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Acromelanism is a form of albinism observed in several vertebrate species. In mammals, acromelanism is known to be caused by mutations in the tyrosinase gene (TYR) that induce a temperature‐sensitive behavior of melanin synthesis, resulting in a characteristic hair color gradient. In birds, several phenotypes consistent with acromelanism have been reported, but their genetic basis remains unknown. This study aimed to identify the genetic basis of an acromelanistic phenotype in domesticated canaries known as pearl and test whether it is caused by the same molecular mechanism described for mammals. To do this, we compared the genomes of pearl and non‐pearl canaries and searched for potentially causative genetic mutations. Our results suggest that the pearl phenotype is caused by a mutation in the TYR gene encoding a TYR‐P45H missense substitution. Our findings further suggest that reports of acromelanism in other bird species might be explained by TYR mutations. [ABSTRACT FROM AUTHOR]

A canary (Serinus canaria) that was presented for consultation due to alterations in its beak and slight deterioration in its general condition, revealed during clinical examination the presence of a large rhinolith in the left nasal opening, which also had its margins markedly distended due to chronic lysis of its edges. The rhinolith was extracted but the bird died days later. Cytological evaluations and isolation in pure culture were carried out from the extracted rhinolith, all of whom supported the diagnosis of mucormycosis, which was later confirmed by molecular techniques. The product obtained by PCR was subsequently sequenced, resulting in a 98 % homology with Lichteimia corymbifera. Although mucormycosis affecting the nasal cavity has been diagnosed with some frequency in humans, it is reported for the first time in birds in the present work.

Usutu virus (USUV) is a flavivirus transmitted to avian species through mosquito bites that causes mass mortalities in wild and captive bird populations. However, several cases of positive dead birds have been recorded during the winter, a vector-free period. To explain how USUV "overwinters", the main hypothesis is bird-to-bird transmission, as shown for the closely related West Nile virus. To address this question, we experimentally challenged canaries with intranasal inoculation of USUV, which led to systemic dissemination of the virus, provided the inoculated dose was sufficient (>102 TCID50). We also highlighted the oronasal excretion of infectious viral particles in infected birds. Next, we co-housed infected birds with naive sentinels, to determine whether onward transmission could be reproduced experimentally. We failed to detect such transmission but demonstrated horizontal transmission by transferring sputum from an infected to a naive canary. In addition, we evaluated the cellular tropism of respiratory mucosa to USUV in vitro using a canary tracheal explant and observed only limited evidence of viral replication. Further research is then needed to assess if and how comparable bird-to-bird transmission occurs in the wild. [ABSTRACT FROM AUTHOR]

The positive relationship between number of introduced individuals and introduction success has been widely proposed in invasion biology on theoretical and empirical grounds. Still, successful establishment has been reported for smaller-than-expected founding populations, thus we suspected that the role of chance in species introductions had been understated. To evaluate this proposition, we modeled the likelihood of success of a known small-introduction event, that of island canaries (Serinus canaria) to Midway Atoll. We built an individual-based, stochastic simulation model, populated with vital rates from wild canaries and related species, and projected population growth for 30 years under a variety of conditions. We used perturbation analysis and logistic regression to evaluate model sensitivities. Our optimistic baseline model returned a probability of establishment of roughly 50%, although the true probability would have been lower if any realized vital rates were below their optimistic values. Both sensitivity analyses were dominated by juvenile mortality, suggesting that a small change in this value has an outsized impact on the likelihood of introduction success. As such, we propose three factors that may have increased the likelihood of success for this introduction: behavioral plasticity in mate selection allowing opportunistic polygamy, resistance to inbreeding depression that is common in species with a history of captive breeding, and a reduction in juvenile mortality rates via human assistance. Our models suggest that chance can play a role in establishment likelihood for small founding populations even under optimistic conditions, but that case-specific factors are likely important in most successful small introductions. [ABSTRACT FROM AUTHOR]

Acoustic communication is fundamentally constrained by noise. In birds, the masking of mating signals (songs) may reduce fitness and, hence, they have evolved various mechanisms to maintain communication in noise. One of these tactics is the adjustment of song timing to avoid overlap with masking sounds, but previous studies yielded contrasting results regarding the occurrence and magnitude of this behavioural plasticity. Here, we investigated how temporal noise avoidance varies with noise intensity. We exposed singing Canaries (Serinus canaria) to playbacks of masking noise of varying amplitude [60–80 dB(A) SPL]. Contrary to our prediction, the birds did not shift song onsets to the silent intervals between noise bursts at high noise amplitudes, nor did they increase singing outside the playback period. Rather, we found that noise generally triggered the onset of song: the Canaries preferentially sang during the noise bursts independent of the noise amplitude. This behaviour is somewhat paradox because it leads to the most unfavourable signal-to-noise ratios. Our results, together with findings from the current literature, indicate marked species differences in the noise-induced song plasticity of birds. Therefore, we suggest a more comprehensive conception of noise that incorporates both supressing and stimulating effects. [ABSTRACT FROM AUTHOR]

Investigations of bacterial communities are on the rise both in human and veterinary medicine. Their role in health maintenance and pathogenic mechanisms is in the limelight of infectious, metabolic, and cancer research. Among the most considered, gut bacterial communities take the cake. Their part in animals was assessed mainly to improve animal production, public health, and pet management. In this regard, canaries deserve attention, being a popular pet and source of economic income for bird-keepers, for whom breeding represents a pivotal point. Thus, the present work aimed to follow gut bacterial communities' evolution along on whole reproductive cycle of 12 healthy female canaries. Feces were collected during parental care, molting, and resting phase, and submitted for 16S rRNA sequencing. Data were analyzed and a substantial presence of Lactobacillus aviarius along all the phases, and a relevant shift of microbiota during molting and rest due to an abrupt decrease of the Vermiphilaceae family were detected. Although the meaning of such change is not clear, future research may highlight unforeseen scenarios. Moreover, Lactobacillus aviarius may be deemed for normal bacteria flora restoration in debilitated birds, perhaps improving their health and productivity. [ABSTRACT FROM AUTHOR]

Usutu virus (USUV) is a flavivirus transmitted to avian species through mosquito bites that causes mass mortalities in wild and captive bird populations. However, several cases of positive dead birds have been recorded during the winter, a vector-free period. To explain how USUV “overwinters”, the main hypothesis is bird-to-bird transmission, as shown for the closely related West Nile virus. To address this question, we experimentally challenged canaries with intranasal inoculation of USUV, which led to systemic dissemination of the virus, provided the inoculated dose was sufficient (>102 TCID50). We also highlighted the oronasal excretion of infectious viral particles in infected birds. Next, we co-housed infected birds with naive sentinels, to determine whether onward transmission could be reproduced experimentally. We failed to detect such transmission but demonstrated horizontal transmission by transferring sputum from an infected to a naive canary. In addition, we evaluated the cellular tropism of respiratory mucosa to USUV in vitro using a canary tracheal explant and observed only limited evidence of viral replication. Further research is then needed to assess if and how comparable bird-to-bird transmission occurs in the wild.

Investigations of bacterial communities are on the rise both in human and veterinary medicine. Their role in health maintenance and pathogenic mechanisms is in the limelight of infectious, metabolic, and cancer research. Among the most considered, gut bacterial communities take the cake. Their part in animals was assessed mainly to improve animal production, public health, and pet management. In this regard, canaries deserve attention, being a popular pet and source of economic income for bird-keepers, for whom breeding represents a pivotal point. Thus, the present work aimed to follow gut bacterial communities’ evolution along on whole reproductive cycle of 12 healthy female canaries. Feces were collected during parental care, molting, and resting phase, and submitted for 16S rRNA sequencing. Data were analyzed and a substantial presence of Lactobacillus aviarius along all the phases, and a relevant shift of microbiota during molting and rest due to an abrupt decrease of the Vermiphilaceae family were detected. Although the meaning of such change is not clear, future research may highlight unforeseen scenarios. Moreover, Lactobacillus aviarius may be deemed for normal bacteria flora restoration in debilitated birds, perhaps improving their health and productivity.

A European goldfinch (Carduelis carduelis), a canary (Serinus canaria), and a lovebird (Agapornis roseicollis) captive-bred at three different private aviaries in Spain were submitted for necropsy with a history of weakness and ruffled feathers, weight loss associated with glossitis, and respiratory disease, respectively. Microscopically, enterocytes in the jejunum and ileum contained colonies of gram- and Stamp-positive, oval to elliptical microorganisms within parasitophorous vacuoles in the apical cytoplasm. Nested PCR using MSP primers that target microsporidian RNA genes produced amplicons of expected size for Encephalitozoon species, and analysis of forward and reverse DNA sequences confirmed the presence of Encephalitozoon hellem in all cases. The main cause of death of all three birds consisted of concurrent infections. However, intestinal encephalitozoonosis may have contributed to exacerbated catabolism. Encephalitozoonosis (or microsporidiosis) has been rarely described in passerine birds.

The domestic canary (Serinus canaria) has been bred for hundreds of years to improve the quality of its plumage and its song. Reproduction in this species occurs seasonally, stimulated by a gradual increase in day length. Although, the occurrence of seasonal breeding in canaries is well known, whether canary reproduction can be manipulated remains unknown. Our objective was to determine whether the conditions of captivity (photoperiod and temperature) can be adjusted to enable canaries to reproduce outside of their natural breeding season. Thirty days before the natural breeding season, canary pairs were assigned and separated into three different groups: External Control (housed outdoors under ambient conditions), Artificial Control (housed artificially indoors under conditions similar to the external conditions), and Artificial Altered (housed artificially indoors for five months, with the photoperiod gradually manipulated to simulate that of the natural breeding season) groups. The number of clutches laid was greater in the Artificial Control than in External Control; however, more birds hatched in the External Control. In the Artificial Altered group, the beginning of the breeding season was delayed when the same parameters were used. Although, further research is needed, this study presents new data to assist in the development of protocols that entail gradual changes in environmental conditions to try to reduce the impacts of the processes on animal welfare. [ABSTRACT FROM AUTHOR]

ABSTRACT: The domestic canary (Serinus canaria) has been bred for hundreds of years to improve the quality of its plumage and its song. Reproduction in this species occurs seasonally, stimulated by a gradual increase in day length. Although, the occurrence of seasonal breeding in canaries is well known, whether canary reproduction can be manipulated remains unknown. Our objective was to determine whether the conditions of captivity (photoperiod and temperature) can be adjusted to enable canaries to reproduce outside of their natural breeding season. Thirty days before the natural breeding season, canary pairs were assigned and separated into three different groups: External Control (housed outdoors under ambient conditions), Artificial Control (housed artificially indoors under conditions similar to the external conditions), and Artificial Altered (housed artificially indoors for five months, with the photoperiod gradually manipulated to simulate that of the natural breeding season) groups. The number of clutches laid was greater in the Artificial Control than in External Control; however, more birds hatched in the External Control. In the Artificial Altered group, the beginning of the breeding season was delayed when the same parameters were used. Although, further research is needed, this study presents new data to assist in the development of protocols that entail gradual changes in environmental conditions to try to reduce the impacts of the processes on animal welfare.

The aim of this review was to provide breeders with practical information about breeding choices and feeding of their breeders in the production and feeding of domestic Canaries (Serinus canarius domesticus), both commercial and hobby purposes today. In canary breeding, proper feeding is very important for breeding selection and obtaining optimum yield from these breeds. The fact that Canary breeding has been carried out mainly for hobby purposes until today has resulted in limited scientific studies for these birds. Due to the absence of serious literal information based on scientific foundations in this breeding field and the lack of breeding standards, traditional methods have emerged as a result of blending the knowledge acquired with master apprentice relations until today and caused practical applications that differ from producer to producer in the field of canary breeding. However, day by day, people's interest in this type of exotic birds is increasing and scientific studies about canary breeding are gaining momentum as a reflection of this interest. In this review, some critical issues in breeding selection and breeding were discussed. [ABSTRACT FROM AUTHOR]

Abstract Background Plasmodium parasites are known to impose fitness costs on their vertebrate hosts. Some of these costs are due to the activation of the immune response, which may divert resources away from self-maintenance. Plasmodium parasites may also immuno-deplete their hosts. Thus, infected individuals may be less able to mount an immune response to a new pathogen than uninfected ones. However, this has been poorly investigated. Methods The effect of Plasmodium infection on bird humoral immune response when encountering a novel antigen was tested. A laboratory experiment was conducted on canaries (Serinus canaria) experimentally infected with Plasmodium relictum (lineage SGS1) under controlled conditions. Birds were immune challenged with an intra-pectoral injection of a novel non-pathogenic antigen (keyhole limpet haemocyanin, KLH). One week later they were challenged again. The immune responses to the primary and to the secondary contacts were quantified as anti-KLH antibody production via enzyme-linked immunosorbent assay (ELISA). Results There was no significant difference in antibody production between uninfected and Plasmodium infected birds at both primary and secondary contact. However, Plasmodium parasite intensity in the blood increased after the primary contact with the antigen. Conclusions There was no effect of Plasmodium infection on the magnitude of the humoral immune response. However, there was a cost of mounting an immune response in infected individuals as parasitaemia increased after the immune challenge, suggesting a trade-off between current control of chronic Plasmodium infection and investment against a new immune challenge.

Parental care involves elaborate behavioural interactions between parents and their offspring, with offspring stimulating their parents via begging to provision resources. Thus, begging has direct fitness benefits as it enhances offspring growth and survival. It is nevertheless subject to a complex evolutionary trajectory, because begging may serve as a means for the offspring to manipulate parents in the context of evolutionary conflicts of interest. Furthermore, it has been hypothesized that begging is coadapted and potentially genetically correlated with parental care traits as a result of social selection. Further experiments on the causal processes that shape the evolution of begging are therefore essential. We applied bidirectional artificial selection on begging behaviour, using canaries (Serinus canaria) as a model species. We measured the response to selection, the consequences for offspring development, changes in parental care traits, here the rate of parental provisioning, as well as the effects on reproductive success. After three generations of selection, offspring differed in begging behaviour according to our artificial selection regime: nestlings of the high begging line begged significantly more than nestlings of the low begging line. Intriguingly, begging less benefitted the nestlings, as reflected by on average significantly higher growth rates, and increased reproductive success in terms of a higher number of fledglings in the low selected line. Begging could thus represent an exaggerated trait, possibly because parent–offspring conflict enhanced the selection on begging. We did not find evidence that we co‐selected on parental provisioning, which may be due to the lack of power, but may also suggest that the evolution of begging is probably not constrained by a genetic correlation between parental provisioning and offspring begging. [ABSTRACT FROM AUTHOR]

Understanding the evolution of mating display traits and preferences for them is a major aim of behavioral and evolutionary ecology. However, isolating the specific traits used as mate choice criteria and the possible genetic underpinnings of both trait and preference has proven difficult, particularly in natural systems offering little experimental control over key variables. In this study, we used discrete color morphs of otherwise phenotypically identical domestic canaries (Serinus canaria) in a mate choice apparatus to test whether breeding-condition female canaries show preference for males of varying color phenotypes (yellow, white, red, or wild-type green), using spatial association as a proxy for choice. We also used synthesized vocal recordings to examine whether females in our population exhibited mate choice for song characteristics, as has been demonstrated in this species. Contrary to previous study, we found that neither white nor yellow females in our colony showed any preference for males associated with songs of differing quality, and yellow females also did not prefer supernormal red or wild-type green males over yellow males. However, yellow—but not white—females demonstrated a preference to associate with yellow males over white males. We hypothesize that preference for brightly colored mates is ancestral in domestic canaries, but that strong artificial selection for white females to reproduce successfully with white males has eliminated the preference for color (along with color itself) in the white canaries.

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Macrorhabdus ornithogaster is an opportunistic yeast that colonizes the gastric mucosa of many avian species. Until now, no studies have focused on the influence of a gastric infection on the balance of the intestinal microbiota of birds. In this study, 44 faecal samples from individual canaries, with and without M. ornithogaster infection, were analysed. The detection of the yeast was evaluated by 18S rRNA PCR. In order to evaluate the impact of the Macrorhabdus infection on the bacterial communities, culture-independent methods, by the use of amplicon-based sequencing as well as 16S rRNA-DGGE, were adopted. The different health status of animals affected the relative abundance of the main OTUs, with a greater diversification of the gut microbiota in healthy animals compared to the infected. In particular, Lactococcus, Pseudomonas, Acinetobacter, Lachnospiraceae, Propionibacterium and Weissella were found to be characteristic of uninfected animals (FDR < 0.05), while Lactobacillus and Candidatus Arthromitus were characteristic of infected animals (FDR < 0.05). Both these taxa have been reported as immunostimulatory, involved in immunological disorders. In infected animals the inferred metagenome assessed by PICRUST clearly showed a positive correlation between the presence of M. ornithogaster and KEGG genes related to ether lipid metabolism, already reported to be immunostimulatory by activation of macrophages and to play a pathophysiological role in several immunological disorders. Finally, our results show an interaction between infection of the digestive tract and intestinal microbiota of pet birds and provide insight into the changing of the complex enteric bacterial community. HIGHLIGHTS: Macrorabdus ornithogaster is a gastric yeast that colonizes a wide range of birds. Differences were found between infected and healthy animals in gut microbiota. Candidatus Arthromitus was closely associated with infected birds. M. ornithogaster can affect intestinal microbiota composition of canaries. [ABSTRACT FROM AUTHOR]

Two dead birds from a flock of domestic canaries (Serinus canaria) were referred with a history of anorexia, weight loss, abdominal distension, and occasional mortality. A slightly enlarged liver and proventriculus were seen on the examination of the abdominal cavity. A large number of yeast resembling Macrorhabdus ornithogaster were observed on gram staining of the proventriculus mucosa. Pseudomonas aeruginosa was isolated on the microbial culture of the liver. The complete genomic sequence of the internal transcribed spacer 1 (ITS1) was determined in Macrorhabdus ornithogaster using panfungal primers. The alignment of the sequence obtained from this study with 6 GenBank deposited ITS1sequences of Macrorhabdus ornithogaster showed some repeated nucleotide substitutions. The complete ITS1 sequence of our study (MF993119) displayed a whole genetic similarity to ITS1 sequences of Macrorhabdus ornithogaster isolated from canaries and finches and clustered into a different group from ITS1 sequences of Macrorhabdus ornithogaster isolated from pssitacines. The ITS1 region is proposed as taxonomically informative for Macrorhabdus ornithogaster isolates from different hosts. [ABSTRACT FROM AUTHOR]

Offspring are selected to demand more resources than what is optimal for their parents to provide, which results in a complex and dynamic interplay during parental care. Parent–offspring communication often involves conspicuous begging by the offspring which triggers a parental response, typically the transfer of food. So begging and parental provisioning reciprocally influence each other and are therefore expected to coevolve. There is indeed empirical evidence for covariation of offspring begging and parental provisioning at the phenotypic level. However, whether this reflects genetic correlations of mean levels of behaviors or a covariation of the slopes of offspring demand and parental supply functions (= behavioral plasticity) is not known. The latter has gone rather unnoticed—despite the obvious dynamics of parent–offspring communication. In this study, we measured parental provisioning and begging behavior at two different hunger levels using canaries (Serinus canaria) as a model species. This enabled us to simultaneously study the plastic responses of the parents and the offspring to changes in offspring need. We first tested whether parent and offspring behaviors covary phenotypically. Then, using a covariance partitioning approach, we estimated whether the covariance predominantly occurred at a between‐nest level (i.e., indicating a fixed strategy) or at a within‐nest level (i.e., reflecting a flexible strategy). We found positive phenotypic covariation of offspring begging and parental provisioning, confirming previous evidence. Yet, this phenotypic covariation was mainly driven by a covariance at the within‐nest level. That is parental and offspring behaviors covary because of a plastic behavioral coadjustment, indicating that behavioral plasticity could be a main driver of parent–offspring coadaptation. In this study, we measured parental provisioning and begging behavior at two different hunger levels using canaries (Serinus canaria) as a model species. Then, using a covariance partitioning approach, we estimated whether the covariance predominantly occurred at a between‐nest level (i.e., indicating a fixed strategy) or at a within‐nest level (i.e., reflecting a flexible strategy). We found positive phenotypic covariation of offspring begging and parental provisioning, mainly driven by a covariance at the within‐nest level, showing a plastic behavioral coadjustment. [ABSTRACT FROM AUTHOR]

Abstract: The Enterobacteriaceae family contains potentially zoonotic bacteria, and their presence in canaries is often reported, though the current status of these in bird flocks is unknown. Therefore, this study aimed to identify the most common genera of enterobacteria from canaries (Serinus canaria) and their antimicrobial resistance profiles. From February to June of 2013, a total of 387 cloacal swab samples from eight domiciliary breeding locations of Fortaleza city, Brazil, were collected and 58 necropsies were performed in canaries, which belonged to the Laboratory of Ornithological Studies. The samples were submitted to microbiological procedure using buffered peptone water and MacConkey agar. Colonies were selected according to their morphological characteristics on selective agar and submitted for biochemical identification and antimicrobial susceptibility. A total of 61 isolates were obtained, of which 42 were from cloacal swabs and 19 from necropsies. The most isolated bacteria was Escherichia coli with twenty five strains, followed by fourteen Klebsiellaspp., twelve Enterobacterspp., seven Pantoea agglomerans, two Serratiaspp. and one Proteus mirabilis. The antimicrobial to which the strains presented most resistance was sulfonamides with 55.7%, followed by ampicillin with 54.1% and tetracycline with 39.3%. The total of multidrug-resistant bacteria (MDR) was 34 (55.7%). In conclusion, canaries harbor members of the Enterobacteriaceae family and common strains present a high antimicrobial resistance rate, with a high frequency of MDR bacteria.

Abstract Isospora bioccai (Cringoli and Quesada 1991) (Protozoa, Apicomplexa, Eimeriidae) is reported and described from captive canaries Serinus canaria forma domestica (Linnaeus 1758) in Mexico. The oöcysts are subspherical, 25.5 × 23.5 μm, with smooth, bilayered wall, ∼1.3 μm thick. Micropyle absent, oöcyst residuum absent, and polar granule present, 4–8 rice-grain-shaped. Sporocysts are ovoidal, 16.7 × 10.5 μm. Stieda body knob-like and substieda body trapezoidal of irregular base. Sporocyst residuum is composed of granules of different sizes. Sporozoites are vermiform with one refractile body and a nucleus. Gamogony was seen in the duodenum. In addition to new locality, this is the first description of I. bioccai from S. canaria. Graphical abstract Image 1 Highlights • The canary (Serinus canaria) as a new host for Isospora bioccai. • Gamogony was seen in the duodenum. • First record of I. bioccai in Fringillidae in Mexico. [ABSTRACT FROM AUTHOR]

Host susceptibility to parasites is likely to be influenced by intrinsic factors, such as host oxidative status determined by the balance between pro-oxidant production and antioxidant defences. As a result, host oxidative status acts as an environmental factor for parasites and may constrain parasite development. We evaluated the role of host oxidative status on infection dynamics of an avian malarial parasite by providing canaries (Serinus canaria) with an antioxidant supplementation composed of vitamin E (a lipophilic antioxidant) and olive oil, a source of monounsaturated fatty acids. Another group received a standard, non-supplemented food. Half of the birds in each group where then infected with the haemosporidian parasite, Plasmodium relictum. We monitored the parasitaemia, haematocrit level, and red cell membrane resistance, as well as the transmission success of the parasite to its mosquito vector, Culex pipiens. During the acute phase, the negative effect of the infection was more severe in the supplemented group, as shown by a lower haematocrit level. Parasitaemia was lower in the supplemented group during the chronic phase only. Mosquitoes fed on supplemented hosts were more often infected than mosquitoes fed on the control group. These results suggest that dietary antioxidant supplementation conferred protection against Plasmodium in the long term, at the expense of a short-term negative effect. Malaria parasites may take advantage of antioxidants, as shown by the increased transmission rate in the supplemented group. Overall, our results suggest an important role of oxidative status in infection outcome and parasite transmission. [ABSTRACT FROM AUTHOR]

Male secondary sexual traits and female mate choice traits must contain heritable variation for sexual selection to operate. However, for female mate choice, especially, this is poorly known. To complicate matters, both male sexual traits and female mate choice typically show condition dependence, implying that environmental effects probably play an important synergistic role. Using a cross-fostering design, we therefore aimed to disentangle genetic, environmental and their potential interacting effects to investigate how they affect the expression of a sexually selected trait (here birdsong) and female mate choice. To assess environmental effects, we focused on the role of the social environment and thus on learned components. Among the different male song traits investigated, we found a high heritability for song bout length and song bout repertoire, as well as an intriguing gene-by-environment interaction for song bout repertoire. Specifically, the tutor appeared to negatively affect the song bout repertoire of the tutee when his genetic father had a large song bout repertoire but had a positive effect on descendants from fathers with small song bout repertoires. In contrast, we did not detect significant heritability in female mate choice. Female mate choice contained a learned component as females significantly disfavoured their foster father in the mate choice tests, indicating a learned inbreeding avoidance. Thus, our study provides important insights into the role of the social environment for both birdsong and female mate choice. However, the absence of a heritable component in female mate choice suggests a need for studies investigating the heritability of female preferences for (heritable) male song traits in order to gain a better understanding of a potential coevolution between male sexual traits and female mate choice. Overall, our results suggest that indirect genetic effects acting during the pre- and postfledging social contexts may play a prominent role in sexual selection. [ABSTRACT FROM AUTHOR]

Animals that use vocal signals to communicate often compensate for interference and masking from background noise by raising the amplitude of their vocalisations. This response has been termed the Lombard effect. However, despite more than a century of research, little is known how quickly animals can adjust the amplitude of their vocalisations after the onset of noise. The ability to respond quickly to increases in noise levels would allow animals to avoid signal masking and ensure their calls continue to be heard, even if they are interrupted by sudden bursts of high-amplitude noise. We tested how quickly singing male canaries (Serinus canaria) exhibit the Lombard effect by exposing them to short playbacks of white noise and measuring the speed of their responses. We show that canaries exhibit the Lombard effect in as little as 300 ms after the onset of noise and are also able to increase the amplitude of their songs mid-song and mid-phrase without pausing. Our results demonstrate high vocal plasticity in this species and suggest that birds are able to adjust the amplitude of their vocalisations very rapidly to ensure they can still be heard even during sudden changes in background noise levels. [ABSTRACT FROM AUTHOR]

The functions of birdsong include attracting a mate and repelling competitors. It is therefore not surprising that, in males in the temperate zone especially, birdsong is often produced in the context of reproduction. Testosterone of gonadal origin increases during the reproductive phase of the annual cycle and can significantly influence song production as well as song development via effects on song crystallization (testosterone secretion at the time of sexual maturity is essential for full crystallization to occur). In males, testosterone of gonadal origin can exert its effects in the brain on song and other reproductive behaviour via its oestrogenic and androgenic metabolites. The widespread distribution of nuclear androgen receptors in the song system and the occurrence of oestrogen receptors in one key forebrain nucleus in certain species as well as the presence of both receptor types in the diencephalon and the midbrain raises questions as to where and how testosterone is exerting its myriad effects on song. By selectively implanting testosterone into specific brain regions of castrated male canaries, Serinus canaria , we have identified the medial preoptic area as a critical site for the induction of a generalized increase in motivation that includes the motivation to sing. Testosterone action in the forebrain song nucleus HVC in contrast increases song stereotypy. Canaries receiving testosterone in the preoptic area and HVC sing stereotypic songs but at a much lower amplitude, indicating that testosterone's effects on amplitude are regulated elsewhere in the brain or the periphery. The lateral part of the magnocellular nucleus anterior nidopallium (LMAN) is a song nucleus that expresses a high density of androgen receptors and plays a role as a song variability generator during song learning. When adult female canaries are treated with testosterone, their song becomes more complex. Lesions to LMAN attenuate these effects on adult behavioural change, suggesting that testosterone may act in LMAN during song ontogeny to modulate changes associated with song crystallization. These anatomically specific effects illustrate how a single hormone can coordinate changes in many aspects of a complex behaviour to facilitate successful reproduction. [ABSTRACT FROM AUTHOR]

Recent studies suggest that cognitive bias could constitute a novel and valid measure of animal welfare. Although interest for a link between personality and cognition is growing, no study to date investigated whether a cognitive bias might be related to the personality of the individuals. We trained 43 domestic canaries ( Serinus canaria ) to discriminate between two sides of a test cage, each side being associated with a different value (attractive or aversive food in a dish). During the test phase, the dish was placed at intermediate locations, representing ambiguous information. Results show evidence of an “optimistic” bias (flying faster to the dish at the ambiguous location) in birds housed in pairs, compared to birds housed singly, suggesting an influence of social context (living conditions) on canaries’ emotions when tested individually. We also studied six traits of individuals’ personality and found that aggressiveness, neophobia, one sociability index and obstinacy were repeatable across social context and/or day-light schedule, whereas the other sociability index, boldness and locomotion were not. No correlation between the birds’ optimism and any of their personality traits was found, suggesting that cognitive bias may be a matter of social context rather than of individual personality. [ABSTRACT FROM AUTHOR]

Prosociality (behaviours that benefit to a recipient without necessarily involving a cost to the actor) has recently been shown to exist in various taxa, including birds. Studies on prosociality in primates found that prosocial tendencies of the subject could be related to sex and parental care, communication from the recipient, cognitive abilities and personality. To investigate the existence of such associations on birds, we conducted a Prosocial Choice Task with domestic canaries (Serinus canaria). In our experiment, the subject could choose between three options: a prosocial, a selfish, and a null option (with no cost for the subject). We also conducted a food sharing experiment and measured several personality traits. Our results highlighted high levels of prosociality and a tendency to reciprocity among reproductive mates. We found a higher propensity to be prosocial in nulliparous individuals than in individuals that have previously been parents, but better sharing abilities in parents than in nulliparous individuals. When they were recipient, parents also used communication more efficiently than nulliparous subjects. Data suggest that parental expertise could enhance subjects' skills in eliciting prosociality. We also highlighted some interaction between prosociality, learning abilities, and some personality traits, proactive individuals being fast learners and more prosocial, while reactive individuals being slow learners and more reciprocal. Our results suggest that prosociality and reciprocity could be linked to personality and cognitive abilities, and that it might be interesting to consider them as parts of individual's cognitive style. • Our results showed high prosociality in canaries among reproductive mates. • Parents exhibited better sharing abilities than nulliparous individuals. • As recipient, parents used communication more efficiently than nulliparous birds. • Proactive individuals were fast learners and were more prosocial. • Reactive individuals were slow learners and were more reciprocal. [ABSTRACT FROM AUTHOR]

Mortalities in a flock of canaries ( Serinus canaria) with respiratory acariasis, pododermatitis caused by Staphylococcus aureus, and macrorhabdosis were investigated by postmortem examination. After a thorough parasitologic study, the tracheal mites were identified as Ptilonyssus morofskyi. Cleaning and disinfection of cages and perches, ivermectin application on the cervical skin of individual birds, enrofloxacin medication, and drinking water acidification with vinegar were used to control mortality. To the best of our knowledge, this is the first report of the occurrence of Ptilonyssus species in captive passerine birds. [ABSTRACT FROM AUTHOR]

There is considerable interest of evolutionary ecologists in the proximate mechanisms that constrain life-history variation. It is increasingly recognized that oxidative stress may be a prime physiological constraint on reproduction, but to the best of our knowledge, this has never been tested experimentally., To fill in this gap, we examined whether a specific and short-term experimental increase of pre-reproductive oxidative stress in females of a songbird (canary, Serinus canaria) would influence reproductive decisions (i.e. when and how many eggs to lay), and reproductive success (hatching and fledging success, number of hatchlings and of fledglings produced by each female), as compared to females whose oxidative stress levels were not manipulated., Our experimental reduction of glutathione, a key antioxidant, increased oxidative stress and affected reproductive decisions: treated females significantly delayed the start of egg laying and laid significantly smaller clutches. However, both hatching and fledging success and the number of hatchlings and of fledglings produced by each female were similar between control and treated females., Our results support the hypothesis that oxidative stress may be one proximate mechanism modulating key life-history traits (such as the timing of laying and clutch size in birds) and therefore may act as a link between prevailing environmental conditions and fitness traits. [ABSTRACT FROM AUTHOR]

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The emergence of bacterial resistance to antibiotic use in veterinary practice is considered a source of multidrug-resistant bacterial infections for humans. Although increasing incidence of antimicrobial resistance in small-animal practices has already been noted, limited information is available about the problem in domestic canaries ( Serinus canaria domestica ). This cross-sectional study describes the prevalence of Gram-negative bacteria among canaries exhibiting clinical disease signs and the antimicrobial sensitivity patterns of the bacterial isolates. During the breeding season, a bacteriological survey was carried out in 50 amateur breeding aviaries from the Messina Province (Sicily, South of Italy) to detect the prevalence of Gram-negative bacteria in sick birds. Fecal samples from breeder canaries were submitted for bacteriological examination. Of 50 breeding aviaries, 43 (86%) were positive for Gram-negative bacteria. Overall, 88 bacterial isolates, representing 12 genera of bacteria, were cultured. The most frequently recovered bacterial species was Escherichia coli (31/88 isolates, 35.2%). Other frequently isolated species were Enterobacter cloacae (9/88 isolates, 10.2%) and Proteus mirabilis (6/88 isolates, 6.8%). Potentially pathogenic species, including Salmonella Typhimurium ( n = 5 strains), Enterobacter sakazakii ( n = 4 strains), and Pseudomonas aeruginosa ( n = 6 strains), were also identified. The 88 isolates displayed significant frequencies of antibiotic resistance. These results confirm the potential presence of multidrug-resistant bacteria in canary facilities, suggesting that measures to educate the public about this risk are necessary. [ABSTRACT FROM AUTHOR]

Increasing levels of anthropogenic noise represent a challenge for animals living in urban areas and birds, especially, may suffer from noisy conditions as they use singing to attract mates. Most anthropogenic noise is low in frequency and singing at high frequencies under noisy urban conditions may avoid masking and thus be a good strategy for breeding success in cities. Despite comparative, correlational and some experimental studies supporting this hypothesis, empirical studies on the impact of noise on sexual behaviour are largely lacking. Domestic canaries, Serinus canaria, provide an excellent model system to test unequivocal sexual responsiveness as receptive females perform copulation solicitation displays (CSD) to male song. We have previously shown that CSD rate was higher for low- than for high-frequency songs. In the current study, we tested whether a typical urban noise spectrum, with a bias towards low frequencies, could undermine sexual preferences. Using overlapping and alternating noise exposure regimes while broadcasting male songs we found that masking by urban noise reduced female responsiveness to low-frequency attractive songs. Under the same conditions the responsiveness to high-frequency songs remained unaffected and, consequently, the sexual preference for low- over high-frequency songs had faded because of the urban noise. We discuss to what extent our results can be extrapolated to other wild bird species and speculate about the adaptive value of the typical upward shift in frequency found in many city birds. [Copyright &y& Elsevier]