Adult Birds Research Articles

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This study is to identify the comparative morphological description of the tongue in two species of domesticated waterbirds, Mallard Anas platyrhynchos (Linnaeus,1758) and Graylag Goose Anser anser (Linnaeus,1758) (Anseriformes, Anatidae). Four adult male birds (two for each species) were collected from the Iraqi environment and used in the current study by buying them from the AL-Ghezil Market, a local market in Baghdad City. Anaesthetized, dissected, and laboratory work were conducted and visually documented. The results of the study showed that the tongue of both birds was characterized by the appearance of being a narrow-elongated organ divided into three areas represented by the apex, the lingual body, and the root. It was noted that there was a median sulcus, lingual prominence, and conical and filiform papillae of varying numbers and distribution on the dorsal surface of the tongue. While the ventral surface was free of lingual papillae, but it might contain in return a triangular squamous plate called a lingual nail or a bar-shaped structure called a lyssa in proportion to the type and nature of nutrition.

ASSESSMENT OF GROWTH PATTERN IN INDIGENOUS KADAKNATH CHICKENS BY NON-LINEAR MODELS

Mathematical growth functions can explain the factors influencing an animal's growth pattern. However, there remains limited understanding of the growth curve of Kadaknath chickens, which is crucial for optimizing management and feeding practices. Therefore, this study aimed to determine the growth curve of indigenous Kadaknath chickens' body weight using four growth curve models: Logistic, Gompertz, Von Bertalanffy, and Richard. We analyzed 96 birds for this study. The models were fitted using Curve Expert and Minitab software, and we compared them based on Akaike’s information, Bayesian information, adjusted R2, and RMSE criteria. The research revealed that the Gompertz and Richard models had higher coefficients of determination (R2) and lower RMSE values in both sexes compared to other models. The age at the inflection point was estimated to be between 11 to 17.5 weeks for males and 9 to 11.4 weeks for females. According to the Richard model, adult male birds weighed 2157g, and females weighed 1297g. In the Gompertz model, male birds weighed 2186g, and females weighed 1468g. The inflection weight of birds in the Richard model was estimated to be 797.53g for males and 519.66g for females, while in the Gompertz model, it was 803.67g for males and 510g for females. In conclusion, our study determined that the Gompertz model is a reliable predictor of the body weight of male and female Kadaknath chickens from hatching to adulthood. The Richard model also demonstrated high reliability, albeit slightly behind the Gompertz model in predictive accuracy. Key words: Body weight, growth pattern, Kadaknath, Non-linear models

West Nile Virus Seroprevalence in Wild Birds and Equines in Madrid Province, Spain.

West Nile virus (WNV) is a re-emerging flavivirus, primarily circulating among avian hosts and mosquito vectors, causing periodic outbreaks in humans and horses, often leading to neuroinvasive disease and mortality. Spain has reported several outbreaks, most notably in 2020 with seventy-seven human cases and eight fatalities. WNV has been serologically detected in horses in the Community of Madrid, but to our knowledge, it has never been reported from wild birds in this region. To estimate the seroprevalence of WNV in wild birds and horses in the Community of Madrid, 159 wild birds at a wildlife rescue center and 25 privately owned equines were sampled. Serum from thirteen birds (8.2%) and one equine (4.0%) tested positive with a WNV competitive enzyme-linked immunosorbent assay (cELISA) designed for WNV antibody detection but sensitive to cross-reacting antibodies to other flaviviruses. Virus-neutralization test (VNT) confirmed WNV antibodies in four bird samples (2.5%), and antibodies to undetermined flavivirus in four additional samples. One equine sample (4.0%) tested positive for WNV by VNT, although this horse previously resided in a WN-endemic area. ELISA-positive birds included both migratory and resident species, juveniles and adults. Two seropositive juvenile birds suggest local flavivirus transmission within the Community of Madrid, while WNV seropositive adult birds may have been infected outside Madrid. The potential circulation of flaviviruses, including WNV, in birds in the Madrid Community raises concerns, although further surveillance of mosquitoes, wild birds, and horses in Madrid is necessary to establish the extent of transmission and the principal species involved.

Reduction of coastal lighting decreases seabird strandings.

Artificial light at night (ALAN) is negatively impacting numerous species of nocturnally active birds. Nocturnal positive phototaxis, the movement towards ALAN, is exhibited by many marine birds and can result in stranding on land. Seabird species facing major population declines may be most at risk. Leach's Storm-Petrels (Hydrobates leucorhous) are small, threatened seabirds with an extensive breeding range in the North Atlantic and North Pacific Oceans. The Atlantic population, which represents approximately 40-48% of the global population, is declining sharply. Nocturnal positive phototaxis is considered to be a key contributing factor. The Leach's Storm-Petrel is the seabird species most often found stranded around ALAN in the North Atlantic, though there is little experimental evidence that reduction of ALAN decreases the occurrence of stranded storm-petrels. During a two-year study at a large, brightly illuminated seafood processing plant adjacent to the Leach's Storm-Petrel's largest colony, we compared the number of birds that stranded when the lights at the plant were on versus significantly reduced. We recorded survival, counted carcasses of adults and juveniles, and released any rescued individuals. Daily morning surveys revealed that reducing ALAN decreased strandings by 57.11% (95% CI: 39.29% - 83.01%) per night and night surveys revealed that reducing ALAN decreased stranding of adult birds by 11.94% (95% CI: 3.47% - 41.13%) per night. The peak stranding period occurred from 25 September to 28 October, and 94.9% of the birds found during this period were fledglings. These results provide evidence to support the implementation of widespread reduction and modification of coastal artificial light as a conservation strategy, especially during avian fledging and migration periods.

Spatiotemporal distribution of Eurasian Spoonbills (Platalea leucorodia) outside the Carpathian Basin – the results of the Hungarian colour-ringing project based on twenty years (2003–2023)

Abstract The Eurasian Spoonbill (Platalea leucorodia) is a migratory waterbird. We used the confirmed observations of colour-ringed individuals (2,735 specimens) of the Hungarian population collected outside the Carpathian Basin between May 2003 and February 2023. 546 Spoonbills occurred in 28 countries. They used mainly the Central Mediterranean Flyway, however, some individuals were seen along the East Atlantic Flyway or the East Mediterranean Flyway. Three individuals were observed north of the Alps, too. A small proportion of Spoonbills crossed the Sahara and they occurred in the Sahel zone, between Sudan in the east and Senegal and Mauritania in the west. A few individuals were observed on Saharan wetlands in Algeria during winter. The most important destination for the Hungarian (Pannonian) population during the migration is Tunisia, where many of them spend the winter, primarily in the tidal area of the Gulf of Gabes. The first adults reached North Africa (Tunisia) on 28 July during their southward migration, while the last ones stayed there until 23 April. The first observation of juveniles in North Africa (Tunisia) happened on 31 August. Immature, 2- and 3-cyold birds spend the summer in unknown numbers in Tunisia. The majority of Pannonian Spoonbills migrate through the Balkans and Italy and some stay there to winter, mainly in Italy. Some of the immatures spent the summer in Italy. In southern Europe, the peak of the spring migration was in March, and the peak of the autumn migration was in September. There was also a difference in the migration of different age groups: in Southern Europe, the migration peak of adult birds falls between March and April, while most of the immatures were observed in May and June during northward migration. The peak of the southward migration in all age groups was observed in September. In the southern part of Europe, there may still be adults migrating north on 13 May, while other adults may already migrate southward on 15 May. The earliest juvenile migrating south was documented on 30 June in Italy.

Surveillance of Parrot Bornavirus in Taiwan Captive Psittaciformes

Parrot bornavirus (PaBV) is an infectious disease linked with proventricular dilatation disease (PDD) with severe digestive and neurological symptoms affecting psittacine birds. Despite its detection in 2008, PaBV prevalence in Taiwan remains unexplored. Taiwan is one of the leading psittacine bird breeders; hence, understanding the distribution of PaBV aids preventive measures in controlling spread, early disease recognition, epidemiology, and transmission dynamics. Here, we aimed to detect the prevalence rate of PaBV and assess its genetic variation in Taiwan. Among 124 psittacine birds tested, fifty-seven were PaBV-positive, a prevalence rate of 45.97%. Most of the PaBV infections were adult psittacine birds, with five birds surviving the infection, resulting in a low survival rate (8.77%). A year of parrot bornavirus surveillance presented a seasonal pattern, with peak PaBV infection rates occurring in the spring season (68%) and the least in the summer season (25%), indicating the occurrence of PaBV infections linked to seasonal factors. Histopathology reveals severe meningoencephalitis in the cerebellum and dilated cardiomyopathy of the heart in psittacine birds who suffered from PDD. Three brain samples underwent X/P gene sequencing, revealing PaBV-2 and PaBV-4 viral genotypes through phylogenetic analyses. This underscores the necessity for ongoing PaBV surveillance and further investigation into its pathophysiology and transmission routes.

Three sympatric host nestlings eavesdrop on cuckoo nestling distress calls.

In predator-prey interactions, the prey faces extreme challenges from predation, which drives the evolution of defense or anti-predator mechanisms. Compared with adult birds, nestlings are more vulnerable but not helpless. However, data on whether nestlings eavesdrop on the danger signals transmitted by other prey nestlings and the mechanisms of eavesdropping remain limited. In brood parasitism, common cuckoo (Cuculus canorus) nestlings, raised by host adults who are not closely related, offer an instructive system for studying the transmission and recognition of danger signals among nestlings of different species that share special relationships. We played back the distress calls of common cuckoo nestlings to nestlings of three sympatric host species (the oriental reed warbler Acrocephalus orientalis, which is a primary host of the common cuckoo, the reed parrotbill Paradoxornis heudei, an occasional host, and the vinous-throated parrotbill Sinosuthora webbiana, which is not parasitized in the study area) to investigate whether the host nestlings reduced their begging behavior. We also quantified the degree of inhibition toward begging behavior for these nestlings. The results revealed that, in response to the distress calls, the three sympatric host species markedly suppressed their begging behavior. This response can likely be attributed to the innate response of host nestlings caused by the general characteristics of distress calls, rather than the acoustic similarity and phylogenetic relationship between host nestlings and cuckoo nestlings. Furthermore, we observed that upon hearing the distress calls of cuckoo nestlings, the oriental reed warbler nestlings exhibited the greatest reduction in the total number of calls compared to the other two host species, potentially owing to stronger predation and parasitic pressures. This study suggests that host nestlings can detect danger signals emitted by parasitic nestlings; however, further investigation is needed to determine whether they can respond to distress calls from unfamiliar nestlings in different regions.

Molecular Detection and Serological Investigation of Newcastle Disease in Intensive, Semi-Intensive, and Backyard Production Systems in Central and Southwestern Areas of Ethiopia.

The purpose of this research is to detect Newcastle disease virus and to assess the seropositivity among backyard, semi-intensive, and intensive farms located in central and southwestern areas of Ethiopia. A total of 239 oropharyngeal and cloacal swab samples were collected from symptomatic birds found in Holeta, Burayu, Jimma towns as well as Seka Chekorsa and Nadhigibe woredas of Jimma Zone. In addition, ninety blood samples were collected from wing veins of unvaccinated birds found in the study areas of Jimma zone. Side-by-side information related to risk factors estimated to contribute to the susceptibility of the disease was collected by interviewing owners of sampled birds. Reverse transcription polymerase-chain reaction (RT-PCR) was conducted to detect NDV. Likewise, Enzyme-linked immunosorbent assay (ELISA) was performed to determine the seropositivity of ND. The proportion of samples where NDV was detected was 24.6%. Similarly, 68.9% of the sampled birds were seropositive. It was observed that adult birds were more likely to encounter the disease than youngs (OR = 11.6; 95% CI: 4.0-33.3; P = 0.000). Birds owned by respondents who leave diseased birds in the flock were more likely infected (OR = 6.2; 95% CI: 1.8-21.2; P=0.004) as compared to those isolated and mode of disposal of dead chicken significantly affect exposure (OR = 0.13; 95% CI: 0.10-4.88; P = 0.044). Likewise, access to veterinary services highly likely reduces susceptibility to the disease (OR = 12.4; 95% CI: 3.2-46.9; P = 0.000). It was also found that birds farmed intensively were the most at risk (OR = 2.8; 95% CI: 0.58-13.71; P = 0.199). Detection of ND from a significant proportion of sampled birds and their high seropositivity percentage revealed the circulation of the virus in the study areas.

Habitat use of Amazonian birds varies by age and foraging guild along a disturbance gradient.

Patterns of habitat use directly influence a species' fitness, yet for many species an individual's age can influence patterns of habitat use. However, in tropical rainforests, which host the greatest terrestrial species diversity, little is known about how age classes of different species use different adjacent habitats of varying quality. We use long-term mist net data from the Amazon rainforest to assess patterns of habitat use among adult, adolescent (teenage) and young understory birds in forest fragments, primary and secondary forest at the Biological Dynamics of Forest Fragments Project in Brazil. Insectivore adults were most common in primary forest, adolescents were equally likely in primary and secondary forest, and all ages were the least common in forest fragments. In contrast to insectivores, frugivores and omnivores showed no differences among all three habitat types. Our results illustrate potential ideal despotic distributions among breeding populations of some guilds of understory birds where adult insectivores may competitively exclude adolescent individuals from primary forest. Secondary forest recovery appears to hold promise as a breeding habitat for frugivore and omnivore species but only as a pre-breeding habitat for insectivores, but as the forest ages, the demographic structure of bird populations should match that of primary forest.

First record of cannibalism by an adult on a chick in the Purple Heron

This short note reports the first documented case of cannibalism in the Purple Heron performed by an adult bird.

Effects of age and captivity on the social structure and migration survival of a critically endangered bird

AbstractReintroductions of threatened species is a conservation strategy utilised around the world. Unfortunately, many translocated individuals have poor rates of survival post‐release. If released individuals are unable to socially integrate into wild populations, they might lose the safety of the group or fail to learn critical skills. We examined the effects of age and captivity on sociality and migration survival for the critically endangered orange‐bellied parrot (Neophema chrysogaster). As part of recovery efforts, adult birds are released in spring to contribute to breeding and juveniles are released in autumn prior to migration. Historically, captive‐bred adults have low rates of migration survival, whereas captive and wild juveniles survive at comparable rates. We investigated both the long‐term impacts of captivity on sociality and how sociality impacted migration survival by constructing social networks and comparing captive and wild birds of different age classes. We found no differences between captive and wild birds, suggesting that released birds integrated into the population. However, juveniles were more strongly connected and demonstrated greater network stability than adults. While we found no impact of sociality on survival, our results provide evidence of different migration strategies previously described for juveniles and adults: adults depart in small groups and juveniles depart as a larger flock a few weeks later. We suggest that the low migration survival of captive‐bred adults may be attributable to this cohort missing the juvenile flocking phase. These results suggest that a juvenile developmental phase may be impactful in this species for future survival.

Antibiotic resistance of P. aeruginosa in the presence and absence of pyocyanin pigment

Purpose: study of antibiotic resistance of Р. aeruginosa strains in the presence and absence of pyocyanin pigment. Materials and methods. Bacteriological studies of pathological material from "asphyxiated embryos", sick chickens and forcibly killed or dead adult birds were carried out according to generally accepted methods. Cultures from bone, brain, heart, liver, spleen, gall bladder, muscles and other organs were carried out on simple, selective and differential diagnostic nutrient media. The sensitivity of P. aeruginosa isolates to antibacterial drugs was determined by diffusion in agar according to the generally accepted method. The results. The obtained results of studies by the diffusion method in agar indicate that the proportion of resistant to the studied antibiotics among non-pigmented isolates was on average 79.00 % (60-100) %, and among strains that formed pyocyanin - 51.00 % (25-100) %. 60.00 % - 90.00 % of resistant non-pigmented isolates were found to fluoroquinolones, 60.00-70.00 % to cephalosporins, 60.00-97.00 % to aminoglycosides. To representatives of semisynthetic penicillins, tetracyclines, and macrolides - 100 % of resistant isolates that did not synthesize pyocyanin were found. Among P. aeruginosa isolates that synthesized pigment, 25.00-40.00 % were resistant to fluoroquinolones, 30.00-35.00 % to cephalosporins, 25.00-50.00 % to aminoglycosides, representatives semi-synthetic penicillins, tetracyclines, macrolides - 100 % of the studied strains. Conclusions. The absence of pigment formation in P. aeruginosa isolates, obtained in association with bacterial pathogens, is not accompanied by the absence of antibiotic resistance. 28 % more antibiotic-resistant isolates were found among non-pigmented isolates compared to isolates that synthesize pyocyanin pigment. The data presented emphasize the need for the use of differential media for the isolation of P. aeruginosa in order to identify non-pigmented strains and prescribe appropriate treatment, which, accordingly, will prevent the spread of latent forms of infection

Feather growth rate and hormone deposition vary with elevation but not reproductive costs in resident Mountain Chickadees

Abstract Many organisms engage in metabolic tradeoffs to manage costs associated with reproductive output which often leads to these costs carrying over into the future. Compensatory mechanisms vary across life history strategies and are expected to result in near-optimal fitness gains for the investor. Here we investigated whether environmental differences associated with increasing montane elevation and variation in reproductive output of a resident passerine songbird, the Mountain Chickadee (Poecile gambeli), were related to physiological conditions during annual molt. Higher elevations are associated with harsher environmental conditions during the winter, which results in later and shorter breeding seasons than at lower elevations. We sampled the outermost tail feathers from adult birds in the fall after their prebasic molt, which initiates closely after reproduction (e.g., after parental care has ceased, ~1–3 weeks). We measured the hormone corticosterone deposited in feathers (fCORT) and feather growth rates for evidence of physiological effort predicted to be driven by several units of reproductive output (e.g., breeding timing, clutch and brood size, and offspring mass). There were no relationships between any measure of reproductive output and feather characteristics between elevations or across years, despite substantial variation in reproductive output in the wider population across this same time. However, birds at the high-elevation site grew their tail feathers significantly faster and had higher fCORT deposition compared to low-elevation birds. These results suggest that although differences in reproductive output and any related signals of associated physiological effort (e.g., fCORT and feather growth rate) may not extend into individual conditions during annual molt, shorter breeding seasons associated with harsher environmental conditions may favor faster feather growth as required by earlier onset of winter.

Histology and immunofluorescent study of the pancreas in lovebird (Agapornis personatus).

Lovebird (Agapornis personatus) is a monotypic species of bird of the lovebird genus in the parrot family Psittaculidae and order Psittaciformes. The present study was designed to investigate the histology and immunohistochemistry of the pancreas in the lovebird. Totally, three adult birds were used. The pancreas was assessed using histological and immunofluorescent staining to detect insulin, glucagon, somatostatin, pancreatic polypeptide (PP) and neuropeptide Y (NY). The exocrine pancreas was composed of pyramidal acinar cells with zymogen granules at the apical cytoplasm. The endocrine pancreas was identified as large alpha, small beta and mixed islets of Langerhans. No intercalated duct was observed. Alpha cells with a density of 28.55% were the most numerous cell type, which were populated throughout the large islets, especially at the periphery. The beta cells with a density of 15.78% were accumulated mostly at the periphery of islets. The delta cells exhibited 17.81% intensity. Despite their lower density, the distribution of delta cells was like that of A cells throughout the islets. PP and NY cells were distinguished with densities of 14.69% and 20.63%, respectively. Although the arrangement of acinar cells, ductal systems and endocrine islets reflects patterns observed in various avian species, the absence of intercalated duct, the presence of three types of Langerhans islets as alpha, beta and mixed islets and the high expression of NY in the islets were some unique features observed in the current study. These findings contribute to the broader understanding of avian pancreas histology.

Newcastle Disease Outbreak in Backyard Poultry: Herbal Remediation Using Phyllanthus Polygonoides and Carica Papaya Leaves

Newcastle disease (ND) is a devastating disease of backyard poultry and causes great economic losses to rural poor. The study was undertaken to assess the effectiveness of herbal extracts of Phyllanthus polygonoides and Carica papaya leaves for control of Newcastle outbreak in backyard poultry. A total of 60 representative desi fowl (chicken 50, turkey 7 and duck 3) from 40 flocks were presented to VCC hospital, VC&RI, Orathanadu for treatment. The samples like oropharyngeal fluid/ clocal swab was collected from 40 birds (flocks) and performed haemagglutination test. Out of 40 birds screened, 18 birds (Chicken-13, turkey- 4 and Duck- 1) were positive for haemagglutination test and showed the presence of Newcastle disease virus and confirmed by PCR. The infected birds were treated with aqueous extract of Carica papaya and Phyllanthus polygonoides leaves @ 0.5ml/ kg b.wt orally for 3 days. Most of the birds recovered in single dose, the moderately infected birds recovered after 3 days of treatment. The herbal extract was also used prophylactically other than the infected birds in their respective flocks to prevent the infection. None of the adult birds in their flocks become infected and protected from infection. The plant juice of Phyllanthus polygonoides and Carica papaya leaves were highly effective for control of ND in backyard poultry, it could be used prophylactically every 30 days to prevent Newcastle disease outbreak in backyard poultry to minimize economic losses to the farmers.

Home ranges and hatching success of threatened Eurasian curlew in north-eastern Europe relates to habitat type: Natural vs. agricultural landscapes

Farmland birds are among the most threatened species in Europe, largely as a result of the intensification of agriculture leading to widespread biodiversity losses. Ground-breeding shorebirds in grassland and arable habitats are particularly exposed to human threats and predation in highly modified landscapes; however, parts of their populations still breed in natural habitats and could provide a reservoir for threatened populations. This study aimed to improve our knowledge of the spatio-temporal use of breeding habitats by Eurasian curlew Numenius arquata arquata in a core area of the population in remote north-eastern Europe. A total of 83 adult birds across Europe were tagged with GPS devices between 2014 and 2022 to analyse their home-range sizes, habitat use and hatching success. Birds were distributed at breeding sites from 52°N to 66°N between Finland and the Ural Mountains. Forty-one percent of individuals nested in bogs, 33% in grassland, and 20% in abandoned farmland. Birds nested predominantly in bogs at northern latitudes and in grassland at southern latitudes, while abandoned farmland was mainly used at intermediate latitudes. The mean home range was largest for birds breeding predominantly in grassland while birds in bogs had the highest hatching success rate. Russia and Finland host the core population of the subspecies N. a. arquata during breeding period, which is essential for preserving the species on a European scale. Their survival may depend on well-preserved bogs and the maintenance of grassland areas, given that large areas of abandoned farmland are destined to become either forest or to be reclaimed for cereal crops or fodder grass in the short and medium terms. Given the large breeding populations in both countries, Russia and Finland have major responsibilities to maintain these essential populations on a biogeographical scale.

Genetic diversity and inbreeding in an endangered island-dwelling parrot population following repeated population bottlenecks

Genetic diversity and population structure can have important implications for the management of threatened species. This is particularly true for small, isolated populations that have experienced significant declines or population bottlenecks. The Norfolk Island green parrot Cyanoramphus cookii is an endangered species at risk of inbreeding and loss of genetic diversity due to its restricted range and the population bottlenecks experienced in recent decades. To assess the severity of inbreeding and loss of genetic diversity in the population we analyzed single nucleotide polymorphisms (SNPs) for 157 unique genetic samples collected from nestlings and randomly captured adult birds between 2015 and 2022. We also assessed the population for genetic structure, calculated sex ratios, and looked for evidence of past population bottlenecks. Our analysis revealed that 17.83% of individuals sampled were highly inbred (F > 0.125), although expected heterozygosity (HE) did not significantly differ from observed heterozygosity (HO) and the average inbreeding coefficient was low. The estimated effective population size (Ne) was 43.8 and we found no evidence of genetic structure. Demographic simulations provided support for scenarios including multiple population bottlenecks, when compared to those with a single population bottleneck or no past bottlenecks. We discuss the implications of our findings for the future management of the species including any potential attempt to establish an insurance population via translocation. Our study highlights the importance of considering population genetics when determining appropriate management actions for threatened species and the need to assess non-model species on an individual basis.

Global prevalence of Plasmodium infection in wild birds: A systematic review and meta-analysis

Avian malaria is a vector-borne parasitic disease caused by Plasmodium infection transmitted to birds by mosquitoes. The aim of this systematic review was to analyze the global prevalence of malaria and risk factors associated with infection in wild birds. A systematic search of the databases CNKI, WanFang, VIP, PubMed, and ScienceDirect was performed from database inception to 24 February 2023. The search identified 3181 retrieved articles, of which 52 articles met predetermined inclusion criteria. Meta-analysis was performed using the random-effects model. The estimated pooled global prevalence of Plasmodium infection in wild birds was 16%.Sub-group analysis showed that the highest prevalence was associated with adult birds, migrant birds, North America, tropical rainforest climate, birds captured by mist nets, detection of infection by microscopy, medium quality studies, and studies published after 2016. Our study highlights the need for more understanding of Plasmodium prevalence in wild birds and identifying risk factors associated with infection to inform future infection control measures.

Severe decline in abundance of Cyathostoma lari, a parasite of the nasal and orbital sinuses of gulls, at their central European nesting grounds.

Cyathostoma lari is a parasite of the nasal and orbital sinuses of gulls and other hosts in Europe and Canada. Here, we provide an overview of previously published data on the prevalence and infection intensity of C. lari in gulls. Furthermore, based on our data, we analyze the spatiotemporal trends in the prevalence and intensity of infection by C. lari in Chroicocephalus ridibundus in Czechia (central Europe; data from 1964 to 2014) and compare them with those obtained from five species of gulls in Karelia (Northwest Russia; data from 2012-2020). Based on our preliminary observations, we hypothesized that C. lari is subject to a decline in certain regions, but this decline is not necessarily applicable throughout its distribution range. We found that the C. lari population crashed in specific parts of its distribution range. The reasons are unknown, but the observed population changes correspond with the diet switch of their core host in Czechia, C. ridibundus. We previously observed a diet switch in Czech C. ridibundus from earthworms (intermediate hosts of C. lari) to other types of food. This diet switch affected both young and adult birds. Nevertheless, it may not necessarily affect populations in other regions, where they depend less on earthworms collected from agrocenoses affected by agrochemicals and trampling. Correspondingly, we found that these changes were limited only to regions where the gulls feed (or fed) on arable fields. In Karelia, where arable fields are scarce, gulls likely continue to feed on earthworms and still display high infection rates by C. lari. Therefore, C. lari, a parasite of the nasal and orbital sinuses of gulls, nearly disappeared from their central European nesting grounds but is still present in better-preserved parts of its distribution range.

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ КАРОТИНСОДЕРЖАЩИХ ПРЕПАРАТОВ В РАЦИОНАХ КУР-НЕСУШЕК

Deficiency of carotene and vitamin A leads to various diseases of young birds, a sharp decrease in the productivity of adult birds. As you know, beta-carotene, unlike vitamin A, does not have toxic properties, it protects the liver from hepatotropic poisons and gives poultry products a good marketable appearance. This paper presents the results of studies on the influence of carotene- containing preparations caroflavin and carophyllin on the body of laying hens and the marketable quality of eggs. We evaluated the productivity of laying hens. After the use of caroflavin and carophyllin, the egg production of hens increased by 2,9% and 3,7%, the amount of carotenoids in the egg yolk increased by 25,2 and 33%, vitamin E – by 23,5 and 64,7%, and vitamin A – by 34,8 and 52,2% compared to the control.