| comparison of serum and lung extracts for surveys of wild animals for antibodies to francisella tularensis biovar palaearctica. | a comparative study of the antibody titer against francisella tularensis biovar palaearctica in serum and lung extract was made using different immunoassays. samples were taken from experimentally-infected goshawks (accipiter gentilis) and european beavers (castor fiber), and in a field survey of wild beavers. good accordance between the antibody titer in serum and in lung extract was found in the experimental studies. however, the antibody titer was generally one- to three-fold lower in lung ex ... | 1988 | 3280838 |
| experimental infection of five species of raptors and of hooded crows with francisella tularensis biovar palaearctica. | sixteen raptors and three hooded crows were infected experimentally with francisella tularensis biovar palaearctica. the birds were infected parenterally or per os. one goshawk, one sparrow hawk and one hooded crow died during the experimental period, and the remaining 16 birds were killed 14-77 days after the first infection. francisella tularensis was not isolated from any bird. antibody levels against f. tularensis measured in nine birds varied from 0 to 1:1,280. in one goshawk with a titer o ... | 1988 | 3280839 |
| trichomoniasis in free-living goshawks (accipiter gentilis gentilis) from great britain. | the goshawk accipiter gentilis has recently been reintroduced into parts of great britain. during the course of a study of one population, lesions of stomatitis were observed in 14 young from five broods and all the affected birds died. postmortem examination of three birds revealed live trichomonas gallinae in exudate from one, and histological findings consistent with a diagnosis of trichomoniasis were made in this and one other bird. it is suggested that trichomoniasis may be a significant mo ... | 1988 | 3352101 |
| prevalence of aspergillus fumigatus in free-living goshawks (accipiter gentilis atricapillus). | during the fall migration of 1972 and 1973 unusually large numbers of goshawks (accipiter gentilis atricapillus) were counted at hawk ridge in duluth, minnesota. these birds were sampled for prevalence of fungi of the genus aspergillus. fungi of this genus were recovered from 26 of 49 birds (53%) in 1972 and 4 of 45 (7%) birds in 1973. aspergillosis was confirmed at necropsy in three wild goshawks in 1972, but none in 1973. the disease was further confirmed at necropsy in 8 of 12 (67%) goshawks ... | 1980 | 7001046 |
| [pasteurellosis in two raptores: the goshawk and sparrow-hawk]. | | 1956 | 13327523 |
| [tuberculosis in raptorial birds. clinical cases and differential diagnosis]. | four cases of avian tuberculosis in two goshawks (accipiter gentilis gentilis), a lanner falcon (falco biarmicus sp.) and a kestrel (falco tinnunculus tinnunculus) are reported. all birds, except for the kestrel, were affected with generalized tuberculosis. clinically, the lanner falcon and kestrel showed lameness due to tuberculous arthritis of a knee joint. one of the goshawks died suddenly. on post-mortem examination, the bird was found to be emaciated, and there was involvement of one knee j ... | 1982 | 7135364 |
| the role of birds as definitive hosts and intermediate hosts of heteroxenous coccidians. | sarcocystis-like oocysts-sporocysts were found in four species of owls (asio otus, bubo bubo, strix aluco, and tyto alba) and in five species of predatory birds (accipiter gentilis, accipiter nisus, buteo buteo, circus aeruginosus, falco tinnunculus). in addition, the muscles of 15 of 41 (36.5%) pheasants (phasianus colchicus) and one of two jays (garrulus glandarius) were found to harbor three types of sarcocystis. three of 15 (20%) infected pheasants had type i cystozoites (6-8 x 2 microns) in ... | 1984 | 6439858 |
| mouse (mus musculus) as intermediate host of sarcocystis sp. from the goshawk (accipiter gentilis). | sporocysts from the goshawk (accipiter gentilis) were experimentally transferred to the mouse (mus musculus). it was found that the goshawk is the host of one of the sarcosporidians inducing muscle sarcocystosis in mice. thin-walled, sporulated oocysts expelled by the goshawk measured 16.5-19.0 x 12.0-13.0 micron. those which measured 12.0-13.5 x 8.2-9.0 micron were widely elliptical, with rounded poles. no asexual reproduction of parasites was detected in the viscera of mice. the cysts started ... | 1986 | 3084365 |
| a comparative study of deep avian foveas. | the foveas of nine avian species, initially selected for the presence of a deep fovea and representing a wide range of eye sizes and ecological habits, were studied with quantitative light microscope techniques. considerable variation was observed in the location and configuration of the avian foveas, although they appeared to be 'convexiclivate' in shape when compared with the fovea of the rhesus monkey. comparisons of foveal cell densities (receptor nuclei and ganglion cells) across species sh ... | 1975 | 811324 |
| lineage 1 and 2 strains of encephalitic west nile virus, central europe. | two different west nile virus (wnv) strains caused lethal encephalitis in a flock of geese and a goshawk in southeastern hungary in 2003 and 2004, respectively. during the outbreak in geese, 14 confirmed human cases of wnv encephalitis and meningitis were reported in the same area. sequencing of complete genomes of both wnv strains and phylogenetic analyses showed that the goose-derived strain exhibits closest genetic relationship to strains isolated in 1998 in israel and to the strain that emer ... | 2006 | 16704810 |
| pathologic and immunohistochemical findings in goshawks (accipiter gentilis) and great horned owls (bubo virginianus) naturally infected with west nile virus. | the carcasses of 25 great horned owls and 12 goshawks were investigated for west nile virus (wnv) infection by immunohistochemistry (ihc) performed on various organs, including brain, spinal cord, heart, kidney, eye, bone marrow, spleen, liver, lungs, pancreas, intestine, and proventriculus, using a wnv-antigen-specific monoclonal antibody and by wnv-specific reverse transcriptase-polymerase chain reaction (rt-pcr), performed on fresh brain tissue only. wnv infection was diagnosed by ihc in all ... | 2005 | 16094831 |
| lead in feathers and delta-aminolevulinic acid dehydratase activity in three raptor species from an unpolluted mediterranean forest (southeastern spain). | this paper presents the levels of lead found in the feathers of adult and blood of nestlings of booted eagle (hieraaetus pennatus), european buzzard ( buteo buteo), and goshawk (accipiter gentilis) sampled in the 1999 and 2000 breeding seasons in a mediterranean forest of the province of murcia (southeastern spain) located far from potential sources of metal contamination. levels of delta-aminolevulinic acid dehydratase activity (delta-alad) in blood were also measured in the nestlings. lead con ... | 2004 | 15386153 |
| long-term demographic analysis in goshawk accipiter gentilis: the role of density dependence and stochasticity. | density dependence and environmental stochasticity are both potentially important processes influencing population demography and long-term population growth. quantifying the importance of these two processes for population growth requires both long-term population as well as individual-based data. i use a 30-year data set on a goshawk accipiter gentilis population from eastern westphalia, germany, to describe the key vital rate elements to which the growth rate is most sensitive and test how en ... | 2007 | 17356810 |
| competitive interactions among raptors in boreal forests. | we examined inter-specific interactions among goshawks ( accipiter gentilis), common buzzards (buteo buteo) and honey buzzards (pernis apivorus) in western finland in 1983-1996. because goshawks are among the largest birds of prey species in boreal forests they may take over the nest of smaller and less-competitive forest-dwelling raptors when searching for suitable places for breeding. accordingly, more than half of newly established goshawk territories were found on the territories previously ... | 2004 | 15375689 |
| reduction of organochlorine residues in goshawk eggs (accipiter gentilis) from northern germany (1971-2002) and increasing eggshell index. | we investigated unhatched eggs (n = 57) of goshawks (accipiter gentilis) from the period 1988--2002 and compared them with eggs (n = 134) from 1971--1978. mean concentrations of pcbs, sigmaddt and hcb in the earlier period were (mg kg(-1) lipid weight) 50.1, 126.6, and 117.7, while the values from the later period were statistically significantly lower: 27.7, 4.1, 0.1, respectively. nevertheless, the concentration of pcb is relatively constant during the last 8-10 years. the variability of resid ... | 2004 | 15666679 |
| pathogenicity of mycoplasma lipofaciens strain ml64 for turkey embryos. | mycoplasma lipofaciens strain ml64, isolated from an egg of a northern goshawk (accipiter gentilis), has been found to be pathogenic for chicken embryos causing mortality during the first 2 weeks of incubation. the same strain was inoculated in turkey embryos to evaluate its pathogenicity and its ability to be transmitted laterally in the hatchery. the strain was found to be pathogenic for turkey embryos, causing a high mortality (88.9%) during late incubation as well as haemorrhages of the legs ... | 2007 | 17899463 |
| bird skins in museum collections: are they suitable as indicators of environmental metal load after conservation procedures? | to find out whether modern conservation treatments alter the level of metals in feathers, we analysed the content of 10 metals in feathers before and after skins were washed with detergent and treated with eulan u-33 (a commonly used preservative at museums). feathers of 31 birds of goshawk accipiter gentilis, eagle owl bubo bubo. feral pigeon columba livia domest, and common eider somateria mollissima were analysed. we found that in most cases metals were partly washed out of the feathers, but ... | 2003 | 12889635 |
| measurement of plasma corticosterone and fecal glucocorticoid metabolites in the chicken (gallus domesticus), the great cormorant (phalacrocorax carbo), and the goshawk (accipiter gentilis). | a method for the non-invasive measurement of glucocorticoid metabolites in feces of chickens was established and validated. after high-performance liquid chromatography (hplc) the presence of at least two fecal immunoreactives was demonstrated, one co-eluting with authentic corticosterone, whereas the second substance migrates close to corticosterone sulphate. we investigated the relationship between corticosterone in blood plasma obtained by a vena brachialis catheter and fecal samples in group ... | 2003 | 12714017 |
| environmental contaminants in liver and kidney of free-ranging northern goshawks (accipiter gentilis) from three regions of germany. | the northern goshawk (accipiter gentilis) is a top predator in the terrestrial food web of large parts of the holarctic. due to its sedentary nature and well-investigated feeding ecology, it represents the most suitable bird of prey species in continental europe for monitoring environmental pollutants. we analyzed the levels of organochlorine pesticides, polychlorinated biphenyls (pcb), and nonessential heavy metals in organ samples of 62 free-ranging northern goshawks found dead or injured in g ... | 2003 | 12948182 |
| time-dependent recovery of mycoplasma lipofaciens (strain ml64) from incubated infertile chicken eggs and dead in shell chicken embryos. | mycoplasmas are pathogens of different avian species, and they are able to be vertically transmitted. even detected, mycoplasma prevalence in raptor eggs is very low. in contrast to poultry, raptor eggs submitted for investigations are usually incubated. to investigate the influence of incubation length on the recovery of mycoplasmas from eggs, infertile specific-pathogen-free chicken eggs and embryos were infected with mycoplasma lipofaciens (strain ml64), which had previously been isolated fro ... | 2008 | 18939632 |
| use of random amplified polymorphic dna analysis and single-enzyme amplified fragment length polymorphism in molecular typing of ornithobacterium rhinotracheale strains. | ornithobacterium rhinotracheale (ort) is a bacterium common to commercial poultry and wild birds throughout the world. it is also known as a causative agent of respiratory diseases. a total of 93 ort isolates originating from chickens, pigeons, ostriches, quail, turkeys, and an asian crested goshawk (accipiter trivirgatus) in taiwan, between 2004 and 2006, were used in this study. high genetic similarity (97%-100%) in 16s rrna sequence was revealed among the 50 randomly selected isolates, in add ... | 2009 | 19432012 |
| helminths isolated from the digestive tract of diurnal raptors in catalonia, spain. | the prevalence of parasitic helminths in the digestive tract of 119 diurnal raptors (falconiformes), which had died in a wildlife rehabilitation centre in catalonia, was studied. the birds belonged to 13 species, with 100 of them (84 per cent) being kestrels (falco tinnunculus), buzzards (buteo buteo), sparrowhawks (accipiter nisus) and goshawks (accipiter gentilis). ninety-five of the birds (79.8 per cent) were infected with helminths. nematodes were the most frequently found helminth (75.6 per ... | 2004 | 14725424 |
| sarcocystis species lethal for domestic pigeons. | a large number of sarcocystis spp. infect birds as intermediate hosts, but pigeons are rarely affected. we identified a novel sarcocystis sp. that causes lethal neurologic disease in domestic pigeons in germany. experimental infections indicated transmission by northern goshawks, and sequence analyses indicated transnational distribution. worldwide spread is possible. | 2010 | 20202429 |
| pcdds/pcdfs, pcbs, and organochlorine pesticides in eggs of eurasian sparrowhawks (accipiter nisus), hobbies (falco subbuteo), and northern goshawks (accipiter gentilis) collected in the area of berlin-brandenburg, germany. | concentrations of polychlorinated dibenzo-p-dioxins (pcdds), polychlorinated dibenzofurans (pcdfs), polychlorinated biphenyls (pcbs), and organochlorine (oc) pesticides were measured in unsuccessfully hatched eggs of three different kinds of predatory birds: 3 eggs of sparrowhawks, 7 eggs of hobbies, and 16 eggs of goshawks collected in the german region of berlin-brandenburg. using toxic equivalency factors for birds, eggs of hobbies contained mean concentrations of 478 pg teq/g fat and 551 pg ... | 2002 | 11994791 |
| [occurrence of parasites in indigenous birds of prey and owls]. | in the present paper a general overview on parasites in birds of prey and owls is given. this part is followed by a study investigating the prevalences and species of parasites in free-ranging birds of prey and owls in berlin and brandenburg state, germany. over a one year period, 84 birds of prey and owls of the following species were examined for the presence of endo- and ectoparasites: common buzzard (buteo buteo) (n = 32), kestrel (falco tinnunculus) (n = 20), sparrowhawk (accipiter nisus) ( ... | 2002 | 11852683 |
| amino acid sequences of hemoglobin from guinea fowl (numida meleagri) and california quail (lophortyx californica) with phylogenetic analysis of major groups of galliformes. | we determined the complete amino acid sequences of the hemoglobin of two species, guinea fowl and california quail, in galliformes from intact globin chain and chemical cleavage fragments in order to analyze the molecular evolution of hemoglobin for the classification of galliformes. galliformes have two types of hemoglobin components, hba and hbd, which consist of identical beta chain and different alpha chains. the sequences are similar to globin chains of galliformes reported previously. thes ... | 2000 | 11195970 |
| organization of telomere sequences in birds: evidence for arrays of extreme length and for in vivo shortening. | telomeres are the specialized ends of chromosomes consisting of highly conserved repeat (5'-ttaggg-3')(n) sequences. lack of information regarding the existence of an in vivo telomere clock function in birds, conflicting data regarding telomere array length in the chicken model, and the paucity of molecular telomere information for other avian species led us to study telomere array organization within and among 18 species and subspecies of birds. most of the species contained between 2% and 4% t ... | 2000 | 11060464 |
| prevalence of haematozoa in birds of prey in catalonia, north-east spain. | blood samples from birds of prey, 95 strigiformes and 190 falconiformes, were examined for the presence of haematozoan parasites. the birds had been admitted to a raptor recovery centre in catalonia, north-east spain. parasites were counted in positive smears. a second blood sample was obtained from 99 birds at least seven days after their arrival at the centre. haematozoa were detected in all seven species of strigiformes and in nine of 19 species of falconiformes. the overall prevalences in th ... | 1999 | 10399244 |
| a juvenile sichuan golden monkey (rhinopithecus roxellana) predated by a goshawk (accipiter gentilis) in the qinling mountains | | 1999 | 10394069 |
| embryonic and neonatal mortality from salmonellosis in captive bred raptors. | in a captive breeding center near rome (italy), cases of embryonic and neonatal death were recorded during the breeding seasons in the european eagle owl (bubo bubo), peregrine falcon (falco peregrinus), buzzard (buteo buteo), and lanner falcon. (falco biarmicus). salmonella havana and s. virchow were isolated. three pulli, clinically infected with s. havana, were successfully treated with enrofloxacin. from two groups of healthy 3- to 4-wk-old eagle owls, salmonella sp. group 61 (61:r:-) and s. ... | 1998 | 9476227 |
| detection and molecular analysis of west nile virus infections in birds of prey in the eastern part of austria in 2008 and 2009. | the emergence of west nile virus (wnv) was expected in austria since the initial discovery of the infection in neighbouring hungary in 2003/2004. in 2008 six cases of west nile disease were diagnosed at the institute for veterinary disease control mödling, austrian agency for health and food safety (ages), involving five goshawks (accipiter gentilis) and one gyrfalcon (falco rusticolus), which were found dead in the eastern austrian federal states of lower austria, vienna and styria, respectivel ... | 2010 | 21276665 |
| molecular characterization of a 6.6-kilodalton borrelia burgdorferi outer membrane-associated lipoprotein (lp6.6) which appears to be downregulated during mammalian infection. | isolated outer membranes of borrelia burgdorferi 297 were utilized to obtain partial amino acid sequence information for a low-molecular-weight, outer membrane-associated polypeptide. degenerate oligonucleotide primers based upon this information were used to amplify a 100-bp probe for detection of the corresponding full-length gene within a b. burgdorferi total genomic library. the relevant open reading frame (orf) encoded a polypeptide comprised of a 17-amino-acid putative signal peptide termi ... | 1997 | 9009290 |
| reference intervals for intraocular pressure measured by rebound tonometry in ten raptor species and factors affecting the intraocular pressure. | intraocular pressure (iop) was measured with the tonovet rebound tonometer in 10 raptor species, and possible factors affecting iop were investigated. a complete ophthalmic examination was performed, and iop was assessed in 2 positions, upright and dorsal recumbency, in 237 birds belonging to the families accipitridae, falconidae, strigidae, and tytonidae. mean iop values of healthy eyes were calculated for each species, and differences between families, species, age, sex, left and right eye, as ... | 2011 | 22216716 |
| emergence of west nile virus lineage 2 in europe: a review on the introduction and spread of a mosquito-borne disease. | west nile virus (wnv) is transmitted by mosquitoes and causes fever and encephalitis in humans, equines, and occasionally wild birds. the virus was first isolated in sub-saharan africa where it is endemic. wnv lineage 1 has been responsible for repeated disease outbreaks in the countries of the mediterranean basin over the past 50 years. this lineage was also introduced into north america in 1999 causing widespread human, equine, and avian mortality. wnv lineage 2, the first wnv lineage to be is ... | 2014 | 25538937 |
| [comparative studies of the release and ability to survive of game pheasants (phasianus colchicus sp.) from intensive and extensive husbandry]. | artificially reared pheasants had been released at an age of 10 weeks on two stands in a suitable habitat with a wild pheasant population in lower saxony, germany. two groups (200 pheasants reared in large fly-aviaries, 200 pheasants reared in dark stables) were bought from commercial breeders who offer pheasants for restocking wild populations. some of the released pheasants were marked with radio-transmitters. there was no significant difference in survival rate between the two rearing groups. ... | 1995 | 7555681 |
| [parasites of austrian birds of prey (falconiformes)]. | during the examination of 158 birds of prey -- buteo buteo (85), falco tinnunculus (30), accipiter gentilis (19), accipiter nisus (18), circus aeruginosus (2), circus pygargus (1), pandion haliaetus (1), pernis apivorus (1), falco subbuteo (1) and faeces samples of falco tinnunculus 4 protozoan species, 1 trematode species, 2 cestode species, 13 nematode species, 2 acanthocephalan species and 5 mallophaga species could be detected. in the buzzard, kestrel and goshawk a new species of capillaria ... | 1980 | 7212374 |
| prevalence of trichomonas gallinae in northern goshawks from the berlin area of northeastern germany. | in recent years, the northern goshawk (accipiter gentilis) has colonized suburban and urban areas in berlin, germany, and elsewhere in europe. because of the high proportion of feral pigeons (columba livia f. domestica) in their diet, urban goshawks are suspected to have a high infection rate with trichomonas gallinae. therefore, from 1998 to 2001, we examined 269 nestlings from 90 nests for infection with t. gallinae by culture of swabs taken from the oropharynx and checked their oropharynx for ... | 2005 | 16107664 |
| brominated flame retardants and other organobromines in norwegian predatory bird eggs. | a set of 62 unhatched eggs was collected from six different predatory bird species throughout norway after incubation period was completed. they were analysed for pbde, pbb, tbbp a and naturally occurring halogenated compounds. bde 47, 99 and 153 were the dominating congeners, with species dependent pbde patterns. bde 153 was observed as the most abundant congener in eggs of peregrine falcon, golden eagle and merlin. the highest pbde level (sum of nine congeners) was found in eggs of white-taile ... | 2005 | 16182862 |
| selective predation on utah prairie dogs. | predation always affects demography and population dynamics, but removal of certain types of individuals is especially consequential. predators strike quickly and commonly avoid areas with human observers, however, and thereby make it difficult to document patterns of predation under natural conditions. at a colony of marked utah prairie dogs (cynomys parvidens), a high frequency of predation in 2005 provided an unusual opportunity to examine susceptibility of five types of individuals to predat ... | 2006 | 17004225 |
| examination of mercury concentration in the feathers of 18 species of birds in southwest iran. | this paper presents the levels of mercury (hg) in tail feathers from different species of birds, in southwest iran (khuzestan to persian gulf). between april and october 2005, we collected tail feathers from 77 birds belonging to 18 species, mostly raptor birds. the birds were collected for the museum natural history, faculty of natural resources and marine sciences of tarbiat modares university. hg concentrations were evaluated in relation to taxonomic affiliation and trophic level. feather hg ... | 2007 | 17307157 |
| congenital neuropathy and dilution of feather melanin in nestlings of urban-breeding northern goshawks (accipiter gentilis). | a pair of northern goshawks (accipiter gentilis) breeding in a public park in the city center of hamburg, germany, raised 12 healthy and five aberrant offspring between 1996 and 2000. aberrant nestlings (three males and two females) had pale silver-blue plumage and displayed severe locomotor disorders. histopathologically, the defects were characterized by adendritic feather melanocytes and mild degeneration of the cerebellar white matter. epidemiologic results were suggestive of a hereditary au ... | 2004 | 15193082 |
| organochlorines in egg samples from norwegian birds of prey: congener-, isomer- and enantiomer specific considerations. | the content of chlorinated persistent organic pollutants was determined in a total of 44 egg samples from 8 different raptor species collected throughout norway in the period 1991-1997. the content of 8 chlorinated bornanes, 9 chlorinated pesticides, and 15 polychlorinated biphenyl congeners (pcb) were determined. the highest average concentrations for pcb were found for eggs from white-tailed sea eagle and peregrine falcon (average sum pcb concentration: 8.9 and 9.1 microg/g wet weight (w.w.), ... | 2002 | 12150443 |
| malaria and risk of predation: a comparative study of birds. | predators have been hypothesized to prey on individuals in a poor state of health, although this hypothesis has only rarely been examined. we used extensive data on prey abundance and availability from two long-term studies of the european sparrowhawk (accipiter nisus) and the eurasian goshawk (accipiter gentilis) to quantify the relationship between predation risk of different prey species and infection with malaria and other protozoan blood parasites. using a total of 31 745 prey individuals o ... | 2007 | 17536704 |
| clinical and pathologic features of lineage 2 west nile virus infections in birds of prey in hungary. | in the southeast of hungary a sparrow hawk (accipiter nisus) and several goshawk (accipiter gentilis) fledglings succumbed to encephalitis manifesting as an acute neurological disease during the summers of 2004 and 2005. both years the causative agent was identified as a lineage 2 west nile virus. this is the first description of clinical, pathological and immunohistochemical findings of infection caused by a neuroinvasive, lineage 2 west nile virus and the first evidence of its circulation in c ... | 2007 | 17627436 |
| organochlorine residues in booted eagle (hieraaetus pennatus) and goshawk (accipiter gentilis) eggs from southeastern spain. | most organochlorine (oc) use has been banned in spain, but these compounds are persistent and may still adversely affect predatory birds. data generally are lacking, however. residues of hexachlorobenzene, alpha-hexachlorocyclohexane, lindane, hexachloro-octahydro-epoxy-dimethanonaphthalene, ddt, dichlorodiphenyldichloroethane, dichlorodiphenyldichloroethylene (dde), and polychlorinated biphenyls (pcbs) were measured in 22 failed eggs of booted eagles (hieraaetus pennatus) and goshawks (accipite ... | 2007 | 17941741 |
| an avipoxvirus infection in a goshawk (accipiter gentilis). | this report describes the nodular lesions found on a young, male european goshawk (accipiter gentilis) which were found to be poxvirus lesions in conjunction with a staphylococcus aureus infection. treatment consisted of surgical removal of the two lesions and amoxicillin/clavulanic acid. the diagnosis of a poxvirus infection was suspected by histology and confirmed with transmission electron microscopy. to our knowledge the goshawk has been reported as being susceptible to avipoxvirus infection ... | 1998 | 18483972 |
| the establishment of an urban bird population. | 1. despite the accelerating global spread of urbanized habitats and its associated implications for wildlife and humans, surprisingly little is known about the biology of urban ecosystems. 2. using data from a 60-year study period, this paper provides a detailed description of how the northern goshawk accipiter gentilis l.--generally considered a shy forest species--colonized the city of hamburg, germany. six non-mutually exclusive hypotheses are investigated regarding the environmental factors ... | 2008 | 18627420 |
| persistent organochlorine contaminants in eggs of northern goshawk and eurasian buzzard from northeastern spain: temporal trends related to changes in the diet. | persistent organochlorine compounds (pesticides and polychlorinated biphenyls) were determined in 24 northern goshawk (accipiter gentilis) and eight eurasian buzzard (buteo buteo) samples of eggs collected between 1988 and 1999 in la segarra (northeast spain), in order to evaluate the changes in exposure and detrimental effects during this period. in the study area, both species exhibited similar levels of contamination, which may be related to their similar diet, mainly based on european rabbit ... | 2003 | 12547524 |
| prevalence of mycoplasmas in eggs from birds of prey using culture and a genus-specific mycoplasma polymerase chain reaction. | mycoplasmas are commensals and pathogens of different avian species, especially poultry and passeriforms. the role of mycoplasmas in raptors has not yet been completely determined, and especially not the possibility of vertical transmission. therefore 424 raptor eggs were examined for the occurrence of mycoplasmas using culture, and 155 of these eggs with a mycoplasma genus-specific polymerase chain reaction (pcr) assay. this pcr was tested for its sensitivity and specificity, especially for use ... | 2007 | 17479375 |
| accuracy and reproducibility of the tonovet rebound tonometer in birds of prey. | to examine the accuracy and reproducibility of intraocular pressure (iop) measurements obtained by the tonovet rebound tonometer. animals studied freshly enucleated healthy eyes of 44 free-ranging birds of prey out of the species haliaeetus albicilla, accipiter gentilis, accipiter nisus, buteo buteo, falco tinnunculus, strix aluco, asio otus and tyto alba euthanized because of unrelated health problems. | 2010 | 20840094 |
| unusual biphasic disease in domestic pigeons (columba livia f. domestica) following experimental infection with sarcocystis calchasi. | a novel sarcocystis species has recently been reported in the domestic pigeon (columba livia f. domestica) as intermediate host, causing severe central nervous signs similar to paramyxovirus-1 or salmonella typhimurium var. cop. infection. transmission of the parasite via the northern goshawk (accipiter gentilis) as definitive host has been established. experimental infection of domestic pigeons with sporocysts excreted by experimentally infected northern goshawks reproduced the natural infectio ... | 2010 | 20945785 |
| high prevalence of sarcocystis calchasi sporocysts in european accipiter hawks. | the emerging sarcocystis calchasi induces a severe and lethal central nervous disease in its intermediate host, the domestic pigeon (columba livia f. domestica). experimental studies have identified the northern goshawk (accipiter g. gentilis) as final host. phylogenetically closely related european sparrowhawks (accipiter n. nisus) and wood pigeons (columba palumbus) have been found to harbor genetically closely related sarcocystis spp. however, data on the prevalence and potential interspecies ... | 2010 | 21074324 |
| pathogenicity of mycoplasma lipofaciens strain ml64, isolated from an egg of a northern goshawk (accipiter gentilis), for chicken embryos. | some mycoplasma species are well-known avian pathogens and are of importance in poultry breeder flocks due to their pathogenic potential for embryos. mycoplasmas are regularly detected in birds of prey, and a strain of mycoplasma lipofaciens that was isolated from an egg of a northern goshawk (accipiter gentilis) was examined for its pathogenicity in specific pathogen free chicken embryos since birds of prey eggs were not available for this purpose. the strain was found to be pathogenic, causing ... | 2007 | 17479376 |
| territorial occupancy dynamics in a forest raptor community. | a markovian modeling approach was used to explore territorial interactions among three forest raptors coexisting in a forested natural area in southeast spain: the booted eagle (hieraaetus pennatus), the common buzzard (buteo buteo) and the northern goshawk (accipiter gentilis). using field data collected over a period of 12 years, 11 annual transition matrices were built, considering four occupancy states for each territory. the model describes transitional processes (colonization, abandonment, ... | 2010 | 21136084 |
| mesopredator release by an emergent superpredator: a natural experiment of predation in a three level guild. | intraguild predation (igp) is widespread but it is often neglected that guilds commonly include many layers of dominance within. this could obscure the effects of igp making unclear whether the intermediate or the bottom mesopredator will bear higher costs from the emergence of a new top predator. | 2010 | 21151912 |
| concentrations of retinol, 3,4-didehydroretinol, and retinyl esters in plasma of free-ranging birds of prey. | this study investigated vitamin a compounds in the plasma of healthy free-ranging central european raptors with different feeding strategies. plasma samples of nestlings of white-tailed sea eagle [white-tailed sea eagle (wtse), haliaeetus albicilla) (n = 32), osprey (pandion haliaetus) (n = 39), northern goshawk (accipiter gentilis) (n = 25), common buzzard (buteo buteo) (n = 31), and honey buzzard (pernis apivorus) (n = 18) and adults of wtse (n = 10), osprey (n = 31), and northern goshawk (n = ... | 2011 | 21895779 |
| host-specific exposure and fatal neurologic disease in wild raptors from highly pathogenic avian influenza virus h5n1 during the 2006 outbreak in germany. | raptors may contract highly pathogenic avian influenza virus h5n1 by hunting or scavenging infected prey. however, natural h5n1 infection in raptors is rarely reported. therefore, we tested raptors found dead during an h5n1 outbreak in wild waterbirds in mecklenburg-western pomerania, germany, in 2006 for h5n1-associated disease. we tested 624 raptors of nine species-common buzzard (385), eurasian sparrowhawk (111), common kestrel (38), undetermined species of buzzard (36), white-tailed sea eagl ... | 2015 | 25879698 |
| age-dependent diet choice in an avian top predator. | age-dependent breeding performance is arguably one of the best-documented phenomena in ornithology. the existence of age-related trends has major implications for life-history theory, but the proximate reasons for these patterns remain poorly understood. it has been proposed that poor breeding performance of young individuals might reflect lack of foraging skills. we investigated this possibility in a medium-sized, powerful raptor-the northern goshawk accipiter gentilis. male goshawks are respon ... | 2006 | 16537129 |
| food-limitation in a generalist predator. | investigating food-limitation in generalist predators is difficult, because they can switch to alternative prey, when one of their staple prey becomes scarce. apart from data on the dynamics of the predator population, a robust study requires: (i) a documentation of the predator's entire prey base; and (ii) an experimental or natural situation, where profitable dietary shifts are impossible, because several preferred prey species decline simultaneously. here, we provide a detailed description of ... | 2006 | 16846915 |
| sarcocystis calchasi sp. nov. of the domestic pigeon (columba livia f. domestica) and the northern goshawk (accipiter gentilis): light and electron microscopical characteristics. | a novel highly pathogenic sarcocystis species has been shown to cycle between the northern goshawk (accipiter gentilis) as definitive host and the domestic pigeon (columba livia f. domestica) as intermediate host. however, genetically based characteristics are only available from very few bird-infecting sarcocystis species. we therefore further characterised morphological properties of this protozoan in both hosts. using light and electron microscopy, oocysts and sporocysts as well as schizonts ... | 2010 | 20033211 |
| higher reproductive success of small males and greater recruitment of large females may explain strong reversed sexual dimorphism (rsd) in the northern goshawk. | reversed sexual dimorphism (rsd), which occurs when the female of a species is larger than the male, is the rule for most birds of prey but the exception among other bird and mammal species. the selective pressures that favour rsd are an intriguing issue in animal ecology. despite the large number of hypotheses proposed to explain the evolution of rsd, there is still no consensus about the mechanisms involved and whether they act on one or both sexes, mainly because few intrapopulation studies h ... | 2015 | 25424156 |
| explosive spread of a neuroinvasive lineage 2 west nile virus in central europe, 2008/2009. | for the first time outside sub-saharan africa, a lineage 2 west nile virus (wnv) emerged in hungary in 2004. it caused sporadic cases of encephalitis in goshawks (accipiter gentilis), other predatory birds, and in mammals. as a consequence, a surveillance program was initiated in hungary and in austria, which included virological, molecular, serological and epidemiological investigations in human beings, birds, horses, and mosquitoes. the virus strain became endemic to hungary, however only spor ... | 2013 | 23570864 |
| west nile virus lineage 2 in sardinian wild birds in 2012: a further threat to public health. | west nile virus (wnv) strains belonging to lineage 2 were detected and isolated from the tissues of a goshawk and two carrion crows in sardinia in august 2012. according to ns3 sequence analysis, the sardinian isolates shared a high level of similarity with those of italian lineage 2 strains which circulated in 2011 and with the homologous sequence of the 2004 hungarian isolate. following the human fatality reported in 2011 in olbia, this study is the first to report the spread and enzootic circ ... | 2013 | 23343580 |
| west nile virus infections in greece: an update. | approximately 2 years have passed since the detection of the first human case of west nile virus (wnv) infection in greece, which was the starting signal of a large outbreak in 2010, followed by a second one in 2011. more than 250 neuroinvasive disease cases with 15% fatality were observed during the two wnv seasons. wnv lineage 2 sequences were obtained from blood donors, culex mosquitoes, wild birds and sentinel chickens. the greek wnv strain shows high genetic relatedness to the goshawk-hunga ... | 2012 | 22943398 |
| 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 |
| chlorinated hydrocarbons and shell thinning in eggs of (accipiter) hawks in ontario, 1986-1989. | eggs of sharp-shinned hawks (accipiter striatus), cooper's hawks (a. cooperii), and northern goshawks (a. gentilis) were collected from nests in south-central ontario from 1986 to 1989. detectable levels of the chlorinated hydrocarbons dde, ddt, ddd, mirex, photomirex, cis-nonachlor, trans-nonachlor, oxychlordane, dieldrin, heptachlor expoxide, hcb and pcb were present in all the eggs analyzed. mean contaminant levels were highest in sharp-shinned hawks, slightly lower in cooper's hawks, and sig ... | 1994 | 15091636 |
| naive juveniles are more likely to become breeders after witnessing predator mobbing. | responding appropriately during the first predatory attack in life is often critical for survival. in many social species, naive juveniles acquire this skill from conspecifics, but its fitness consequences remain virtually unknown. here we experimentally demonstrate how naive juvenile siberian jays (perisoreus infaustus) derive a long-term fitness benefit from witnessing knowledgeable adults mobbing their principal predator, the goshawk (accipiter gentilis). siberian jays live in family groups o ... | 2017 | 28035889 |
| temporal trends in mercury concentrations in raptor flight feathers stored in an environmental specimen bank in galicia (nw spain) between 2000 and 2013. | temporal trends in hg concentrations were investigated in primary flight feathers from 319 specimens of three birds of prey: p7 in the northern goshawk (accipiter gentilis), p6 in the common buzzard (buteo buteo) and p5 in the tawny owl (strix aluco). the samples were stored in a regional environmental specimen bank and belonged to specimens which died between 2000 and 2013 in galicia (nw spain). we would expect to see a decline in hg concentrations across the study period, as data of atmospheri ... | 2017 | 27995410 |
| indirect effects of the generalist avian predator, the goshawk, on life history of an uncommon prey species, the stock dove. | predators account for lethal effects in their prey, but importantly also for non-lethal indirect effects through the presence and the activity of predators. such non-lethal effects include altered timing of reproduction, incidence of reproduction, clutch size and quality of offspring produced. we investigated the effects of goshawks accipiter gentilis on reproduction of the stock dove columba oenas in 1723 breeding events during 2006-2015 in northern denmark, while simultaneously accounting for ... | 2016 | 27589971 |
| food availability and predation risk, rather than intrinsic attributes, are the main factors shaping the reproductive decisions of a long-lived predator. | deciphering the causes of variation in reproductive success is a fundamental issue in ecology, as the number of offspring produced is an important driver of individual fitness and population dynamics. little is known, however, about how different factors interact to drive variation in reproduction, such as whether an individual's response to extrinsic conditions (e.g. food availability or predation) varies according to its intrinsic attributes (e.g. age, previous allocation of resources towards ... | 2016 | 26990178 |
| conservation of avian diversity in the sierra nevada: moving beyond a single-species management focus. | as a result of past practices, many of the dry coniferous forests of the western united states contain dense, even-aged stands with uncharacteristically high levels of litter and downed woody debris. these changes to the forest have received considerable attention as they elevate concerns regarding the outcome of wildland fire. however, attempts to reduce biomass through fuel reduction (i.e., thinning of trees) are often opposed by public interest groups whose objectives include maintaining habi ... | 2013 | 23667579 |
| intraguild predation and competition impacts on a subordinate predator. | intraguild (ig) predation and interspecific competition may affect the settlement and success of species in their habitats. using data on forest-dwelling hawks from finland, we addressed the impact of an ig predator, the northern goshawk accipiter gentilis (goshawk), on the breeding of an ig prey, the common buzzard buteo buteo. we hypothesized that the subordinate common buzzard avoids breeding in the proximity of goshawks and that interspecific competitors, mainly strix owls, may also disturb ... | 2016 | 26841931 |
| intraguild predation leads to cascading effects on habitat choice, behaviour and reproductive performance. | intraguild predation (igp) is a commonly recognized mechanism influencing the community structure of predators, but the complex interactions are notoriously difficult to disentangle. the mesopredator suppression hypothesis predicts that a superpredator may either simultaneously repress two mesopredators, restrain the dominant one and thereby release the subdominant mesopredator, or elicit different responses by both mesopredators. we show the outcome arising from such conditions in a three-level ... | 2016 | 26781959 |
| seasonal effects of habitat on sources and rates of snowshoe hare predation in alaskan boreal forests. | survival and predation of snowshoe hares (lepus americanus) has been widely studied, yet there has been little quantification of the changes in vulnerability of hares to specific predators that may result from seasonal changes in vegetation and cover. we investigated survival and causes of mortalities of snowshoe hares during the late increase, peak, and decline of a population in interior alaska. from june 2008 to may 2012, we radio-tagged 288 adult and older juvenile hares in early successiona ... | 2015 | 26717577 |
| habitat effects on the breeding performance of three forest-dwelling hawks. | habitat loss causes population declines, but the mechanisms are rarely known. in the european boreal zone, loss of old forest due to intensive forestry is suspected to cause declines in forest-dwelling raptors by reducing their breeding performance. we studied the boreal breeding habitat and habitat-associated breeding performance of the northern goshawk (accipiter gentilis), common buzzard (buteo buteo) and european honey buzzard (pernis apivorus). we combined long-term finnish bird-of-prey dat ... | 2015 | 26422684 |
| large increase in nest size linked to climate change: an indicator of life history, senescence and condition. | many animals build extravagant nests that exceed the size required for successful reproduction. large nests may signal the parenting ability of nest builders suggesting that nests may have a signaling function. in particular, many raptors build very large nests for their body size. we studied nest size in the goshawk accipiter gentilis, which is a top predator throughout most of the nearctic. both males and females build nests, and males provision their females and offspring with food. nest volu ... | 2015 | 26154876 |
| evaluation of trail-cameras for analyzing the diet of nesting raptors using the northern goshawk as a model. | diet studies present numerous methodological challenges. we evaluated the usefulness of commercially available trail-cameras for analyzing the diet of northern goshawks (accipiter gentilis) as a model for nesting raptors during the period 2007-2011. we compared diet estimates obtained by direct camera monitoring of 80 nests with four indirect analyses of prey remains collected from the nests and surroundings (pellets, bones, feather-and-hair remains, and feather-hair-and-bone remains combined). ... | 2015 | 25992956 |
| pathogenic bacteria and timing of laying. | pathogenic bacteria constitute a serious threat to viability of many organisms. because growth of most bacteria is favored by humid and warm environmental conditions, earlier reproducers in seasonal environments should suffer less from the negative consequences of pathogenic bacteria. these relationships, and the effects on reproductive success, should be particularly prominent in predators because they are frequently exposed to pathogenic microorganisms from sick prey. here, we presented and te ... | 2015 | 25937910 |
| effects of the fukushima daiichi nuclear accident on goshawk reproduction. | although the influence of nuclear accidents on the reproduction of top predators has not been investigated, it is important that we identify the effects of such accidents because humans are also top predators. we conducted field observation for 22 years and analysed the reproductive performance of the goshawk (accipiter gentilis fujiyamae), a top avian predator in the north kanto area of japan, before and after the accidents at the fukushima daiichi nuclear power plant that occurred in 2011. the ... | 2015 | 25802117 |
| spatial assessment of the potential risk of avian influenza a virus infection in three raptor species in japan. | avian influenza a, a highly pathogenic avian influenza, is a lethal infection in certain species of wild birds, including some endangered species. raptors are susceptible to avian influenza, and spatial risk assessment of such species may be valuable for conservation planning. we used the maximum entropy approach to generate potential distribution models of three raptor species from presence-only data for the mountain hawk-eagle nisaetus nipalensis, northern goshawk accipiter gentilis and peregr ... | 2016 | 26972333 |
| high seroprevalence of antibodies to toxoplasma gondii in wild animals from portugal. | we report an investigation of antibodies to toxoplasma gondii in 52 wild birds and 20 wild mammals from northern and central areas of portugal by using the modified agglutination test. the birds comprised 26 common buzzards (buteo buteo), five tawny owls (strix aluco), four white storks (ceconia ceconia), three eurasian eagle owls (bubo bubo), three northern goshawks (accipiter gentilis), two booted eagles (hieraaetus pennatus), two common barn owls (tyto alba), two eurasian sparrowhawks (accipi ... | 2010 | 21104273 |
| genetic is901 rflp diversity among mycobacterium avium subsp. avium isolates from four pheasant flocks. | is901 rflp analysis of 36 mycobacterium avium subsp. avium (maa) isolates from 15 pheasants (phasianus colchicus) and two goshawks (accipiter gentilis) from four pheasant farms was performed. using this method, six different is901 rflp types (e, f, g, m, q, and v) were identified. the distribution of is901 rflp profiles was tightly linked to individual flocks. matching is901 rflp profiles observed in the present study indicate maa transmission between pheasants and goshawks in the same locality. ... | 2013 | 23388436 |
| use of raptors for biomonitoring of heavy metals: gender, age and tissue selection. | the concentrations of cadmium, mercury and lead were determined in liver, kidney and feathers of accipiter gentilis, buteo buteo and strix aluco. no significant differences in the concentrations of metals were observed in relation to either age or gender. cadmium levels in feathers and in kidney were significantly correlated (p < 0.01 or p < 0.05) in all species. in b. buteo, cadmium concentrations in feathers and in liver were also correlated (p < 0.01), as were the concentrations of lead in fe ... | 2011 | 21336862 |
| accipiter hawks (accipitridae) confirmed as definitive hosts of sarcocystis turdusi, sarcocystis cornixi and sarcocystis sp. ex phalacrocorax carbo. | sarcocystis is a large genus of protozoan parasites with complex heteroxenous life cycles. for many species, either the intermediate or the definitive host is still unknown. in this study, 116 accipiter hawks (eurasian sparrowhawks and northern goshawks) were investigated for the presence of sarcocystis spp. in their intestinal tract or their faeces. to gain a wide distribution, samples were collected throughout germany within 2 years. it was possible to detect sarcocystis-like oocysts in 65 sam ... | 2016 | 27083188 |
| the occurrence and pathogenicity of serratospiculum tendo (nematoda: diplotriaenoidea) in birds of prey from southern italy. | the air sacs of free-ranging birds of prey (n= 652) from southern italy, including 11 species of accipitriformes and six of falconiforms, were examined for infections with serratospiculum tendo (nematoda: diplotriaenoidea). of the 17 species of birds examined, 25 of 31 (80.6%) peregrine falcons (falco peregrinus) from calabria region and a single northern goshawk (accipiter gentilis) from campania region were infected with s. tendo, suggesting a strong host specificity for the peregrine falcon. ... | 2016 | 25772632 |
| climatic conditions cause complex patterns of covariation between demographic traits in a long-lived raptor. | environmental variation can induce life-history changes that can last over a large part of the lifetime of an organism. if multiple demographic traits are affected, expected changes in climate may influence environmental covariances among traits in a complex manner. thus, examining the consequences of environmental fluctuations requires that individual information at multiple life stages is available, which is particularly challenging in long-lived species. here, we analyse how variation in clim ... | 2015 | 25403010 |
| sarcocystis calchasi is distinct to sarcocystis columbae sp. nov. from the wood pigeon (columba palumbus) and sarcocystis sp. from the sparrowhawk (accipiter nisus). | sarcocystis calchasi has been identified as causative agent of a newly discovered central nervous disease in domestic pigeons (columba livia f. domestica) observed for the first time in germany in 2006. initial studies have indicated that this parasite is highly pathogenic for domestic pigeons after ingestion of low doses of sporocysts shed by the northern goshawk (accipiter gentilis). here we tested whether phylogenetically related birds might regularly harbor sarcocystis species. five wood pig ... | 2010 | 20381254 |
| use of random amplified polymorphic dna to identify several novel markers for sex identification in the crested serpent eagle and crested goshawk. | the crested serpent eagle (spilornis cheela hoya) has no distinct sexual dimorphic traits. in the current study, we report the results of an ee0.6 (ecori 0.6-kb fragment) sequence applied to s. cheela hoya and a novel random amplified polymorphic dna (rapd) marker that can be used to sex individuals within the species s. cheela hoya and accipiter trivigatus formosae (crested goshawk). we used sex-specific primers for the avian chd1 (chromo-helicase-dna-binding 1) gene and the ee0.6 sequence in p ... | 2009 | 19560806 |
| viability selection on prey morphology by a generalist predator. | prey use their locomotory capacity to escape predators, and there should thus be strong viability selection on locomotory morphology of prey. we compared feather morphology of wood pigeons columba palumbus killed by goshawks accipiter gentilis with that of survivors to quantify directional and quadratic selection on primary and rectrix feathers. the goshawk is mainly a predator attacking by surprise, leaving wood pigeons with an ability to accelerate fast at a selective advantage. there was dire ... | 2009 | 19344382 |
| genetic data from 28 str loci for forensic individual identification and parentage analyses in 6 bird of prey species. | twenty-eight str loci were screened in wild populations of six bird of prey species providing allele frequencies and population genetic parameters necessary for the application of strs in wildlife forensic genetic casework. individual str loci were validated according to forensic recommendations in specimens of golden eagle (aquila chrysaetos), goshawk (accipiter gentilis), merlin (falco columbarius), peregrine falcon (falco peregrinus), gyr falcon (falco rusticolus) and saker falcon (falco cher ... | 2009 | 19215871 |
| [sem studies on the connective tissue cores of the lingual papillae of the northern goshawk (accipiter gentilis)]. | the lingual papillae and their connective tissue cores (ctcs) of the northern goshawk were examined by scanning electron microscopy (sem). the length of the tongue was approximately 2.5 cm. the median groove divided the body of the tongue into symmetrical parts. at a point approximately 2/3 of the length, there were large conical papillae between the body and the root of the tongue, the apices of which were pointed towards the posterior part of the tongue. under the light microscopy, the filifor ... | 2008 | 18807946 |
| clinical signs and diagnosis of thiamine deficiency in juvenile goshawks (accipiter gentilis). | between 2002 and 2006, a large number of juvenile northern goshawks (accipiter gentilis) with central nervous signs were examined. they were aged between 45 and 55 days and had been fed on frozen and thawed day-old chicks. high-performance liquid chromatography showed that the birds had whole blood thiamine levels between 2.2 and 6.0 microg/l; the concentrations of other blood constituents were within their reference ranges. treatment with thiamine hydrochloride rapidly resolved the clinical sig ... | 2008 | 18708655 |
| age and sex-selective predation moderate the overall impact of predators. | currently, there is no general agreement about the extent to which predators impact prey population dynamics and it is often poorly predicted by predation rates and species abundances. this could, in part be caused by variation in the type of selective predation occurring. notably, if predation is selective on categories of individuals that contribute little to future generations, it may moderate the impact of predation on prey population dynamics. however, despite its prevalence, selective pred ... | 2015 | 25334013 |
| diet shift induced rapid evolution of size and function in a predatory bird. | a predator's body size correlates with its prey size. change in the diet may call for changes in the hunting mode and traits determining hunting success. we explored long-term trends in sternum size and shape in the northern goshawk by applying geometric morphometrics. tetraonids, the primary prey of the goshawk, have decreased and been replaced by smaller birds in the diet. we expected that the size of the goshawk has decreased accordingly more in males than females based on earlier observation ... | 2014 | 25217047 |
| observations on the right ovary of birds of prey: a histological and immunohistochemical study. | in most avian species, only the left ovary and oviduct are developed in the adult bird. right ovaries and oviducts usually do not mature further after hatching and remain only rudimentary. however, occurrence of a functional right ovary is frequently found in several species of birds of prey. in this study, we investigated the occurrence of the right ovaries and their morphology in these bird species. four examined wild bird species possessed a right ovary: long-eared owl, common buzzard, sparro ... | 2015 | 24895012 |
| territory occupancy rate of goshawk and gyrfalcon: no evidence of delayed numerical response to grouse numbers. | two recent studies on territory occupancy rates of goshawk accipiter gentilis and gyrfalcon falco rusticolus report a 2-3-year-delayed numerical response to grouse numbers, which is a requirement for a hypothesis of predator-generated grouse cycles. the time lags were assumed to reflect the average age of sexual maturity in the raptor species. in southern norway, however, subadult (two-year-old) goshawk hens occupied only 18-25% of territories where occupancy was not recorded in the preceding ye ... | 2007 | 17549523 |
| lifespan analyses of forest raptor nests: patterns of creation, persistence and reuse. | structural elements for breeding such as nests are key resources for the conservation of bird populations. this is especially true when structural elements require a specific and restricted habitat, or if the construction of nests is costly in time and energy. the availability of nesting-platforms is influenced by nest creation and persistence. in a mediterranean forest in southeastern spain, nesting-platforms are the only structural element for three forest-dwelling raptor species: booted eagle ... | 2014 | 24717935 |
| antiparasite treatments reduce humoral immunity and impact oxidative status in raptor nestlings. | parasites are natural stressors that may have multiple negative effects on their host as they usurp energy and nutrients and may lead to costly immune responses that may cause oxidative stress. at early stages, animals may be more sensitive to infectious organisms because of their rapid growth and partly immature immune system. the objective of this study was to explore effects of parasites by treating chicks of two raptor species (northern goshawk accipiter gentilis and white-tailed sea eagle h ... | 2013 | 24455145 |
| hunting behaviour and breeding performance of northern goshawks accipiter gentilis, in relation to resource availability, sex, age and morphology. | animal territories that differ in the availability of food resources will require (all other things being equal) different levels of effort for successful reproduction. as a consequence, breeding performance may become most strongly dependent on factors that affect individual foraging where resources are poor. we investigated potential links between foraging behaviour, reproductive performance and morphology in a goshawk accipiter gentilis population, which experienced markedly different resourc ... | 2013 | 23995242 |
| do warning calls boost survival of signal recipients? evidence from a field experiment in a group-living bird species. | warning calls are a widespread anti-predator adaptation, which can signal unprofitability to predators or alert other potential targets of the predator. although it is tacitly assumed that the recipients of warning calls experience a reduction in predation risk, this crucial assumption remains untested. here i tested this hypothesis with a field experiment in the group-living siberian jay, perisoreus infaustus. i exposed male or female breeding adults that were foraging together with a non-breed ... | 2013 | 23941356 |