Determination of Coagulation Parameters by Whole Blood Dynamic Viscoelastic Coagulometry in Strigiformes.

No reference values are available in Strigiformes to evaluate blood coagulation using dynamic viscoelastic coagulometry (DVC) with the Sonoclot (Sienco, Boulder, CO, USA) analyzer. The objectives of this study were 1) to assess the feasibility of DVC in Strigiformes, 2) to calculate the index of individuality of each coagulation parameter, and 3) to assess interspecies variability and establish reference intervals, if relevant, based on the index of individuality. Fresh whole blood samples were obtained from healthy Strigiformes, including 13 barred owls (Strix varia), 10 great horned owls (Bubo virginianus), 6 snowy owls (Bubo scandiacus), and 7 eastern screech owls (Megascops asio), and analyzed with DVC with glass bead (gb) and kaolin clay (k) coagulation activators. Activated clotting time (ACT), clot rate (CR), and platelet function were determined immediately after collection using fresh native whole blood. Intraindividual variability was assessed with a second fresh native whole blood sample from 5 barred owls. Interindividual variability was assessed using a Kruskall-Wallis test. For the parameters gbACT (n = 35), gbCR (n = 34), and kACT (n = 27), no significant differences were detected between species (all P ≥ 0.05). Based on low index of individuality, global Strigiformes reference intervals were determined for gbACT (32.3-852.5 seconds; n = 35), gbCR (0-20.1 units/min; n = 29), and kACT (0-1570.3 seconds; n = 27). In conclusion, DVC can be used in Strigiformes and the gb coagulation activator would be more appropriate when basal individual values are not available in a tested individual.

Density-dependent winter survival of immatures in an irruptive raptor with pulsed breeding.

Highly mobile predators can show strong numerical responses to pulsed resources, sometimes resulting in irruptions where large numbers of young invade landscapes at a continental scale. High production of young in irruption years may have a strong influence on the population dynamics unless immature survival is reduced compared to non-irruption years. This could occur if subordinate individuals (mainly immatures) are forced into suboptimal habitats due to density-dependent effects in irruption years. To test whether irruptive individuals had lower survival than non-irruptive ones, we combined necropsy results (N = 365) with telemetry (N = 185) from more than 20 years to record timing and causes of mortality in snowy owls (Bubo scandiacus), which irrupt into eastern North America during winter following high breeding output caused by lemming peaks in the Arctic. Mortality was more than four times higher in irruption years than non-irruption years, but only for immatures, and occurred disproportionately in early winter for immatures, but not adults. Mortality was also higher in eastern North America, where owl abundance fluctuates considerably between years, compared to core winter regions of the Arctic and Prairies where populations are more stable. Most mortality was not due to starvation, but rather associated with human activity, especially vehicle collisions. We conclude that immature snowy owls that irrupt into eastern North America are limited by density-dependent factors, such as increased competition forcing individuals to occupy risky human-altered habitats. For highly mobile, irruptive animals, resource pulses may have a limited impact on population dynamics due to low subsequent survival of breeding output during the nonbreeding season.

Risk Factors and Prognosis for Humeral Fractures in Birds of Prey: A Retrospective Study of 461 Cases from 2000 to 2015.

The objectives of this retrospective study were 1) to characterize humeral fractures in raptors at a rehabilitation program, 2) to determine risk factors for closed and compound humeral fractures in the raptors, and 3) to investigate prognostic factors for humeral fractures in raptors. Of the 6017 birds of prey admitted over 15 years to the Université de Montréal raptor rehabilitation program, 461 birds presented with a humeral fracture. The highest occurrences of humeral fractures were documented in short-eared owls (33%; Asio flammeus), Northern hawk-owls (24%; Surnia ulula), long-eared owls (20%; Asio otus), and Northern harriers (19%; Circus hudsonius). Humeral fractures were more common in males, and species from the intermediate weight group (300 g to 1 kg) were more likely to have compound humeral fractures than birds from the lower and higher weight groups. Humeral fractures of the middle and distal third of the bone were diagnosed as compound more often than fractures of the proximal third. A correlation between the occurrences of humeral fractures and the relative average width of the humerus for each species was observed and suggests that species with slender humeri have an increased likelihood of compound humeral fractures. Following the triage criteria used at this rehabilitation program, surgical (119 birds) or nonsurgical (77 birds) treatments were attempted. Release rate for birds without concomitant conditions in which a treatment was attempted was 39.3% (59/150) and did not significantly differ between closed and compound fractures, which suggests that the triage criteria used for compound fractures in this program were adequate. Our findings emphasize that raptors should not be systematically euthanatized when presented with compound humeral fractures to a rehabilitation facility.

Outcomes of Birds of Prey with Surgical or Traumatic Wing Amputation: A Retrospective Study from 1995 to 2017.

Surgical amputation of a limb is often required to treat raptor orthopedic injuries at rehabilitation centers. In some cases, amputation is an alternative to euthanasia if the bird's welfare is deemed appropriate under human care. The outcome for raptors maintained in a captive setting following wing amputation is poorly documented. A retrospective study was conducted in a Canadian raptor rehabilitation facility to assess the outcomes and complications observed in captive and free-living raptors with partial or complete, surgical or traumatic amputations of the wing. Data from raptors admitted to the rehabilitation center from 1995 to 2017 were reviewed. Overall, 32 records were included in this retrospective study from 11 species of raptors with surgical or traumatic wing amputations. Survival times of the 23 birds with an amputated wing (median: 1070 days, range: 68 days to 13 years and 1 month) were significantly (P = .02) longer than the survival times of the 404 non-amputated birds (median: 696 days, range 37 days to 27 years and 3 months). Complications occurred in 13 of 30 birds (43%) during the recovery period, with 9 of 30 (30%) birds developing life-threatening complications. Maladaptation to captivity was the leading cause of euthanasia during this period. After placement in captivity, 3/23 (13%) birds developed complications related to the amputation site. Based on this study, we conclude that some birds can tolerate partial or complete wing amputation, but the decision to place a bird in a captive setting should encompass the bird's ability to cope with human interaction and the availability of an adapted and safe enclosure for the animal.

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.

Horner Syndrome in Birds of Prey.

Horner syndrome, which results from oculosympathetic denervation, has rarely been reported in birds. A retrospective study was conducted in a raptor rehabilitation program to gain further insight into Horner syndrome in birds. Data from 5128 live raptors admitted over 20 years were reviewed. Horner syndrome was identified in 22 individuals from 13 different species. Raptors from the orders Strigiformes, Accipitriformes, and Falconiformes were affected, with the last order being underrepresented. Ptosis of the upper eyelid was the most commonly reported clinical sign in the birds diagnosed with Horner syndrome, having been noted in 21 cases. Signs of traumatic injury, such as fractures, wounds, and hematomas, were documented in 18 cases. Among the 22 cases, 12 birds were euthanatized, 3 died in treatment, and 7 were successfully released back into the wild.

Preliminary Findings of Structure and Expression of Opioid Receptor Genes in a Peregrine Falcon ( Falco peregrinus), a Snowy Owl ( Bubo scandiacus), and a Blue-fronted Amazon Parrot ( Amazona aestiva).

To further knowledge of the physiology of opioid receptors in birds, the structure and expression of the µ-, δ-, and κ-opioid receptor genes were studied in a peregrine falcon ( Falco peregrinus), a snowy owl ( Bubo scandiacus), and a blue-fronted Amazon parrot ( Amazona aestiva). Tissue samples were obtained from birds that had been euthanatized for poor release prognosis or medical reasons. Samples were taken from the brain (telencephalon, thalamus, pituitary gland, cerebellum, pons, medulla oblongata, mesencephalon), the spinal cord and dorsal root ganglions, and plantar foot skin. Messenger RNA was recovered, and reverse transcription polymerase chain reaction (RT-PCR) was performed to generate complementary DNA (cDNA) sequences. Gene structures were documented by directly comparing cDNA sequences with recently published genomic sequences for the peregrine falcon and the blue-fronted Amazon parrot or by comparisons with genomic sequences of related species for the snowy owl. Structurally, the avian µ-opioid receptor messenger RNA (mRNA) species were complex, displaying differential splicing, alternative stop codons, and multiple polyadenylation signals. In comparison, the structure of the avian κ-receptor mRNA was relatively simple. In contrast to what is seen in humans, the avian δ-receptor mRNA structure was found to be complex, demonstrating novel 3-prime coding and noncoding exons not identified in mammals. The role of the δ-opioid receptor merits further investigation in avian species.

Thyroid Hormones, Retinol and Clinical Parameters in Relation to Mercury and Organohalogen Contaminants in Great Blue Heron (Ardea herodias) Nestlings from the St. Lawrence River, Québec, Canada.

The exposure and effects of persistent environmental contaminants were investigated in great blue heron (Ardea herodias) nestlings sampled in 2001, 2002, 2006, and 2007 in freshwater and estuarine heronries along the St. Lawrence River, Québec (Canada). Biomarkers (retinoids, thyroid hormones, and clinical parameters) and contaminants (organochlorine contaminants, polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs), and mercury (Hg)) were analyzed in blood, and Hg was analyzed in feathers (generally 9 nestlings per colony and 4 colonies per year). Feather Hg and most contaminants detected in blood were found in higher concentrations in birds from freshwater than estuarine colonies more distant from the pollution sources. Among freshwater colonies, Ile aux Hérons showed the highest levels of contaminants, with mean Hg concentrations of 8.4 and 0.55 mg/kg in feathers and plasma, respectively, and plasma ΣBFRs of 19.6 ng/g ww. The highest mean ΣPCBs, 56.5 ng/g ww, was measured at Grande Ile in 2001. The levels of contaminants in heron nestlings were generally below critical thresholds for adverse effects observed on reproduction or survival. Retinol, dehydroretinol (DROH), and thyroid hormone concentrations differed significantly among colonies. Retinol concentrations were negatively related to ΣPCBs, whereas DROH concentrations were negatively related to Hg and total and free triiodothyronine (T3) concentrations were negatively related to ΣBFRs. These results indicate that contaminants from the St. Lawrence River could impair the development and fitness of great blue heron nestlings and emphasize the need for more research on the great blue heron population to assess their health and nutritional status.

Evaluation of High Dosages of Oral Meloxicam in American Kestrels ( Falco sparverius ).

To evaluate the toxicity of short-term high doses of meloxicam in American kestrels ( Falco sparverius ), 32 male captive-born, 1- to 4-year-old American kestrels were randomly assigned to 4 groups: 3 groups treated with meloxicam (n = 9 per group) and a control group (n = 5). Meloxicam was administered orally via feeding tube in the proventriculus at 2, 10, and 20 mg/kg every 12 hours for 7 days for the treatment groups, while the control group received saline solution. The birds were evaluated for the presence of clinical signs, abnormalities in the complete blood cell count and in the plasma biochemical panel for the 20-mg/kg group, and gross and histopathologic lesions. No clinical signs or mortality were observed in any group. No significant differences of clinical relevance were found in results of the packed cell volume, total solids, and biochemical panel, and no evidence of renal toxicity was found in the treatment or control groups. A significant correlation was found between hepatic lipidosis and meloxicam dose (P = .02). Two of 9 birds in the 20-mg/kg group developed gastric ulcers, although this result was not significant. None of the birds in the 2- and 10-mg/kg groups had similar lesions. Finally, meloxicam dosages up to 20 mg/kg did not result in nephrotoxicity in American kestrels. Further toxicologic studies to evaluate hepatotoxicity and gastrotoxicity of meloxicam in avian species are needed.

Assessment of regrowth of flight feathers after manual removal in American kestrels (Falco sparverius).

The objective of this study was to evaluate if extraction of broken feathers outside the molting period was an efficient method to induce growth of new flight feathers as part of the rehabilitation process of raptors with damaged plumage. Primaries, secondaries, and rectrices (four of each) were removed under general anesthesia from 10 American kestrels (Falco sparverius) using two different protocols: with and without filling the follicle with bismuth subnitrate (Orbeseal) to prevent it from sealing. Birds were kept in large aviaries under natural daylight and outdoor temperatures. Rate and quality of growth of new feathers were assessed regularly for 4 mo. Results were significantly different between the types of feathers: 100% of rectrices, 58% of secondaries, and 8% of primaries started to grow within the 4 winter months, and 95% of rectrices, 30% of secondaries, and 0% of primaries completed their growth normally within this period. The use of Orbeseal did not improve the outcome. The tail feathers began to grow between the second and third weeks at about 2.7 mm/day, and growth was completed within 7 wk. Rate, starting time, and duration of remigial growth were less predictable and varied widely among individuals. Although the exact impact of these extractions on the natural molt is still unclear, most of the primaries that were plucked during this study failed to regrow normally during the following molt. In conclusion, plucking damaged tail feathers in kestrels can successfully decrease the duration of rehabilitation. However, this procedure would not be recommended for wing feathers.

Mortality and morbidity associated with gunshot in raptorial birds from the province of Quebec: 1986 to 2007.

Although raptors have been protected for decades in Quebec they are still regular victims of poaching. The objective of this study was to characterize cases of raptor shootings in Quebec over the last 2 decades. We reviewed clinical files, radiographs, and pathology reports on 4805 free-flying birds of prey admitted to the Faculté de médecine vétérinaire between 1986 and 2007. Evidence of gunshots was detected in 6.4% of the birds. Large species, such as ospreys, turkey vultures, snowy owls, and bald eagles represented the most frequently targeted species. The percentage of shot birds has decreased from 13.4% during 1991 to 1992 to 2.2% in 2006 to 2007. Potential reasons for this trend include a decrease in the presence of firearms in raptor habitats and changes in human attitude towards raptorial birds.

Characteristics of antebrachial fractures associated with a successful outcome among free-ranging birds of prey that received treatment in a rehabilitation program.

OBJECTIVE: To identify characteristics of antebrachial fractures associated with a successful outcome (ie, bird released back into the wild after regaining normal flight ability, without being returned to the rehabilitation program within 1 month afterward) for free-ranging birds of prey admitted to a rehabilitation program. ANIMALS: 620 birds of prey (representing 24 species) with antebrachial fractures admitted alive to a rehabilitation program from August 1986 through December 2015. PROCEDURES: The medical record of each bird was reviewed to obtain information on species, age, sex, year of admission, fracture characteristics, and treatments administered. Outcome was classified as successful or unsuccessful on the basis of available data. Multivariable logistic regression was used to identify fracture characteristics associated with outcome. RESULTS: 519 of 620 (84%) birds received treatment, and a successful outcome was recorded for 245 (47%) treated birds. Birds with closed (vs open) fractures were significantly more likely to have a successful outcome. Birds with concomitant radial and ulnar fractures involving the same third of the antebrachium (vs other types of antebrachial fractures) were significantly less likely to have a successful outcome, although birds with this type of fracture were significantly more likely to have a successful outcome when the fracture was localized to the middle or distal (vs proximal) third of the antebrachium. CONCLUSIONS AND CLINICAL RELEVANCE: The characteristics of antebrachial fractures associated with a successful or unsuccessful outcome in this study may be useful in the development of triage protocols for birds of prey in other rehabilitation centers.

Monitoring of the ventilatory status of anesthetized birds of prey by using end-tidal carbon dioxide measured with a microstream capnometer.

The relationship between end-tidal partial pressure of carbon dioxide (PETCO2), arterial partial pressure of carbon dioxide (PaCO2), and blood pH in isoflurane-anesthetized raptors was evaluated. PaCO2 and pH were determined in serial arterial samples from isoflurane anesthetized birds and compared with concurrent end-tidal partial pressure of carbon dioxide measured with a Microstream sidestream capnograph. Forty-eight paired samples, taken from 11 birds of prey (weighing 416-2,062 g), were used to determine correlations coefficients between PaCO2 and PETCO2, and between PETCO2 and pH. Limits of agreement between PaCO2 and PETCO2 also were calculated. Strong correlations were observed between PaCO2 and PETCO2 (r = 0.94; P < 0.0001) as well as between PETCO2 and pH (r = -0.90; P < 0.0001). However, the level of agreement between PaCO2 and PETCO2 varied considerably. Low values of PETCO2, ranging from 18 to 29 mm Hg, exceeded the concomitantly measured values of PaCO2 by an average of 6.0 mm Hg (6.0 +/- 1.9 mm Hg; mean +/- SD). Conversely, high values of PETCO2, ranging from 50 to 63 mm Hg, were on average 7.6 mm Hg (7.6 +/- 9.8 mm Hg) lower than values of PaCO2. In the 30 to 49 mm Hg range for PETCO2, the difference between PETCO2 and PaCO2 was on average 1.0 mm Hg (1.0 +/- 8.5 mm Hg). These results suggest that the capnograph used provided a sufficiently accurate estimation of arterial partial pressure of carbon dioxide for birds weighing > 400 g and receiving manual positive ventilation with a Bain system. In our study, the linear relationship observed between the pH and the end-tidal partial pressure of carbon dioxide suggested that the monitoring of end-tidal partial pressure of carbon dioxide also can be useful to prevent respiratory acidosis.

Analgesic effects of meloxicam administration on postoperative orthopedic pain in domestic pigeons (Columba livia).

OBJECTIVE: To assess the analgesic effects of 2 doses of meloxicam on the degree of postoperative orthopedic pain in pigeons. ANIMALS: 21 domestic pigeons (Columba livia). PROCEDURES: In each bird, a standardized osteotomy of 1 femur was performed and the fracture was immobilized with an intramedullary pin. Birds were randomly allocated to receive saline (0.9% NaCl) solution (control) or meloxicam (0.5 mg/kg [low dose] or 2.0 mg/kg [high dose]). The first treatment was administered i.m. after surgery was completed. Subsequent treatments were administered p.o. every 12 hours for 9 days. Degree of postoperative pain was assessed for the first 4 days after surgery by use of 3 methods: an electronic perch for assessment of weight-bearing load differential of the pelvic limbs, 4 pain scales, and analysis of video-recorded partial ethograms for bird activity and posture. RESULTS: No significant differences were observed between the control group and the low-dose meloxicam group in any tested variable. The high-dose meloxicam group had a greater degree of weight bearing on the affected limb from the second to the fourth postoperative day as well as lower pain scores for at least the first 2 postoperative days, compared with the other groups. Return to presurgical behavior was achieved faster in pigeons that received high-dose meloxicam than in the other groups. No adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of meloxicam at 0.5 mg/kg appeared ineffective in minimizing postoperative orthopedic pain in pigeons, but the 2.0 mg/kg dose provided quantifiable analgesia that appeared safe in this species in experimental conditions.

Evaluation of a fracture pain model in domestic pigeons (Columba livia).

OBJECTIVE: To validate a model of postfracture pain in perching birds. ANIMALS: 21 adult domestic pigeons (Columba livia). PROCEDURES: In each bird, a standardized osteotomy of 1 femur was performed and the fracture was immobilized with an intramedullary pin. Degree of postoperative pain was evaluated 6 times/d for 4 days by use of 3 methods: an electronic perch for assessment of weight-bearing load differential of the pelvic limbs, 4 numeric rating pain scales for assessment of pain (all of which involved the observer in the same room as the bird), and analysis of video-recorded (observer absent) partial ethograms for bird activity and posture. Measurements obtained were compared with data collected before the surgery to evaluate the ability of these methods to detect pain. RESULTS: The weight-bearing load differential was a sensitive, specific, reliable, and indirect measure of fracture-associated pain in the model used. Two of 4 tested pain scales (fractured limb position and subjective evaluation of degree of pain) were sensitive and specific for detecting pain and were reliable in a research setting. Interobserver reliability of the 4 pain scales was excellent. Partial ethograms were sensitive for identifying pain-associated behavior in pigeons, particularly during the first 2 days after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: The fracture pain model was reliable and reproducible and may be useful for experimental studies involving postsurgical pain in pigeons. Weight-bearing load differential was the most sensitive and specific means of determining degree of pain in pigeons during the first 4 days after hind limb fracture induction.

Second generation anticoagulant rodenticides in predatory birds: Probabilistic characterisation of toxic liver concentrations and implications for predatory bird populations in Canada.

Second-generation anticoagulant rodenticides (SGARs) are widely used to control rodent pests but exposure and poisonings occur in non-target species, such as birds of prey. Liver residues are often analysed to detect exposure in birds found dead but their use to assess toxicity of SGARs is problematic. We analysed published data on hepatic rodenticide residues and associated symptoms of anticoagulant poisoning from 270 birds of prey using logistic regression to estimate the probability of toxicosis associated with different liver SGAR residues. We also evaluated exposure to SGARs on a national level in Canada by analysing 196 livers from great horned owls (Bubo virginianus) and red-tailed hawks (Buteo jamaicensis) found dead at locations across the country. Analysis of a broader sample of raptor species from Quebec also helped define the taxonomic breadth of contamination. Calculated probability curves suggest significant species differences in sensitivity to SGARs and significant likelihood of toxicosis below previously suggested concentrations of concern (<0.1mg/kg). Analysis of birds from Quebec showed that a broad range of raptor species are exposed to SGARs, indicating that generalised terrestrial food chains could be contaminated in the vicinity of the sampled areas. Of the two species for which we had samples from across Canada, great horned owls are exposed to SGARs to a greater extent than red-tailed hawks and the liver residue levels were also higher. Using our probability estimates of effect, we estimate that a minimum of 11% of the sampled great horned owl population is at risk of being directly killed by SGARs. This is the first time the potential mortality impact of SGARs on a raptor population has been estimated.