Free-ranging Birds Of Prey Research Articles

Prevalence of anticoagulant rodenticide exposure in red-tailed hawks (Buteo jamaicensis) and utility of clotting time assays to detect coagulopathy.

Anticoagulant rodenticides (ARs) continue to be used across the United States as a method for controlling pest rodent species. As a consequence, wild birds of prey are exposed to these toxicants by eating poisoned prey items. ARs prevent the hepatic recycling of vitamin K and thereby impede the post-translational processing of coagulation factors II, VII, IX, and X that are required for procoagulant complex assembly. Through this mechanism of action, ARs cause hemorrhage and death in their target species. Various studies have documented the persistence of these contaminants in birds of prey but few have attempted to use affordable and accessible diagnostic tests to diagnose coagulopathy in free-ranging birds of prey. In our study free-ranging red-tailed hawks were found to be exposed to difethialone and brodifacoum. Eleven of sixteen (68%) livers tested for AR exposure had detectable residues. Difethialone was found in 1/16 (6%), and brodifacoum was detected in 10/16 (62%) liver samples that were tested for rodenticide residues. Difethialone was found at a concentration of 0.18 ug/g wet weight and brodifacoum concentrations ranged from 0.003-0.234 ug/g wet weight. Two out of 34 (6%) RTHA assessed for blood rodenticide had brodifacoum in serum with measured concentrations of 0.003 and 0.006 ug/g. The range of clotting times in the prothrombin time (PT) and Russell's viper venom time assays for control RTHA were 16.7 to 39.7 s and 11.5 to 91.8 s, respectively. One study bird was diagnosed with clinical AR intoxication with a brodifacoum levels in blood of 0.006 and 0.234 ug/g wet weight in blood and liver respectively, a packed cell volume (PCV) of 19%, and PT and RVVT times of >180 s. No correlation was found between PT and RVVT in the control or free-range RTHA, and there was no relationship found between the presence of liver anticoagulant residues and clotting times in the PT and RVVT.

A RETROSPECTIVE STUDY OF FEMORAL FRACTURES IN WILD BIRDS OF PREY: 119 CASES.

A retrospective study was performed to describe patient and fracture characteristics, treatments, complications, and outcomes associated with femoral fractures in free-ranging birds of prey. Cases were identified from the electronic database and included raptors admitted with femoral fractures at the Bird of Prey Clinic of the Université de Montréal, from 1986 to 2018. In total, 119 individuals from 24 species, with 123 femoral fractures, were included in the study. Twenty-seven birds (23%) were declared dead upon arrival. Ninety-two birds (77%) were admitted alive; 80 with acute fractures and 12 with a fracture that had already healed. A conservative treatment (cage rest) was used to manage eight fractures. Surgical repair was attempted on 34 femoral fractures in 33 birds. An intramedullary pin alone was used in 28 cases (82%), and an external skeletal fixator-intramedullary pin tie-in fixator was used in 6 cases (18%). For surgically treated fractures, 19 healed (in 18 birds), 4 did not heal, and 11 birds died or were euthanized before healing could be achieved. Of the 23/34 fractures where the healing process could be assessed, healing rate for comminuted fractures (11/23) was 91% (10/11). Surgical complications occurred in 10 cases (including 7 cases of migration and loosening of the pin, and 1 case of osteomyelitis), leading to euthanasia in 4 cases. Out of the 21 birds with acute femoral fracture upon presentation that were released, 14 had received a surgical treatment and 7 had received a conservative treatment. Nine of the 21 released birds (43%) had at least one other fractured bone. The majority of deaths and euthanasia occurred within 2 wk after admission (51/59; 86%). Thirteen birds were euthanized primarily because of their femoral fracture. Thirteen birds died in treatment and 33 were deemed nonreleasable and euthanized because of a comorbidity not related to the femoral fracture.

Release Rates and Complications for Birds of Prey With Antebrachial Fractures at a Veterinary Teaching Hospital.

A retrospective case series that included 253 free-ranging birds of prey admitted to a rehabilitation center was conducted to describe the treatment and outcome of antebrachial fractures. Medical records from birds of prey belonging to 21 species admitted with antebrachial fracture between 1989 and 2015 at the University of California, Davis, were reviewed. Species distribution on admission, treatment, outcome, and complications were described by fracture category and species. Among 134 birds treated after initial triage on the day of admission, 4 bone/ wing categories were identified: 83 birds had an ulnar fracture only; 18 birds had a radial fracture only; 28 birds had a concomitant fracture of the radius and ulna on the same wing; and 5 birds had bilateral antebrachial fractures. Logistic regressions were performed to determine which factors were associated with a positive outcome within each of these 4 categories. Among birds having only an ulnar fracture, those with a closed fracture were significantly more likely to be released than birds with open fractures (P = .03; odds ratio = 5.43, 95% confidence interval: 1.29-28.12). In addition, birds with a fracture of the middle third of the ulna were significantly more likely to be released than birds diagnosed with a single fracture of the proximal third of the ulna (P = .02; odds ratio = 4.54, 95% confidence interval: 1.35-16.64). No significant prognostic factor was detected in other fracture categories.

Use of blood clotting assays to assess potential anticoagulant rodenticide exposure and effects in free-ranging birds of prey

Non-target wildlife, particularly birds of prey, are widely exposed to and acutely poisoned by anticoagulant rodenticides (ARs). An unresolved issue surrounding such exposure, however, is the potential for sublethal effects. In particular, the consequences of AR exposure and resulting coagulopathy on health and survival of unintentionally exposed animals, which often encounter a multitude of anthropogenic stressors, are understudied. In a wildlife rehabilitation setting, AR intoxication may be masked by more obvious injuries related to collision with vehicles or electrocution, thereby obfuscating proximate from ultimate cause of mortality. An assessment of coagulation function of admitted wildlife may provide a means of identifying animals exhibiting sublethal coagulopathy, and ultimately ensuring provision of appropriate and swift treatment. In conjunction with routine diagnostics for injury and disease, we performed two blood clotting assays (prothrombin time, Russell's viper venom time) affected by vitamin K-dependent coagulopathy of samples from six species of live raptors admitted to a rehabilitation facility. We also measured clotting time in pre-fledgling barn owl chicks (Tyto furcata) from 10 nest sites in Lower Mainland Canada. Prolonged clotting time or failure to form a clot altogether was observed in 23.0% of 61 sampled raptors admitted to the rehabilitation facility. This is a biologically significant proportion of individuals given the fortuitous and likely biased nature by which raptors are found and admitted to rehabilitation facilities. In contrast, there was little evidence of coagulopathy in 19 pre-fledgling barn owl chicks. The utility of avian coagulation tests for diagnosing AR exposure is promising, yet there remains a need to establish species specific reference values and standardize assay methodologies among testing facilities.

Validation of a QuECheRS method for analysis of neonicotinoids in small volumes of blood and assessment of exposure in Eurasian eagle owl (Bubo bubo) nestlings

Neonicotinoid pesticides have gained great interest in the last years both for agricultural and domestic use. Since the information on their environmental distribution or the effects derived from exposure to ecosystems and biota is scarce, new analytical techniques are being developed for monitoring studies. In this sense, two extraction techniques based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology to detect the neonicotinoids authorised in Spain (acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, nitenpyram and thiamethoxam) were adapted and compared: a) using acetate buffer (AB); and b) using citrate buffer (CB). For detection and quantification, high performance liquid chromatography coupled with time of flight mass spectrometry (HPLC/TOF-MS) was used. The CB method provided a wide range of recoveries (68–134%) and accuracy (4–9%). The AB method provided good recoveries (59–76%, 59% corresponded to clothianidin) precision (4–11%) linearity (0.987–0.998%) and limit of quantification (2–10ng/mL) for all the compounds. To test the effectiveness of the technique, we analysed 30 blood samples of free-ranging nestlings of Eurasian eagle owl (Bubo bubo). The only compound detected, in one nestling from a dry land farming area, was imidacloprid, with a concentration of 3.28ng/mL. To our knowledge, this is the first study of neonicotinoid pesticides in free-ranging birds of prey using non-destructive samples, providing the first insight for biomonitoring studies. Further studies, including toxicokinetics and toxicodynamics, are recommended to assess the risk for these species.

West Nile and st. Louis encephalitis viruses antibodies surveillance in captive and free-ranging birds of prey from Argentina.

We evaluated the prevalence of WNV and SLEV neutralizing antibodies in captive and free-ranging raptors from Argentina by plaque-reduction neutralization test. Eighty plasma samples from 12 species were analyzed. Only one captive adult Crowned Eagle (Harpyhaliaetus coronatus) was WNV seropositive (prevalence: 1.25%; antibody titer of 1:80). Two captive Crowned Eagles were SLEV seropositive (prevalence: 2.50%; antibody titers: 1:80 and 1:40).These findings expand the geographic distribution of WNV and SLEV and confirm their activity in central and northeastern Argentina. West Nile virus activity in Argentina may represent a potential threat to Crowned Eagles and other endangered raptors in this country.

Plasma concentration of α-tocopherol in different free-ranging birds of prey

In this study, we investigated the α-tocopherol plasma concentrations in healthy free-ranging nestlings of the white-tailed sea eagle (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) as well as of free-ranging adults of the white-tailed sea eagle (n = 10), osprey (n = 31), and northern goshawk (n = 45). α-Tocopherol plasma concentrations were determined by reverse-phase high-performance liquid chromatography. α-Tocopherol plasma concentrations in nestlings of osprey, white-tailed sea eagle, and northern goshawk did not differ significantly amongst the species, but the common buzzard and honey buzzard nestlings had significantly lower α-tocopherol plasma concentrations than nestlings of the other species (both P < 0.001). Adult male ospreys and white-tailed sea eagles had significantly higher α-tocopherol concentrations compared to adult females (both P < 0.005). Adult ospreys and northern goshawks had significantly higher α-tocopherol plasma concentrations compared to their nestlings (both P < 0.001). In adult female northern goshawks, plasma concentrations of α-tocopherol increased significantly before egg laying (P < 0.001). These results demonstrate α-tocopherol plasma concentrations in birds of prey to be species specific and influenced by age and reproductive status.

Use of polymerase chain reactions to detect Mycoplasma gallisepticum, Mycoplasma imitans, Mycoplasma iowae, Mycoplasma meleagridis and Mycoplasma synoviae in birds of prey

Certain Mycoplasma spp. are pathogens of poultry, but little is known of the role of mycoplasmas in disease of birds of prey. Species-specific polymerase chain reactions (PCRs) for the detection of the poultry pathogens Mycoplasma gallisepticum, Mycoplasma imitans, Mycoplasma iowae, Mycoplasma meleagridis and Mycoplasma synoviae were therefore evaluated for use in birds of prey. The specificities of the PCR methods were established using avian and other mycoplasmas and also selected walled bacteria. The sensitivities of the different PCR assays varied between 100 fg and 10 pg DNA. Fifty-three tracheal swabs from healthy captive and free-ranging birds of prey were then investigated using these PCRs, and in no case was an amplicon obtained for M. gallisepticum/M. imitans, M. iowae or M. synoviae. Species-specific primers for M. meleagridis amplified a product from eight birds of prey but restriction enzyme analysis as well as sequencing of PCR products demonstrated these results to be false positives. Alignment studies of the sequenced products with the 16S rRNA gene sequence of various Mycoplasma species in GenBank demonstrated an identity of 91% to M. meleagridis but of 98% to Mycoplasma buteonis or Mycoplasma gallopavonis. Isolation and attempted identification of these mycoplasmas suggested it may be a previously unrecognized species.

Isolation of Mycoplasma meleagridis from free-ranging birds of prey in Germany.

In this study tracheal swabs and air sac biopsies of 68 raptors of different species that were found injured or debilitated in Germany were investigated for the occurrence of mycoplasmas. Mycoplasma meleagridis, Mycoplasma falconis, Mycoplasma buteonis, Mycoplasma gypis and five mycoplasma isolates not identified so far could be isolated from 32 (47%) birds. Mycoplasma meleagridis could be detected in five birds. These birds did not show clinical signs or histopathological alterations in air sac biopsies related to the infection.

Serological survey for rabies antibodies in raptors from California.

Fifty-three newly captive birds of prey were tested serologically for neutralizing antibodies against rabies virus, using a fluorescent focus inhibition test. No significant antibody titers were detected with this sensitive and specific technique in any of these birds. This study supports the contention that free-ranging birds of prey are of limited importance in the epidemiology of rabies.