentrations µg/g dry weight (dw) averaged (least squares mean ± standard error) higher for raptors that generally consume > 75% avian prey (sharp-shinned hawk accipiter striatus: n = 113; 4.35 ± 0.45 µg/g dw, peregrine f ... | 2019 | 30761431 |
| skydancerplex: a novel str multiplex validated for forensic use in the hen harrier (circus cyaneus). | the hen harrier (circus cyaneus) is a bird of prey which is heavily persecuted in the uk because it preys on the game bird red grouse (lagopus lagopus scoticus). to help investigations into illegal killings of hen harrier, a str multiplex kit containing eight short tandem repeat (str) markers and a chromohelicase dna binding protein 1 (chd 1) sexing marker was developed. the multiplex kit was tested for species specificity, sensitivity, robustness, precision, accuracy and stability. full profile ... | 2016 | 26881329 |
| spatial heterogeneity and scale-dependent habitat selection for two sympatric raptors in mixed-grass prairie. | sympatric predators are predicted to partition resources, especially under conditions of food limitation. spatial heterogeneity that influences prey availability might play an important role in the scales at which potential competitors select habitat. we assessed potential mechanisms for coexistence by examining the role of heterogeneity in resource partitioning between sympatric raptors overwintering in the southern great plains. we conducted surveys for wintering red-tailed hawk (buteo jamaice ... | 2017 | 28861257 |
| reliable and robust molecular sexing of the hen harrier (circus cyaneus) using pcr-rflp analysis of the chd 1 gene. | the hen harrier (circus cyaneus) is a bird of prey that is persecuted in the united kingdom, and there is a need for a dna-based individual identification and sexing system for the use in forensic investigations. this study reports a new set of pcr primers for the chromo-helicase-dna-binding protein 1 gene, which allows sexing using pcr-rflp. instead of exonic primers that amplify across a large intron, this set consists of a primer within the intron, enabling reduction in amplicon sizes from 35 ... | 2013 | 23278127 |
| the functional response of a generalist predator. | predators can have profound impacts on the dynamics of their prey that depend on how predator consumption is affected by prey density (the predator's functional response). consumption by a generalist predator is expected to depend on the densities of all its major prey species (its multispecies functional response, or msfr), but most studies of generalists have focussed on their functional response to only one prey species. | 2010 | 20523722 |