Raptor Pediatrics

Neonatal and juvenile raptors may differ from adults in their husbandry, disease predispositions, and medical therapies. There are differences between captive bred juveniles and those presented for rehabilitation to the wild, which must be taken into consideration for successful long-term outcomes. In captive settings, many metabolic and infectious diseases may be linked to problems with diet. The successful rehabilitation and release of wild raptor chicks requires special precautions beyond avoiding imprinting.

How fast can raptors see?

Birds, and especially raptors, are highly visual animals. Some of them have the highest spatial resolving power known in the animal kingdom, allowing prey detection at distance. While many raptors visually track fast-moving and manoeuvrable prey, requiring high temporal resolution, this aspect of their visual system has never been studied before. In this study, we estimated how fast raptors can see, by measuring the flicker fusion frequency of three species with different lifestyles. We found that flicker fusion frequency differed among species, being at least 129 Hz in the peregrine falcon, Falco peregrinus, 102 Hz in the saker falcon, Falco cherrug, and 81 Hz in the Harris's hawk, Parabuteo unicinctus We suggest a potential link between fast vision and hunting strategy, with high temporal resolution in the fast-flying falcons that chase fast-moving, manoeuvrable prey and a lower resolution in the Harris's hawk, which flies more slowly and targets slower prey.

New insights into the clinico-histopathological and molecular features of Pelecitus (Filarioidea: Onchocercidae) from a raptor bird

Some Onchocercidae nematodes such as Pelecitus are parasites of medical and veterinary importance. The adult stage of Pelecitus has been reported infecting birds, and the microfilaria has been associated to human blindness. However, in some of these cases, the nematode was incompletely identified at the species level due to the scarcity of morphological taxonomic keys and, also, to the lack of molecular diagnostic analysis. Here, we report a new Pelecitus species in a crested caracara (Caracara cheriway) producing a severe tenosynovitis and microfilarial dermatitis. It is also the first record of Pelecitus in an American bird of prey. Clinical and histopathological features are described, contributing towards our understanding of the pathogenesis of Pelecitus and the health and conservation of wild bird populations. Our study also provides new information on the molecular diagnosis of this parasite and highlights the potential role of wild birds as Pelecitus reservoirs, and health risk for humans and wildlife.

First detection of Cryptosporidium parvum in falcons (Falconiformes): Diagnosis, molecular sequencing, therapeutic trial and epidemiological assessment of a possible emerging disease in captive falcons

Cryptosporidiosis in raptors and falcons is well-known to be caused by Cryptosporidium baileyi and associated mainly with respiratory pathology. This report presents the diagnosis of an atypical cryptosporidiosis event caused by Cryptosporidium parvum, that to the authors' knowledge, is a case observed for the first time in falcons. Two falcons (Gyrfalcon x Peregrine hybrids) were presented for annual check without any clinical signs. Hematology, biochemistry, fecal and crop parasitology, radiographic and endoscopic examinations were performed. Endoscopy revealed microcystic formation of the caudal lung field in the two falcons, adhesions and air sac alterations. Sampling and subsequent cytology revealed fungal spores and acid fast stain organisms (identified as Cryptosporidium spp.). Feces and affected lung tissue was further send for Cryptosporidium spp.-DNA detection. Fecal samples and lung tissue tested positive for Cryptosporidium spp. gp60 gene by PCR. By sequence analysis of the gp60 gene locus, diagnosis of C. parvum was confirmed with 100% homology. Despite the fact that falcons didn't recover after 1 month of therapy, eight months after the initial examination they were clinically healthy and had satisfactory flying performance. No other falcons were observed with C. parvum infections in the facility so far. The possible source, infection route and implications are discussed.

Veterinary Aspects of Bird of Prey Reproduction

Captive breeding has contributed to successful restoration of many species of birds of prey. Avicultural techniques pioneered by raptor breeders include double clutching, direct fostering, cross-fostering, hatch and switch, hacking, imprinting male and female falcons for semen collection, and artificial insemination techniques. However, reproductive failure occurs related to management problems, including hygiene measures, food quality issues, breeding flock structure, or individual health issues of breeding birds. These may result in non-egg laying females, low-quality eggs, or infertile eggs caused by male infertility. Veterinary care of breeding collections is extremely important. This article provides an overview of veterinary involvement in raptor breeding projects.

The visual system of diurnal raptors: updated review

OBJECTIVE

Diurnal birds of prey (raptors) are considered the group of animals with highest visual acuity (VA). The purpose of this work is to review all the information recently published about the visual system of this group of animals.

MATERIAL AND METHODS

A bibliographic search was performed in PubMed. The algorithm used was (raptor OR falcon OR kestrel OR hawk OR eagle) AND (vision OR «visual acuity» OR eye OR macula OR retina OR fovea OR «nictitating membrane» OR «chromatic vision» OR ultraviolet). The search was restricted to the «Title» and «Abstract» fields, and to non-human species, without time restriction.

RESULTS

The proposed algorithm located 97 articles.

CONCLUSIONS

Birds of prey are endowed with the highest VA of the animal kingdom. However most of the works study one individual or a small group of individuals, and the methodology is heterogeneous. The most studied bird is the Peregrine falcon (Falco peregrinus), with an estimated VA of 140 cycles/degree. Some eagles are endowed with similar VA. The tubular shape of the eye, the large pupil, and a high density of photoreceptors make this extraordinary VA possible. In some species, histology and optic coherence tomography demonstrate the presence of 2foveas. The nasal fovea (deep fovea) has higher VA. Nevertheless, the exact function of each fovea is unknown. The vitreous contained in the deep fovea could behave as a third lens, adding some magnification to the optic system.

vespertinus), Hungary

Hepatitis E virus (HEV), family Hepeviridae, has raised considerable public health concerns because of its zoonotic potential; however, the animal to animal transmissions and the natural chain of hepevirus infections in wildlife are less known. Using random amplification and next generation sequencing technology a novel HEV in birds of prey was serendipitously identified in Hungary. HEV RNA was detected in total of 2 (18%) of the 11 and 1 (14%) of the 7 faecal samples from common kestrels and red-footed falcons, respectively. High faecal viral load (2.03×10(8) genomic copies/ml) measured by qPCR. The complete genome of strain kestrel/MR22/2014/HUN (KU670940) HEV is 7033-nt long including a 35-nt 5'end and a 63-nt 3'end (excluding the poly(A)-tail). Sequence analyses indicated that the ORF1 (4920nt/639 aa), ORF2 (1989nt/662 aa) and ORF3 (360nt/119aa) proteins of kestrel/MR22/2014/HUN shared the highest identity (58.1%, 66.8% and 28.5%) to the corresponding proteins of ferret, rat and human genotype 4 Orthohepeviruses, respectively. Interestingly, the ORF3 protein is potentially initiated with leucine (L) using an alternate, non-AUG (UUG) start codon. This study reports the identification and complete genome characterization of a novel Orthohepevirus species related to mammalian HEVs in birds of prey. It is important to recognize all potential hosts, reservoirs and spreaders in nature and to reconstruct the phylogenetic history of hepeviruses.

Immunochemical analysis of fumigaclavine mycotoxins in respiratory tissues and in blood serum of birds with confirmed aspergillosis

The ergoline alkaloid fumigaclavine A (FuA) is one of the major mycotoxins produced by Aspergillus fumigatus, the main causative fungal agent of avian aspergillosis. To study in situ production of FuA, post-mortem respiratory tissues of various avian species, as well as blood samples of falcons (Falco sp.), were analysed by enzyme immunoassay (EIA). At a detection limit of 1.5 ng/ml, FuA EIA positive results were obtained for tissue samples from seven (64%) out of 11 birds with confirmed aspergillosis, with a maximum concentration of 38 ng/g, while all controls (n = 7) were negative. No FuA could be detected in blood serum (detection limit 0.7 ng/ml) of 15 falcons, experimentally inoculated with A. fumigatus conidia. Fungal mycelium material from tissue of clinical aspergillosis cases, cultured on malt extract agar, was highly positive in the FuA EIA in milligrams per gram range. Chromatographic analysis of mycelium extracts revealed the co-presence of FuA and the structurally related fumigaclavine C (FuC). Alkaline hydrolysis of FuA and FuC yielded the corresponding deacetylation products, FuB and FuE. This is the first report showing that fumigaclavine alkaloids are produced by A. fumigatus in situ during the course of clinical aspergillosis in birds; however, the role of these compounds in the pathogenesis of this disease is still unknown.

Genome analysis of a novel, highly divergent picornavirus from common kestrel (Falco tinnunculus): the first non-enteroviral picornavirus with type-I-like IRES

Although the number of identified avian-borne picornaviruses (family Picornaviridae) is continuously increasing there remains several species-rich avian host groups, such as the order Falconiformes (with 290 bird species) from which picornaviruses have not been identified. This study reports the first complete genome of a novel, highly divergent picornavirus, named as Falcovirus A1 (KP230449), from the carnivorous bird, the common kestrel (Falco tinnunculus, order Falconiformes). Falcovirus A1 has the longest 3D(RdRp) genome region and distant phylogenetic relationship to the Hepatitis A virus 1 (Hepatovirus) and Avian encephalomyelitis virus 1 (Tremovirus). It has a type-I (enterovirus-like) IRES in the 5'UTR - identified for the first time among avian-borne picornaviruses suggesting that type-I IRES is not restricted only to enteroviruses and providing further evidence of mosaicism of this region among different picornavirus genera.

Falcons pursue prey using visual motion cues: new perspectives from animal-borne cameras

This study reports on experiments on falcons wearing miniature videocameras mounted on their backs or heads while pursuing flying prey. Videos of hunts by a gyrfalcon (Falco rusticolus), gyrfalcon (F. rusticolus)/Saker falcon (F. cherrug) hybrids and peregrine falcons (F. peregrinus) were analyzed to determine apparent prey positions on their visual fields during pursuits. These video data were then interpreted using computer simulations of pursuit steering laws observed in insects and mammals. A comparison of the empirical and modeling data indicates that falcons use cues due to the apparent motion of prey on the falcon's visual field to track and capture flying prey via a form of motion camouflage. The falcons also were found to maintain their prey's image at visual angles consistent with using their shallow fovea. These results should prove relevant for understanding the co-evolution of pursuit and evasion, as well as the development of computer models of predation and the integration of sensory and locomotion systems in biomimetic robots.

Molecular characterization of the complete genome of falconid herpesvirus strain S-18

Falconid herpesvirus type 1 (FaHV-1) is the causative agent of falcon inclusion body disease, an acute, highly contagious disease of raptors. The complete nucleotide sequence of the genome of FaHV-1 has been determined using Illumina MiSeq sequencing. The genome is 204,054 nucleotides in length and has a class E organization. The genome encodes approximately 130 putative protein-coding genes, of which 70 are orthologs of conserved alphaherpesvirus and Mardivirus proteins. Three FaHV-1 genes (UL3.5, UL44.5 and CIRC) were identified that encode protein homologues unique to Mardivirus and Varicellovirus. The genome also encodes homologues to the Mardivirus genes LORF2, LORF3, LORF4, LORF5, SORF3 and SORF4. An opal mutation resulting in premature termination was identified in the FaHV-1 UL43 gene. Phylogenetically, FaHV-1 resides in a monophyletic group with the other Mardiviruses but, along with anatid herpesvirus 1, represents a more distant divergence from the rest of the Mardivirus genus.