Female Budgerigars Research Articles

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.

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

Sex determination in budgerigars using radiographic pelvimetry.

The purpose of this study was to assess the pelvimetric values obtained from radiographic pelvis images of budgerigars in terms of sexual dimorphism. The objectives included determining linear osteometric and angle measurements of the pelvis, as well as calculating the length-to-width ratios among different pelvimetric measurements. Additionally, the study aimed to reveal the correlations between age and body weight with both the pelvimetric measurements and ratio measurements in these animals. In this study, measurements of linear distance, angle and length-to-width ratios were obtained from ventrodorsal images of the pelvis in a sample of 60 budgerigars, consisting of 30 males and 30 females. Subsequently, the statistical analysis of the obtained measurement values was performed. When analysing the morphometric measurement values based on sex, it was observed that all linear measurements (L1, L2, L3, L4, L5, L6, L7, L8, L9, L10 and L11) were higher in males, whereas the angle measurements (A1, LA2 and RA2) were found to be significantly greater in females (p<0.05). Additionally, both male and female budgerigars exhibited a greater pre-acetabular length of the ilium compared to the post-acetabular length. Moreover, there were mostly positive significant correlations between age and body weight with the pelvic measurement values in both sexes (p<0.05). The obtained biometric measurement values from pelvimetric X-ray images in budgerigars were analysed to assess sexual dimorphism. Furthermore, this study presents fundamental morphometric data that can be valuable for clinical, taxonomic, phylogenetic, ornithological, allometric and characterization studies of budgerigars.

Co-Infestation of Dermoglyphus sp. and Syringophilus sp. Causing Pruritic Dermatitis in a Budgerigar (Melopsittacus undulatus) – A Case Report

An 18-month-old, female budgerigar was brought to Small Animal Clinics Out- Patient Medicine unit with the signs of restlessness, excessive preening and damaged, ruffled feathers. Physical examination revealed loss of feathers in the periocular area and head. Feather samples collected from affected area revealed the presence of quill mites, Dermoglyphus sp. and Syringophilus sp The bird was diagnosed to have dermatitis due to heavy quill mite infestation. The bird was treated with ivermectin (0.2mg/Kg, PO) and repeated once in 10 days intervals for 40 days. The owner was advised to clean the cages and nest boxes thoroughly and keep the affected birds in a separate cages to check the spread of mite infestation.

Is consonance attractive to budgerigars? No evidence from a place preference study

Consonant tone combinations occur naturally in the overtone series of harmonic sounds. These include sounds that many non-human animals produce to communicate. As such, non-human animals may be attracted to consonant intervals, interpreting them, e.g., as a feature of important social stimuli. There is preliminary evidence of attraction to consonance in various bird species in the wild, but few experimental studies with birds. We tested budgerigars (Melopsittacus undulatus) for attraction to consonant over dissonant intervals in two experiments. In Experiment 1, we tested humans and budgerigars using a place preference paradigm in which individuals could explore an environment with multiple sound sources. Both species were tested with consonant and dissonant versions of a previously studied piano melody, and we recorded time spent with each stimulus as a measure of attraction. Human females spent more time with consonant than dissonant stimuli in this experiment, but human males spent equal time with both consonant and dissonant stimuli. Neither male nor female budgerigars spent more time with either stimulus type. In Experiment 2, we tested budgerigars with more ecologically relevant stimuli comprised of sampled budgerigar vocalizations arranged into consonant or dissonant chords. These stimuli, however, also failed to produce any evidence of preference in budgerigar responses. We discuss these results in the context of ongoing research on the study of consonance as a potential general feature of auditory perception in animals with harmonic vocalizations, with respect to similarities and differences between human and budgerigar vocal behaviour, and future methodological directions.

Are cognitive abilities under selection by female choice? A comment on Chen et al. (2019)

A recent paper by Chen et al. (2019, Science, 363 (6423), 166–167) found that female budgerigars, Melopsittacus undulatus, show a preference for males that are successful problem solvers. Is this result sufficient to conclude that mate choice influences the evolution of cognitive abilities? Here, we consider what we currently know about the relationship between problem solving and cognition. We argue that it is premature to conclude, based on these findings, that cognitive abilities have evolved in part through sexual selection by female choice.

Problem-solving males become more attractive to female budgerigars.

Darwin proposed that mate choice might contribute to the evolution of cognitive abilities. An open question is whether observing the cognitive skills of an individual makes it more attractive as a mate. In this study, we demonstrated that initially less-preferred budgerigar males became preferred after females observed that these males, but not the initially preferred ones, were able to solve extractive foraging problems. This preference shift did not occur in control experiments in which females observed males with free access to food or in which females observed female demonstrators solving these extractive foraging problems. Our results suggest that direct observation of problem-solving skills increases male attractiveness and that this could contribute to the evolution of the cognitive abilities underlying such skills.

Who's a clever boy then?

Sexual Selection There is considerable value in choosing a smart mate. The suggestion that mate choice has thus shaped the evolution of cognition has been around since Darwin's time, but testing this hypothesis is difficult. Chen et al. found that female budgerigars shifted their preference to previously nonpreferred males after these males demonstrated the ability to solve a problem that stumped the originally preferred males (see the Perspective by Striedter). This preference shift was specific to problem-solving and to choosing males. Science , this issue p. [166][1]; see also p. [120][2] [1]: /lookup/doi/10.1126/science.aau8181 [2]: /lookup/doi/10.1126/science.aaw1811

MiRNAome expression profiles in the gonads of adult Melopsittacus undulatus.

The budgerigar (Melopsittacus undulatus) is one of the most widely studied parrot species, serving as an excellent animal model for behavior and neuroscience research. Until recently, it was unknown how sexual differences in the behavior, physiology, and development of organisms are regulated by differential gene expression. MicroRNAs (miRNAs) are endogenous short non-coding RNA molecules that can post-transcriptionally regulate gene expression and play a critical role in gonadal differentiation as well as early development of animals. However, very little is known about the role gonadal miRNAs play in the early development of birds. Research on the sex-biased expression of miRNAs in avian gonads are limited, and little is known about M. undulatus. In the current study, we sequenced two small non-coding RNA libraries made from the gonads of adult male and female budgerigars using Illumina paired-end sequencing technology. We obtained 254 known and 141 novel miRNAs, and randomly validated five miRNAs. Of these, three miRNAs were differentially expressed miRNAs and 18 miRNAs involved in sexual differentiation as determined by functional analysis with GO annotation and KEGG pathway analysis. In conclusion, this work is the first report of sex-biased miRNAs expression in the budgerigar, and provides additional sequences to the avian miRNAome database which will foster further functional genomic research.

Sex Differences in Rhythmic Preferences in the Budgerigar (Melopsittacus undulatus): A Comparative Study with Humans.

A variety of parrot species have recently gained attention as members of a small group of non-human animals that are capable of coordinating their movements in time with a rhythmic pulse. This capacity is highly developed in humans, who display unparalleled sensitivity to musical beats and appear to prefer rhythmically organized sounds in their music. Do parrots also exhibit a preference for rhythmic over arrhythmic sounds? Here, we presented humans and budgerigars (Melopsittacus undulatus) – a small parrot species that have been shown to be able to align movements with a beat – with rhythmic and arrhythmic sound patterns in an acoustic place preference paradigm. Both species were allowed to explore an environment for 5 min. We quantified how much time they spent in proximity to rhythmic vs. arrhythmic stimuli. The results show that humans spent more time with rhythmic stimuli, and also preferred rhythmic stimuli when directly asked in a post-test survey. Budgerigars did not show any such overall preferences. However, further examination of the budgerigar results showed an effect of sex, such that male budgerigars spent more time with arrthymic stimuli, and female budgerigars spent more time with rhythmic stimuli. Our results support the idea that rhythmic information is interesting to budgerigars. We suggest that future investigations into the temporal characteristics of naturalistic social behaviors in budgerigars, such as courtship vocalizations and head-bobbing displays, may help explain the sex difference we observed.

Cutaneous leiomyosarcoma with osteoid metaplasia in a budgerigar (Melopsittacus undulatus): a case report

Cutaneous leiomyosarcoma with osteoid metaplasia was diagnosed at the base of the right wing in a five-year-old female budgerigar. Grossly, the tumour mass was well circumscribed and solitary, and had a nodular appearance on section. On histological examination, the mass was composed of randomly arranged bundles of spindle-shaped cells that included mitotic, multi-nucleated and bizarre cells. In addition, within and between tumour areas, there were osteoid metaplasia foci. The bony trabeculae were usually localised in the areas around the haemorrhage, and exhibited focal mineralisation. Tumour cells were stained red using Masson’s trichrome staining method. In addition, tumour cells were intensively positive for smooth muscle actin and focally positive for desmin and vimentin, but were negative for CD68 and S100 by immunohistochemical staining. The tumour reported here was defined as a cutaneous leiomyosarcoma with osteoid metaplasia by histopathological and immunohistochemical findings. Our findings may indicate that osteoid metaplasia should be considered in leiomyosarcoma in budgerigars.

Male-like testosterone levels inhibit oviposition in a female parrot: A breeding experiment in budgerigars

Abstract Studies in several songbird species have shown that treating females with the androgenic steroid hormone testosterone (T) can negatively affect female reproductive behaviors and breeding success. As the effects of T on females appear to be species-specific, it is not clear if similar effects of high T occur in non-songbird species. Here, we studied the effects of T supplementation on female reproductive behavior and oviposition in the budgerigar, Melopsittacus undulatus, a small monogamous parrot species with distinct sex differences in parental behavior. We experimentally increased T concentrations to male-like levels in T-treated females compared to controls and we allowed females to breed. We found no significant effects of treatment on the latency to enter the nestbox but T treatment significantly interfered with oviposition. Our results show that T-treated females were seven times less likely to produce a clutch than control females. As we found that T treatment had a strong inhibitory effect on oviposition, our results indicate that female budgerigars suffer fitness costs from male-like plasma T levels. Therefore, it may be possible that, also in non-songbird species, selection for higher T levels in males is constrained by a correlated response to selection which imposes fitness costs on females in terms of reproduction. Evaluating whether or not this is indeed the case requires further work combining different approaches to the study of the evolution of male and female testosterone levels.

Influence of mate preference and laying order on maternal allocation in a monogamous parrot species with extreme hatching asynchrony

It is well established that in many avian species, prenatal maternal resource allocation varies both between and within clutches and may affect offspring fitness. Differential allocation of maternal resources, in terms of egg weight and yolk composition, may therefore allow the female to adjust brood reduction and to fine-tune reproductive investment in accordance with the expected fitness returns. The adaptive value of such maternal resource allocation is thought to be context-dependent as well as species-specific. We investigated the effects of female preference for her mate on the allocation of prenatal maternal resources in the budgerigar, Melopsittacus undulatus, a monogamous species of parrot that shows an extreme hatching asynchrony. We assessed mate preferences in a two-way preference test and allowed females two breeding rounds: one with the preferred and one with the non-preferred partner. We found no effect of preference on either latency to lay or clutch size, but females mated with the preferred partner laid eggs that contained significantly more yolk. Their eggs also contained significantly more androstenedione but not testosterone. Our results suggest that in this species, female preference may influence maternal resource allocation, and that the functional roles of each androgen in the yolk should be considered separately. In addition, we found a significant effect of laying order on egg and yolk weight as well as on yolk testosterone and androstenedione levels. These measures, however, did not change linearly with the laying order and render it unlikely that female budgerigars compensate for the extreme hatching asynchrony by adjusting within-clutch allocation of prenatal maternal resources.

Bare-part color in female budgerigars changes from brown to structural blue following testosterone treatment but is not strongly masculinized.

Whereas several studies have shown that experimentally increased levels of the androgenic steroid testosterone can affect female behavior, fewer studies have focused on the activational effects of exogenous testosterone on female morphology. With respect to colorful displays in birds, almost exclusively the effects of testosterone manipulation on female carotenoid-based colorations have been studied. Other color types such as structural colors (i.e. UV, blue and violet colors that result from differential light reflection in the nanostructures of the tissue) remain largely unstudied. Here, we investigated the short- and long-term effects of exogenous testosterone on the expression of structural bare-part coloration in female budgerigars, Melopsittacus undulatus. In this parrot species, bare-part coloration is expressed in the cere, a structure over the beak which is brown in females and structural blue in males. We experimentally increased plasma testosterone levels in testosterone-treated females (T-females) compared to controls (C-females) and we performed weekly spectrophotometric measurements of the cere for five weeks after implantation and one measurement after ten weeks. We also estimated the extent to which testosterone masculinized female cere color by comparing the experimental females with untreated males. We found significant effects of testosterone on cere color from week four after implantation onwards. T-females expressed significantly bluer ceres than C-females with higher values for brightness and UV reflectance. T-female cere color, however, remained significantly less blue than in males, while values for brightness and UV reflectance were significantly higher in T-females than in males. Our quantitative results show that exogenous testosterone induces the expression of structural blue color in females but does not strongly masculinize female cere coloration. We provide several potential pathways for the action of testosterone on structural color.

A case of cutaneous angiolipoleiomyoma (angiomyolipoma) in a budgerigar (Melopsittacus undulatus)

We report a case of cutaneous angiolipoleiomyoma (angiomyolipoma) found on the anterior wall of the ventral part of the abdomen of a three-year-old female budgerigar (Melopsittacus undulatus). Histologic examination of the well-circumscribed, surgically removed tumour (1.5 cm in diameter) showed a benign admixed proliferation of blood vessels of different size, smooth muscle bundles, and mature adipose tissue, without evidence of malignancy. Endothelial cells of the haemangioma component were positive for claudin-5 endothelium-specific immunohistochemical marker, and the leiomyoma component was positive for α-smooth muscle actin. The differentiated lipocytes showed S-100 protein positivity. The Ki-67 labelling index was 2 to 3%. The mesenchymal tumour was negative for HMB45 melanocytic immunhistochemical marker. To the best of our knowledge, this is the first report describing a cutaneous angiolipoleiomyoma in a budgerigar with histological and immunohistochemical analyses.

A test of multiple hypotheses for the function of call sharing in female budgerigars, Melopsittacus undulatus.

In many social species group, members share acoustically similar calls. Functional hypotheses have been proposed for call sharing, but previous studies have been limited by an inability to distinguish among these hypotheses. We examined the function of vocal sharing in female budgerigars with a two-part experimental design that allowed us to distinguish between two functional hypotheses. The social association hypothesis proposes that shared calls help animals mediate affiliative and aggressive interactions, while the password hypothesis proposes that shared calls allow animals to distinguish group identity and exclude nonmembers. We also tested the labeling hypothesis, a mechanistic explanation which proposes that shared calls are used to address specific individuals within the sender-receiver relationship. We tested the social association hypothesis by creating four-member flocks of unfamiliar female budgerigars (Melopsittacus undulatus) and then monitoring the birds' calls, social behaviors, and stress levels via fecal glucocorticoid metabolites. We tested the password hypothesis by moving immigrants into established social groups. To test the labeling hypothesis, we conducted additional recording sessions in which individuals were paired with different group members. The social association hypothesis was supported by the development of multiple shared call types in each cage and a correlation between the number of shared call types and the number of aggressive interactions between pairs of birds. We also found support for calls serving as a labeling mechanism using discriminant function analysis with a permutation procedure. Our results did not support the password hypothesis, as there was no difference in stress or directed behaviors between immigrant and control birds.

Hot or not: the effects of exogenous testosterone on female attractiveness to male conspecifics in the budgerigar.

An increasing number of studies indicate that not only females but also males can be selective when choosing a mate. In species exhibiting male or mutual mate choice, females may benefit from being attractive. While male attractiveness is often positively influenced by higher plasma levels of the androgenic hormone testosterone, it has been shown that testosterone can masculinise female behavior and morphology in several bird species, potentially rendering them less attractive. In this study, we investigated whether female budgerigars, Melopsittacus undulatus , suffer from increased plasma testosterone levels through a negative effect on their attractiveness to males. We experimentally increased plasma testosterone levels in testosterone-treated females (T-females) compared to controls (C-females) and allowed males to choose between a T- and a C-female in a two-way choice situation. Although testosterone treatment significantly affected female behavioral and morphological characteristics, males did not show a significant difference in preference between T- and C-females. These results suggest that experimentally increasing testosterone levels in females does not appear to influence male preference during initial mate choice. Our findings indicate that selection for higher levels of testosterone in male budgerigars is probably not constrained by a correlated response to selection causing negative effects on female attractiveness during initial mate choice. Evaluating whether or not a potential constraint may arise from negative testosterone-induced effects on other fitness related traits in females requires further work.

Differences in number and distribution of striatal calbindin medium spiny neurons between a vocal-learner (Melopsittacus undulatus) and a non-vocal learner bird (Colinus virginianus)

Striatal projecting neurons, known as medium spiny neurons (MSNs), segregate into two compartments called matrix and striosome in the mammalian striatum. The matrix domain is characterized by the presence of calbindin immunopositive (CB+) MSNs, not observed in the striosome subdivision. The existence of a similar CB+ MSN population has recently been described in two striatal structures in male zebra finch (a vocal learner bird): the striatal capsule and the Area X, a nucleus implicated in song learning. Female zebra finches show a similar pattern of CB+ MSNs than males in the developing striatum but loose these cells in juveniles and adult stages. In the present work we analyzed the existence and allocation of CB+ MSNs in the striatal domain of the vocal learner bird budgerigar (representative of psittaciformes order) and the non-vocal learner bird quail (representative of galliformes order). We studied the co-localization of CB protein with FoxP1, a transcription factor expressed in vertebrate striatal MSNs. We observed CB+ MSNs in the medial striatal domain of adult male and female budgerigars, although this cell type was missing in the potentially homologous nucleus for Area X in budgerigar. In quail, we observed CB+ cells in the striatal domain at developmental and adult stages but they did not co-localize with the MSN marker FoxP1. We also described the existence of the CB+ striatal capsule in budgerigar and quail and compared these results with the CB+ striatal capsule observed in juvenile zebra finches. Together, these results point out important differences in CB+ MSN distribution between two representative species of vocal learner and non-vocal learner avian orders (respectively the budgerigar and the quail), but also between close vocal learner bird families.

Testosterone stimulates the expression of male-typical socio-sexual and song behaviors in female budgerigars (Melopsittacus undulatus): An experimental study

The hormonal control of sex differences in behavior has been extensively studied, particularly in mammals and birds. Studies have shown that the activational potential of the androgenic sex steroid testosterone (T) on male-typical behaviors in females seems to be species- as well as behavior-specific in birds. It is therefore important to study the activational effects of T in a great variety of bird species and on a wide range of behaviors, preferably in social conditions that favor their expression. Here, we investigated the activational effects of T on vocal, socio-sexual (i.e. affiliative and non-vocal courtship behaviors), aggressive and approach behavior in females of the budgerigar, Melopsittacus undulatus, a highly social monogamous parrot species. We experimentally supplemented T-females with male-like plasma T levels compared to controls. First, we observed females when they were individually housed. We found that T-females performed male-like levels of warbling song, sang significantly longer, but not more song bouts and produced more socio-sexual behaviors than controls. Then, we consecutively confronted females with a female, a dummy, and a male conspecific. T-females showed a significantly shorter latency to interact in all three social contexts. In both intrasexual and intersexual contexts, T-females performed significantly higher levels of approach and socio-sexual behavior, including “mounting (attempts)”, a strictly male behavior, which was not observed in control females. Aggression in a non-reproductive context did not appear to be sensitive to T supplementation. Our data indicate that in the budgerigar even marked sex differences in socio-sexual behavior may depend on the activational effects of T, while this is generally not the case in other species.

Solitary adenoma in the proventriculus of a budgerigar (Melopsittacus undulatus) diagnosed by immunochemistry — Short communication

The authors describe a solitary adenoma in a 5.5-year-old female Budgerigar (Melopsittacus undulatus). The tumour was partially blocking the lumen of the proventriculus and filled it almost completely. Decreased passage of food towards the gizzard and the intestines developed in the bird as result of the obstruction, which periodically hindered the passage, leading to slow emaciation. An epithelial tumour composed of irregular glandular acini was diagnosed by histological examination. Immunohistochemical reaction with pancytokeratin showed a positive cytoplasmic reaction both in the neoplastic and the normal glandular structures.