Budgerigars Research Articles

Otoacoustic emissions but not behavioral measurements predict cochlear-nerve frequency tuning in an avian vocal-communication specialist.

Frequency analysis by the cochlea forms a key foundation for all subsequent auditory processing. Stimulus-frequency otoacoustic emissions (SFOAEs) are a potentially powerful alternative to traditional behavioral experiments for estimating cochlear tuning without invasive testing, as is necessary in humans. Which methods accurately predict cochlear tuning remains controversial due to only a single animal study comparing SFOAE-based, behavioral, and cochlear frequency tuning in the same species. The budgerigar ( Melopsittacus undulatus ) is a parakeet species with human-like behavioral sensitivity to many sounds and the capacity to mimic speech. Multiple studies show that budgerigars exhibit a perceptual "auditory fovea" with sharpest behavioral frequency tuning at mid frequencies from 3.5-4 kHz, in contrast to the typical pattern of monotonically increasing tuning sharpness for higher characteristic frequencies. We measured SFOAE-based and cochlear-afferent tuning in budgerigars, for comparison to previously reported behavioral results. SFOAE-based and cochlear-afferent tuning sharpness both increased monotonically for higher frequencies, in contrast to the behavioral pattern. Thus, SFOAE-based tuning in budgerigars accurately predicted cochlear frequency tuning, and both measures aligned with typical patterns of cochlear tuning in other species. Given divergent behavioral tuning in budgerigars, which could reflect specializations for central processing of masked signals, these results highlight the value of SFOAEs for estimating cochlear tuning and caution against direct inference of cochlear tuning from behavioral results.

Common cuckoo eggs are more resistant to puncture by the host

The puncture resistance hypothesis suggests that thick-shelled eggs of parasitic birds can resist puncture-ejection by the host. However, few experiments have yet been conducted to test this hypothesis in terms of natural host behavior (e.g., pecking at foreign eggs). To explore whether the eggshells of common cuckoos (Cuculus canorus) are resistant to puncture-ejection by their common hosts, Oriental reed warblers (Acrocephalus orientalis), we designed experiments to investigate if and how breeding Oriental reed warblers peck at foreign eggs that includes common cuckoo, Oriental reed warbler and budgerigar (Melopsittacus undulatus) eggs. The results showed that, given the same frequency of egg pecking, the probability of eggshell breakage was 87.5% for eggs of the Oriental reed warbler and 0% for eggs of the common cuckoo, with a significant difference (P = 0.001, Fisher's exact test). Our study shows clearly that common cuckoos' eggshells are less susceptible to puncture-ejection than those of Oriental reed warblers and budgerigars. This indicates that the eggshells of common cuckoos can resist host Oriental reed warblers' puncture-ejection, supporting the puncture resistance hypothesis.

Uric Acid Ingluviolith in a Budgerigar (Melopsittacus undulatus).

This clinical report describes an adult, female budgerigar (Melopsittacus undulatus) diagnosed with an ingluviolith. The patient presented for intermittent regurgitation, and a palpable foreign body was present in the crop. Radiographs showed a radiopaque foreign body, and computed tomography showed an approximately 16 × 12 mm (length 3 width) structure in the crop with a soft tissue and focally mineralized center and a 2-3 mm-thick mineral-attenuating shell. An ingluviotomy was performed. The stone was first analyzed using polarized optical crystallography, a method that cannot analyze uric acid salts, and was incorrectly deemed a cystine calculus. The calculus was then analyzed using infrared spectroscopy and x-ray diffractometry and was confirmed to be a shell of subcrystalline to monoclinic crystals of anhydrous uric acid (C5H4N4O3) encrusting aggregates of numerous, threadlike, protein-based fibers. This case presents new information regarding avian ingluviolithiasis. The large size of the calculus indicates formation in the crop, and coprophagia linked to stress is thought to be the potential reason for urate and feather ingestion.

Persistent vocal learning in an aging open-ended learner reflected in neural FoxP2 expression

BackgroundMost vocal learning species exhibit an early critical period during which their vocal control neural circuitry facilitates the acquisition of new vocalizations. Some taxa, most notably humans and parrots, retain some degree of neurobehavioral plasticity throughout adulthood, but both the extent of this plasticity and the neurogenetic mechanisms underlying it remain unclear. Differential expression of the transcription factor FoxP2 in both songbird and parrot vocal control nuclei has been identified previously as a key pattern facilitating vocal learning. We hypothesize that the resilience of vocal learning to cognitive decline in open-ended learners will be reflected in an absence of age-related changes in neural FoxP2 expression. We tested this hypothesis in the budgerigar (Melopsittacus undulatus), a small gregarious parrot in which adults converge on shared call types in response to shifts in group membership. We formed novel flocks of 4 previously unfamiliar males belonging to the same age class, either “young adult” (6 mo − 1 year) or “older adult” (≥ 3 year), and then collected audio-recordings over a 20-day learning period to assess vocal learning ability. Following behavioral recording, immunohistochemistry was performed on collected neural tissue to measure FoxP2 protein expression in a parrot vocal learning center, the magnocellular nucleus of the medial striatum (MMSt), and its adjacent striatum.ResultsAlthough older adults show lower vocal diversity (i.e. repertoire size) and higher absolute levels of FoxP2 in the MMSt than young adults, we find similarly persistent downregulation of FoxP2 and equivalent vocal plasticity and vocal convergence in the two age cohorts. No relationship between individual variation in vocal learning measures and FoxP2 expression was detected.ConclusionsWe find neural evidence to support persistent vocal learning in the budgerigar, suggesting resilience to aging in the open-ended learning program of this species. The lack of a significant relationship between FoxP2 expression and individual variability in vocal learning performance suggests that other neurogenetic mechanisms could also regulate this complex behavior.

Returning to the Wilderness: Potential Habitat Suitability of Non-Native Pet Birds in South Africa.

The global trade of non-native pet birds has increased in recent decades, and this has accelerated the introduction of invasive birds in the wild. This study employed ensemble species distribution modelling (eSDM) to assess potential habitat suitability and environmental predictor variables influencing the potential distribution of non-native pet bird species reported lost and sighted in South Africa. We used data and information on lost and found pet birds from previous studies to establish and describe scenarios of how pet birds may transition from captivity to the wild. Our study revealed that models fitted and performed well in predicting the suitability for African grey (Psittacus erithacus), Budgerigar (Melopsittacus undulatus), Cockatiel (Nymphicus hollandicus), Green-cheeked conure (Pyrrhura molinae), Monk parakeet (Myiopsitta monachus), and Rose-ringed parakeet (Psittacula krameri), with the mean weighted AUC and TSS values greater than 0.765. The predicted habitat suitability differed among species, with the suitability threshold indicating that between 61% and 87% of areas were predicted as suitable. Species with greater suitability included the African grey, Cockatiel, and Rose-ringed parakeet, which demonstrated significant overlap between their habitat suitability and reported lost cases. Human footprint, bioclimatic variables, and vegetation indices largely influenced predictive habitat suitability. The pathway scenario showed the key mechanisms driving the transition of pet birds from captivity to the wild, including the role of pet owners, animal rescues, adoption practices, and environmental suitability. Our study found that urban landscapes, which are heavily populated, are at high risk of potential invasion by pet birds. Thus, implementing a thorough surveillance survey is crucial for monitoring and evaluating the establishment potential of pet species not yet reported in the wild.

Subclinical peripheral inflammation has systemic effects impacting central nervous system proteome in budgerigars

Regulation of neuroimmune interactions varies across avian species. Little is presently known about the interplay between periphery and central nervous system (CNS) in parrots, birds sensitive to neuroinflammation. Here we investigated the systemic and CNS responses to dextran sulphate sodium (DSS)- and lipopolysaccharide (LPS)-induced subclinical acute peripheral inflammation in budgerigar (Melopsittacus undulatus). Three experimental treatment groups differing in DSS and LPS stimulation were compared to controls. Individuals treated with DSS showed significant histological intestinal damage. Through quantitative proteomics we described changes in plasma (PL) and cerebrospinal fluid (CSF) composition. In total, we identified 180 proteins in PL and 978 proteins in CSF, with moderate co-structure between the proteomes. Between treatments we detected differences in immune, coagulation and metabolic pathways. Proteomic variation was associated with the levels of pro-inflammatory cytokine mRNA expression in intestine and brain. Our findings shed light on systemic impacts of peripheral low-grade inflammation in birds.

Tumour or haemorrhage?: Differential diagnosis of an unknown mass within the brain of a budgerigar (Melopsittacus undulatus) using a novel imaging pipeline

AbstractWe report on a previously healthy zoo specimen of an adult budgerigar (Melopsittacus undulatus, obtained with permission from Southwick's Zoo) found deceased in its enclosure. To assess cause of death and ensure the absence of an infectious neoplasia, we used an integrated multiscale brain‐imaging workflow, previously only used on mammals. The specimen was imaged with microcomputed tomography before and after enhancing soft‐tissue contrast with diffusible iodine‐based contrast‐enhanced microcomputed tomography. Scans revealed an orbital blowout fracture and an unidentified large mass across majority of the diencephalon, striatum and midbrain caudal to the right orbit. After destaining, neural pathohistology confirmed the mass as a brain haemorrhage with no evidence of neoplasia or inflammation. We conclude that this specimen died of head trauma, likely from a head‐on collision within its enclosure. This multiscale imaging workflow (diffusible iodine‐based contrast‐enhanced microcomputed tomography followed by destaining and pathohistology) can improve our evaluation of differential diagnoses in avian specimens.

Macroscopic and microscopic characteristics of uropygial gland of budgerigars (Melopsittacus undulatus)

Objective: This study was carried out to investigate the anatomical, morphometric, topographic, and histological features of the uropygial gland in adult male and female budgerigars (Melopsittacus undulatus).
 Material-Method: For this study, the glandula uropygialis of fourteen adult budgerigars (7 male, 7 female) were used in the study. This glandular structure located between the caudal vertebrae and pygostyle was removed by careful dissection. Morphological and histological characteristics of the dissected glandula uropygialis were determined. In addition, morphometric measurements and index calculations were performed. Tissue samples taken to determine the histological structure of the gland were stained with Hematoxylin & Eosin (H&E), Masson Trichrome's and Periodic Acid Schiff-Alcian Blue.
 Result: In the study, it was determined that the gland structure was heart shaped and consisted of two lobes, a papilla and a draining duct system. Uropygial gland weight was determined as 1.57±0.96 g in male birds and 1.52±0.09 g in female birds. As a result of the statistical evaluation, there were significant differences between the sexes in the parameters of lobe width (P

COMPARISON OF THREE MIDAZOLAM-BASED SEDATION PROTOCOLS IN BUDGERIGARS (MELOPSITTACUS UNDULATUS) AND BLACK-CHEEKED LOVEBIRDS (AGAPORNIS NIGRIGENIS).

This randomized, crossover study evaluated three sedation protocols administered subcutaneously in nine budgerigars (Melopsittacus undulatus) and nine black-cheeked lovebirds (Agapornis nigrigenis). All protocols included midazolam (5 mg/kg), combined with butorphanol (5 mg/kg) (BM), medetomidine (20 lg/kg) (MM), or alfaxalone (13 mg/kg) (AM). Mortalities from suspected cardiorespiratory arrest were observed when AM was used in lovebirds, even after reduction of alfaxalone dosage to 3 mg/kg, and therefore this protocol was excluded from further use in this species. Induction and recovery times were recorded and their quality assessed. Sedation depth and heart and respiratory rates were measured every 5 min and radiographic positioning was attempted at 10 and 20 min. At 30 min, midazolam and medetomidine were reversed with flumazenil (0.05 mg/kg, SC), and atipamezole (0.2 mg/kg, SC), respectively. MM consistently provided deep sedation in both species, with successful radiographic positioning at every attempt. As expected, heart rate was often lower with MM than with other protocols, but no associated complications were noted. In budgerigars, BM had the lowest radiographic positioning success rate (10 min: 5/9, 20 min: 3/9), whereas in lovebirds it provided significantly deeper sedation (P < 0.001), allowing radiographic positioning in all subjects. In both species, BM provided the shortest recovery times. AM resulted in reliable radiographic positioning of all budgerigars at 10 min, but not at 20 min (5/ 9), and provided consistently poor recoveries. This study highlights how differently two psittacine species of similar size may react to the same sedation protocols. AM sedation cannot be fully reversed and produced significant undesirable effects, several of which have been previously reported with alfaxalone administration to avian species. The authors therefore caution against using alfaxalone-midazolam combinations in budgerigars and black-cheeked lovebirds. Both BM and MM provided reliable sedation in these species, and appear to be suitable alternatives to AM.

Do domestic budgerigars perceive predation risk?

Predation risk may affect the foraging behavior of birds. However, there has been little research on the ability of domestic birds to perceive predation risk and thus adjust their feeding behavior. In this study, we tested whether domestic budgerigars (Melopsittacus undulatus) perceived predation risk after the presentation of specimens and sounds of sparrowhawks (Accipiter nisus), domestic cats (Felis catus), and humans, and whether this in turn influenced their feeding behavior. When exposed to visual or acoustic stimuli, budgerigars showed significantly longer latency to feed under sparrowhawk, domestic cat, and human treatments than with controls. Budgerigars responded more strongly to acoustic stimuli than visual stimuli, and they showed the longest latency to feed and the least number of feeding times in response to sparrowhawk calls. Moreover, budgerigars showed shorter latency to feed and greater numbers of feeding times in response to human voices than to sparrowhawk or domestic cat calls. Our results suggest that domestic budgerigars may identify predation risk through visual or acoustic signals and adjust their feeding behavior accordingly.

Successful Therapeutic Management of Knemidocoptiasis in a Budgerigar (Melopsittacus Undulatus) – A Case Report

A blue coloured male Budgerigar (Melopsittacus undulatus) was presented to the Veterinary Clinical Complex, VCRI, Orathanadu, TANUVAS with the history of pruritus, feather loss, yellowish lesion on the face, legs and feet with decreased appetite for the past one week. On clinical examination bird appeared dull, depressed and scaly lesions in face and legs. Parasitological examination revealed the presence of adult Knemidocoptes sp., The bird was treated with oral Ivermectin @ 200μg/kg body weight, benzyl benzoate topical application with the multivitamin supplementation. The bird was uneventfully recovered after two weeks of treatment.

An Influx of Non-Native Bird Species into the Natural Environment Owing to the Accidental Release of Pet Birds in Japan.

The escape of pet birds into the wild raises concerns about the introduction of invasive avian species. This study investigated the impact of escaped pet birds on the introduction of non-native species in Japan. Data sourced from four lost-and-found pet websites between January 2018 and December 2021 revealed 12,125 recorded escapes exhibiting both daily occurrences and seasonal fluctuations. Statistical modeling identified the monthly average temperature (positively correlated) and maximum electricity demand (negatively correlated) as influential factors. Text analysis revealed "window" and "open" as frequently cited reasons for escapes. Budgerigars (Melopsittacus undulatus) and Cockatiels (Nymphicus hollandicus) accounted for 76% of the total escape, suggesting a low perceived risk of establishment in nonnative environments. Interestingly, two globally established invasive species, the Rose-ringed Parakeet (Psittacula krameri) and Monk Parakeet (Myiopsitta monachus), were among the escaped birds. While the Rose-ringed Parakeet is locally naturalized in Tokyo and its adjacent prefectures, the Monk Parakeet failed to establish itself in Japan. Despite the limited number of escaped Monk Parakeets, ongoing efforts are crucial for preventing the potential re-establishment of species with such capabilities.

Parrots in the wild in Polish cities.

Amateur breeding of parrots as pets has contributed to many species being found in areas where they never occurred in the wild, particularly in warmer regions, but also in the temperate climates of North America and Europe. Climate change is likely to exacerbate this process. We hypothesised that parrots occurred in the wild in the cities of Poland, especially the rose-ringed parakeet, as there are reports of breeding sites in the literature. Using information on lost, found and sighted parrots posted on social media, we have analysed the extent of parrot emergence in Poland. In a period of less than two years (from October 2018, through 2019 and from June to the end of December 2021), 2,675 parrot specimens of 49 species were found in the wild. The most frequently observed species were cockatiel Nymphicus hollandicus (N = 962), budgerigar Melopsittacus undulatus (N = 884) and rose-ringed parakeet Psittacula krameri (N = 182). Parrots were most frequently observed in urban areas, in regions characterized by a higher population size, a higher income and a higher proportion of people with a university degree. Our study shows that the occurrence of parrots, especially rose-ringed parakeets in the wild, needs to be monitored as new breeding sites may appear.

Normal behavioral discrimination of envelope statistics in budgerigars with kainate-induced cochlear synaptopathy

Cochlear synaptopathy is a common pathology in humans associated with aging and potentially sound overexposure. Synaptopathy is widely expected to cause “hidden hearing loss,” including difficulty perceiving speech in noise, but support for this hypothesis is controversial. Here in budgerigars (Melopsittacus undulatus), we evaluated the impact of long-term cochlear synaptopathy on behavioral discrimination of Gaussian noise (GN) and low-noise noise (LNN) signals processed to have a flatter envelope. Stimuli had center frequencies of 1–3kHz, 100-Hz bandwidth, and were presented at sensation levels (SLs) from 10 to 30dB. We reasoned that narrowband, low-SL stimuli of this type should minimize spread of excitation across auditory-nerve fibers, and hence might reveal synaptopathy-related defects if they exist. Cochlear synaptopathy was induced without hair-cell injury using kainic acid (KA). Behavioral threshold tracking experiments characterized the minimum stimulus duration above which animals could reliably discriminate between LNN and GN. Budgerigar thresholds for LNN-GN discrimination ranged from 40 to 60ms at 30dB SL, were similar across frequencies, and increased for lower SLs. Notably, animals with long-term 39–77% estimated synaptopathy performed similarly to controls, requiring on average a ∼7.5% shorter stimulus duration (-0.7±1.0dB; mean difference ±SE) for LNN-GN discrimination. Decision-variable correlation analyses of detailed behavioral response patterns showed that individual animals relied on envelope cues to discriminate LNN and GN, with lesser roles of FM and energy cues; no difference was found between KA-exposed and control groups. These results suggest that long-term cochlear synaptopathy does not impair discrimination of low-level signals with different envelope statistics.

Entopallium Lost GFAP Immunoreactivity during Avian Evolution: Is GFAP a “Condition Sine Qua Non”?

Introduction: The present study demonstrates that in the same brain area the astroglia can express GFAP (the main cytoskeletal protein of astroglia) in some species but not in the others of the same vertebrate class. It contrasts the former opinions that the distribution of GFAP found in a species is characteristic of the entire class. The present study investigated birds in different phylogenetic positions: duck (Cairina moschata domestica), chicken (Gallus gallus domesticus), and quails (Coturnix japonica and Excalfactoria chinensis) of Galloanserae; pigeon (Columba livia domestica) of a group of Neoaves, in comparison with representatives of other Neoaves lineages, which emerged more recently in evolution: finches (Taeniopygia guttata and Erythrura gouldiae), magpie (Pica pica), and parrots (Melopsittacus undulatus and Nymphicus hollandicus). Methods: Following a perfusion with 4% buffered paraformaldehyde, immunoperoxidase reactions were performed with two types of anti-GFAP: monoclonal and polyclonal, on floating sections. Results: The entopallium (formerly “ectostriatum,” a telencephalic area in birds) was GFAP-immunopositive in pigeon and in the representatives of Galloanserae but not in songbirds and parrots, which emerged more recently in evolution. The lack of GFAP expression of a brain area, however, does not mean the lack of astroglia. Lesions induced GFAP expression in the territory of GFAP-immunonegative entopallia. It proved that the GFAP immunonegativity is not due to the lack of capability, but rather the suppression of GFAP production of the astrocytes in this territory. In the other areas investigated besides the entopallium (optic tectum and cerebellum), no considerable interspecific differences of GFAP immunopositivity were found. It proved that the immunonegativity of entopallium is due to neither the general lack of GFAP expression nor the incapability of our reagents to detect GFAP in these species. Conclusion: The data are congruent with our proposal that a lack of GFAP expression has evolved in different brain areas in vertebrate evolution, typically in lineages that emerged more recently. Comparative studies on GFAP-immunopositive and GFAP-immunonegative entopallia may promote understanding the role of GFAP in neural networks.

Anterior forebrain pathway in parrots is necessary for producing learned vocalizations with individual signatures

Parrots have enormous vocal imitation capacities and produce individually unique vocal signatures. Like songbirds, parrots have a nucleated neural song system with distinct anterior (AFP) and posterior forebrain pathways (PFP). To test if song systems of parrots and songbirds, which diverged over 50 million years ago, have a similar functional organization, we first established a neuroscience-compatible call-and-response behavioral paradigm to elicit learned contact calls in budgerigars (Melopsittacus undulatus). Using variational autoencoder-based machine learning methods, we show that contact calls within affiliated groups converge but that individuals maintain unique acoustic features, or vocal signatures, even after call convergence. Next, we transiently inactivated the outputs of AFP to test if learned vocalizations can be produced by the PFP alone. As in songbirds, AFP inactivation had an immediate effect on vocalizations, consistent with a premotor role. But in contrast to songbirds, where the isolated PFP is sufficient to produce stereotyped and acoustically normal vocalizations, isolation of the budgerigar PFP caused a degradation of call acoustic structure, stereotypy, and individual uniqueness. Thus, the contribution of AFP and the capacity of isolated PFP to produce learned vocalizations have diverged substantially between songbirds and parrots, likely driven by their distinct behavioral ecology and neural connectivity.

Genome sequence of parvovirus from budgerigar (Melopsittacus undulatus).

Here, we report a parvovirus genome identified in Melopsittacus undulatus. The genome is 4,547 bp long and codes for two major open reading frames (ORFs): the non-structural replicase protein 1 (NS1) and the structural capsid gene (VP1). Phylogenetic analysis shows that this virus belongs to the genus Chaphamaparvovirus.

Histological Correlates of Auditory Nerve Injury from Kainic Acid in the Budgerigar (Melopsittacus undulatus).

Loss of auditory nerve afferent synapses with cochlear hair cells, called cochlear synaptopathy, is a common pathology in humans caused by aging and noise overexposure. The perceptual consequences of synaptopathy in isolation from other cochlear pathologies are still unclear. Animal models provide an effective approach to resolve uncertainty regarding the physiological and perceptual consequences of auditory nerve loss, because neural lesions can be induced and readily quantified. The budgerigar, a parakeet species, has recently emerged as an animal model for synaptopathy studies based on its capacity for vocal learning and ability to behaviorally discriminate simple and complex sounds with acuity similar to humans. Kainic acid infusions in the budgerigar produce a profound reduction of compound auditory nerve responses, including wave I of the auditory brainstem response, without impacting physiological hair cell measures. These results suggest selective auditory nerve damage. However, histological correlates of neural injury from kainic acid are still lacking. We quantified the histological effects caused by intracochlear infusion of kainic acid (1mM; 2.5 µL), and evaluated correlations between the histological and physiological assessments of auditory nerve status. Kainic acid infusion in budgerigars produced pronounced loss of neural auditory nervesoma (60% on average) in the cochlearganglion, and of peripheral axons, at time points 2 or more months following injury. The hair cell epithelium was unaffected by kainic acid. Neural loss was significantly correlated with reduction of compound auditory nerve responses and auditory brainstem response wave I. Compound auditory nerve responses and wave I provide a useful index of cochlear synaptopathy in this animal model.

Papillary Cystadenocarcinoma in a Budgerigar (Melopsittacus undulatus)

Budgerigar (Melopsittacus undulatus) is a tiny colorful parrot and one of the most popular pets worldwide. This study was performed on a 5-year-old male budgerigar with a large and fluid-filled mass in the anterior part of the neck. Fine needle aspiration was accomplished to determine tumor origin, and the tumor content was cultured on blood and MacConkey agars (aerobic and anaerobic conditions). Besides, tumor ultrasonography and whole-body radiographs were done in the lateral and ventrodorsal positions. Finally, the tumor was removed, fixed in 10% neutral buffered formalin, and stained with hematoxylin and eosin (H &amp; E). The radiology and ultrasonography results showed that the tumor (5.2×4×3.7 cm) had a homogenous structure filled with echogenic fluid content. The tumor content culture revealed no bacterial growth. Histopathologically, the mass was composed of cystic spaces with invagination of the lining epithelial cells, forming intraluminal papillae. The tumor was diagnosed as a papillary cystadenocarcinoma.

Comparison of a Hybrid Intramedullary Pin with External Fixation Procedure and a Tape Splint on Tibiotarsal Fractures in Budgerigars (Melopsittacus undulatus): A Retrospective Study

Comparison of a Hybrid Intramedullary Pin with External Fixation Procedure and a Tape Splint on Tibiotarsal Fractures in Budgerigars (Melopsittacus undulatus): A Retrospective Study