Bird Body Research Articles

Species-specific accumulation of microplastics in different bird species from South China: A comprehensive analysis

Microplastics are widespread in many bird species, but the inter-specific variations of microplastic contamination are still unclear. The present study measured microplastics in 24 bird species from South China and investigated the impacts of bird physiological and ecological traits on microplastic contamination. The median abundances of microplastics ranged between 5–167 particles per individual or 0.023–3.58 particles per g body weight. Approximately 60 % of microplastics were within the size range 20–50 µm, with the primary polymer types of polypropylene (PP) and polyethylene terephthalate (PET). There was no significant correlation between microplastic abundances and bird body weights and trophic levels (δ15N) in different bird species. Insectivorous birds had significantly higher abundances of microplastics smaller than 0.1 mm than granivorous, piscivorous, and carnivorous birds (p < 0.01), which was further supported by the meta-analysis of microplastic contamination in birds. On contrary, meta-analysis results indicate that piscivorous birds tend to accumulate larger microplastics (> 1 mm) than other bird species. Microplastic contamination in different bird species was more influenced by diet source rather than trophic level and body weight. Potential ecotoxicological risks were observed for most insectivorous species in the preliminary risk assessment. Particular concern should be paid on insectivorous birds, which have been scarcely studied for microplastics but were at high exposure risks of microplastics among bird species.

Birds as sacred ‘children of god’, beholders of spirit and symbols of twinhood: Human–bird interaction among the Nuer in western Ethiopia

Abstract The deep connection between Indigenous communities and nature plays a pivotal role in biodiversity conservation. Ethiopia, one of Africa's priority countries for bird conservation, harbours 821 bird species and 83 ethnic groups of Indigenous people. However, cultural and spiritual ties between Indigenous peoples and bird species remain largely unexplored. This is particularly true for remote Indigenous communities such as the Nuer. Relying on preexisting bird survey data, we conducted focussed group discussions and semi‐structured interviews with Indigenous Nuer in western Ethiopia to explore human–bird interactions and documented associated traditional ecological knowledge and considered their conservation implications. We found that Nuers have strong ties with birds. In Nuer community, birds are collectively known by three interchangeable terms: ‘gaatkuoth’ to mean sacred children of god, ‘kuoth’ meaning bearers of spirit and ‘diit’ symbols of human twins (since birds nurture multiple offspring, they associate the incidence of twins in human with birds). We identified 71 culturally important bird species that were used in seven different use categories. Among these species, 10 were used as bushmeat, five for traditional medicine, eight as fish indicators, seven as omens (believed to indicate upcoming misfortunes), three as amulets (believed to protect against danger when bird's body parts are used as necklaces and bracelets), three as season indicators and 45 for their scenic beauty. An informant consensus factor for species in all use categories was &gt;90%, except for the scenic value, indicating a high homogeneity of knowledge about species uses. Bird species with multiple uses have significant cultural values among locals, emphasizing the need to understand these values in conservation efforts. Nuer traditional systems regulate the direct use of birds including for bushmeat. Hunting is permitted only by impoverished households during severe food shortages and is prohibited for those with a history of twins in their ancestry. The Nuer people exhibit a profound cultural connection to birds, viewing them as sacred and spiritually valuable beings. This deep‐seated reverence and traditional knowledge highlight the importance of integrating Indigenous perspectives into bird conservation strategies to enhance their effectiveness and respect cultural values. Read the free Plain Language Summary for this article on the Journal blog.

Small Endemic Birds and Hot Climate: Avian and Environmental Predictors of Avifauna Road Mortality in Santa Cruz Galapagos

In the Galapagos Islands, the main road in Santa Cruz is one of the elements involved in bird road mortality along with vehicles and the impacted species. This study reports the number of roadkilled birds found on the road from the Itabaca Channel to Puerto Ayora, and the main factors, whether avian or environmental, involved in bird roadkill mortality. We collected individual carcasses in 2004, 2005, 2006, and 2018 with a prevalence of 278, 252, 265, and 294, respectively, across 21 species. The endemic Yellow Warbler Setophaga petechia aureola was the most affected bird. We used a PRIDIT model to rank the top avian and environmental predictors of road mortality. We found that for the sampled years, bird body size (i.e., 8–35 g) and the endemism status (i.e., endemic/native) were the main predictors of roadkill mortality, along with seasonality (i.e., hot season). Weaker predictors related to the bird (i.e., age and sex) and the environment (ecosystem, road slope, vegetation, or precipitation) are also reported as determinants of roadkill mortality. This study on avian mortality aims to inform conservation strategies to reduce the rate of wildlife avian roadkill on Santa Cruz Island and other islands with similar problems.

Neural Basis of Categorical Representations of Animal Body Silhouettes.

Neural activities differentiating bodies versus non-body stimuli have been identified in the occipitotemporal cortex of both humans and nonhuman primates. However, the neural mechanisms of coding the similarity of different individuals' bodies of the same species to support their categorical representations remain unclear. Using electroencephalography (EEG) and magnetoencephalography (MEG), we investigated the temporal and spatial characteristics of neural processes shared by different individual body silhouettes of the same species by quantifying the repetition suppression of neural responses to human and animal (chimpanzee, dog, and bird) body silhouettes showing different postures. Our EEG results revealed significant repetition suppression of the amplitudes of early frontal/central activity at 180-220 ms (P2) and late occipitoparietal activity at 220-320 ms (P270) in response to animal (but not human) body silhouettes of the same species. Our MEG results further localized the repetition suppression effect related to animal body silhouettes in the left supramarginal gyrus and left frontal cortex at 200-440 ms after stimulus onset. Our findings suggest two neural processes that are involved in spontaneous categorical representations of animal body silhouettes as a cognitive basis of human-animal interactions.

Low Velocity Bird-Like Impact Behavior on Honeycomb Composite Structure

Composite materials are widely used in primary aerospace structures such as wing components and fuselage panels; however, their major disadvantage is their vulnerability to transverse impact loads that can lead to internal delamination and fibre/matrix separation. In this study, the effect of a low-velocity impact which simulates bird impact on a honeycomb sandwich composite plates produced by a co-curing technique for a typical unmanned air vehicle (UAV) was studied both experimentally and numerically. The surface plates of the composite samples were produced from carbon fibre/epoxy prepreg material. Nomex honeycomb core material was used to make the composite sandwich structure via an autoclave process. For the bird-like impact test, the tip of the impactor was coated with thick, tough rubber to simulate a bird strike; the diameter of the impactor was 25 mm to ensure similarity with a bird called Pica nuttalli (magpie), which has a mass of 155 g and is the closest bird body to the simulations. Three different predetermined impact scenarios with kinetic energy 380 Joule, 276 Joule, and 224 Joule were applied to the samples with rubber impactors of similar density, to simulate bird impact events with different impact directions. The impact behaviour was characterised by velocity-time, force-time, and displacement-time graphs. Different levels of damage were observed in the composite samples, but none of the sandwich test samples were perforated, and it could therefore be concluded that the unmanned air vehicle could land without risk to flight safety. This low-velocity bird-like impact was also modelled and analysed using a numerical program to verify the results, and it was concluded that the verified model could also be used for the preliminary design verification of dynamic bird-impact tests within the 10% sensitivity range.

Effect of dietary inclusion of 25-hydroxyvitamin D₃ and vitamin E on performance, gut health, oxidative status, and immune response in laying hens infected with coccidiosis

Vitamin D3 (25-hydroxyvitamin D3 (VD)) and vitamin E (VE) have proven to have immunomodulatory and antioxidant functions along with capacities to improve the reproductive function in chickens. Coccidiosis in laying hens at different stages of growth has been shown to negatively affect performance, immune response, and oxidative status, thus increasing the cost of production. A study was conducted to evaluate the influence of dietary VD or VE on performance, gut health, immune response, and oxidative status of laying hens at peak production. Laying hens (23 wk-of-age, n = 225) were randomly allocated into 5 treatment groups (n = 9 hens/replicate) with 5 replicate groups each: 1) unchallenged control (UC), 2) pair-fed control (PF), 3) challenged control (CC), 4) challenged control top-dressed with 5,000 IU of 25-hydroxyvitamin D3 (VD) per kg of diet, and 5) challenged control top-dressed with 100 IU of DL-α-tocopherol (VE). At 25 wk-of-age, hens grouped in CC, VD, and VE were challenged with mixed Eimeria spp. to induce coccidiosis. VD or VE supplemented hens did not impact bird body weight; however, egg production increased by 10.36% and 13.77%, respectively (P < 0.0001). Furthermore, the gut health of the hens was improved with either VD or VE supplementation, as indicated by lowered gut permeability and intestinal lesion scores (P < 0.05). VE significantly reduced the heterophil count (P = 0.0490) alongside numerically increasing the peripheral CD4+ and CD8+ T cells and monocyte counts (P > 0.05). Both VD or VE increased the TAC at 14 DPI compared to UC (P<0.05). Preliminary findings suggest that dietary VD or VE supplementation has the potential to improve gut health, modulate the immune response, and increase egg production in coccidiosis-infected laying hens.

PECULIARITIES OF THE INFLUENCE OF TYLOZIN ON THE METABOLISM OF PROTEINS AND AMINO ACIDS IN CHICKEN

Over the last decade, poultry farming, both for meat and eggs, has been widely developed in our country. Poultry products are widely used in the diets of the population. In this problem, it is necessary to observe the careful application of antimicrobial drugs to productive animals, as they are used by humans and not to disturb the ecosystem and not cause the formation of resistant microflora. Taking into consideration that veterinary medicine should be more preventive than curative, the problems of poultry treatment are poorly described, it was decided that it is necessary to work with healthy organisms. Because the physiological reactivity of the body changes with pathologies even without medical interventions. Methods of using macrolides and other pharmacological agents in sick animals and poultry are described in the literature, but there are not enough works that would highlight the data on the effect of this agent on protein and amino acid metabolism in healthy chickens. In addition, it is known that metabolic processes in poultry take place with a fairly high intensity, and this is definitely reflected in the amount of doses of various drugs, and antibiotics in particular. Medicines in the bird's body, accordingly, are biotransformed more quickly and removed from the body faster with droppings and eggs, others accumulate in various organs and muscles. Therefore, it is important to know how the biosynthesis of the main proteins and the level of free amino acids changes under the action of the antimicrobial agent Tylozin on the days of administration and in the period after the administration of the antibiotic. The results of the research are informative. The work is devoted to the study of the influence of an antimicrobial drug from the pharmacological group of macrolides on the metabolism of amino acids and proteins in chickens in a comparative aspect. At the same time, egg production in laying hens aged 140-150 days was taken into account. The influence of different doses of Tylosin on the protein and amino acid composition of chickens during the period of use and after the end of drug administration was studied. It was established that changes in the metabolism of total protein, its fractions and amino acid nitrogen in the blood serum occur naturally, long-term, in different directions and, proportionally, depend on the dose of the drug. The effect of the drug was studied in minimum, average and maximum doses.

The Intensity of Lipid Peroxide Oxidation Processes and the System State of Antioxidant Protection of Broiler Chicken Due to the Action of the Synbiotic Preparation in Complex with the Disinfectant

Developing methods for increasing the immune reactivity and antioxidant potential of the bird's body during critical periods of growth is an urgent task today. The purpose of the research was to find out the influence of the synbiotic "Biomagn" in combination with the disinfectant "Diolide" on the intensity of the processes of peroxide oxidation of lipids and the activity of the system of antioxidant protection in the organism of chickens. The research was carried out on 2 groups of chickens, 100 in each, starting from 1 to 41 days of age: the control group was fed with standard compound feed (SCF); the chickens of the experimental group were fed with SCF, and the synbiotic preparation "Biomagn" based on 0.5 kg per ton of compound feed. The experimental group received a solution of the preparation "Diolide" with water. For conducting immunological research, blood was taken from chickens at different age periods: from 10-, 27-, 31-, and 41-day-old chickens. The use of the synbiotic preparation "Biomagn" in combination with the disinfectant "Diolide" in the chickens of the experimental group normalized the intensity of the processes of lipid peroxidation and oxidative modification of proteins in the poultry's organism - a decrease was established (p &amp;lt;0.05–0.001) in GPO content and TBK-active products and aldehyde derivatives oxidative modification of proteins in the blood compared to the control. The detected event was determined by increased activity of the enzyme link of the antioxidant protection system of the organism of chickens.

Influence of Hydroponic Feed With Phytobiotic Action on the Poultry Slaughter Parameters

The article describes the study of feeding birds by adding fenugreek plants, licorice root, amaranth grains to the feed ration of chickens, which have a phytobiotic effect and hydroponic grown grains of corn, barley, amaranth and fenugreek, which have high nutritional qualities and influence on the slaughter performance of birds in farms and private farms. The main indicators of the slaughter yield of the products of slaughter of young hens are analyzed: slaughter live weight, the mass of non-stranded carcass, the mass of half-gutted carcasses, the mass of gutted carcasses, and also the slaughter yield. Studies have established that the live weight of broilers of the experimental group before slaughter is higher by 13.19% (p≤0.001), an indicator of the control group. The differences are established due to the positive influence of chelating microelements on the biochemical processes in the bird's body, which in turn leads to the effective assimilation of the nutritional components of the diet, as well as the feed supplement, do not cause changes in the clinical state, pathological changes at macro- and microscopic levels in the body of broiler chickens.

Sistem Monitoring Pakan dan Air Minum Burung Peliharaan Pemakan Biji Berbasis Internet Of Things

Grain-eating songbirds are often kept as a hobby. These birds have beautiful feather colors and melodious voices. One of the obstacles to maintaining songbirds is that the owner needs more time. The owner is busy working and going out of town, which can cause the bird not to get adequate feed and water, and the owner is also unable to monitor the health condition of the bird. Based on this, a songbird feeding and monitoring system based on IoT was created to monitor the remaining food and drinks in the tank using NodeMCU ESP32 as a system control and data sender to the internet. The system can provide feed and drinking water for pet birds automatically and is connected via the internet to Blynk to send monitoring results. Based on monitoring results, the feed consumption of seed-eating songbirds is 4.74 grams daily, equivalent to 43.14% of the bird's body weight.

Effect of cuprum proteinate on blood parameters in broiler chickens

The data obtained during the scientific and economic experiment show that the replacement of copper sulfate with copper proteinate in broiler chickens, even in smaller doses, did not significantly affect hematological and biochemical blood parameters. Some increase in the total level of albumins and globulins, the activity of aspartate aminotransferase and alanine aminotransferase, and the content of calcium, phosphorus and copper in blood serum was noted. Introduction of cuprum proteinate to compound feed to broiler chickens of the third experimental group in doses of 13.9; 12.6 and 9.0 g/t (on average for 42 days – 12.5 g/t) contributed to a probable increase in total protein by 14.2 % (Р &lt; 0.05) on the 30th day of the experiment and by 12.3 % (Р &lt; 0.05) on the 42nd day of the experiment compared to the control group. At the same time, the level of albumins increased by 11.9 % (Р &lt; 0.05) and 15.8 % (Р &lt; 0.05), and globulins by 12.0 % (Р &lt; 0.05) and 10.7 %, respectively. This fact shows that reducing the dose of cuprum proteinate has a positive effect on protein synthesis, activation of albumin and globulin synthesis occurs, which reduces the load on the immune system of broiler chickens and has a positive effect on protein metabolism. On the 42nd day of the experiment, the calcium content in the blood of all groups increased, but in the experimental groups it was higher than the control indicator in the second group by 4.8 % and by 5.6 % in the third experimental group. Regarding the level of Phosphorus in the blood serum of experimental groups of broiler chickens, its amount increased to 1.85–1.96 mmol/l on the 42nd day. The content of cuprum in the blood of broiler chickens, which were fed cuprum proteinate as part of compound feed, was probably higher than the indicator of the control group. Chickens of the second experimental group, which were fed cuprum proteinate in quantities of 18.2; 16.8 and 12.0 g/t of compound feed exceeded their counterparts by 14.0–16.3 % (Р &lt; 0.05). Broiler chickens of the third experimental group, which were added to compound feed with cuprum proteinate in doses of 13.9, 12.6 and 30 g/t, prevailed on day 30 of the experiment by 18.8 % (Р &lt; 0.01), and on day 42 day by 18.9 % (Р &lt; 0.01). A higher level of Calcium and Phosphorus in the blood serum of experimental broiler chickens indicates an increase in the resistance of the bird to infections and better mineralization of bone tissue. Feeding of cuprum proteinate to broiler chickens makes it possible to reduce the dose of the trace element in compound feed, which reduces the burden on the bird's body and increases the biological availability of mineral compounds.

Illuminating the Mysteries of the Smallest Birds: Hummingbird Population Health, Disease Ecology, and Genomics.

Hummingbirds share biologically distinctive traits: sustained hovering flight, the smallest bird body size, and high metabolic rates fueled partially by nectar feeding that provides pollination to plant species. Being insectivorous and sometimes serving as prey to larger birds, they fulfill additional important ecological roles. Hummingbird species evolved and radiated into nearly every habitat in the Americas, with a core of species diversity in South America. Population declines of some of their species are increasing their risk of extinction. Threats to population health and genetic diversity are just beginning to be identified, including diseases and hazards caused by humans. We review the disciplines of population health, disease ecology, and genomics as they relate to hummingbirds. We appraise knowledge gaps, causes of morbidity and mortality including disease, and threats to population viability. Finally, we highlight areas of research need and provide ideas for future studies aimed at facilitating hummingbird conservation.

Bird color and taxonomic diversity are negatively related to human disturbance in urban parks

Abstract. Recently, studies have shown that highly urbanized areas are numerically dominated by birds with grey plumage, probably favoring camouflage with impervious grey surfaces. However, patterns of bird color diversity in urban green areas remain unexplored. In urban parks, sites surrounded by highly urbanized areas may be dominated by grey bird species, whereas urban parks with pedestrians that feed birds may favor commensal birds which also have grey plumage. Thus, we explore the relationship between environmental variables and bird taxonomic and color diversity in urban parks. Bird surveys were conducted twice by fixed points in urban parks of six cities in central Argentina. Bird color diversity was assessed by characterizing bird plumage coloration in different parts of the bird body and the presence of plumage sexual dimorphism, polymorphism, and iridescence. Then, color richness and color diversity (abundance-based) were calculated with species mean pairwise distance. Null models were used to quantify richness-corrected color diversity. Bird species richness and diversity increased with green-area size, and bird diversity decreased with increasing pedestrian traffic. Color richness decreased with increasing car traffic, whereas color diversity was positively related to green-area size and negatively related to car and pedestrian traffic. Richness-corrected color diversity related negatively to car and pedestrian traffic. The abundance of grey birds increased in parks near the urban centers and related positively to pedestrian and car traffic. The abundance of yellow birds increased in parks near rural areas or small cities. Color diversity increased with green-area size, but richness-corrected color diversity ceased to be related to area size. Therefore, the increase in color diversity with area size was mediated by increases in species richness. Color diversity was clustered in parks with the highest human disturbance, favoring the abundance of grey species which probably took advantage of food discarded by humans.

Relationship between Fat Status, Stage of Gonadal Maturity and Hormonal Variation of Turdus philomelos (C.L. Brehm, 1831) Wintering in Apulia during 2018-2020.

In this study, we aimed to evaluate the development of the fattening condition and the reproductive status of the song thrush from December to February. For this purpose, the chemical and fatty acid compositions of the pectoral muscle were analyzed in relation to the fattening state of the birds. Moreover, their reproductive activity was evaluated via the anatomical and pathological examination of tissues and through the assessment of sex steroid profiles. One hundred ninety-five thrushes captured by local hunters during the 2018-2019 and 2019-2020 hunting seasons in different provinces of the Apulia region in Italy were used. The first step was the measurement of bird body mass, and the amount of subcutaneous body fat was estimated visually. During post-mortem examinations, the pectoral muscle was excised and used for chemical and fatty acid analysis and a hormone assay, respectively. Moreover, ovaries and testicles were evaluated to determine the degree of maturation and thus the reproductive status of the birds. The results regarding fattening status and fatty acid profile confirmed that in January-February, thrushes change their diet, increasing their intake of oleic acid, likely to better cope with low temperatures and prepare for long-distance migration. In both male and female thrushes, the concentrations of sex hormones confirmed a phase of reproductive quiescence from December to February, which was also confirmed through histological examination of the gonads.

House sparrows are heavier on organic and integrated-production farms than on conventional farms

The negative impact of conventional farming on avian biodiversity has been increasingly documented. However, the potential effects of different farming practices on bird populations' health remain unclear. We aimed to investigate whether different farming practices (organic, integrated production, conventional/intensive) have differential effects on the body mass - as a proxy for body condition - and biomarkers of oxidative stress in house sparrows (Passer domesticus), a model species strongly associated with human activities and still abundant in Switzerland. We captured a total of 681 birds in 19 organic farms, 20 integrated-production farms (labelled “IP-Suisse”) and 18 conventional farms, and measured bird body mass and tarsus length, as well as levels of malondialdehydes (MDA, a marker of oxidative damage to lipids), superoxide dismutase (SOD, a first-line antioxidant enzyme) activity, and the ratio of oxidized over reduced glutathione (GSSG/GSH, a marker of cellular oxidative stress) in blood and sperm as biomarkers of the systemic oxidative stress endured by birds. Our findings show that house sparrows living in integrated and organic farms were 2.39 % and 4.33 % heavier than birds living in conventional farms, but we did not find any difference in tarsus length, suggesting that birds were of similar size. In addition, we did not find any difference in oxidative stress markers across farming practices. Our results highlight the potential benefits of sustainable farming practices, such as organic and integrated farming, for bird populations and emphasize the need for mitigating the negative impact of agricultural intensification on biodiversity through practices that may enhance the birds’ health and thus lead to positive population dynamics.

Selective logging intensity and time since logging drive tropical bird and dung beetle diversity: a case study from Amazonia

SummaryUnderstanding how selective logging affects biodiversity is crucial to planning cost-effective conservation strategies in tropical forests, yet there is limited understanding of its impacts on fauna functional diversity in the tropical Americas. We assessed how selective logging intensification and time since logging influence multiple metrics of fauna functional integrity in the Brazilian Amazon by collecting bird and dung beetle data within 48 logging management units that had experienced varying exploitation intensities between 1.5–2.0 and 5.0–6.0 years before the faunal surveys. We investigated assemblage responses and used functional attributes to assess changes in functional diversity, specialization, originality and species rarity. Using point counts and pitfall traps, we collected 5081 records of 182 bird species and 7892 dung beetles from 45 species. Logging intensification led to significant declines in most dung beetle responses and bird body mass, whereas time since logging was a key driver of dung beetle and bird functional and taxonomic diversity. Our study presents novel empirical evidence of how logging intensification effects vary across taxa, ecological metrics and time since logging, which is key to informing forest conservation and further investigating environmental degradation impacts on tropical biodiversity.

Morphostructure of the broiler liver when using adaptogens during growth and fattening

The effectiveness of modern poultry farming depends on many factors, the main of which is the food supply. In addition, preventive work, including vaccination and preventive measures that increase the resistance of chickens and their survival, is an important factor. The article presents comparative results on the use of various adaptogens. The aim of the study was to evaluate the macro-microstructure of the broiler liver when using adaptogens of various origins during growth and fattening. The objectives of the study were: to evaluate changes in the macro- and microstructure of the liver after fattening broilers, when feeding adaptogens of various origins, while comparing the preventive effectiveness of adaptogens in diseases of the digestive system, the effectiveness of fattening and the safety of livestock. For the first time, an organoleptic veterinary and sanitary assessment of the quality of giblets was carried out in comparison with microscopic changes after feeding various feed additives of domestic production with the properties of adaptogens. An adaptogen has been identified that maximally reduces the incidence of broilers in diseases of the digestive system and liver, the main organ responsible for metabolic processes in the body. In addition, an adaptogen has been identified that allows maximizing the efficiency of using the feed base for growing and fattening broilers. Such an adaptogen is an organic adaptogen – peat-sapropel concentrate. The effectiveness of the used domestic feed additives, which are adaptogens, depends on the composition of these additives, it is mainly determined by the mineral composition and biologically active additives included in their composition. The used feed additives have organoprotective properties, increase the nonspecific resistance of the bird's body, increase the efficiency of using the feed base, and increase the survival rate of chickens. Accordingly, they increase the efficiency of meat and poultry farming.

The effect of phytobiotic preparations on the digestibility of macronutrients by laying hens

Currently, intensive industrial use of poultry facilities and a large concentration of livestock negatively affect the bacterial background and, consequently, the microflora of the bird body. Due to the settlement of opportunistic and pathogenic microflora in the microbiocenosis of the chicken gastrointestinal tract, after 10-11 months of productivity, laying hens either weaken in egg production or in egg quality. The article describes the results of the absorption of calcium and phosphorus macronutrients by the body of laying hens when phytobiotics are introduced into the feed. According to the research results, it was determined that in birds receiving phytopreparations, the absorption of calcium and phosphorus increased by 10.13 and 10.31% compared with the control, and the content of these elements in the tibia increased by 2.30 and 1.54%, respectively, on average during the experiment. During the studies, the egg weight of the experimental chickens exceeded the control by 1.03-5.26%, while the shell strength was higher by 0.72-1.73%.

The oldest fossil bird-like footprints from the upper Triassic of southern Africa.

Footprint morphology reflects the anatomy of the trackmaker's foot and is direct evidence for the animal's behaviour. Consequently, fossil tracks can be used to infer ancient diversity, ethology, and evolutionary trends. This is particularly useful for deep-time intervals during which the early history of an animal group is reliant upon limited fossil skeletal material. Fossil tracks of early birds and theropods, the co-existing dinosaurian ancestors of birds, co-occur in the rock record since the Early Cretaceous. However, the evolutionary transition from dinosaur to bird and the timing of the birds' origin are still contested. Skeletal remains of the basal-most birds Aurornis, Anchiornis, Archaeopteryx and Xiaotingia are Middle to Late Jurassic, while tracks with tentative bird affinities, attributed to dinosaurs, are known from as early as the Late Triassic. Here, we present numerous, well-provenanced, Late Triassic and Early Jurassic tridactyl tracks from southern Africa, with demonstrable bird-like affinities, predating basal bird body fossils by c. 60 million years.

An upright life, the postural stability of birds: a tensegrity system.

Birds are so stable that they can rest and even sleep standing up. We propose that stable static balance is achieved by tensegrity. The rigid bones can be held together by tension in the tendons, allowing the system to stabilize under the action of gravity. We used the proportions of the bird's osteomuscular system to create a mathematical model. First, the extensor muscles and tendons of the leg are replaced by a single cable that follows the leg and is guided by joint pulleys. Analysis of the model shows that it can achieve balance. However, it does not match the biomechanical characteristics of the bird's body and is not stable. We then replaced the single cable with four cables, roughly corresponding to the extensor groups, and added a ligament loop at the knee. The model is then able to reach a stable equilibrium and the biomechanical characteristics are satisfied. Some of the anatomical features used in our model correspond to innovations unique to the avian lineage. We propose that tensegrity, which allows light and stable mechanical systems, is fundamental to the evolution of the avian body plan. It can also be used as an alternative model for bipedal robots.