Respiratory Diseases of Parrots: Anatomy, Physiology, Diagnosis and Treatment.

This article is aimed to help the reader to understand better how to diagnose and treat different respiratory diseases in Psittaciformes (parrot-like birds). The article starts from a review of avian respiratory anatomy and physiology, and then moves forward into diagnostic techniques, most common diseases, split in species and anatomic location, and common treatment regimens.

Study of laser actions by bird's feathers with photonic crystals.

Random lasers had been made by some biomaterials as light scattering materials, but natural photonic crystals have been rarely reported as scattering materials. Here we demonstrate the ability of natural photonic crystals to drive laser actions by sandwiched the feathers of the Turquoise-Fronted Amazon parrot and dye between two plastic films. Parrot feathers comprise abundant photonic crystals, and different color feathers compose of different ratios of the photonic crystal, which directly affect the feather reflectance. In this study, the multi-reflection scattering that occurred at the interface between the photonic crystal and gain media efficiently reduce the threshold; therefore, the more photonic crystal constitutes in the feathers; the lower threshold can be obtained. The random lasers can be easily made by the integration of bird feather photonic crystals and dye with a simple and sustainable manufacturing approach.

The endocast of the Night Parrot (Pezoporus occidentalis) reveals insights into its sensory ecology and the evolution of nocturnality in birds.

The Night Parrot (Pezoporus occidentalis) is a rare, nocturnal parrot species that has largely escaped scientific investigation due to its behaviour and habitat preferences. Recent field studies have revealed some insights into Night Parrot behaviour, but nothing is known of its sensory abilities. Here, we used µCT scans of an intact Night Parrot specimen to determine if its visual system shares similarities with other nocturnal species. The endocast of the Night Parrot revealed relatively small optic lobes and optic foramina, especially compared with closely related grass parakeets, but no apparent differences in orbit dimensions. Our data suggests that the Night Parrot likely has lower visual acuity than most other parrots, including its congener, the Eastern Ground Parrot (P. wallicus). We propose that the visual system of the Night Parrot might represent a compromise between the need to see under low light conditions and the visual acuity required to detect predators, forage, and fly. Based on the endocast and optic foramen measurements, the Night Parrot fits into a common pattern of decreased retinal input to the optic lobes in birds that should be explored more thoroughly in extant and extinct species.

Computed tomographic and radiographic morphometric study of cardiac and coelomic dimensions in captive blue-fronted Amazon parrots (Amazona aestiva, Linnaeus, 1758) with varying body condition scores.

This study aimed to assess radiographic and tomographic cardiac parameters, including width and length of the heart, and the ratio of heart width to coelom width of blue-fronted Amazon parrots (Amazona aestiva) with varying body condition scores. Thirty-five captive birds were included in the study and were allocated into one of three groups according to their respective body condition score: lean, ideal and obese. No differences were observed among the groups with regard to radiographic and tomographic measurements. Computed tomography enabled better identification of the structures of the cardiovascular system without interference from the overlying structures of the celomatic cavity observed in radiographic images. However, radiographic examinations should still be considered the standard screening method to identify cardiac alterations, such as increased or reduced organ dimensions. Standardizing the techniques and measurements performed in this study may serve as a basis for further research in the field.

Radiographic anatomy of the cockatiel (Nymphicus hollandicus) axial and appendicular skeleton.

Cockatiels are popular pets. Still, despite medical and surgical relevance, the radiographic anatomy of the cockatiel (Nymphicus hollandicus) skeleton, like that of different wild and exotic bird species, has seldom been described. This study set out to describe the radiographic anatomy of the cockatiel skeleton. Twelve adult male and nine adult female specimens were radiographed using a digital X-ray system and different views. The radiographic anatomy of these birds was similar to that of other Psittacidae. However, some particularities inherent to the target species were detected, such as the presence of four flexion zones in the skull (craniofacial, nasal, jugal arch and palatine), complete bony orbit comprising a suborbital arch, 34-38 vertebrae (10 or 11 cervical, 8 or 9 thoracic, 9 or 10 lumbosacral, 5 or 6 caudal vertebrae and a pygostyle comprising 2 fused vertebrae), eight or nine pairs of ribs and a notarium made up of fused T2-T6 vertebrae. Poor radiopacity of the notarium, ribs and respective uncinate processes, and synsacral vertebrae made demarcation of these structures difficult. The appendicular skeleton of the cockatiel was very similar to that of other Psittacidae, and there were no gender-related differences.

The multifactorial nature of beak and skull shape evolution in parrots and cockatoos (Psittaciformes).

BACKGROUND: The Psittaciformes (parrots and cockatoos) are characterised by their large beaks, and are renowned for their ability to produce high bite forces. These birds also possess a suite of modifications to their cranial architecture interpreted to be adaptations for feeding on mechanically resistant foods, yet the relationship between cranial morphology and diet has never been explicitly tested. Here, we provide a three-dimensional geometric morphometric analysis of the developmental and biomechanical factors that may be influencing the evolution of psittaciformes' distinctive cranial morphologies. RESULTS: Contrary to our own predictions, we find that dietary preferences for more- or less- mechanically resistant foods have very little influence on beak and skull shape, and that diet predicts only 2.4% of the shape variation in psittaciform beaks and skulls. Conversely, evolutionary allometry and integration together predict almost half the observed shape variation, with phylogeny remaining an important factor in shape identity throughout our analyses, particularly in separating cockatoos (Cacatuoidea) from the true parrots (Psittacoidea). CONCLUSIONS: Our results are similar to recent findings about the evolutionary trajectories of skull and beak shape in other avian families. We therefore propose that allometry and integration are important factors causing canalization of the avian head, and while diet clearly has an influence on beak shape between families, this may not be as important at driving evolvability within families as is commonly assumed.

Comparison of Dorsoventral Erect and Ventrodorsal Supine Radiographic Views for the Evaluation of Intracoelomic Organs in Clinically Normal African Grey Parrots (Psittacus erithacus).

Standard positioning for radiographic evaluation may require sedation and can be deleterious in critically ill birds. A prospective crossover study was performed in 15 clinically normal African grey parrots (Psittacus erithacus) to describe an alternative, unrestrained radiographic view. Whole-body radiographs were obtained in unrestrained dorsoventral erect (DVE) views and in anesthetized ventrodorsal supine (VDS) views. Visualization of various anatomic items in each view was scored by 3 observers. The surface area of the air sacs and the width of the heart, liver, thorax, and cardiohepatic waist were measured in DVE and VDS views. Measurements were obtained by 3 observers, and 1 observer repeated the measurements twice. Intraobserver and interobserver agreement were assessed. Major rotation of the coelom and superimposition of the limbs over the coelom were, respectively, observed in 4 of 15 (27%) and 15 of 15 (100%) of the DVE views and not observed in VDS views. The evaluation of the respiratory tract structures was considered limited in DVE views compared with VDS views, and the surface areas of the air sacs were significantly smaller. The proventriculus and ventriculus were more visible in the DVE view. The visualization of the heart was not significantly different between the 2 views. The absolute measures of heart, liver, and cardiohepatic waist width were significantly larger in the DVE view compared with the VDS view. Moderate intraobserver and interobserver agreement was observed in the evaluation of the 2 views. In conclusion, the DVE view could be adequate to assess the heart and the upper digestive tract. This positioning is likely to provide clinically relevant information for cases in which general anesthesia or dorsal recumbency is contraindicated.

New Insight into Parrots' Mitogenomes Indicates That Their Ancestor Contained a Duplicated Region.

Mitochondrial genomes of vertebrates are generally thought to evolve under strong selection for size reduction and gene order conservation. Therefore, a growing number of mitogenomes with duplicated regions changes our view on the genome evolution. Among Aves, order Psittaciformes (parrots) is especially noteworthy because of its large morphological, ecological, and taxonomical diversity, which offers an opportunity to study genome evolution in various aspects. Former analyses showed that tandem duplications comprising the control region with adjacent genes are restricted to several lineages in which the duplication occurred independently. However, using an appropriate polymerase chain reaction strategy, we demonstrate that early diverged parrot groups contain mitogenomes with the duplicated region. These findings together with mapping duplication data from other mitogenomes onto parrot phylogeny indicate that the duplication was an ancestral state for Psittaciformes. The state was inherited by main parrot groups and was lost several times in some lineages. The duplicated regions were subjected to concerted evolution with a frequency higher than the rate of speciation. The duplicated control regions may provide a selective advantage due to a more efficient initiation of replication or transcription and a larger number of replicating genomes per organelle, which may lead to a more effective energy production by mitochondria. The mitogenomic duplications were associated with phenotypic features and parrots with the duplicated region can live longer, show larger body mass as well as predispositions to a more active flight. The results have wider implications on the presence of duplications and their evolution in mitogenomes of other avian groups.

Parrots have evolved a primate-like telencephalic-midbrain-cerebellar circuit.

It is widely accepted that parrots show remarkable cognitive abilities. In mammals, the evolution of complex cognitive abilities is associated with increases in the size of the telencephalon and cerebellum as well as the pontine nuclei, which connect these two regions. Parrots have relatively large telencephalons that rival those of primates, but whether there are also evolutionary changes in their telencephalon-cerebellar relay nuclei is unknown. Like mammals, birds have two brainstem pontine nuclei that project to the cerebellum and receive projections from the telencephalon. Unlike mammals, birds also have a pretectal nucleus that connects the telencephalon with the cerebellum: the medial spiriform nucleus (SpM). We found that SpM, but not the pontine nuclei, is greatly enlarged in parrots and its relative size significantly correlated with the relative size of the telencephalon across all birds. This suggests that the telencephalon-SpM-cerebellar pathway of birds may play an analogous role to cortico-ponto-cerebellar pathways of mammals in controlling fine motor skills and complex cognitive processes. We conclude that SpM is key to understanding the role of telencephalon-cerebellar pathways in the evolution of complex cognitive abilities in birds.

Anatomy of the forelimb musculature and ligaments of Psittacus erithacus (Aves: Psittaciformes).

Parrots (order Psittaciformes) are a rather homogeneous group of birds that can be easily distinguished by the notably modified morphology of the skull and hindlimb. Detailed description of the forelimb morphology in these birds has never been provided, though parrots are often used as model objects in flight studies. Parrots are also considered the closest living relatives of the perching birds (Passeriformes), and thus knowledge of the wing morphology in Psittaciformes is important for understanding the evolution of the locomotor apparatus on the way to the most speciose group of birds. Here we provide a comprehensive illustrated description of the wing morphology (musculature and ligaments) of the African grey parrot (Psittacus erithacus) and compare it with several closely related taxa of the high clade Eufalconimorphae and more distantly related outgroups (based on personal dissections and literature data). We note a general similarity of the wing musculature between P. erithacus and Falconidae. A number of features common with the outgroup Columbidae supports a generally plesiomorphic structure of the forelimb in parrots as compared with the Passeriformes. Nevertheless, the wing of the Psittaciformes displays a series of structural (likely autapomorphic) modifications, which can be explained in terms of adaptations for flight with vertical body. An analysis of the anatomical data for parrots (ratio of wing elevators and highly unusual development of the M. supracoracoideus), which is based on the current experiment-based knowledge of the flapping flight in birds, allows us to hypothesize that parrots are able to produce useful aerodynamic force during the upstroke, which is also known for pigeons and hummingbirds. This supposed ability of vertical flight and the zygodactyl foot together link the origin of parrots with the dense (likely tropical) forests.

Comparison of three computed tomographic angiography protocols to assess diameters of major arteries in African grey parrots (Psittacus erithacus).

OBJECTIVE To evaluate 3 contrast medium infusion (CMI) protocols for CT angiography (CTA) and measurement of major artery diameters in African grey parrots (Psittacus erithacus). ANIMALS 9 African grey parrots with no detectable cardiovascular disease. PROCEDURES Each bird was anesthetized and underwent placement of an IV catheter in the left basilic vein and 16-slice CTA scanning (started at peak aortic enhancement) with each of 3 CMI protocols at ≥ 1-month intervals. Protocol 1 involved catheter flushing with saline (0.9% NaCl) solution and IV infusion of iopamidol (2 mL) followed by saline solution (0.2 mL; total infused volume, 5 mL). Protocol 2 involved IV infusion of iopamidol (2 mL) followed by saline solution (0.4 mL; total infused volume, 2.4 mL). Protocol 3 involved catheter flushing with saline solution and IV administration of iopamidol (2 mL; total infused volume, 4.8 mL). The diameters of 6 major arteries were measured by 2 observers, and intra- and interobserver agreement, time-enhancement variables, and patient factors affecting contrast medium enhancement were assessed. RESULTS Among the 3 CMI protocols, CTA-derived arterial diameters differed significantly. Measurements obtained with protocol 2 were significantly larger than those obtained with the other protocols. Uniformity of the time-enhancement variables differed among CMI protocols. Patient factors had nonsignificant effects on contrast medium enhancement. CONCLUSIONS AND CLINICAL RELEVANCE Of the CMI protocols assessed, a 2-phase CMI protocol with a post-CMI saline solution flush was the most reliable for CTA-derived measurements of the major thoracic and abdominal arteries in African grey parrots. However, further technique modification is needed.

A species dependent response to the pro-epileptic drug pentylentetrazole in birds.

Epilepsy is common disorder that affects over 50 million people worldwide. Birds remain a promising yet largely under-explored model of epilepsy. This study reports the comparison of the response of two species of birds, Australian Parrots (APs) and Sparrows (SPs), to a pro-epileptic drug, Pentylenetetrazole (PTZ). PTZ injections caused myoclonic jerks (MCJs) and tonic clonic seizures (TCSs) in both species. The frequency of MCJs in APs was greater at the dose of 75mg/kg compared to both 50mg/kg and 25mg/kg while it was not significantly different in SPs. The comparison of APs and SPs showed that the frequency of MCJs was greater in APs compared to SPs at 25mg/kg and 75mg/kg while its latency was reduced at 25mg/kg and 50mg/kg. Interestingly SPs had a reduced latency of TCSs compared to APs at 75mg/kg. Glutamatergic and Gabaergic cell count was conducted to determine an association with the epileptic response to PTZ. The Glutamatergic cell counts for SPs was significantly greater than APs and conversely the Gabaergic cell counts in APs was higher compared to SPs. The reason for this difference in findings needs to be further investigated. This study shows that birds, and APs and SPs in particular, are a valid, interesting and under-explored model of epilepsy that should be further explored in order to understand the mysteries of epilepsy.

Reproductive Disorders in Parrots.

Disease affecting the reproductive tract of the companion parrot is often impacted by physiologic and environmental stimuli. In conjunction with appropriate medical management, some birds diagnosed with reproductive disorders may be successfully treated. Once the bird is diagnosed with a disease condition affecting the reproductive tract, therapeutic measures are focused on stabilizing and supporting the patient, and surgical intervention is required only in the most severe cases. Hormonal therapy with synthetic, long-acting GnRH agonists should be considered for chronic reproductive disease conditions in which decreasing ovarian activity can help alleviate certain disease processes.

Complete mitochondrial genome of Blue-winged Macaw (Primolius maracana).

abtract The presence of bare facial area distinguishes Macaws from other members of the Arini tribe. Genera and species of the Macaw group differ in pattern of this bare skin as well as in body size. Individuals of the genera: Diopsittaca, Orthopsittaca, and Primolius are significantly smaller than the members of the genera: Anodorhynchus, Cyanopsitta, and the most species of the genus Ara. The genus Primolius contains three species: P. auricollis, P. couloni, and P. maracana, which are classified as medium-sized Macaws. So far, mitochondrial genome representative for the genus was sequenced only for Primolius couloni species. Primolius maracana mitogenome, which was sequenced in this study, will be indispensable to refine the phylogenetic relationships between Primolius species, as results of molecular researches seems to be inconsistent with Primolius species morphology.

The status of three little known names proposed by Miranda-Ribeiro (1926) and the synonymization of Pyrrhura snethlageae Joseph & Bates, 2002 (Psittaciformes: Psittacidae: Arinae).

The presence of complex geographic variation among species allied to the absence of clear morphological breaks among populations has led to many poorly defined taxa in the genus Pyrrhura (Psittacidae: Arinae: Arini). This article addresses nomenclature of the Pyrrhura picta species complex, particularly the identity of three little-known names introduced by Miranda-Ribeiro (1926): Pyrrhura luciani ochrotis, P. l. pallescens and P. l. melanoides. We show that these names represent subjective synonyms of Pyrrhura snethlageae Joseph & Bates, 2002. Furthermore, we argue that Pyrrhura pallescens (Miranda-Ribeiro, 1926) n. comb. should be considered as the valid senior name because: (1) there is no doubt about the type locality (near the type locality of P. snethlageae) and, as a consequence, it "will best serve stability and universality of nomenclature" as recommended by the International Code of Zoological Nomenclatural, and; (2) it corresponds to the most common phenotype usually referred to as P. snethlageae, the species name that has been used for bird specimens from this region. Those considering P. snethlageae lucida Arndt, 2008 as a valid taxon should refer to this population as Pyrrhura pallescens lucida (Arndt, 2008) n. comb. In a near future P. pallescens melanoides (Miranda-Ribeiro, 1926) n. comb. is likely to be considered the best senior synonym of P. p. lucida given its type locality (Teles Pires River, MT).

Normal computed tomographic features and reference values for the coelomic cavity in pet parrots.

BACKGROUND: The increasing popularity gained by pet birds over recent decades has highlighted the role of avian medicine and surgery in the global veterinary scenario; such a need for speciality avian medical practice reflects the rising expectation for high-standard diagnostic imaging procedures. The aim of this study is to provide an atlas of matched anatomical cross-sections and contrast-enhanced CT images of the coelomic cavity in three highly diffused psittacine species. RESULTS: Contrast-enhanced computed tomographic studies of the coelomic cavity were performed in 5 blue-and-gold macaws, 4 African grey parrots and 6 monk parakeets by means of a 4-multidetector-row CT scanner. Both pre- and post-contrast scans were acquired. Anatomical reference cross-sections were obtained from 5 blue-and-gold macaw, 7 African grey parrot, and 9 monk parakeet cadavers. The specimens were stored in a -20 °C freezer until completely frozen and then sliced at 5-mm intervals by means of a band saw. All the slices were photographed on both sides. Individual anatomical structures were identified by means of the available literature. Pre- and post-contrast attenuation reference values for the main coelomic organs are reported in Hounsfield units (HU). CONCLUSIONS: The results provide an atlas of matched anatomical cross-sections and contrast-enhanced CT images of the coelomic cavity in three highly diffused psittacine species.

Descrição anatômica de esqueletos de papagaios do gênero Amazona através da utilização de radiografias / Anatomical description of Amazona gender parrot's skeletons through the use of radiography

O esqueleto de papagaios da espécie Amazona aestiva foi descrito e comparado com representantes de outras espécies do gênero Amazona. Para tanto, foram utilizados 22 exemplares da espécie Amazona aestiva; dois das espécies Amazona vinacea; Amazona rhodocorythae, Amazona farinosa, além de um exemplar das espécies Amazona brasiliensis e Amazona pretrei, doados após morte natural pelo Criadouro Poços de Caldas. Foram realizadas radiografias de corpo inteiro, variando de decúbito lateral direito ou esquerdo, no caso das projeções latero-laterais, e em decúbito dorsal, no caso da projeção ventro-dorsal. Independentemente da espécie, os crânios dos papagaios estudados puderam ser classificados como pró-cinéticos, por apresentarem liberdade de movimentos em sua porção rostral. Na maioria dos casos, a coluna vertebral esteve formada por 12 vértebras cervicais, seis vértebras torácicas livres, sinsacro (formado pela fusão da última vértebra torácica, 7 lombosacrais e uma caudal), cinco vértebras caudais livres e pelo pigóstilo (formado por três vértebras caudais fusionadas) e, apesar de diferenças pontuais, o esqueleto apendicular torácico e pélvico se mostrou muito semelhante ao observado para outros gêneros de aves e, inclusive, não foi possível observar dimorfismo sexual através das características anatômicas dos esqueletos dos papagaios trabalhados.

This study describes the skeleton of Amazona aestiva parrots and compared it with representatives of other Amazona species. To this end, we used 22 specimens of Amazona aestiva, two specimens each of Amazona vinacea; Amazona rhodocorythae, Amazona farinosa and one specimen each of Amazona brasiliensis and Amazona pretrei donated after natural death by Poços de Caldas Breeding Park. Full body radiographs were taken, in either the right or left lateral decubitus position, in the case of laterolateral projections, and in supine position, in the case of ventrodorsal projection. Regardless of the species, skulls of the parrots were classified as prokinetic, because of free movements in their rostral portion. In most cases, the spine consisted of: 12 cervical vertebrae, six free thoracic vertebrae, synsacrum (formed by the fusion of the last thoracic vertebrae, 7 lumbosacral vertebrae and one caudal vertebrae), five free caudal vertebrae and the pygostyle (formed by three fused caudal vertebrae). Despite punctual differences, thoracic and pelvic appendicular skeleton proved to be very similar to that observed for other genera of birds. In addition, there was no sexual dimorphism considering the anatomical characteristics of the skeletons of parrots analyzed.

The first fossil parrot (Aves, Psittaciformes) from Siberia and its implications for the historical biogeography of Psittaciformes.

Modern parrots (crown Psittaciformes) are a species-rich group of mostly tropical and subtropical birds with a very limited fossil record. A partial tarsometatarsus from the late Early Miocene of Siberia (Baikal Lake) is the first pre-Quaternary find of crown Psittaciformes in Asia (and Siberia in particular) and is also the northern-most find of this bird order worldwide. This find documents a broad geographical distribution of parrots during the warmest phase of the Miocene (the so-called 'Miocene Climatic Optimum'), which has implications for the historical biogeography of Psittaciformes. The presence of parrots on both sides of the Pacific Ocean at the end of the Early Miocene implies a (most probably eastwards) trans-Beringian dispersal which likely took place about 16-18 Ma. The broad Eurasian distribution of parrots in the past further supports a hypothesis that ancestors of modern genera Coracopsis and Agapornis could reach Africa from Eurasia.

Comparative brain morphology of Neotropical parrots (Aves, Psittaciformes) inferred from virtual 3D endocasts.

Psittaciformes are a very diverse group of non-passerine birds, with advanced cognitive abilities and highly developed locomotor and feeding behaviours. Using computed tomography and three-dimensional (3D) visualization software, the endocasts of 14 extant Neotropical parrots were reconstructed, with the aim of analysing, comparing and exploring the morphology of the brain within the clade. A 3D geomorphometric analysis was performed, and the encephalization quotient (EQ) was calculated. Brain morphology character states were traced onto a Psittaciformes tree in order to facilitate interpretation of morphological traits in a phylogenetic context. Our results indicate that: (i) there are two conspicuously distinct brain morphologies, one considered walnut type (quadrangular and wider than long) and the other rounded (narrower and rostrally tapered); (ii) Psittaciformes possess a noticeable notch between hemisphaeria that divides the bulbus olfactorius; (iii) the plesiomorphic and most frequently observed characteristics of Neotropical parrots are a rostrally tapered telencephalon in dorsal view, distinctly enlarged dorsal expansion of the eminentia sagittalis and conspicuous fissura mediana; (iv) there is a positive correlation between body mass and brain volume; (v) psittacids are characterized by high EQ values that suggest high brain volumes in relation to their body masses; and (vi) the endocranial morphology of the Psittaciformes as a whole is distinctive relative to other birds. This new knowledge of brain morphology offers much potential for further insight in paleoneurological, phylogenetic and evolutionary studies.

Theoretical morphology and development of flight feather vane asymmetry with experimental tests in parrots.

Asymmetry in flight feather vane width is a major functional innovation associated with the evolution of flight in the ancestors of birds. However, the developmental and morphological basis of feather shape is not simple, and the developmental processes involved in vane width asymmetry are poorly understood. We present a theoretical model of feather morphology and development that describes the possible ways to modify feather development and produce vane asymmetry. Our model finds that the theoretical morphospace of feather shape is redundant, and that many different combinations of parameters could be responsible for vane asymmetry in a given feather. Next, we empirically measured morphological and developmental model parameters in asymmetric and symmetric feathers from two species of parrots to identify which combinations of parameters create vane asymmetry in real feathers. We found that both longer barbs, and larger barb angles in the relatively wider trailing vane drove asymmetry in tail feathers. Developmentally, longer barbs were the result of an offset of the radial position of the new barb locus, whereas larger barb angles were produced by differential expansion of barbs as the feather unfurls from the tubular feather germ. In contrast, the helical angle of barb ridge development did not contribute to vane asymmetry and could be indicative of a constraint. This research provides the first comprehensive description of both the morphological and developmental modifications responsible for vane asymmetry within real feathers, and identifies key steps that must have occurred during the evolution of vane asymmetry.