Reproductive performance of Peregrine falcons relative to the use of organochlorine pesticides, 1946-2021.

Populations of some fish- and meat-eating birds suffered dramatic declines globally following the introduction of organochlorine pesticides during the late 1940s and 1950s. It has been hypothesised that these population declines during the 1950s-1970s were largely driven by a combination of reproductive failure due to eggshell-thinning, egg breakage and embryonic death attributable to DDT and its metabolites, and to enhanced mortality attributable to the more toxic cyclodiene compounds such as aldrin and dieldrin. Using 75 years (1946-2021) of Peregrine falcon (Falco peregrinus) monitoring data (315 unique nest-sites monitored for 6110 nest-years), we studied the breeding performance of a resident Peregrine population in southern Scotland relative to the spatiotemporal pattern of organochlorine pesticide use. We show that (i) Peregrine breeding success and measures of breeding performance increased substantially following the reduction in, and subsequently a complete ban on, the use of organochlorine pesticides; (ii) improvements in Peregrine breeding performance were more dramatic in southeastern Scotland where agriculture was the predominant land use than in southwestern Scotland where there was less arable and more forested land; (iii) Peregrines nesting closer to the coast generally had higher fledging success (that is, a higher proportion of clutches that produced at least one fledgeling) than those nesting inland farther away from the coast; (iv) low temperatures and excessive rain in May negatively affected Peregrine fledging success; and (v) Peregrine abundance increased in parallel with improvements in reproductive performance following the reduction and then complete ban on the use of organochlorine pesticides in the UK. However, recovery was gradual and occurred over four decades, and rate of recovery varied among measures of reproductive performance (egg, nestling and fledgeling production). Our results suggest that the temporal pattern of organochlorine pesticide use strongly influenced Peregrine reproductive parameters but that the pattern of influence differed regionally. Overall results are consistent with the hypothesis that reproductive failure caused by organochlorine pesticides was an important driver of the decline in the south Scottish Peregrine population, and that improvements in all measures of breeding performance following a reduction and eventual ban on organochlorine use facilitated the observed increase in this population.

Evaluation of the Impact of the Peregrine Falcon (Falco peregrinus peregrinus) Reintroduction Process on Captive-Bred Population.

The main objective of this study was to determine the impact of increased demand for peregrine falcons via breeding (mainly Polish, Czech, German and Slovak) on the genetic structure of the birds. In the analysis, 374 specimens from six countries were sampled in 2008-2019 (omitting 2009), and all the birds analyzed were released into the wild as part of the Polish reintroduction program. The assessment of genetic variation was based on a well-known panel of 10 microsatellite markers described for the species. We calculated a fixation index for the samples from each year, and based on this, we determined the level of inbreeding. We also performed an analysis using the Bayesian cluster method, assuming that 1-19 hypothetical populations would define the division that best fit the samples. The most probable division was into two groups; in the first group, the samples from individuals delivered in 2013 were most often segregated; moreover, in this year, a jump in inbreeding, expressed by the fixation index, was observed.

Morphological and molecular characterization of Prosthogonimus falconis n. sp. (Trematoda; Prosthogonimidae), found in a peregrine falcon (Falco peregrinus) (Aves: Falconidae) in the United Arab Emirates.

At a routine health check of a female peregrine falcon, 23 trematodes preliminary identified as Prosthogonimus sp. were removed from the bursa of Fabricius. Based on morphological and molecular examination, a new species, Prosthogonimus falconis, was described. The pear-shaped flukes were 4.3-6.9 mm long, with greatest width posterior to testes. Tegumental spines measuring between 17 and 21 µm long covered the whole body. Length and width ratio of oral to ventral suckers were 1:1.3. Extracaecal, multifollicular vitelline glands commenced prior to acetabulum and terminated posterior to testes. Eggs in the distal uterus measured 21 × 12 µm. Molecular analysis of internal transcribed spacer 2, cytochrome c oxidase subunit 1 and NADH dehydrogenase subunit 1 gene regions revealed that the new species described here is phylogenetically closest to Prosthogonimus cuneatus and Prosthogonimus pellucidus clusters.

Malar stripe size and prominence in peregrine falcons vary positively with solar radiation: support for the solar glare hypothesis.

Many falcons (Falco spp.) exhibit a distinct dark plumage patch below the eye, termed the malar stripe. This stripe is hypothesized to reduce the amount of solar glare reflected into the eyes while foraging, thereby increasing hunting efficiency in bright conditions. Here, we use a novel, global-scale correlative approach to test this 'solar glare hypothesis' in peregrine falcons (Falco peregrinus), the most widespread falcon species, using web-sourced photographs from across the species' global range. We found that the size and prominence of the malar stripe were positively associated with average annual solar radiation, but not with other environmental variables, such as temperature and rainfall. Our results provide the first published evidence for the hypothesis that this plumage feature functions to reduce the amount of solar glare reflected into the falcon's eyes, thereby improving the ability to pinpoint and target agile prey in bright conditions.

Case Report: Multiple Cavernous Pericardial Lymphangioma (Pericardial Lymphangiomatosis) in a Captive Peregrine Falcon (Falco peregrinus brookei).

A 12-year-old female peregrine falcon (Falco peregrinus brookei) from a private raptor breeding facility that presented a good body condition, died suddenly without showing previous symptoms. At necropsy, in the coelomic cavity, multiple cystic structures demarcated by a thin transparent wall and filled with a serous content were observed. They were firmly adhered to the cranial part of the epicardium and adjacent tissues and occupied the entire thoracic area of the coelomic cavity. Microscopically, emerging simultaneously from several areas the epicardium, multiple irregular channels and cystic spaces, lined by a single endothelial cell layer and separated by fibrovascular septa containing smooth muscle tissue, were observed. Immunohistochemical examination revealed that the neoplastic endothelial cells positively immunolabelled for the pan-endothelial marker factor VIII-related antigen but immunostained negative for cytokeratins (PCK26) while strong positivity for sarcomeric α-smooth muscle actin (α-SMA) was detected in the cystic walls. Based on the morphological and immunohistochemical findings, lesions were determined as consistent with a multiple cavernous pericardial lymphangioma, or pericardial lymphangiomatosis, a rare vascular neoplasm. The animal also showed a diffuse chronic perihepatitis, a necrotic area in the liver and foci of cartilaginous metaplasia and calcification in the aorta and vena cava. Literature review, particularly on the epidemiology of lymphangioma, demonstrated the rarity of this tumor in the different animal species and in this location, particularly in birds, being the first report of this type of tumor in a peregrine falcon.

Assessment of the Genetic Potential of the Peregrine Falcon (Falco peregrinus peregrinus) Population Used in the Reintroduction Program in Poland.

Microsatellite DNA analysis is a powerful tool for assessing population genetics. The main aim of this study was to assess the genetic potential of the peregrine falcon population covered by the restitution program. We characterized individuals from breeders that set their birds for release into the wild and birds that have been reintroduced in previous years. This was done using a well-known microsatellite panel designed for the peregrine falcon containing 10 markers. We calculated the genetic distance between individuals and populations using the UPGMA (unweighted pair group method with arithmetic mean) method and then performed a Principal Coordinates Analysis (PCoA) and constructed phylogenetic trees, to visualize the results. In addition, we used the Bayesian clustering method, assuming 1-15 hypothetical populations, to find the model that best fit the data. Units were segregated into groups regardless of the country of origin, and the number of alleles and observed heterozygosity were different in different breeding groups. The wild and captive populations were grouped independent of the original population.

Attack behaviour in naive gyrfalcons is modelled by the same guidance law as in peregrine falcons, but at a lower guidance gain.

The aerial hunting behaviours of birds are strongly influenced by flight morphology and ecology, but little is known of how this relates to the behavioural algorithms guiding flight. Here, we used GPS loggers to record the attack trajectories of captive-bred gyrfalcons (Falco rusticolus) during their maiden flights against robotic aerial targets, which we compared with existing flight data from peregrine falcons (Falco peregrinus). The attack trajectories of both species were well modelled by a proportional navigation (PN) guidance law, which commands turning in proportion to the angular rate of the line-of-sight to target, at a guidance gain N However, naive gyrfalcons operate at significantly lower values of N than peregrine falcons, producing slower turning and a longer path to intercept. Gyrfalcons are less manoeuvrable than peregrine falcons, but physical constraint is insufficient to explain the lower values of N we found, which may reflect either the inexperience of the individual birds or ecological adaptation at the species level. For example, low values of N promote the tail-chasing behaviour that is typical of wild gyrfalcons and which apparently serves to tire their prey in a prolonged high-speed pursuit. Likewise, during close pursuit of typical fast evasive prey, PN will be less prone to being thrown off by erratic target manoeuvres at low guidance gain. The fact that low-gain PN successfully models the maiden attack flights of gyrfalcons suggests that this behavioural algorithm is embedded in a guidance pathway ancestral to the clade containing gyrfalcons and peregrine falcons, though perhaps with much deeper evolutionary origins.

Redescription of Serratospiculum seurati Bain & Mawson, 1981 (Nematoda; Diplotriaenidae) from Peregrine falcon (Falco peregrinus Tunstall, 1771).

Air sac nematodes from birds are known for more than 200 years now and Filaria attenuata was the first described species from falcons, owl and corvid birds. The superficial description and the loss of the original material made F. attenuata a species inquirenda. Seurat (1915) redescribed the species with material from lanner falcon and pallid harrier from Algeria and based on this description Bain and Mawson, Rec S Aust Mus 18:265-28, (1981) created a new species, Serratospiculum seurati, by adding some, slightly divergent, measurements. The current paper is based on light and scanning electron microscopy of five male and 10 female S. seurati specimens from a Peregrine falcon that acquired the infection in Pakistan. The length of the slender male and female nematodes varied between 42-70 and 165-221 mm, respectively, spicules of unequal shape and length measured 292-325 and 638-785 µm. S. seurati was also found in Saker, Barbary and crossbreed falcons.

Effects of Perching Surfaces and Foot Bandaging on Central Metatarsal Foot Pad Weight Loading of the Peregrine Falcon (Falco peregrinus).

Pododermatitis is prevalent in falcons and is characterized by inflammation and infection of the plantar aspect of the feet, particularly at the central metatarsal pad. Suboptimal perch design and increased weight loading on the plantar skin have been proposed as major risk factors for the development of pododermatitis. Prevention and treatment are challenging, but weight load reduction on the affected area of the foot is an accepted goal of initial treatment. To date, to our knowledge no studies have compared the performance of different bandage-perch surface combinations on weight redistribution away from the central metatarsal pad. An ex vivo factorial experiment was designed using the feet from a peregrine falcon cadaver to quantify weight load reduction on the central metatarsal pad with different combinations of perch surfaces (wood, neoprene, artificial turf) and bandages (none, interdigital, silicone shoe). Feet were attached to a digital force gauge mounted on a manual test stand for compression testing. Weight loading at the central metatarsal pad was measured using a small force sensor. Perch-surface combinations in randomized order were tested at 250 g, 500 g, and 1 kg with 9 replicates per foot. At 250 g, all combinations reduced measured metatarsal pad forces, but otherwise performed similarly. As compression forces increased, differences emerged with the shoe combinations performing better overall, followed by a group including the neoprene and artificial turf-interdigital bandage combinations, and a third group including the interdigital/wood and no bandage-artificial turf. All combinations performed better than control (no bandage on wood). This study may assist veterinarians in selecting appropriate perching surface/bandage combinations when treating falcons with pododermatitis.

Status and trends of circumpolar peregrine falcon and gyrfalcon populations.

The peregrine falcon (Falco peregrinus) and the gyrfalcon (Falco rusticolus) are top avian predators of Arctic ecosystems. Although existing monitoring efforts are well established for both species, collaboration of activities among Arctic scientists actively involved in research of large falcons in the Nearctic and Palearctic has been poorly coordinated. Here we provide the first overview of Arctic falcon monitoring sites, present trends for long-term occupancy and productivity, and summarize information describing abundance, distribution, phenology, and health of the two species. We summarize data for 24 falcon monitoring sites across the Arctic, and identify gaps in coverage for eastern Russia, the Arctic Archipelago of Canada, and East Greenland. Our results indicate that peregrine falcon and gyrfalcon populations are generally stable, and assuming that these patterns hold beyond the temporal and spatial extents of the monitoring sites, it is reasonable to suggest that breeding populations at broader scales are similarly stable. We have highlighted several challenges that preclude direct comparisons of Focal Ecosystem Components (FEC) attributes among monitoring sites, and we acknowledge that methodological problems cannot be corrected retrospectively, but could be accounted for in future monitoring. Despite these drawbacks, ample opportunity exists to establish a coordinated monitoring program for Arctic-nesting raptor species that supports CBMP goals.

Distraction Osteogenesis in Two Wild Raptors.

Distraction osteogenesis was used in 2 wild raptor patients for the repair of tibiotarsal fractures. The first case was a hatching year female peregrine falcon (Falco peregrinus) admitted with an open oblique right distal tibiotarsal fracture. The fracture was surgically managed with the external skeletal fixator intramedullary pin tie-in technique (ESF-IM pin tie-in). Appropriate healing of the fracture site occurred with the ESF-IM pin tie-in. However, there was significant pelvic limb shortening of the affected leg, and the bird consequently developed pododermatitis on the contralateral foot. The second case was an adult female great horned owl (Bubo virginianus) that was admitted with a closed, partially healed, overriding right tibiotarsal fracture. Because of the advanced stage of this fracture, which presented with a fibrous callus, and the already apparent pelvic limb shortening, the ESF-IM pin tie-in was not used. Both patients were fitted with a circular external skeletal fixator (CESF), and distraction osteogenesis was performed until the length of the pelvic limb was deemed anatomically adequate. It is critical that rehabilitated raptors be released without any physical conditions that may reduce their ability to survive and reproduce in the wild. Pelvic limb shortening can potentially predispose a raptor patient to pododermatitis, even with fatal consequences, in both captive and wild environments. The orthopedic technique used here proved useful to repair the limb shortening in both raptor cases, and each bird fully recovered and was released.

Avian surface reconstruction in free flight with application to flight stability analysis of a barn owl and peregrine falcon.

Birds primarily create and control the forces necessary for flight through changing the shape and orientation of their wings and tail. Their wing geometry is characterised by complex variation in parameters such as camber, twist, sweep and dihedral. To characterise this complexity, a multi-view stereo-photogrammetry setup was developed for accurately measuring surface geometry in high resolution during free flight. The natural patterning of the birds was used as the basis for phase correlation-based image matching, allowing indoor or outdoor use while being non-intrusive for the birds. The accuracy of the method was quantified and shown to be sufficient for characterising the geometric parameters of interest, but with a reduction in accuracy close to the wing edge and in some localised regions. To demonstrate the method's utility, surface reconstructions are presented for a barn owl (Tyto alba) and peregrine falcon (Falco peregrinus) during three instants of gliding flight per bird. The barn owl flew with a consistent geometry, with positive wing camber and longitudinal anhedral. Based on flight dynamics theory, this suggests it was longitudinally statically unstable during these flights. The peregrine falcon flew with a consistent glide angle, but at a range of air speeds with varying geometry. Unlike the barn owl, its glide configuration did not provide a clear indication of longitudinal static stability/instability. Aspects of the geometries adopted by both birds appeared to be related to control corrections and this method would be well suited for future investigations in this area, as well as for other quantitative studies into avian flight dynamics.

Perfluoroalkyl substances (PFASs) and polychlorinated naphthalenes (PCNs) add to the chemical cocktail in peregrine falcon eggs.

A suite of perfluoroalkyl substances (PFASs) and polychlorinated naphthalenes (PCNs) were determined in 41 peregrine falcon eggs collected in South Greenland between 1986 and 2014. Median concentrations of perfluorinated sulfonic acids (ΣPFSA) and perfluorinated carboxylic acids (ΣPFCA) were 303 ng/g dry weight (dw) (58 ng/g wet weight, ww) and 100 ng/g dw (19 ng/g ww), respectively, which was comparable to other studies. Perfluorooctane sulfonate (PFOS) accounted for 94% on average of all PFSAs, but did not show a significant time trend. Perfluorohexane sulfonate (PFHxS), perfluoroheptane sulfonate (PFHpS) and perfluorodecane sulfonate (PFDS) showed non-linear decreases over the study period, while some long-chain PFCAs increased significantly. The PCN profile was dominated by the penta-, hexa- and tetrachlorinated congeners CN-52/60, CN-66/67 and CN-42. CN-54, an indicator of combustion, accounted for 2.4% of ΣPCN on average. All PCN congeners showed a decreasing tendency, which was significant for lipid-normalized concentrations of CN-53, CN-54 and CN-63. The ΣPCN median concentration was 21 ng/g lipid weight, which is in the high end of concentrations reported for bird eggs. The PCN and PFAS concentrations add to an already high contaminant burden and a complex chemical cocktail in the peregrine falcon population in Greenland, mainly reflecting contaminant exposure during migration and winter stays in Central and South America.

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.

Serratospiculosis in Captive Peregrine Falcons (Falco peregrinus) in Switzerland.

Infection with Serratospiculum species was identified in a captive peregrine falcon (Falco peregrinus) in Switzerland. Pathologic and parasitologic examination results revealed generalized severe granulomatous airsacculitis, with intralesional adults, larvae, and eggs of Serratospiculum species. Subsequently, an individual coprological analysis of the remaining 15 falcons (peregrine falcons and gyrfalcons [Falco rusticolus]) from the same owner was performed. Eggs of Serratospiculum species (4 birds) and Capillaria species (11 birds), and oocysts of Caryospora species (1 bird) were detected. Treatment with ivermection (2 mg/kg SC) was effective, as none of the falcons excreted Serratospiculum species eggs 10 days after one dose. To our knowledge, this is the first report of infection with Serratospiculum species in captive falcons in Europe.

First time identification of Acanthamoeba genotypes in the cornea samples of wild birds; Is Acanthamoeba keratitis making the predatory birds a target?

Acanthamoeba is a free-living amoeba which can be isolated from environment and among others well known as an opportunist protozoan parasite causing infections in humans and animals. Eyes are extremely important for the wild birds and losing sight ability due to Acanthamoeba can be dangerous. The studies on Acanthamoeba infection in wild birds is very few in world and Turkey therefore we aimed to screen deceased wild birds found in Izmir and Manisa provinces located in western Turkey using PCR and non-nutrition agar (NNA) plate method. Cornea samples were obtained from 18 deceased wild birds. During the external examination, signs of keratitis were observed in two Eurasian sparrowhawks (Accipiter nisus). All of the corneal samples were analyzed by two PCR methods and NNA plate. According to results, the Acanthamoeba positivity in corneal samples was 16.6% and 5.5% by PCR and plate method, respectively. According to sequencing data, two of isolates belonged to genotype T5 and one was genotype T4. In conclusion, Acanthamoeba infection was detected in wild bird cornea samples with/without keratitis for the first time in the world. The result of this study also show that Acanthamoeba can be a cause of keratitis in wild birds of Turkey and thus these predator birds can be a target of other wild animals due to loss of sight ability. In terms of public health, these results show the importance of wild birds as a source of Acanthamoeba infection in nature.

Striking pseudogenization in avian phylogenetics: Numts are large and common in falcons.

Nuclear copies of mitochondrial genes (numts) are a well-known feature of eukaryotic genomes and a concern in systematics, as they can mislead phylogenetic inferences when inadvertently used. Studies on avian numts initially based on the chicken genome suggest that numts may be uncommon and relatively short among birds. Here we ask how common numts are in falcons, based on recently sequenced genomes of the Saker falcon (Falco cherrug) and Peregrine falcon (F. peregrinus). We identified numts by BLASTN searches and then extracted CYTB, ND2 and COI sequences from them, which were then used for phylogeny inference along with several sequences from other species in Falconiformes. Our results indicate that avian numts may be much more frequent and longer than previously thought. Phylogenetic inferences revealed multiple independent nuclear insertions throughout the history of the Falconiformes, including cases of sequences available in public databases and wrongly identified as authentic mtDNA. New sequencing technologies and ongoing efforts for whole genome sequencing will provide exciting opportunities for avian numt research in the near future.

Legacy or colonization? Posteruption establishment of peregrine falcons (Falco peregrinus) on a volcanically active subarctic island.

How populations and communities reassemble following disturbances are affected by a number of factors, with the arrival order of founding populations often having a profound influence on later populations and community structure. Kasatochi Island is a small volcano located in the central Aleutian archipelago that erupted violently August 8, 2008, sterilizing the island of avian biodiversity. Prior to the eruption, Kasatochi was the center of abundance for breeding seabirds in the central Aleutian Islands and supported several breeding pairs of peregrine falcons (Falco peregrinus). We examined the reestablishment of peregrine falcons on Kasatochi by evaluating the genetic relatedness among legacy samples collected in 2006 to those collected posteruption and to other falcons breeding along the archipelago. No genotypes found in posteruption samples were identical to genotypes collected from pre-eruption samples. However, genetic analyses suggest that individuals closely related to peregrine falcons occupying pre-eruption Kasatochi returned following the eruption and successfully fledged young; thus, a genetic legacy of pre-eruption falcons was present on posteruption Kasatochi Island. We hypothesize that the rapid reestablishment of peregrine falcons on Kasatochi was likely facilitated by behavioral characteristics of peregrine falcons breeding in the Aleutian Islands, such as year-round residency and breeding site fidelity, the presence of an abundant food source (seabirds), and limited vegetation requirements by seabirds and falcons.

VITAMIN B6 (PYRIDOXINE HYDROCHLORIDE) TOXICOSIS IN FALCONS.

This manuscript reports three independent accidental cases of vitamin (Vit) B6 toxicosis in gyrfalcons (Falco rusticolus) and peregrine falcons (Falco peregrinus) and a toxicology study that was conducted to characterize the clinical responses of gyrfalcons and gyrfalcon × peregrine falcons to a range of single intramuscular (IM) and oral (PO) doses of Vit B6. Both lethal and nonlethal doses were determined. Twelve female gyrfalcons died following IM injection of 1 ml of a vitamin B preparation. Within 30 min of injection, the birds passed pistachio green-colored urates and progressed to vomiting, anorexia, cessation of normal activity, ptosis, collapse, and death, occurring 24-36 hr post injections. Three individuals vomited frothy, partially digested blood and had clonic spasms and convulsions. Postmortem and histopathology revealed multifocal severe hepatic necrosis, splenic lymphoid tissue depletion and hemorrhages with arterial necrosis, and acute renal tubular necrosis. Following administration of a different, oral, mineral-vitamin supplement, a total of 21 peregrine falcons in two separate European facilities died suddenly. Histology of the liver showed diffuse congestion and multifocal coagulative necrosis with mild infiltration of heterophils. The particular nutritional supplement, used by both breeders, was analyzed and found to contain 5-9.7% Vit B6. Other randomly selected lots of the product contained 0.007-0.27% Vit B6. According to the product label, Vit B6 should have been present at 0.004%. To confirm the hypothesis that Vit B6 was responsible for the deaths of the falcons in Abu Dhabi, Vit B6 (British Pharmacopoeia [BP] grade) in powder form was diluted in water for injection and administered IM to four groups of falcons. Groups of four gyrfalcon × peregrine hybrid falcons or gyrfalcons (or both) were given a single IM dose of 5, 10, 15, or 20 mg/kg of Vit B6 or received an oral dose of 25, 50, or 75 mg of Vit B6. Only birds in the lowest-dose groups survived. The maximum nonlethal single doses of Vit B6 in falcons were 5 mg/kg i.m. and 25 mg/kg p.o.

Vertebral Osteomyelitis and Septic Arthritis Associated With Staphylococcus hyicus in a Juvenile Peregrine Falcon ( Falco peregrinus ).

A 6-week-old, parent-reared peregrine falcon ( Falco peregrinus ) was presented with spastic hypertonus of its hind limbs of unknown origin and duration. Radiologic examination revealed smooth periosteal reactions ventrally at thoracic vertebrae 5 to 7. Contrast-enhanced computed tomography identified the swelling as inflammation; antibiotic, antimycotic, anti-inflammatory, and analgesic treatments were initiated, and vitamins and minerals were supplemented. Because the bird's condition did not improve after 10 days, it was euthanatized and submitted for postmortem examination. On histopathologic examination, chronic, active osteomyelitis was diagnosed in thoracic vertebrae 5 to 7, and chronic, active arthritis was present in both the right shoulder and left elbow joints. Staphylococcus hyicus was isolated from these 3 locations, as well as from lungs and liver, indicating a chronic septic staphylococcosis. Although infections with Staphylococcus species are occasional causes of vertebral osteomyelitis in juvenile poultry with active growth plates, it is only sporadically reported in raptors and companion birds. This case report is the first description of the clinical features and diagnostic and pathologic findings in a juvenile peregrine falcon with hematogenous osteomyelitis and arthritis associated with septicemia caused by S hyicus.