Dissertations / Theses on the topic 'Grey parrots'

Thesis (MPhil (Animal Sciences))--University of Stellenbosch, 2004.<br>African Grey Parrots are now being bred on a commercial scale in South Africa, mainly for the export market. In order to produce the best breeding results it is necessary to formulate balanced diets but no research has been done on the feeding value for African Grey parrots of ingredients used in formulating diets. Once the apparent metabolisable energy (AME) of extruded maize for African Greys has been established it will be possible to calculate the AME of other ingredients such as full fat soya, soya oil cake or sunflower oil cake. By feeding an extruded mix containing a known amount of maize mixed with a known amount of soya oil cake and establishing experimentally the AME of the mix, the AME of soya oil cake for African Greys can be calculated by difference. This information will make it possible to decide whether AME results obtained for poultry can be used in formulating diets for African Grey parrots. The study consisted of two parts where the determination of the apparent metabolisable energy (AME) of extruded maize and the practical application thereof in formulating parrot diets, and the economic viability of a commercial African Grey parrot breeding operation was investigated. A reference procedure adopted by several European laboratories for the in vivo determination of metabolisable energy (ME) was used to determine the apparent metabolisable energy (AME) of extruded whole maize for African Grey parrots. The long term goal is to make a well balanced, extruded diet for these birds. Extruded maize is the form in which maize is generally included in commercial parrot diets and was therefore chosen as the experimental feed. Maize can be conveniently extruded with other single ingredients such as full fat soyabean meal, soyabean oil cake meal or sunflower oil cake meal to determine, by difference, the AME of those ingredients. For the first part of the study, ten, 3-year-old African Grey parrots were individually housed and fed in cages designed to facilitate collection of the faeces. Cage design varied between a tall type (n=6) and a low type (n=4). The parrots were acclimatized to their new environment before the trial commenced to ensure normal feeding behaviour. The average AME value established for the ten African Grey Parrots was 16.8 MJ/kg. In the trial it became apparent that it is very difficult to get consistent results with the cages used and a modified cage design is proposed for the future. The second part of the study investigated the economic viability of breeding African Grey parrots commercially, with extruded maize as part of their diet. It was generally concluded that the breeding of African Grey parrots for the pet market can be considered as an economical venture.

This dissertation is a report on the investigation of the vocal behavior of free-living Grey Parrots (Psittacus erithacus) that inhabit the Congo Basin in Central Africa. I observed Grey Parrots in the Central African Republic and Cameroon and made audio recordings of their vocalizations. The results of spectrographic analysis of vocalizations lend support to the assertion that Grey Parrots produce calls that fall into four major acoustical classes--tonal, harmonic, noisy-harmonic, and noisy--and that these call classes may be subdivided into as many as 39 different acoustical types. A reliability study of this classification scheme demonstrated that both clustering of these acoustical types into aggregate categories and the combined method of visual inspection and basic spectrographic measurement enable reliable classification of calls into classes, types and also subtypes. The majority of calls in the observed repertoire belong to pure tonal call class, which may suggest that a large proportion of Grey Parrot calling behavior is adapted for tonal call production. Grey Parrots may also adjust the acoustic characteristics of their calls to better adapt them to their environment and communication needs. Both observations of Grey Parrots and analysis of the acoustic and production characteristics of their calls indicate that Grey Parrots may share functional call types of some New World and Australian parrot species. Some Grey Parrot calling vocal behavior parallels that of captive Grey Parrots in the laboratory. I conclude with an exploration of possible reasons why Grey Parrots possess such a diverse vocal repertoire.

Parrots are among the most endangered birds in the world, owing to the international pet trade, and habitat degradation. Grey Parrot Psittacus erithacus, the most traded wild-caught species, has suffered a steep decline across its vast African range. This PhD investigates Grey Parrot’s ecology to understand the mechanisms by which harvest and habitat loss affect populations. The island of Príncipe was chosen as a study area owing to its healthy Grey Parrot population, its tradition of parrot harvest and the disturbed-to-pristine range of habitats. Parrot densities were exceptionally high (mean±SE: 53±3 parrots km-1), and their distribution within the island was shown to change significantly between pre- and post-breeding season. The presence of nest tree species was the best predictor of densities in the former (F = 2.99, p = 0.07), while slope and food tree species were in the latter (F = 3.0, p < 0.05 and F = 8.04, p < 0.01). Variation in habitat use across seasons highlights the importance of opportunely timed surveys, and the need of preserving a matrix of habitats. Three simple and inexpensive methods were tested, which may be useful where more precise methods cannot be used. Simple encounter rates were shown to be a workable proxy for actual densities: a relationship was found between the two (R2=0.8, df=9, p=0.01). Long watches proved to be far less accurate and suitable only in limited cases (i.e. enough vantage points overlooking small areas and numerous encounters). Counts along flyways were suggested to be a good monitoring method, although further testing is required. Nest densities were found to be very high (mean±SE: 16.8±7.9 and 72.4±26.2 nests km-2 in secondary and primary forest respectively) compared to those elsewhere. The habitat characteristics measured didn’t affect productivity, suggesting that cavity characteristics may be more important. The best demographic data available on the species, were used to build a Population Viability Model to investigate its population dynamics in the face of harvest and habitat loss. In Príncipe, Grey Parrots were shown to have increased rapidly after a trade ban was put in place, highlighting the recovery potential of the species. Harvest alone was shown to be harmless only when small quotas (e.g. 600 chicks year-1) are yielded from large populations, while habitat loss lowered the predicted maximum population size. The interaction of these threats can be much more unpredictable. The effects of harvest are worsened if poorly regulated or techniques that include the harvesting of adults are used. Extinctions were predicted to occur with significant delay (≥40 years), and the conservation implications were discussed. Finally, the contribution of this thesis to the understanding of Grey Parrots ecology and conservation is highlighted and research priorities identified.

Although young children can sometimes produce words in a near perfect form at a very early stage, several diary studies revealed that these correct first productions are usually followed by less faithful renditions, only to be returned later to relative accuracy. In order to investigate if this nonlinear pattern of children vocal production called “phonological regression” might also be shared with birds, we examined here the trajectory of vocal development of a young African Grey parrot (Athena) who is learning referential English. Parrots are excellent model systems for the study of speech acquisition as they possess advanced cognitive skills and are expert imitators of the human voice. By tracking Athena’s acquisition of vowel-like sounds over the course of fifteen months using audio recordings and acoustic software programs, we analyzed her vocal development over time, from her first squeaks to her more distinct pronunciations, and compared her progress with human children and other parrots in the lab. Not one, but multiple U-shaped curves characterized her acquisition of isolated labels. Our results indicate that, like human children, parrots can experience the phenomenon of phonological regression.

In Ghana, many large avian frugivores face very serious threats, including habitat loss, hunting, and capture for the pet trade. However, basic ecological information is lacking for most species including the heavily-traded Grey Parrot Psittacus erithacus. The aim of my PhD was therefore to investigate the current distribution, abundance and ecology of Grey Parrot and other large frugivores to help inform their future conservation. I conducted surveys for twenty species of pigeons, parrots, turacos and hornbills in forty-two 10 km × 10 km survey squares in southwest Ghana. Only two species, West African Pied Hornbill Lophoceros semifasciatus and African Green Pigeon Treron calvus, were recorded in most survey squares. The most restricted and rare species included large-bodied species such as Great Blue Turaco Corythaeola cristata, Yellow-casqued Hornbill Ceratogymna elata and Black-casqued Hornbill C. atrata. Canonical Correspondence Analysis showed that large hornbills were especially restricted to large forest reserves with low anthropogenic disturbance. I then used Maxent to predict more precisely the distribution of the frugivores across Ghana, and identify their responses to predictors such as land cover types, enhanced vegetation index (EVI), human population density, and climate data. Frugivores showed varying associations with Ghana’s large forest reserves, with Afep Pigeon Columba unicincta, Great Blue Turaco, and Black Dwarf Hornbill Tockus hartlaubi among the most restricted. Most species had highest occurrence probabilities in the southwest of the country. The main driver of distributions was land cover type, with forest habitats preferred in 90% of species. Differences in human population density and EVI were seldom important. The large southwestern forest reserves are key sites for Ghana’s frugivores, and it is crucial that they are adequately protected and managed. Grey Parrot is believed to have undergone rapid population decline, yet there are almost no quantitative data properly supporting this from anywhere within its huge range. I reviewed its historical abundance across Ghana, undertook targeted searches across the country’s forest zone, repeated counts at 22 parrot roosts first performed two decades ago and gauged around 900 people’s perceptions of the decline and its causes. In over 150 days of fieldwork, just 32 groups were recorded. Encounter rates were 15 times lower than those from the early 1990s. No active roosts, i.e. roosts in current use, were found, and just a handful of birds seen near three roosts that each harboured 700–1200 birds two decades ago. Interviewees stressed the importance of very tall trees of commercially important timber species for nesting and roosting. Ghana has lost 90–99% of its Grey Parrots since 1992, and there is no evidence that, away from one or two localities, declines are less severe anywhere else in West Africa. Despite declines, Grey Parrots paradoxically remain reasonably widely distributed. I developed multiple historical and current Maxent models for the species based on various presence data sources: field surveys from the early 1990s and 2012–14, records from the Global Biodiversity Information Facility, and interview data. Models of historical distribution showed high suitability over much of the study area. Current distributions were predicted to be much more patchy, with large areas unsuitable, but with high suitability in the extreme south/southwest. Historically, Grey Parrot distribution was correlated most strongly with high rainfall, while current distribution is more closely linked with land use. Levels of exploitation of Grey Parrots have been unsustainable and regulation of the trade through quota schemes and enforcement of trade embargoes needs to be strengthened. Ghana should also reintroduce shade cocoa agriculture to improve habitat quality for the Grey Parrot and other frugivores.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2016.<br>Stable isotope analyses have been used to infer diets of organisms, define trophic partitioning, and infer geographic origins of species. It has further been applied to forensic ecology to infer the origins of deceased humans and illegally traded animal (elephant ivory and rhinoceros horn) and plant (cycads, coca, and cannabis) material. However, no research has focused on the isotope analysis of avian material in forensic ecology. African grey parrots Psittacus erithacus are one of the most traded species in the world, with the trade often being illegal, and the origins of confiscated or deceased specimens being unknown. The aim of this study was to determine if stable isotopes (δ 13C, δ 15N, and δ 2H) in African grey parrot feathers could be used to determine the wild or captive origins of birds. African grey parrot feathers (primary, body, and tail) differed isotopically so standardising isotope values of African grey parrot feathers to a single feather type was recommended, to maintain consistent sampling and allow for comparisons to be drawn between different feather types. African grey parrot feathers from unknown origins can be identified as wild or captive using δ 13C and δ 2H values, but not δ 15N values. Known wild and captive feathers possibly differ isotopically from one another because of dietary and location differences. Wild African grey parrots inhabit and feed in isotopically depleted C3 forests compared to captive African grey parrots which are usually fed C4 based foods with more positive isotope values. Wild African grey parrot δ 2H isotope values were the most negative in the central region of their native distribution. The ability to differentiate wild from captive African grey parrots, as well as infer basic origins (East from West Africa) may improve the monitoring of the illegal trade as well as help in tracing illegally traded parrots.<br>LG2017

碩士<br>國立臺灣大學<br>臨床動物醫學研究所<br>107<br>Blood pressure is one of the vital signs in clinical medicine, its’ reading provides a direct evaluation of systemic circulation. However, in birds, blood pressure measurement is not performed routinely during physical examination owing to special physiologic, anatomic limitations and inaccuracy of indirect blood pressure measurement in avian patients. Intraosseous catheter is now the most commonly used route in avian fluid therapy, especially for those small sized or are hypotensive that makes the vessel inaccessible. In human medicine, similar limitations were encountered in neonatal or critically illed patients, some research has found that intraosseous catheter can be placed more quickly, easily, and with lower complications. Hence, recently, more and more researches has focused on the relationship between intraosseous pressure and arterial pressure, and try to find if the intraosseous pressure measurement could replace blood pressure measurement in clinical condition In this study, we used 12 healthy sub-adult or adult African grey parrots (Psittacus erithacus) as experimental subjects. Each bird was maintained under general anesthesia condition, a 24 gauge catheter was installed into the deep radial artery and a 22 guage needle was installed into the ulna medullary cavity respectively. Both catheters connected to a disposable pressure sensor, and arterial pressure waveform and intraosseous pressure waveforms were recorded for 10 minutes. The arterial pressure values were normally distributed while the intraosseous pressure values were not. The average of arterial systolic, mean, diastolic pressure values are 118.90±11.66(94.50-136.02) mmHg, 94.86±17.97(66.89-129.51) mmHg and 79.66±20.42(49.05-117.87) mmHg. The average of intraosseous mean pressure values is 49.17± 29.94(2.03-93.21) mmHg, and the average heart rate is 315.19± 101.14(158.20-490.60) beat per minute. There’s no correlation between arterial pressure values and intraosseous pressure values. A positive relationship between heart rate and mean intraosseous pressure values was found and the correlation coefficient was 0.58. Though future research may need to determine the efficacy of intraosseous pressure, based on its easier and less time consuming techniques, it is still a potential method for further clinical use in avian patients.

碩士<br>國立臺灣大學<br>臨床動物醫學研究所<br>103<br>Atherosclerosis is probably the most common cardiovascular disease in parrots. Nowadays, ante-mortem diagnosis of atherosclerosis in birds is still difficult. In humans, CT-A has long been used as a non-invasive, sensitive tool to identify calcified and non-calcified plaques in major arteries. At this time, it seems to be a promising method to evaluate the avian cardiovascular system. The objective of our study was to establish the CT-A protocol using the dual-headed power injector in African Grey parrots (Psittacus erithacus) as well as reference range of attenuation value and diameters of the major arteries. 16-slice CT scanning was used to measure the region of interest (ROI) in 6 major arteries. Before scanning, each bird underwent physical, blood, and cardiologic examination and were considered healthy. Each bird was under general anesthesia during CT-A procedure. The dual-headed power injector with saline chaser technique was used to administer contrast medium and saline flush. We used the real-time bolus-tracking method, and triggered the scan manually once the peak enhancement of ascending aorta was reached. The measurements were obtained by 2 clinicians double-blindly. The reference range before and after contrast medium administration via body, pulmonary, and bone window were set up accordingly. Inter-observer consistency in measurements was high in post-contrast values via a body window. Hence, we suggested performing CT-A in parrots with contrast medium administration in body window. However, further studies will be needed to improve the potential and utility of CT-A in diagnosis of atherosclerosis in parrots.

The aim of the study was to map the repertoire of vocalization of four wild-caught grey parrots (Psittacus erithacus), two males and two females. Data were collected during nine days from June to November 2008 by recording of vocalization in standardized conditions. Recorded sounds (3 052) were categorized according to their characteristics using both visual inspection of spectrograms and listening. We found 70 different call types, which were combined into 18 bigger groups. We found no subject to use the whole repertoire. Important differences were found both between individuals and between males and females. almost all call types were used throuthout the whole period of recording. Model spectrograms of all call types are shown. Key words: grey parrot, Psittacus erithacus, repertoire, vocalization

This diploma thesis is focused on research of individual recognition in African grey parrots based on visual cues from stimulus card made from photographs of familiar conspecifics, specifically on testing the significance of selected visual features. Theoretical part of the thesis deals with the general individual recognition ability followed by specifics of this ability in humans, non-human primates and birds including African grey parrot. Great attention is paid specifically to the individual recognition ability in humans, since it is the aim of this thesis to interpret the results of hypotheses testing comparatively. In order to test the hypotheses seven modifications of conspecifics' photographs were created. Experiment employed matching-to- sample as method, subjects were three African grey parrots. Findings were to a large extent in accordance with findings of analogical studies that used human subjects. Results imply, that visual information in African grey parrot is processed holistically, with structure and pigmentation of feathers on the abdominal part of the parrot having most likely the highest significance for successful individual recognition of a familiar conspecific. Key words: individual recognition, African grey parrot, comparative cognition, visual recognition

Human speech is considered to be unique means of communication. The beginnings of human vocalization, which develops into the speech, however, have some patterns or principles which can also be found in animal communication. It has been discovered that there are similarities between humans and animals in terms of social organization, neural control, cognition and function of vocal signals. Moreover, it seems that birds, parrots specifically, have closer parallels with humans in these respects than with other primates. Vocal ontogeny was, however, at least in parrots, investigated only marginally. Therefore it has become the subject of this study. African grey parrots (Psittacus erithacus) show a wide range of cognitive abilities and are thus suitable species for comparison with humans. The aim of this study was to map the early vocal development of African grey parrots until age of 11 weeks. Then it was possible to compare it theoretically with the early vocal development of children. The repertoire was mapped using video recordings of four fledglings of feral African grey parrots, which are in possession of FHS UK Prague. The recordings were analysed acoustically and visually with audio software Sound Forge Pro 11 and Sound Forge Audio Studio 10. After identifying the repertoire we used stage...

Over the past decade, cage and aviary birds have dramatically increased in popularity as pets. African Grey parrot (Psittacus erithacus) is a species of parrot that belongs to the order Psittaciformes of the Class Aves. Grey parrots are very popular pets due to their intelligence and their ability to mimic human voices, both in tone and range of each person. According to “BirdLife International”, as of 2015 two species of Grey parrots are considered: the African Grey parrot (Psittacus erithacus) and the Timneh parrot (Psittacus timneh). The most commonly seen in clinical practice is the African Grey parrot (Psittacus erithacus). Despite bird species being approximately twice as more as mammal species, studies on the hematological parameters of healthy individuals are still scarce in avian species. Furthermore, hematological profiles are critical to the understanding of several disease processes, being particularly useful as diagnostic tools in clinical practice, since birds tend to hide clinical signs of disease. The objective of the present work is to evaluate the influence of variability factors such as age, sex, diet and sedation on the hematological parameters of healthy African Grey parrots and to compare those parameters with the published reference intervals (RI). Data from blood samples of African Grey parrot (Psittacus erithacus) healthy individuals was collected in Zoològic Veterinaris (Barcelona). Blood samples (n=459) were taken during March 2009 to July 2017 from animals (n=239) that were examined in first consultations or check-ups. The animals had no alterations in the clinical examination and no alterations were found in the serum biochemistry analysis, coprology testing or other tests performed. Hematological testing was performed to determine hematocrit (Hct), mean hemoglobin concentration (MHC), mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), total erythrocyte count (RBC), total leukocyte count (WBC), and differential leukogram with absolute and relative counts. All hematological testing was performed in an in-house laboratory and sampling and analysis methods remained constant throughout the whole study. Animals with 0 to 4 years of age showed higher values of Hct (p<0,001), Hgb (p=0,023) and RBC (p=0,018) and lower values of MCHC (p=0,008), WBC (p=0,012) and heterophils (p<0,001) than older animals. Monocytes exhibited significant differences (p=0,035) between different age groups. Females presented higher values of hematocrit, Hgb and RBC (p<0,001) compared to males. Sedated animals showed lower values of WBC (p<0,001), heterophils (p=0,006), lymphocytes (p=0,003) and monocytes (p=0,03) but higher values of Hgb (p=0,01), MCH (p=0,025) and MCHC (p< 0,001). Additionally, part of the hemograms displayed values outside the RI, namely MCV, WBC and monocyte values. Our results suggest that age and sex influence hematological parameters in African Grey parrots. Sedation also affects these parameters, and may help to reduce the stress associated to blood collection. These results can contribute to the creation of databases that would help to establish appropriate RI for this species.<br>Na última década, as aves têm sido animais de companhia cada vez mais populares. O Papagaio-cinzento (Psittacus erithacus) é uma espécie de papagaio que pertence à ordem Psittaciformes e à Classe Aves. A popularidade crescente deste animal como animal de companhia deve-se, em grande parte, à sua inteligência e à sua capacidade de imitar vozes humanas, quer no timbre, quer na amplitude de voz. De acordo com a associação “BirdLife International”, e a partir de 2015, são consideradas 2 espécies de Papagaios-cinzentos: o Papagaio-cinzento-do-Congo (Psittacus erithacus) e o Papagaio-cinzento-de-Timneh (Psittacus timneh). A mais frequente em clínica é o Papagaio-cinzento-do-Congo designado por Papagaio-cinzento (Psittacus erithacus). Os parâmetros hematológicos de aves saudáveis não têm sido alvo de estudos tão aprofundados como os de mamíferos, apesar de existirem aproximadamente o dobro de espécies de aves. Os perfis hematológicos são fundamentais para a compreensão de inúmeros processos de doença, sendo particularmente úteis como ferramentas de diagnóstico na prática clínica, uma vez que as aves tendem a ocultar sinais clínicos de doença. O objectivo do presente estudo é avaliar a influência de factores de variabilidade como a idade, sexo, dieta e sedação nos parâmetros hematológicos de Papagaios-cinzentos saudáveis e comparar os valores obtidos com os valores de referência estabelecidos. Dados de amostras de sangue pertencentes a indivíduos saudáveis da espécie Papagaio-cinzento (Psittacus erithacus) foram obtidos na Zoològic Veterinaris (Barcelona). As colheitas de sangue (n=459) foram realizadas em animais (n=239) que foram submetidos a exame do estado geral em primeiras consultas ou em consultas de rotina durante o período compreendido entre março de 2009 e julho de 2017. Os indivíduos não apresentaram alterações no exame de estado geral, bem como não demonstraram alterações nos exames bioquímicos, coprológicos e outros testes realizados. Foram realizados testes hematológicos de modo a determinar o hematócrito, concentração de hemoglobina, volume corpuscular médio, hemoglobina corpuscular média, concentração de hemoglobina corpuscular média, contagem total de eritrócitos, contagem total de leucócitos, contagem diferencial de leucócitos, tanto absoluta como relativa. Todos estes exames foram efectuados no laboratório do hospital e as metodologias de colheita e análise foram mantidas constantes ao longo do estudo. Verificou-se que os animais com idades compreendidas entre 0 e 4 anos exibiam valores mais elevados de Hct (p<0,001), Hgb (p=0,023) e RBC (p=0,018), e valores mais baixos de MCHC (p=0,008), WBC (p=0,012) e heterófilos (p<0,001) quando comparados com os animais mais velhos. Os monócitos mostraram diferenças significativas (p=0,035) entre diferentes idades. Relativamente ao sexo, as fêmeas apresentaram valores mais elevados de hematócrito, Hgb e RBC (p<0,001) quando comparadas com os machos. Animais sedados tinham valores mais baixos de WBC (p<0,001), heterófilos (p=0,006), linfócitos (p=0,003) e monócitos (p=0,03), mas valores mais elevados de Hgb (p=0,01), MCH (p=0,025) e MCHC (p< 0,001). Uma porção dos hemogramas mostrou valores fora dos valores de referência, nomeadamente MCV, WBC e valores de monócitos.

The ability to communicate referentially has been historically viewed as being uniquelly human. However, with the increasing amount of studies discussing the communicative faculty of animals in the context of the evolution of human language, there is now growing evidence that this ability is present in many animal species, too. Although we know a lot about mimetic abilities of domesticated African grey parrots' (Psittacus erithacus) and their competence to use human words in a referential way, we know very little about the elements of referentiality in their natural vocalization. Our goal in this work was to find, whether and in which context is functionally referential vocalization in this species of birds present. We were determining its presence by the experiment, in which we have exposed four captured African grey parrot, in the ownership of FHS UK Prague, to stimuli that in other animal species usually elicit functionally referential vocalization: predators and prefered type of food. We analysed the behaviour and vocalizations of the tested birds by analytic softwares Interact, respectively Soundforge 0.8. We find out, that despite the fact that birds reaponded to our experimental objects appropriatelly (i.e. "predators" caused more fear and the like), they give the major amout of...