The impact of lead poisoning from ammunition sources on raptor populations in Europe

Poisoning caused by ingestion of spent lead (Pb) ammunition in food items is a common cause of death of raptors. However, there has been no previous attempt to assess the impact of lead poisoning on populations of raptors throughout Europe or examine how this relates to the prevalence of hunting. We used measurements of lead concentration in the liver from over 3000 raptors of 22 species found dead or dying in the wild in 13 countries and a lead poisoning threshold of 20 ppm (dry weight) to assess the proportion of these in which lead poisoning caused or contributed to death. The prevalence of lead poisoning as a cause of death of raptors varied substantially among European countries and was positively correlated across countries with the reported number of hunters per unit area. Ten species had a non-zero proportion of individuals with concentrations exceeding the lead poisoning threshold ranging between 0.3% and 16.5%. The estimated annual conditional death rate from lead poisoning for these ten species averaged 0.44% (range 0.06-0.85%). Scavenging species feeding regularly on carcasses of game animals,tended to have a high annual probability of death from lead poisoning. So too did some predators which only sometimes scavenge, but prey on frequently hunted birds, such as gamebirds, waterfowl and pigeons, which may contain ingested or embedded lead shot. Small-bodied predators had a low annual probability of death from lead poisoning. Modelling indicated that European populations of adult raptors of the ten focal species averaged 6.0% smaller (range 0.2-14.4%) than they would be without the effects of lead poisoning. A given rate of lead poisoning mortality resulted in greater expected population reductions for species with high annual survival rate and late age at first breeding.

Tracking pan-continental trends in environmental contamination using sentinel raptors-what types of samples should we use?

Biomonitoring using birds of prey as sentinel species has been mooted as a way to evaluate the success of European Union directives that are designed to protect people and the environment across Europe from industrial contaminants and pesticides. No such pan-European evaluation currently exists. Coordination of such large scale monitoring would require harmonisation across multiple countries of the types of samples collected and analysed-matrices vary in the ease with which they can be collected and the information they provide. We report the first ever pan-European assessment of which raptor samples are collected across Europe and review their suitability for biomonitoring. Currently, some 182 monitoring programmes across 33 European countries collect a variety of raptor samples, and we discuss the relative merits of each for monitoring current priority and emerging compounds. Of the matrices collected, blood and liver are used most extensively for quantifying trends in recent and longer-term contaminant exposure, respectively. These matrices are potentially the most effective for pan-European biomonitoring but are not so widely and frequently collected as others. We found that failed eggs and feathers are the most widely collected samples. Because of this ubiquity, they may provide the best opportunities for widescale biomonitoring, although neither is suitable for all compounds. We advocate piloting pan-European monitoring of selected priority compounds using these matrices and developing read-across approaches to accommodate any effects that trophic pathway and species differences in accumulation may have on our ability to track environmental trends in contaminants.

An overview of existing raptor contaminant monitoring activities in Europe

Biomonitoring using raptors as sentinels can provide early warning of the potential impacts of contaminants on humans and the environment and also a means of tracking the success of associated mitigation measures. Examples include detection of heavy metal-induced immune system impairment, PCB-induced altered reproductive impacts, and toxicity associated with lead in shot game. Authorisation of such releases and implementation of mitigation is now increasingly delivered through EU-wide directives but there is little established pan-European monitoring to quantify outcomes. We investigated the potential for EU-wide coordinated contaminant monitoring using raptors as sentinels. We did this using a questionnaire to ascertain the current scale of national activity across 44 European countries. According to this survey, there have been 52 different contaminant monitoring schemes with raptors over the last 50years. There were active schemes in 15 (predominantly western European) countries and 23 schemes have been running for >20years; most monitoring was conducted for >5years. Legacy persistent organic compounds (specifically organochlorine insecticides and PCBs), and metals/metalloids were monitored in most of the 15 countries. Fungicides, flame retardants and anticoagulant rodenticides were also relatively frequently monitored (each in at least 6 countries). Common buzzard (Buteo buteo), common kestrel (Falco tinnunculus), golden eagle (Aquila chrysaetos), white-tailed sea eagle (Haliaeetus albicilla), peregrine falcon (Falco peregrinus), tawny owl (Strix aluco) and barn owl (Tyto alba) were most commonly monitored (each in 6-10 countries). Feathers and eggs were most widely analysed although many schemes also analysed body tissues. Our study reveals an existing capability across multiple European countries for contaminant monitoring using raptors. However, coordination between existing schemes and expansion of monitoring into Eastern Europe is needed. This would enable assessment of the appropriateness of the EU-regulation of substances that are hazardous to humans and the environment, the effectiveness of EU level mitigation policies, and identify pan-European spatial and temporal trends in current and emerging contaminants of concern.

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 = 45) were investigated with reversed-phase-high-performance liquid chromatography (RP-HPLC). In WTSE, northern goshawks and common buzzards retinol were the main plasma component of vitamin A, whilst in ospreys and honey buzzards, 3,4-didehydroretinol predominated. The median of the retinol plasma concentration in the nestlings group ranged from 0.12 to 3.80 μm and in the adult group from 0.15 to 6.13 μm. Median plasma concentrations of 3,4-didehydroretinol in nestlings ranged from 0.06 to 3.55 μm. In adults, northern goshawks had the lowest plasma concentration of 3,4-didehydroretinol followed by WTSE and ospreys. The plasma of all investigated species contained retinyl esters (palmitate, oleate, and stearate). The results show considerable species-specific differences in the vitamin A plasma concentrations that might be caused by different nutrition strategies.

Haemosporidian blood parasites in European birds of prey and owls

Avian blood parasites have been intensively studied using morphological methods with limited information on their host specificity and species taxonomic status. Now the analysis of gene sequences, especially the mitochondrial cytochrome b gene of the avian haemosporidian species of Haemoproteus, Plasmodium, and Leucocytozoon, offers a new tool to review the parasite specificity and status. By comparing morphological and genetic techniques, we observed nearly the same overall prevalence of haemosporidian parasites by microscopy (19.8%) and polymerase chain reaction (PCR) (21.8%) analyses. However, in contrast to the single valid Leucocytozoon species (L. toddi) in the Falconiformes we detected 4 clearly distinctive strains by PCR screening. In the Strigiformes, where the only valid Leucocytozoon species is L. danilewskyi, we detected 3 genetically different strains of Leucocytozoon spp. Two strains of Haemoproteus spp. were detected in the birds of prey and owls examined, whereas the strain found in the tawny owl belonged to the morphospecies Haemoproteus noctuae. Three Plasmodium spp. strains that had already been found in Passeriformes were also detected in the birds of prey and owls examined here, supporting previous findings indicating a broad and nonspecific host spectrum bridging different bird orders.

Specific status and pathogenicity of syngamid nematodes in bird species (Ciconiformes, Falconiformes, Gruiformes) from Germany

A total of 549 birds from four orders were examined for nematodes in their respiratory system from 1995 to 2000. Twelve individuals of Falconiformes (n = 503), one of Gruiformes (n = 22) and one of Ciconiformes (n = 1), but no bird of the order Strigiformes (n = 23) were infected with syngamids. The syngamid species included Hovorkonema variegatum, Syngamus trachea and Cyathostoma trifurcatum from the trachea, bronchi and air sacs, with H. variegatum being the most prevalent. Cyathostoma trifurcatum from a black stork Ciconia nigra is a new record for Germany. The marsh harrier Circus aeruginosus and the white-tailed sea eagle Haliaeetus albicilla are new hosts for H. variegatum. Morphological characters such as the dorsal rays of the bursa copulatrix, length of the spicules and the mouth capsule are used to differentiate species of the family Syngamidae. Egg size is different between S. trachea and H. variegatum. In addition to morphological characters, the nucleotide sequence of the SSU ribosomal gene was determined for H. variegatum. Pairwise comparisons with the SSU sequence of S. trachea (AF036606) revealed sequence difference of 2.6%. The nucleotide sequence of the second internal transcribed spacer of ribosomal DNA for different populations of H. variegatum was also determined. Pairwise comparisons revealed two separate strains with a sequence difference of 14.0% to 14.5% suggesting the existence of a cryptic species. Pathological findings associated with H. variegatum were found in 7 of 12 cases and consisted of thickened air sac walls and lesions or granuloma at the site of attachment of the worm, which occasionally involved the underlaying tissues. Lymphoplasmocytic air sacculitis was the most prominent histological lesion found.

[Case report: Libyostrongylus douglassii-associated proventriculitis in ostriches in Germany]

Cases of Libyostrongylus douglassii-associated proventriculitis in an adult female ostrich and two ostrich chicks occurring on two farms in different federal states of Germany are described. The adult bird was recently bought and kept under quarantaine conditions without contact to other animals of the herd. Without developing clinical signs of illness, the animal died. At necropsy, typical lesions of wireworm infection were found. The lining of the stomach had a moth-eaten appearance. Massive amounts of adult stages of trichostrongyloid nematodes were diagnosed in histological specimens of the proventricular mucosa and under the koilin layer of the ventriculus. The worms were isolated from the proventriculus and identified as L. douglassii. The feces of the bird contained high amounts of typical eggs of the worms with a medium size of approximately 70 x 40 microm. A polyphasic degeneration of heart and skeletal muscle was diagnosed in addition to the wireworm infection and interpreted to be a result of a malnutrition (Vit. E-/selenium deficiency). The ostrich chicks were reared on another farm and submitted for necropsy because of high mortality (8 out of 12 chicks died). A massive invasion of the proventricular mucosa with L. douglassi was macroscopically and histologically detected at necropsy of the anemic birds.

Avipoxvirus infection in peregrine falcons (Falco peregrinus ) from a reintroduction programme in Germany

Poxvirus infections are common in domestic birds in Germany, but they are rare in birds of prey. Only species of falconidae imported from Arabian or Asian countries have so far tested positive for poxvirus, and, among these, only raptors kept for falconry. As part of a reintroduction programme in the northern county of Mecklenburg-Western Pomerania, which is adjacent to the Baltic Sea, 21 young peregrine falcons were released into the wild; six of them died and one was examined postmortem, its tissues being examined by light and electron microscopy. In addition, an ELISA for fowlpox, pigeonpox and canarypox was applied. No virus could be isolated and propagation in culture failed, but virus particles were detected by electron microscopy in lesions from its skin and tongue.

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 Germany from 1995 to 2001. Our results indicate significant differences in the contaminant burden of northern goshawks between three regions in Germany. Presumably, these differences were caused by different application periods and legislative restrictions before the German reunion, especially for the use of DDT in agriculture and forestry. Extraordinarily high residues of PCBs and DDE, the main metabolite of DDT, were found mainly in livers of northern goshawks inhabiting Berlin. Body condition is highly negatively correlated with the contamination level of the individual, especially for the persistent and lipophilic organochlorines and for mercury. PCB concentrations in hepatic tissue increase rapidly with age, and birds in their first summer had significantly lower levels than birds in their first winter or older. Adult female northern goshawks from Berlin had significantly higher hepatic concentrations of most of the higher-chlorinated PCBs and of cadmium than males from the same region. Cadmium residues were in general higher in renal tissue than in hepatic tissue, and cadmium levels in kidneys increased with age. Lead concentrations indicative of acute lead poisoning were detected in one bird and suggested in two others. All other heavy metal concentrations were low and represent background levels for birds of prey in Germany.

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 groups of five chickens after an ACTH and a dexamethasone injection to stimulate and to suppress adrenal activity. A control group received a saline injection. After ACTH plasma cortisol concentrations increased 16-fold after 1.5 h to levels between 19 and 38 ng/ml and dropped to pre-treatment levels (1.1-2.5 ng/ml) 4h after stimulation. Dexamethasone did not result in a distinct suppression of adrenocortical activity and plasma corticosterone dropped only slightly below pre-treatment levels. The concentrations in fecal metabolites corresponded to the changes in the levels of biological active hormone in plasma. Fecal peak excretion (105-295 ng/g) was obtained with a delay of approximately 4 h compared to plasma. The profile obtained after ACTH challenge reflected a broader and dampened pattern of glucocorticoid secretion and provided a more integrated measure of adrenal activity. Dexamethasone treatment did not induce a measurable decrease in fecal metabolites and concentrations fluctuated around a mean of 30.0+/-9.9 ng/g, almost identical to those obtained from the saline treatment group (29.4+/-13.9 ng/g). In a separate experiment the effect of an alternative capture method (remote-controlled injection system) was investigated in cormorants. Plasma corticosterone measurements revealed a significantly diminished stress reaction compared to traditional trapping (1.24+/-0.78 vs. 10.9+/-12.1 ng/ml). Investigations whether goshawk nestlings infected with Trichomas gallinae differ in fecal corticosterone metabolite concentrations compared to healthy subjects revealed no significant changes. However, a significant correlation was found between the glucocorticoid metabolite concentrations and the number of nestlings per nest. The demonstration that adrenal activity can be detected by the assay is a prerequisite that ecologically meaningful levels of imposed stress can be validated. Therefore, non-invasive measurements of fecal metabolites are a promising perspective to monitor stress in birds.

Chaunocephalus ferox in free-living white storks in central Spain

Ten out of 42 (23.8%) white storks (Ciconia ciconia) admitted to two rehabilitation centers in central Spain had lesions caused by the trematode Chaunocephalus ferox in the small intestinal wall. Fourteen of the examined birds were adults, five were subadults, and 23 were chicks of various ages. Parasitation was 32% (n = 8) in chicks and 13% (n = 2) in adult birds, whereas no juvenile bird was affected. Among dead birds, stork chicks affected by C. ferox lesions had a lower body weight (2196.1 g, SD = 814.2) than storks without lesions (2965.8 g, SD = 742.9, P < 0.05). Two chicks were additionally infected with Salmonella subspecies I serotype enteritidis 1,9,12: g, m:1, 7. Prevalence of the parasite in the examined birds was lower than in a population of Asian open-billed storks (Anastomus oscitans), in which it was pathogenic due to the destruction of the tunica muscularis and formation of large granulomatous lesions in the wall of the postduodenal portion of the small intestine. Pathogenic alterations caused by C. ferox are presumed to be related to numbers of adults present. Because storks admitted to rehabilitation centers suffer stress due to various reasons that may lower their immune response and exacerbate existing infections, the analysis of fecal sediments of white storks admitted for rehabilitation is recommended.

Identification and analysis of a new hepadnavirus in white storks

We identified, cloned, and functionally characterized a new avian hepadnavirus infecting storks (STHBV). STHBV has the largest DNA genome of all avian hepadnaviruses and, based on sequence and phylogenetic analysis, is most closely related to, but distinct from, heron hepatitis B virus (HHBV). Unique for STHBV among the other avian hepadnaviruses is a potential HNF1 binding site in the preS promoter. In common only with HHBV, STHBV has a myristylation signal on the S and not the preS protein, two C terminally located glycosylation sites on the precore/core proteins and lacks the phosphorylation site essential for the transcriptional transactivation activity of duck-HBV preS protein. The cloned STHBV genomes were competent in gene expression, replication, and viral particle secretion. STHBV infected primary duck hepatocytes very inefficiently suggesting a restricted host range, similar to other hepadnaviruses. This discovery of stork infections unravels novel evolutionary aspects of hepadnaviruses and provides new opportunities for hepadnavirus research.

Heavy metals in soft tissue of white-tailed eagles found dead or moribund in Germany and Austria from 1993 to 2000

Residues of the potentially toxic metals lead, mercury, and cadmium were analyzed in liver and kidney tissue of 61 free-ranging white-tailed eagles (Haliaeetus albicilla) found dead or moribund in Germany and Austria between 1993 and 2000. Highest values and the widest range were detected for lead in liver and for mercury in kidney tissue. Lead concentrations considered to induce lethal lead poisoning (>5 ppm wet wt) were determined in 28% of liver samples. Lead fragments were detected it the gizzards of two specimens, presumably having died from lead intoxication. Histopathological findings in a recently dead white-tailed eagle indicating acute lead exposure comprise degenerative Purkinje cells in the cerebrellum and inclusion bodies in renal tubular cells. Mercury residues in organs are decreasing compared to former studies in periods when organomercury compounds were used as seed dressing. All cadmium values were low or are at background levels in white-tailed eagles. The present study clearly identities lead as a toxic metal poison in white-tailed eagles in Germany and Austria.

Heavy metals in soft tissue of white-tailed eagles found dead or moribund in Germany and Austria from 1993 to 2000

Residues of the potentially toxic metals lead, mercury, and cadmium were analyzed in liver and kidney tissue of 61 free-ranging white-tailed eagles (Haliaeetus albicilla) found dead or moribund in Germany and Austria between 1993 and 2000. Highest values and the widest range were detected for lead in liver and for mercury in kidney tissue. Lead concentrations considered to induce lethal lead poisoning (>5 ppm wet wt) were determined in 28% of liver samples. Lead fragments were detected it the gizzards of two specimens, presumably having died from lead intoxication. Histopathological findings in a recently dead white-tailed eagle indicating acute lead exposure comprise degenerative Purkinje cells in the cerebrellum and inclusion bodies in renal tubular cells. Mercury residues in organs are decreasing compared to former studies in periods when organomercury compounds were used as seed dressing. All cadmium values were low or are at background levels in white-tailed eagles. The present study clearly identities lead as a toxic metal poison in white-tailed eagles in Germany and Austria.

Strigea falconispalumbi in Eurasian buzzards from Germany

Eighty-three free-living Eurasian buzzards (Buteo buteo) from three different areas in Germany were examined for adult stages and the metacercaria of the trematode Strigea falconispalumbi. Prevalences of adult parasites in the small intestine was 36% (Berlin/Brandenburg), 28% (Lower Saxony) and 3% (Baden-Württemberg). Metacercaria in the connective tissue of the neck were found in 58%, 55%, and 10% of birds from the respective areas. Significant differences in the prevalence of S. falconispalumbi adults and metacercaria between the areas were attributed to the different abundance of freshwater which is the key habitat for two intermediate hosts.