Captive Flocks Research Articles

Transmission dynamics of highly pathogenic avian influenza virus at the wildlife-poultry-environmental interface: A case study

Avian influenza viruses (AIVs) regularly circulate between wild and domestic bird populations. Following several high-profile outbreaks, highly pathogenic AIVs (HPAIV) with zoonotic potential have been the subject of increasing attention. While we know that HPAIV is transmitted between domestic birds, wildlife, and the environment, little is known about persistence and spillover/back at these interfaces. We integrated the test results of samples collected on and around an infected domestic poultry premise (IP) where H5N1 HPAIV was confirmed in a flock of poultry in 2022 in Southern Ontario, Canada to explore the transmission cycle of AIVs in wildlife and the environment. We sampled a captive flock of Mallards (Anas platyrhynchos) that resided on site, sediment samples collected from water bodies on site, and examined samples collected through surveillance within a 100 km radius of the IP from live wild ducks and sick and dead wildlife. We found serologic evidence of H5 exposure in the captive mallards that resided on site despite no evidence of morbidity or mortality in these birds and no PCR positive detections from samples collected at two different timepoints. Genetic material from the same H5N1 HPAIV subtype circulating in the domestic birds and from low pathogenicity avian influenza viruses were detected in wetlands on site. The results of live and sick and dead surveillance conducted within a 100 km radius confirmed that the virus was circulating in wildlife before and after IP confirmation. These results suggest that biosecurity remains the most critical aspect of minimising spillover/back risk in a virus that has been shown to circulate in asymptomatic wild birds and persist in the surrounding environment.

Vocal functional flexibility in a nonprimate vocal learning species

Abstract Can nonhuman animals use the same acoustic signal to transmit different illocutions on different occasions? This communicative capacity is known as vocal functional flexibility and occurs, for example, in speech, when a sentence serves different illocutionary forces or functions on different occasions based on changes to visual and intonational cues. Although common in human speech, there is a lack of clear evidence for this ability in other species. Here, we examined a likely candidate, the Brown-headed Cowbird (Molothrus ater), which is a vocal-learning songbird species that develops a repertoire of structurally distinct song types. Most of this species’ songs are directed towards conspecific males and females less than a meter away, making it unusually easy to determine the apparent target of songs, unlike the broadcast songs done by most songbirds. Songs directed to other males have clear aggressive/threatening intent, while those to females involve courtship/sexual intent. Extensive prior work shows that male cowbirds perform the visual display that accompanies singing differently in these two social settings and also modulate the intonation of song types differently. Because of these display and tonal modulations, constancy of song type usage across male- vs female-directed singing would provide evidence of vocal functional flexibility. Herein, we examined 4,828 songs in three captive flocks containing twenty-four males and thirty females during the breeding season. Males did not use their song types randomly and had strongly favored songs and less commonly used ones. Importantly, favored song types and less commonly used ones were the same whether directing courtship song to a female, aggressive song to another male or singing nonsocially with no receiver nearby. Results were consistent within and across the three flocks, providing strong evidence of vocal functional flexibility. These findings indicate that some species may evolve the ability to modulate and exaggerate visual display components and prosody more than vocal presentation per se because a learned phonological system in this and possibly other species is constrained by its vital role as an indicator trait.

Prevalence, genotypes, and infection risk factors of psittacine beak and feather disease virus and budgerigar fledgling disease virus in captive birds in Hong Kong

Psittacine beak and feather disease virus (PBFDV) and budgerigar fledgling disease virus (BFDV) are significant avian pathogens that threaten both captive and wild birds, particularly parrots, which are common hosts. This study involved sampling and testing of 516 captive birds from households, pet shops, and an animal clinic in Hong Kong for PBFDV and BFDV. The results showed that PBFDV and BFDV were present in 7.17% and 0.58% of the samples, respectively. These rates were lower than those reported in most parts of Asia. Notably, the infection rates of PBFDV in pet shops were significantly higher compared to other sources, while no BFDV-positive samples were found in pet shops. Most of the positive samples came from parrots, but PBFDV was also detected in two non-parrot species, including Swinhoe’s white-eyes (Zosterops simplex), which had not been reported previously. The ability of PBFDV to infect both psittacine and passerine birds is concerning, especially in densely populated urban areas such as Hong Kong, where captive flocks come into close contact with wildlife. Phylogenetic analysis of the Cap and Rep genes of PBFDV revealed that the strains found in Hong Kong were closely related to those in Europe and other parts of Asia, including mainland China, Thailand, Taiwan, and Saudi Arabia. These findings indicate the presence of both viruses among captive birds in Hong Kong. We recommend implementing regular surveillance for both viruses and adopting measures to prevent contact between captive and wild birds, thereby reducing the transmission of introduced diseases to native species.

Experimental assessment of laser scarecrows for reducing avian damage to sweet corn.

Birds damage crops, costing millions of dollars annually, and growers utilize a variety of lethal and nonlethal deterrents in an attempt to reduce crop damage by birds. We experimentally tested laser scarecrows for their effectiveness at reducing sweet corn (Zea mays) damage. We presented 18 captive flocks of free-flying European starlings (Sturnus vulgaris) with fresh sweet corn ears distributed on two plots where laser and control treatments were alternated each day and allowed each flock to forage over 5 days. In 16 trials, fresh sweet corn ears were mounted on wooden sticks distributed from 0 to 32 m from laser units (Stick Trials), and in two trials birds foraged on ripe corn grown from seed in the flight pen (Natural Trials). We aimed to determine if laser-treated plots had significantly less damage overall and closer to the laser unit, and whether birds became more or less likely to forage in laser-treated plots over time. Lasers reduced damage overall, marginally in Stick Trials and dramatically in Natural Trials. Damage increased during each week in both trial types. Damage increased significantly with distance from lasers, and significant treatment effects occurred up to ~20 m from lasers. Our results concur with recent field trials demonstrating strong reductions in sweet corn damage when lasers are deployed. This study provides a first look at how birds respond to repeated laser exposure and whether damage increases with distance from lasers. Key differences between pen and field trials are discussed. © 2023 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

An Acute Mortality Event Associated with Novel Macrorhabdus ornithogaster Infection and Underlying Factors in a Newly-Established Captive Group of American White Ibis (Eudocimus albus) Nestlings.

Twenty-four American white ibis (Eudocimus albus) nestlings were collected in Florida (USA) on 17 April 2017 to establish a captive flock. On 7 May 2017, three birds died suddenly, following severe lethargy, hemorrhaging from the mouth and nares, anorexia, and production of bright-green colored feces. An additional ibis with delayed growth and pathological fractures was euthanized 18 May 2017. Severe ventriculitis associated with Macrorhabdus ornithogaster was noted in all four birds, bacterial sepsis was confirmed in one bird by culture and histologic examination, and bacterial endotoxemia was suspected in two birds based on gross and histologic examination, but no bacteria were isolated from these birds. Birds also had vitamin E liver levels consistent with coagulopathy previously described in pelicans. We sampled feces from 91 adult, free-living, healthy ibis in Florida in July 2017 and found 71% were shedding organisms with morphologic characteristics consistent with Macrorhabdus sp. Molecular characterization of the ibis-origin M. ornithogaster showed it was phylogenetically related to numerous M. ornithogaster sequences. It is unknown if M. ornithogaster infection resulted in clinical disease as a result of dietary or stress-related dysbiosis, or other factors. Macrorhabdus-associated disease has not previously been confirmed in wading birds. We discuss potential associations of gastric M. ornithogaster infection with morbidity and mortality in these cases and highlight the need for additional studies on this pathogen in free-living birds.

The evaluation of five serological assays in determining seroconversion to peste des petits ruminants virus in typical and atypical hosts

Peste des petits ruminants (PPR) is an infectious viral disease, primarily of small ruminants such as sheep and goats, but is also known to infect a wide range of wild and domestic Artiodactyls including African buffalo, gazelle, saiga and camels. The livestock-wildlife interface, where free-ranging animals can interact with captive flocks, is the subject of scrutiny as its role in the maintenance and spread of PPR virus (PPRV) is poorly understood. As seroconversion to PPRV indicates previous infection and/or vaccination, the availability of validated serological tools for use in both typical (sheep and goat) and atypical species is essential to support future disease surveillance and control strategies. The virus neutralisation test (VNT) and enzyme-linked immunosorbent assay (ELISA) have been validated using sera from typical host species. Still, the performance of these assays in detecting antibodies from atypical species remains unclear. We examined a large panel of sera (n = 793) from a range of species from multiple countries (sourced 2015–2022) using three tests: VNT, ID VET N-ELISA and AU-PANVAC H-ELISA. A sub-panel (n = 30) was also distributed to two laboratories and tested using the luciferase immunoprecipitation system (LIPS) and a pseudotyped virus neutralisation assay (PVNA). We demonstrate a 75.0–88.0% agreement of positive results for detecting PPRV antibodies in sera from typical species between the VNT and commercial ELISAs, however this decreased to 44.4–62.3% in sera from atypical species, with an inter-species variation. The LIPS and PVNA strongly correlate with the VNT and ELISAs for typical species but vary when testing sera from atypical species.

Age-Related Change in the Association Choices of Two Species of Juvenile Flamingos.

Flamingos are colonial species commonly kept in zoos, well known for their bright plumage and elaborate courtship displays. This project aimed to determine the differences in flock position and association preferences of juvenile Greater Flamingos (Phoenicopterus roseus) and Caribbean Flamingos (P. ruber) housed in the same zoological collection. Little research has been conducted on the association preferences of juvenile flamingos, especially in captive flocks, and therefore this study collected data using photographs taken throughout 2014 and 2015 to further understand association patterns. Data were collected on the age category of each juvenile flamingo observed, the age of their nearest neighbour and their position within the flock, and the location within an enclosure zone at different times of the day. The results showed that Greater Flamingo juveniles mainly associated with individuals of their own age and were most likely positioned at the periphery of their flock significantly more of the time until approximately 24 months of age. Sub-adult Greater Flamingos spent significantly more time associating with adult flamingos at the centre of the flock. In contrast, data collected on Caribbean Flamingos indicated that juveniles did not segregate themselves from the adults as distinctively. Birds aged 13-24 months were observed significantly more at the centre of the flock and had more associations with adult flamingos, in a similar manner to that observed in Greater Flamingos. Due to population management needs, juvenile Caribbean Flamingos were removed from the flock at the start of 2015 and this may have influenced the association and location preferences of the remaining young flamingos. In conclusion, these results indicated that captive juvenile flamingos were often seen away from adult birds and that sub-adult flamingos returned to the heart of their natal flock to associate significantly more with other adult individuals, potentially preparing for mate selection and breeding. Captive enclosure should therefore be spacious enough to enable young flamingos to remove themselves from adult birds so that behavioural development can be unaffected by artificially high rates of aggression.

Wing condition does not negatively impact time budget, enclosure usage, or social bonds in a flock of both full-winged and flight-restrained greater flamingos.

Zoo management techniques for captive birds, such as flight restraint and enclosure type, may affect behavioral performance and are consequently worthy of investigation. Flamingos are amongst the most popular of zoo-housed birds and, as such, research into their captive management and associated behavioral responses are widely applicable to many thousands of individuals. As a highly social species, understanding social bonds and behavior of the individual bird and the flock overall can help inform decisions that support husbandry and population management. In this project, 41 greater flamingos at Bristol Zoo Gardens were observed for 49 days across spring and summer 2013 to assess the following: (i) social associations within the flock, (ii) overall activity patterns, and (iii) distribution of time within specific enclosure zones for both full-winged and flight-restrained birds living in the same enclosure. Results showed that pinioning interacted with age in regard to flamingo time-activity patterns, but wing condition did not significantly influence association patterns, performance of social interactions, or performance of breeding behavior. Social network analysis revealed that associations were nonrandom and flamingos, of either wing condition, displayed different roles within the network. Birds of similar age formed the strongest bonds. Enclosure usage was not even, suggesting that the flamingos favored specific areas of the enclosure during the observation period. This study showed that wing condition does not affect flamingo behavior, social bonds, or space use, and that age and sex have more of an overall influence on what flamingos do, and with whom they chose to do it. Further research should extend this study into other, larger captive flocks to further refine behavioral measures of welfare for these popular zoo birds.

Evidence for maintenance of key components of vocal learning in ageing budgerigars despite diminished affiliative social interaction.

In some species, the ability to acquire new vocalizations persists into adulthood and may be an important mediator of social interactions. While it is generally assumed that vocal learning persists undiminished throughout the lifespan of these open-ended learners, the stability of this trait remains largely unexplored. We hypothesize that vocal learning exhibits senescence, as is typical of complex cognitive traits, and that this decline relates to age-dependent changes in social behaviour. The budgerigar (Melopsittacus undulatus), an open-ended learner that develops new contact call types that are shared with social associates upon joining new flocks, provides a robust assay for measuring the effects of ageing on vocal learning ability. We formed captive flocks of 4 previously unfamiliar adult males of the same age class, either 'young adults' (6 mo-1 y) or 'older adults' (≥ 3 y), and concurrently tracked changes in contact call structure and social interactions over time. Older adults exhibited decreased vocal diversity, which may be related to sparser and weaker affiliative bonds observed in older adults. Older adults, however, displayed equivalent levels of vocal plasticity and vocal convergence compared to young adults, suggesting that many components of vocal learning are largely maintained into later adulthood in an open-ended learner.

What’s Black and White and Pink All Over? Lesser Flamingo Nocturnal Behaviour Captured by Remote Cameras

The study of animal behaviour is important for the development of husbandry and management practices for zoo-housed species. Yet, data are typically only collected during daylight hours, aligning with human work schedules rather than animal activity patterns. To remedy this, 24 h data collection is needed. This study investigated the behaviour of a captive flock of lesser flamingos to understand temporal changes in their time-activity patterns. Two remote camera traps were placed around the birds’ outdoor enclosure and one within the indoor house. Counts of birds visible within specific enclosure zones were recorded from photographic data. Behaviour was defined as active or inactive, and modified Spread of Participation Index (SPI) was used to calculate enclosure zone occupancy. Results indicated that lesser flamingos are active overnight, and to a similar amount as in the daytime. Proportions of birds observed as active were significantly higher at later times of the day (i.e., dusk) when compared to the number of active birds in the morning. Enclosure usage was diverse and indoor and outdoor zones could be used by different numbers of birds at different times of the day. Variation in enclosure usage may indicate the changing needs of the flamingos when housed indoors overnight and when they have night-time access to an outdoor enclosure. This research has identified the need for further research into the nocturnal behaviour and space use of lesser flamingos and suggests the need for 24 h research in captive birds, and other zoo-held species, especially when species are locked indoors or face behavioural restriction overnight due to biosecurity measures surrounding zoonoses outbreaks, e.g., Avian Influenza.

Observation of an Attempted Forced Copulation within a Captive Flock of Greater Flamingos (Phoenicopterus roseus)

Flamingos (Phoenicopteriformes) are obligate colonial species that nest in large colonies, with monogamous pairs rearing a single chick following a synchronised group courtship display. Within this relatively simplistic behavioural description, deviations from these social and reproductive norms are apparent. Same sex pairings, multi-bird relationships and extra pair copulations are documented in the literature. Flamingos display highly sexually selected characteristics of plumage colour, carotenoid accumulation and diversity of display movements that underpin mate choice decisions. The brightest birds in best body condition are more successful at breeding. Therefore, documented mate guarding of female birds by male partners, is a relevant response to maximise investment in a pair bond. Limited information that describes the action of forced copulation by the male flamingo and the response of the female bird is available in the literature. This paper describes an occurrence of an attempted forced copulation by an older male Greater Flamingo to a younger female bird. Such behaviour may be an artefact of the captive environment, and limited mate choice when compared to the sizes of wild flocks, or it could be regularly apparent in the wild and therefore worthy of more scrutiny and empirical study.

REFERENCE VALUES AND COMPARISON OF BLOOD CHEMISTRY AND PLASMA PROTEIN VALUES BETWEEN GOLD STANDARD ANALYZERS AND FOUR POINT-OF-CARE DEVICES IN FREE-RANGING CANVASBACKS (AYTHYA VALISINERIA).

Accurate, timely, and cost-effective blood chemistry analysis is an essential tool for directing emergency treatment, monitoring the health status of captive and free-ranging individuals and flocks, and improving the efficacy of conservation actions. Blood samples were obtained from 52 canvasbacks (Aythya valisineria) that were captured on San Francisco Bay, California, during December 2017 as part of a long-term study. Reference values and clinical agreement were determined for blood chemistry and plasma protein parameters among four commonly used point-of-care devices (VetScan® VS2, i-STAT®, AlphaTRAK®2 glucometer, refractometer) and two gold standard laboratory analyzers (Roche cobas® c501, Helena SPIFE 3000 system). Canvasback reference values were generally within expected ranges for Anatidae species with the exception of higher upper limits for sodium and chloride. Creatine kinase and aspartate transaminase values exceeded a published threshold for diagnosis of capture myopathy even though study birds were captured using low-stress techniques and successfully released. With the exception of higher alkaline phosphatase in hatch-year canvasbacks, no age or sex differences were observed for any analyte in this population that was captured during a nonbreeding period. Analysis of analyzer agreement found raw VetScan aspartate transaminase, calcium, glucose, and uric acid values; corrected VetScan albumin, potassium, sodium, and total protein values; raw i-STAT glucose and potassium values; and corrected i-STAT sodium and chloride values were clinically interchangeable with Roche cobas values. Raw VetScan and i-STAT glucose values were also interchangeable. However, none of the Roche or point-of-care analyzer plasma protein values were in clinical agreement with gold standard electrophoresis values. The findings of this study highlight the need for analyzer- or technique-specific reference values and provide biologists and veterinarians quantitative reference values using currently available analyzers to better assess and respond to the health of individuals and populations.

Understanding sociality and behavior change associated with a nesting event in a captive flock of great white pelicans

Zoo-housed pelicans are commonplace, but their breeding record is poor and little research is published on the activity patterns, as potential predictors of nesting, of captive flocks. Existing literature shows that comparative research can provide useful information for husbandry and conservation planning for pelican populations. The opportunity arose to investigate the time-activity budget and social network of a breeding flock of captive great white pelicans. Three chicks were hatched in June and July 2016 and one in March 2017. Data on state behaviors, space use, and association preferences were collected around these nesting events, from October 2016 to February 2017 and July to October 2017. Results suggest that pre-nesting periods were associated with heightened flock-wide vigilance, suggesting that vigilance may be a precursor for courtship or nesting activity. Social network analysis revealed nonrandom associations between birds and a social structure across the flock, in which subadults seemed to associate more with each other than with adult birds. A limited visitor effect was noted; whilst no overall behavior change was apparent with different numbers of visitors, pelicans did widen their enclosure usage with increased visitor presence. These data are relevant to those attempting to breed this pelican, who wish to know more about the daily behavior patterns of this species across the season and physiological state, and who wish to understand pelican social structure, which is useful to the planning and implementation of bird moves or changes to the social environment of the flock. Further extending such research to include uninterrupted observation over a successful breeding event is recommended.

SARCOCYSTOSIS IN A CAPTIVE FLOCK OF THICK-BILLED PARROTS (RHYNCHOPSITTA PACHYRHYNCHA) FROM 2005 TO 2016: MORBIDITY, MORTALITY, DIAGNOSTICS, AND MANAGEMENT STRATEGIES

Sarcocystosis was diagnosed in a captive flock of thick-billed parrots (Rhynchopsitta pachyrhyncha) at the Wildlife Conservation Society's Queens Zoo. Since the index case in 2005, 45% of mortalities in birds over 30 days of age were due to sarcocystosis. Sarcocystis falcatula was repeatedly identified as the causative agent. The disease predominantly affected younger adult parrots. Administration of antiparasitic medications prior to development of respiratory signs prolonged life in infected birds, but disease was fatal until utilization of a three-drug combination (pyrimethamine, trimethoprim-sulfamethoxazole, and ponazuril). This protocol may require in excess of 6 mo of therapy to achieve clinical resolution of active disease. Plasma creatine kinase activity was found to be the most useful test in diagnosing infection and monitoring response to therapy. Polymerase chain reaction (PCR) for apicomplexan organisms on antemortem whole blood, blood smears, or dried blood spots helped confirm suspected cases, but due to the poor sensitivity was sometimes misleading when assessing response to therapy or resolution of clinical disease. Preventive measures, focusing on exclusion and removal of Virginia opossums (Didelphis virginiana) from zoo grounds failed to curtail the occurrence of sarcocystosis in the flock. Other preventative steps, such as modification of feeding stations to exclude potential arthropod paratenic hosts and prophylaxis trials with diclazuril, appeared to successfully mitigate new infections. Given the diagnostic and therapeutic challenges, prevention of exposure to S. falcatula is essential to ex-situ conservation efforts for thick-billed parrots.

Ocular Examinations and Investigation of Intraocular Pressure, Tear Production, Central Corneal Thickness, and Corneal Touch Threshold in a Captive Flock of Atlantic Puffins (Fratercula arctica)

Ocular examinations were completed on a group of 10 Atlantic puffins (Fratercula arctica), 5 males and 5 females that ranged in age from 8 months to older than 30 years. The exams consisted of intraocular pressure/rebound tonometry, tear production/phenol red thread test, central corneal thickness/ultrasound pachymetry, and corneal sensitivity/esthesiometry. On ocular examination, there were no corneal abnormalities observed. Bilateral cataracts were diagnosed in 8 puffins, 6 of which were considered incipient, focal subcapsular opacities. One bird had hypermature cataracts and was removed from the study and excluded from data analysis; the other birds had no evidence of ophthalmic pathology that would interfere with diagnostic results (n = 9). All results for 9 birds were included in the study, with the exception of 1 puffin's tear production, which was too low for accurate assessment and was excluded from data analysis. There were no significant differences between right and left eye measurements for intraocular pressure, corneal thickness, and corneal sensitivity. The median intraocular pressure for both eyes (OU) was 13 mm Hg with an interquartile range [IQR] of 12-15 mm Hg. The median corneal thickness OU was 241 µm, IQR 233-248 µm. The median corneal sensitivity OU was 1.13 cm, IQR 0.81-1.50 cm. There was a significant difference between right and left eye measurements for tear production (right eye median, 7.5 mm/15 s, IQR 6.5-9.3 mm/15 s; and left eye median, 5.0 mm/15 s, IQR 4.0-7.3 mm/15 s) (P= .03), with the right eye producing more tears than the left. However, 1 puffin was determined to be an outlier, and when removed, there was no longer a significant difference (OU median, 7.0 mm/15 s, IQR 4.6-8.0 mm/15 s) (P = .38). There was no significant difference between sex and intraocular pressure, tear production, and corneal sensitivity. However, there was a significant difference between sex and corneal thickness (P = .02), with males (left eye median, 249 µm, IQR 241-249 µm) having thicker corneas than females (left eye median, 236 µm, 234-238 µm). Although sample size precluded statistical testing, there appeared to be an association between opacities and increasing age. There were no associations between age and intraocular pressure, tear production, or corneal thickness. There was a moderate correlation between age and corneal sensitivity, with older birds showing decreased corneal sensitivity (r = -0.57). Although the sample size of 9 birds was small, these findings provide preliminary ranges for ocular parameters of Atlantic puffins.

Avian Egg Timers: Female Cowbirds Judge Past, Present, and Future When Making Nest Parasitism Decisions

The cognitive demands associated with brood parasitism are substantial. Not only must female parasites locate nests and assess their suitability for parasitism, they must also time parasitism to correspond with the breeding behavior of the host. Keeping track of the reproductive state of hosts for a variety of nests allows the parasite to select a nest where their egg can be incubated successfully. Thus, nest selection decisions are integral to obligate brood parasites’ reproductive success. In captive breeding flocks of brown-headed cowbirds (Molothrus ater), I studied (1) females’ abilities to time a host nest’s readiness for parasitism and (2) the timing of females’ nest selection decisions. I found that cowbirds can attend to the amount of time that elapsed since a host egg was added to a nest and can use that information to choose a nest for parasitism. Females made their choice of nest during prospecting the day before they laid, and, once decided, they did not update their decisions on the day of laying. Taken together, the results reveal that female cowbirds process substantial amounts of information about location, time, number, and rate in order to plan for future parasitism. This research program reveals that species-typical decisions integrate a variety of general and specialized cognitive abilities to allow females to behave adaptively and maximize reproductive success.

Survey of Reticuloendotheliosis Virus in Wild Turkeys (Meleagris gallopavo) in Texas, USA.

Reticuloendotheliosis virus (REV) is an immunosuppressive and sometimes oncogenic avian retrovirus that establishes lifelong infection in a wide range of avian species. REV-infected wild birds roaming near at-risk captive flocks, such as is the case for the highly endangered Attwater's Prairie Chicken (APC; Tympanuchus cupido attwateri), could act as a reservoir for viral transmission. In wild birds, prevalence rates of REV are low and appearance of associated disease is uncommon. During 2016-17, nearly half of all captive adult APC mortality at Fossil Rim Wildlife Center captive breeding facility in Glen Rose, Texas, US was attributed to REV infection. The unusually high REV prevalence rate prompted us to survey for this virus in wild galliforms throughout the region. From 2016-17, 393 blood samples collected from two subspecies of Wild Turkeys (Meleagris gallopavo) were tested for REV proviral DNA through amplification of the viral 3' long terminal repeat and segments of the viral pol gene. In REV-affected counties, 5% (5/98) of native Rio Grande Wild Turkeys (Meleagris gallopavo intermedia) were identified as REV-positive. In addition, we detected REV in one of 62 Eastern Wild Turkeys (Meleagris gallopavo silvestris) that had been imported during conservation efforts. To better determine protective measures, continued surveillance, including collection and genetic analysis of REV-infected samples, is necessary to identify sources of REV outbreaks in captive APC flocks.

Evaluation of two unmanned aircraft systems as tools for protecting crops from blackbird damage

In response to a need for mitigating blackbird damage to crops, we evaluated the effectiveness of two unmanned aircraft systems (UAS or drones) to protect crops from blackbird damage. UAS are known to elicit behavioral and physiological responses in wildlife and have been proposed as a means to protect row crop agriculture from avian pest depredation. We evaluated the behavioral responses of captive and free-ranging red-winged blackbirds to a fixed-wing and a rotary-wing (multi-rotor, quadcopter) UAS by comparing preflight behaviors to behaviors during UAS approach. Due to the flight limitations of the respective UAS, the fixed-wing and rotary-wing were evaluated at different altitudes. Behavioral responses of captive and free-ranging blackbirds to approaching UAS were categorized as no response, alertness, or attempted escape/flight. Neither captive nor free-ranging flocks of red-winged blackbirds displayed behavioral responses to approaches by the fixed-wing UAS when flown at or above 52 m above ground level (AGL). However, both captive and free-ranging flocks exhibited behavioral responses to the rotary-wing UAS when flown within 30 m AGL. Behavioral responses of blackbirds to the rotary-wing UAS were more pronounced with lower altitude approaches. Our findings suggest that UAS have the potential to modify blackbird behavior in a way that may reduce sunflower crop depredation.

Detection and Characterization of Circovirus in Canary Flocks.

Circovirus infections have been documented in adult and nestling canaries (Fringillidae) but the distribution of the virus in the world is not yet known. In captive canary flocks, Circovirus infections have been reported based on the clinical observations. In this study, the presence of both canary circovirus (CaCV) and chicken anemia virus (CAV) in canary flocks was investigated. Virus strains were detected by PCR and direct sequencing of amplified products. Nucleotide sequences were aligned and compared with existing data in GenBank. PCR identified CaCV-positive birds, giving an overall positivity rate of 25%, but all samples were negative for CAV. According to the sequencing data, three distinct strains were identified. Our results indicated a relationship between genetic variation in the replicase gene ( rep) and the geographic regions as well as the feasibility of using the rep gene for virus detection and molecular epidemiology investigations. We are reporting detection and characterization of canary circovirus based on the rep gene. Sequencing results and sequence identity analysis revealed that the rep gene could be used for detecting and discriminating the members of family Circoviridae. This manuscript is the first report of canary circovirus in Iran and of three new strains in the world.

Quantifying the social structure of a large captive flock of greater flamingos (Phoenicopterus roseus): Potential implications for management in captivity

An appropriate social environment for species held in captivity is key for ensuring both good welfare and reproductive performance. Species with a complex social structure may suffer if their social requirements are not taken into consideration as part of management and husbandry strategies. Here we aim to understand the drivers of social structure, and the link between social structure and reproduction in a flock of 281 greater flamingos (Phoenicopterus roseus) at WWT Slimbridge Wetland Centre. Proximity-based associations between birds were measured three and four times per day (depending upon season and husbandry) from 2012 to 2016. To determine the effect of reproductive activity on social structure, display and nesting behaviour were also recorded for the 2015 breeding season (April–July). Results showed that birds displayed a wider range of social relationships, and that affiliations within the flock were not random. This flamingo flock was differentiated into discrete subgroups, and social structure was stable across some years, but not over all seasons. Social bonds were more consistent across seasons into the nesting period rather than outside of it. During breeding, not all birds that displayed built a nest, and not all displaying birds nested. Future research should further investigate differences in display and nesting patterns within a flock, and determine how the social structure of large flocks compares to smaller flocks of this species. Comparing captive data to information on wild bird sociality would be relevant to highlight any differences in patterns of assortment and connectivity.