Species Of Free-living Birds Research Articles

Skyglow relieves a crepuscular bird from visual constraints on being active

Artificial light at night significantly alters the predictability of the natural light cycles that most animals use as an essential Zeitgeber for daily activity. Direct light has well-documented local impacts on activity patterns of diurnal and nocturnal organisms. However, artificial light at night also contributes to an indirect illumination of the night sky, called skyglow, which is rapidly increasing. The consequences of this wide-spread form of artificial night light on the behaviour of animals remain poorly understood, with only a few studies performed under controlled (laboratory) conditions. Using animal-borne activity loggers, we investigated daily and seasonal flight activity of a free-living crepuscular bird species in response to nocturnal light conditions at sites differing dramatically in exposure to skyglow. We find that flight activity of European Nightjars (Caprimulgus europaeus) during moonless periods of the night is four times higher in Belgium (high skyglow exposure) than in sub-tropical Africa and two times higher than in Mongolia (near-pristine skies). Moreover, clouds darken the sky under natural conditions, but skyglow can strongly increase local sky brightness on overcast nights. As a result, we find that nightjars' response to cloud cover is reversed between Belgium and sub-tropical Africa and between Belgium and Mongolia. This supports the hypothesis that cloudy nights reduce individual flight activity in a pristine environment, but increase it when the sky is artificially lit. Our study shows that in the absence of direct light pollution, anthropogenic changes in sky brightness relieve nightjars from visual constraints on being active. Individuals adapt daily activities to artificial night-sky brightness, allowing them more time to fly than conspecifics living under natural light cycles. This modification of the nocturnal timescape likely affects behavioural processes of most crepuscular and nocturnal species, but its implications for population dynamics and interspecific interactions remain to be investigated.

Prevalence of Enterococcus spp. and the Whole-Genome Characteristics of Enterococcus faecium and Enterococcus faecalis Strains Isolated from Free-Living Birds in Poland.

Enterococci as opportunistic bacteria are important for human health. Due to the prevalence and ease of acquisition and transfer of their genes, they are an excellent indicator of environmental contamination and the spread of antimicrobial resistance. The aim of the study was to assess the prevalence of Enterococcus spp. in wild birds in Poland, determination of antimicrobial susceptibility and WGS analysis of Enterococcus (E.) faecium and E. faecalis. For this purpose, 138 samples from various species of free-living birds were tested, with 66.7% positive results. Fourteen species were detected, with E. faecalis being the most common, followed by E. casseliflavus and E. hirae. In antimicrobial susceptibility testing, 10.0% of E. faecalis and 50.0% of E. faecium showed resistance to one antimicrobial agent, in addition the MDR phenotype which was found in one E. faecium. The most common resistance phenotype included tetracycline and quinupristin/dalfopristin. The WGS analysis confirmed the significant advantage of the virulence gene diversity of E. faecalis strains over E. faecium. In addition, plasmid replicons were found in 42.0% of E. faecalis and 80.0% of E. faecium. The obtained results confirm free-living birds can be a reservoir of Enterococcus spp. with a considerable zoonotic potential.

Conservation of birds in an urban environment – wild bird fauna at the Osijek Zoo, Croatia

Zoos are our closest, independent, and continuous link to nature. Apart from providing the opportunity to observe captive and exotic wild animals, they also attract various species of wild birds. For that purpose, the main goal of this study was to provide a list of free-living bird species at the Osijek Zoo. During 2021, fieldwork was performed monthly using a point count transect, except during the breeding season when counts were performed twice a month. A total of 61 species were recorded, belonging to 31 families distributed in 15 orders. The most frequently recorded species were Hooded crow, Corvus cornix and Great tit, Parus major. Five species observed at the Osijek Zoo are listed as endangered species in the Red Book of Birds of Croatia: critically endangered: European roller, Coracias garrulus; endangered: Great egret, Ardea alba and Western marsh harrier, Circus aeruginosus; vulnerable: Little egret, Egretta garzetta and Black stork, Ciconia nigra. It appears that the Osijek Zoo provides a good foundation for a high diversity of bird fauna, indicating that this is a good quality urban area. The Osijek Zoo should also strive to preserve this abundant avifauna, by educating the public on conservation, and forbidding any potentially disturbing behaviours.

Integument carotenoid-based colouration reflects contamination to perfluoroalkyl substances, but not mercury, in arctic black-legged kittiwakes

Anthropogenic activities are introducing multiple chemical contaminants into ecosystems that act as stressors for wildlife. Perfluoroalkyl substances (PFAS) and mercury (Hg) are two relevant contaminants that may cause detrimental effects on the fitness of many aquatic organisms. However, there is a lack of information on their impact on the expression of secondary sexual signals that animals use for mate choice. We have explored the correlations between integument carotenoid-based colourations, blood levels of carotenoids, and blood levels of seven PFAS and of total Hg (THg) in 50 adult male black-legged kittiwakes (Rissa tridactyla) from the Norwegian Arctic during the pre-laying period, while controlling for other colouration influencing variables such as testosterone and body condition. Kittiwakes with elevated blood concentrations of PFAS (PFOSlin, PFNA, PFDcA, PFUnA, or PFDoA) had less chromatic but brighter bills, and brighter gape and tongue; PFOSlin was the pollutant with the strongest association with bill colourations. Conversely, plasma testosterone was the only significant correlate of hue and chroma of both gape and tongue, and of hue of the bill. Kittiwakes with higher concentrations of any PFAS, but not of THg, tended to have significantly higher plasma concentrations of the carotenoids astaxanthin, zeaxanthin, lutein, and cryptoxanthin. Our work provides the first correlative evidence that PFAS exposure might interfere with the carotenoid metabolism and the expression of integument carotenoid-based colourations in a free-living bird species. This outcome may be a direct effect of PFAS exposure or be indirectly caused by components of diet that also correlate with elevated PFAS concentrations (e.g., proteins). It also suggests that there might be no additive effect of THg co-exposure with PFAS on the expression of colourations. These results call for further work on the possible interference of PFAS with the expression of colourations used in mate choice.

Radiographic evaluation of cardiac size in the white stork (Ciconia ciconia)

Physical examination of the cardiovascular system in birds is quite difficult compared to other animals. As in humans and mammalian animals, radiography is a reliable diagnostic tool to identify cardiovascular disorders in birds. However, cardiovascular radiography studies for birds are very limited and reference information is lacking. In this study the aim was to determine the reference values of cardiac radiographic measurements that can be used especially in the diagnosis of cardiomegaly in storks, which is a free-living bird species. For this purpose, 26 white storks without cardiovascular disorders were used in the study. Radiographs were taken in lateral and ventrodorsal projections. Five measurements: heart length (61.70 ± 6.69 mm), heart width (51.65 ± 4.84), carina length (139.80 ± 10.05), thoracic width (87.45 ± 6.58), and coracoid width (10.24 ± 1.20) were performed. The ratio of the heart width to thoracic width was 59.16%. The ratio of heart length to carina length was 44.28%. Heart width correlates significantly and positively with the thoracic width (R: 0.556, R2: 0.310, P: 0.003). The heart width can be estimated by using the thoracic width values with the regressionbased formula in the results of this study. Clinically, it can be determined whether an individual case falls between the minimum or maximum reference values for heart width or length. The results presented in this study may provide clinicians with reference information regarding cardiomegaly.

Potential reverse spillover of infectious bursal disease virus at the interface of commercial poultry and wild birds

Recently, multiple spillover events between domesticated poultry and wild birds have been reported for several avian viruses. This phenomenon highlights the importance of the livestock-wildlife interface in the possible emergence of novel viruses. The aim of the current study was to investigate the potential spillover and epidemiological links of infectious bursal disease virus (IBDV) between wild birds and domestic poultry. To this end, twenty-eight cloacal swabs were collected from four species of free-living Egyptian wild birds (i.e. mallard duck, bean goose, white-fronted goose and black-billed magpie). Genetic and phylogenetic analysis of three positive isolates revealed that the IBDV/USC-1/2019 strain clustered with previously reported very virulent IBDV (vvIBDV) Egyptian isolates. Interestingly, two other wild bird-origin isolates (i.e. IBDV/USC-2/2019 and IBDV/USC-3/2019) grouped with a vaccine strain that is being used in commercial poultry. In conclusion, our results revealed the molecular detection of vaccine and vvIBDV-like strains in Egyptian wild birds and highlighted the potential role of wild birds in IBDV epidemiology in disease-endemic regions.

Point-of-care blood analyzers measure the nutritional state of eighteen free-living bird species

Point-of-care devices offer the potential to democratize a suite of physiological endpoints and assess the nutritional state of wild animals through plasma metabolite profiling. Measurements of plasma metabolites typically occur on frozen tissue in the laboratory, thus dissociating measurements from field observations. Point-of-care devices, widely used in veterinary and human medicine, provide rapid results (seconds or minutes) allowing in situ measurements of wild animals in remote areas without the need for access to freezers. Using point-of-care devices, we measured glucose, triglyceride, cholesterol and β-hydroxybutyrate levels in plasma from 18 wild bird species spanning nine families and three orders. The values from six different point-of-care devices correlated strongly with one another, and with traditional laboratory measurements from stored plasma (R2 = 0.70–0.90). Although POC devices provided accurate relative values in wild birds, absolute values varied from laboratory measurements by up to 50% illustrating the need for calibration equations. Furthermore, three case studies showed the potential for point-of-care devices at research stations where participants do not have access to a lab and sample preservation is difficult: (i) at a remote seabird colony, birds that were provided with supplemental food had higher levels of glucose and lower β-hydroxybutyrate and cholesterol levels than unfed birds, suggesting they were in a better nutritional state; (ii) at a migration monitoring station, levels of triglycerides of two migratory songbirds increased with time of day, implying that they were fattening during stopover; and (iii) for diving seabirds, individuals that worked harder (shorter surface intervals) had higher glucose and lower β-hydroxybutyrate implying that nutritional state is an index of foraging effort and success. We demonstrate that point-of-care devices, once validated, can provide accurate measurements of the nutritional state of wild birds. Such real-time measurements can aid in ecological research and monitoring, care of wildlife at rehabilitation centres, and in veterinary medicine of exotics.

The influence of natural variation and organohalogenated contaminants on physiological parameters in white-tailed eagle (Haliaeetus albicilla) nestlings from Norway

Environmental exposure to organohalogenated contaminants (OHCs), even at low concentrations, may cause detrimental effects on the development and health of wild birds. The present study investigated if environmental exposure to OHCs may influence the variation of multiple physiological parameters in Norwegian white-tailed eagle (Haliaeetus albicilla) nestlings. Plasma and feather samples were obtained from 70 nestlings at two archipelagos in Norway in 2015 and 2016. The selected physiological parameters were plasma concentrations of thyroid hormones (thyroxine, T4 and triiodothyronine, T3), plasma proteins (prealbumin, albumin, α1-, α2-, β- and γ-globulins) and selected blood clinical chemical parameters (BCCPs) associated with liver and kidney functioning. Feather concentrations of corticosterone (CORTf) were also included to investigate the overall stress level of the nestlings. Concentrations of all studied physiological parameters were within the ranges of those found in other species of free-living birds of prey nestlings and indicated that the white-tailed eagle nestlings were in good health. Our statistical models indicated that perfluoroalkyl substances (PFASs) and legacy OHCs, such as polychlorinated biphenyls, organochlorinated pesticides and polybrominated diphenyl ethers, influenced only a minor fraction of the variation of plasma thyroid hormones, prealbumin and CORTf (5-15%), and partly explained the selected BCCPs (<26%). Most of the variation in each studied physiological parameter was explained by variation between nests, which is most likely due to natural physiological variation of nestlings in these nests. This indicates the importance of accounting for between nest variation in future studies. In the present nestlings, OHC concentrations were relatively low and seem to have played a secondary role compared to natural variation concerning the variation of physiological parameters. However, our study also indicates a potential for OHC-induced effects on thyroid hormones, CORTf, prealbumin and BCCPs, which could be of concern in birds exposed to higher OHC concentrations than the present white-tailed eagle nestlings.

Long-lived birds suffer less from oxidative stress

BackgroundOxidative stress, caused by an imbalance between reactive oxygen species and antioxidants, is thought to be an important intrinsic mechanism for aging. Ecologists have tested this hypothesis in birds, although the evidence supporting the link between oxidative stress and lifespan has so far been ambiguous. Two previous studies based on a wide range of different free-living bird species provided contradictory findings: antioxidants were negatively associated with survival rate in one study, but positively associated with longevity in another.MethodsIn this study, we identified possible shortcomings in previous research, and then used the comparative methods to test whether long-lived birds experience less oxidative stress reflected by four blood redox state markers (total antioxidant status, uric acid, total glutathione, malondialdehyde) based on data for 78 free-living species.ResultsRelatively long-lived bird species had high levels of antioxidants (total antioxidant status, total glutathione) and low levels of reactive oxygen species (malondialdehyde). These associations were independent of statistical control for any effects of body mass, sampling effort and similarity among taxa due to common phylogenetic descent.ConclusionsThe direction of these associations is consistent with the oxidative stress theory of aging.

Longevity and life history coevolve with oxidative stress in birds.

1. The mechanisms that underpin the evolution of ageing and life histories remain elusive. Oxidative stress, which results in accumulated cellular damages, is one of the mechanisms suggested to play a role. 2. In this paper, we set out to test the "oxidative stress theory of ageing" and the "oxidative stress hypothesis of life histories" using a comprehensive phylogenetic comparison based on an unprecedented dataset of oxidative physiology in 88 free-living bird species. 3. We show for the first time that bird species with longer lifespan have higher non-enzymatic antioxidant capacity and suffer less oxidative damage to their lipids. We also found that bird species featuring a faster pace-of-life either have lower non-enzymatic antioxidant capacity or are exposed to higher levels of oxidative damage, while adult annual mortality does not relate to oxidative state. 4. These results reinforce the role of oxidative stress in the evolution of lifespan and also corroborate the role of oxidative state in the evolution of life histories among free-living birds.

Associations of urban environmental pollution with health-related physiological traits in a free-living bird species

Urban environmental pollution results in contamination of the tissues of synanthropic organisms by toxic trace elements with potential impacts on human health. Passerine birds may serve as convenient indicators of such contamination. In this study we investigated the effect of blood and plumage contamination with heavy metals (lead Pb, cadmium Cd, copper Cu, chromium Cr) and arsenic metalloid (As) on condition, health and ornamental colour in free-living great tit (Parus major) males from 13 cities across the Czech Republic (EU), mist netted during the early breading season (April–May). Our results showed a significant association of heavy metal tissue contamination with immune function, namely leukocyte composition in the avian blood circulation. High heavy metal contamination in bird feathers was linked to a high heterophil/lymphocyte (H/L) ratio, indicating long-term stress in individuals inhabiting heavily polluted environments. In contrast, males with higher concentrations of heavy metals in blood had a lower H/L ratio, assumingly due to the direct toxicity of heavy metals in certain cell types. This is also supported by traits indicative of anaemia-like haemolytic conditions (decreased absolute erythrocyte count) and increased haematopoiesis (a tendency for increased frequencies of immature erythrocytes). We did not find any association of heavy metal contamination with the bacteriolytic activity of plasma complement, feather growth or ornamentation (black breast stripe area and yellow colouration). There was no significant relationship between heavy metal contamination in blood or feathers and PM10 pollution at the study sites. Our correlational study is the first to show on a large geographic scale that despite strict European air pollution regulations and regular monitoring that have allowed general improvements in atmospheric contamination, non-degradable heavy metals persistently contaminate animal blood and feathers in anthropogenic environments at levels that may have subclinical yet physiological effects with varied influence on health.

Isolation and characterization of genotype XIII Newcastle disease virus from Emu in India.

Newcastle disease virus (NDV) infects at least 241 species of pet and free-living birds in addition to domesticated avian species. Wild, feral and domesticated birds are recognized reservoirs of NDV, and contribute to the epidemiology of NDV in the domesticated poultry. The biological and molecular characterization of velogenic NDV (vNDV) from emus is limited. In this study, 54 tissues were collected from eight Emu flocks between May 2010 and January 2012 from highly poultry-dense areas of India including Namakkal, Hyderabad and Bareilly regions. The presence of vNDV was confirmed by virus isolation, fusion (F)-gene based RT-PCR, sequencing of the cleavage site and the virulence scored. One out of eight flocks received from Hyderabad region was found positive for NDV and the in vivo pathotyping revealed the isolate to be vNDV type. The sequence analysis revealed that the isolate had cleavage site of 112-R-R-R-K-R-F-117, which is typical for vNDV. Sequence and phylogenetic analysis of the partial 'F' gene coding regions suggested that the NDV strain belongs to genotype XIII. The Emu isolate had 98-100% nucleotide identity with the vNDVs previously reported in poultry flocks of India. The findings of present study based on the biological and molecular characterization of Emu-origin vNDV, highlights the circulation of genotype XIII in Emus for the first time in the country. There is need to understand the possible spill over of these genetically diverse NDV strains into the commercial poultry and their possible implications in disease control strategies.

Delta-aminolevulinic acid dehydratase (δALAD) activity in four free-living bird species exposed to different levels of lead under natural conditions

The purposes of this study were: (1) to determine the δALAD activity and δALAD ratio in blood of four free-living bird species (Griffon vulture, Eagle owl, Slender-billed gull and Audouin’s gull); (2) and to investigate the correlations between δALAD activity/ratio and Pb concentrations in blood samples. A decrease was observed in δALAD activity in Griffon vultures and Eagle owls exposed to Pb. In addition, negative relationships were found between δALAD ratio or δALAD activity and Log blood Pb levels in Griffon vultures and Eagle owls, and these relationships were stronger in areas with the highest Pb exposure. We provide equations that may be helpful to estimate δALAD activity and δALAD ratio using blood Pb concentrations. Regarding gull species, δALAD activity found in the present study may be considered the normal activity in Slender-billed gull and Audouin’s gull species, since very low blood Pb concentrations and no correlations were found in these species. Although both δALAD activity and δALAD ratio are sensitive biomarkers of Pb exposure and effect in birds, the use of δALAD ratio may improve the results. Besides, this study provides blood threshold concentrations at which Pb bears effects on δALAD enzyme (5µg/dl in Eagle owl; 8µg/dl in Griffon vulture; and probably >2µg/dl in Slender-billed gull and Audouin’s gull). Our findings show that Eagle owl seems to be more sensitive to δALAD enzymatic inhibition by Pb than Griffon vultures. Eagle owls and Griffon vultures exhibited up to 79% and 94% decrease in δALAD activity when blood Pb concentrations exceeded 19 and 30µg/dl, respectively. Regarding the effects related with δALAD inhibition, significant negative correlations were found between δALAD activity and hematocrit in Eagle owls and Griffon vultures, which may be related to compensatory response associated with a decrease in δALAD activity. In addition, an effect on creatine kinase activity and total proteins in plasma was found in Griffon vultures. The significant negative correlations found between δALAD activity and tGSH in Griffon vulture, and between δALAD activity and Log CAT activity in Eagle owls, may be related to a protective response of antioxidant system against reactive oxygen species (ROS). The negative relationship found between δALAD activity and TBARS levels in Griffon vulture is probably related to an induction of lipid peroxidation by ROS that may be generated by δALA accumulation when δALAD activity is depressed. δALAD activity and δALAD ratio in blood are suggested as important nondestructive biomarkers for Pb exposure and effect for future biomonitoring studies in Griffon vulture and Eagle owl. Further studies are recommended to provide new data on Pb concentrations at which δALAD activity is affected in different wild bird species and to elucidate why different species tolerate Pb in different ways.

Salmonella spp. as a cause of mortality and clinical symptoms in free-living garden bird species in Poland.

Some species of garden birds are considered to be sensitive to Salmonella (S.) spp. infections. The aim of this study was to determine the cause of mortality of six free-living birds in one private property in suburban area of Wrocław (Poland). In 2013 Poland experienced prolonged winter, with low temperatures and snow precipitations. During March and April, two dead individuals of the Eurasian siskin (Carduelis spinus) and four dead individuals of the Greenfinch (Carduelis chloris) were found in proximity of the bird feeder. At the time of ringing procedure in the same area, faecal samples of all individuals belonging to these two species of birds were collected, regardless clinical symptoms. In total, twenty two faecal samples of birds belonging to both bird species were collected in the same property. All of them were Salmonella enterica subsp. enterica serovar Typhimurium positive. The visible illness among European siskins and Greenfinches, caused by S. Typhimurium, sug- gests that both Eurasian siskin and Greenfinch may be potential reservoirs of Salmonella spp. Therefore they might play a role in transmission of zoonotic pathogens to other garden bird species or to people.

Aerobic cloacal and pharyngeal bacterial flora in six species of free-living birds.

The purpose of this study was to investigate the culturable aerobic pharyngeal and cloacal bacterial flora of free-living birds, to determine the physiological bacterial microbiota, to identify possible interactions between feeding behaviour and the composition of the pharyngeal and cloacal microflora and to investigate the occurrence of pathogenic bacteria. Cloacal and pharyngeal swabs of 167 free-living birds, including water rails (Rallus aquaticus), spotted crakes (Porzana porzana), mute swans (Cygnus olor), barn swallows (Hirundo rustica), reed warblers (Acrocephalus scirpaceus) and black cormorants (Phalacrocorax carbo) from Germany, were cultured to determine the prevalence of aerobic bacteria. Statistical analysis of bacterial findings and feeding behaviour was performed. A widespread soil and water bacteria were isolated, which are expected to be present in the habitat and food. However, some potentially avian- and human-pathogenic bacteria, such as Aeromonas hydrophila, Elizabethkingia meningoseptica, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli, were also recovered. Free-living birds of the examined species harbour several environmental bacteria, which could be facultative pathogenic. Prevalence of bacteria in healthy free-living birds of the species included in this survey is influenced by environmental and alimentary factors.

Senescence in cell oxidative status in two bird species with contrasting life expectancy

Oxidative stress occurs when the production of reactive oxygen species (ROS) by an organism exceeds its capacity to mitigate the damaging effects of the ROS. Consequently, oxidative stress hypotheses of ageing argue that a decline in fecundity and an increase in the likelihood of death with advancing age reported at the organism level are driven by gradual disruption of the oxidative balance at the cellular level. Here, we measured erythrocyte resistance to oxidative stress in the same individuals over several years in two free-living bird species with contrasting life expectancy, the great tit (known maximum life expectancy is 15.4 years) and the Alpine swift (26 years). In both species, we found evidence for senescence in cell resistance to oxidative stress, with patterns of senescence becoming apparent as subjects get older. In the Alpine swift, there was also evidence for positive selection on cell resistance to oxidative stress, the more resistant subjects being longer lived. The present findings of inter-individual selection and intra-individual deterioration in cell oxidative status at old age in free-living animals support a role for oxidative stress in the ageing of wild animals.

Correction: Natural Cross Chlamydial Infection between Livestock and Free-Living Bird Species

Juan A. Fargallo, Pablo Vergara, Deseada Parejo and Eva Banda, as co-authors of the article published in PLOS ONE (2010) titled “Natural Cross Chlamydial Infection between Livestock and Free-Living Bird Species”, request the retraction of this publication. The Ethics Committee of the Spanish Superior Council of Scientific Research (CSIC) has carried out an investigation in relation to concerns about potential scientific misconduct by Jesus A. Lemus, who was also a co-author of this article. The investigation has questioned the validity of the laboratory analyses conducted by Dr. Lemus in relation to this study, and was unable to establish at which laboratories the analyses were conducted. Specifically, the authors have been unable to verify the validity of the Chlamydophila analyses for sheep abortions, sheep faeces, sheep stable dust, kestrel nest dust and insects. There are also concerns about the validity of the results obtained for the Chlamydophila serovar characterization, genetic diversity and MSLT analyses for Chamydophila. As a result, the authors wish to retract the article.

Fibroblasts from long-lived bird species are resistant to multiple forms of stress

Evolutionary senescence theory postulates that aging results from the declining force of natural selection with increasing chronological age. A goal of comparative studies in the biology of aging is to identify genetic and biochemical mechanism(s) driving species-specific differences in the aging process that are the end product of life history trade-offs. We hypothesized that cells from long-lived bird species are more resistant to stress agents than are cells from short-lived species, and that cells from birds are more resistant to stress than are cells from relatively short-lived mammals of similar size. We tested primary fibroblast cultures from 35 species of free-living birds for their resistance to multiple forms of cellular stress and found that cell lines from longer-lived species were resistant to death caused by cadmium (R(2)=0.27, P=0.002), paraquat (R(2)=0.13, P=0.03), hydrogen peroxide (R(2)=0.09, P=0.07) and methyl methanesulfonate (R(2)=0.13, P=0.03), as well as to the metabolic inhibition seen in low-glucose medium (R(2)=0.37, P<0.01). They did not differ in their resistance to UV radiation, or to thapsigargin or tunicamycin, inducers of the unfolded protein response. These results were largely consistent even after accounting for the influence of body mass and phylogeny. Cell lines from longer-lived bird species also proliferate more rapidly than cells from short-lived birds, although there was no relationship between proliferation and stress resistance. Finally, avian fibroblasts were significantly more resistant than rodent fibroblasts to each of the tested stressors. These results support the idea that cellular resistance to injury may be an important contributor to the evolution of slow aging and long lifespan among bird species, and may contribute to the relatively long lifespan of birds compared with rodents of the same body size.

Avian trichomoniasis: a study of lesions and relative prevalence in a variety of captive and free‐living bird species as seen in an Australian avian practice

Studies of avian trichomoniasis in the literature are limited to some extent, often being confined to a single bird species or group of species within a bird Order. Some incidence studies have been reported for free-living birds, and occasionally for captive birds. Very few reports describe the prevalence and types of lesions seen for a wide range of bird species, especially from a clinical perspective. Retrospective study of avian practice records from a 10-year period. Emphasis on the types of presentations and relative prevalence of trichomoniasis in a variety of captive and free-living bird species encountered in Australian avian practice. The occurrence of trichomoniasis in several novel species (lorikeets, corvids and a cuckoo species), plus its distinctive presentation in southern boobook owls (Ninox boobook), is documented. Trichomoniasis should be a differential diagnosis for birds presenting with regurgitation or upper gastrointestinal abscesses, even if motile trichomonads are not found in wet preparations from crop washes or lesions.

Natural Cross Chlamydial Infection between Livestock and Free-Living Bird Species

The study of cross-species pathogen transmission is essential to understanding the epizootiology and epidemiology of infectious diseases. Avian chlamydiosis is a zoonotic disease whose effects have been mainly investigated in humans, poultry and pet birds. It has been suggested that wild bird species play an important role as reservoirs for this disease. During a comparative health status survey in common (Falco tinnunculus) and lesser (Falco naumanni) kestrel populations in Spain, acute gammapathies were detected. We investigated whether gammapathies were associated with Chlamydiaceae infections. We recorded the prevalence of different Chlamydiaceae species in nestlings of both kestrel species in three different study areas. Chlamydophila psittaci serovar I (or Chlamydophila abortus), an ovine pathogen causing late-term abortions, was isolated from all the nestlings of both kestrel species in one of the three studied areas, a location with extensive ovine livestock enzootic of this atypical bacteria and where gammapathies were recorded. Serovar and genetic cluster analysis of the kestrel isolates from this area showed serovars A and C and the genetic cluster 1 and were different than those isolated from the other two areas. The serovar I in this area was also isolated from sheep abortions, sheep faeces, sheep stable dust, nest dust of both kestrel species, carrion beetles (Silphidae) and Orthoptera. This fact was not observed in other areas. In addition, we found kestrels to be infected by Chlamydia suis and Chlamydia muridarum, the first time these have been detected in birds. Our study evidences a pathogen transmission from ruminants to birds, highlighting the importance of this potential and unexplored mechanism of infection in an ecological context. On the other hand, it is reported a pathogen transmission from livestock to wildlife, revealing new and scarcely investigated anthropogenic threats for wild and endangered species.