Bacteria from the Amycolatopsis genus associated with a toxic bird secrete protective secondary metabolites.

Uropygial gland secretions of birds consist of host and bacteria derived compounds and play a major sanitary and feather-protective role. Here we report on our microbiome studies of the New Guinean toxic bird Pachycephala schlegelii and the isolation of a member of the Amycolatopsis genus from the uropygial gland secretions. Bioactivity studies in combination with co-cultures, MALDI imaging and HR-MS/MS-based network analyses unveil the basis of its activity against keratinolytic bacteria and fungal skin pathogens. We trace the protective antimicrobial activity of Amycolatopsis sp. PS_44_ISF1 to the production of rifamycin congeners, ciromicin A and of two yet unreported compound families. We perform NMR and HR-MS/MS studies to determine the relative structures of six members belonging to a yet unreported lipopeptide family of pachycephalamides and of one representative of the demiguisins, a new hexapeptide family. We then use a combination of phylogenomic, transcriptomic and knock-out studies to identify the underlying biosynthetic gene clusters responsible for the production of pachycephalamides and demiguisins. Our metabolomics data allow us to map molecular ion features of the identified metabolites in extracts of P. schlegelii feathers, verifying their presence in the ecological setting where they exert their presumed active role for hosts. Our study shows that members of the Actinomycetota may play a role in avian feather protection.

Avian-inspired embodied perception in biohybrid flapping-wing robotics.

Avian feather intricate adaptable architecture to wing deformations has catalyzed interest in feathered flapping-wing aircraft with high maneuverability, agility, and stealth. Yet, to mimic avian integrated somatic sensation within stringent weight constraints, remains challenging. Here, we propose an avian-inspired embodied perception approach for biohybrid flapping-wing robots. Our feather-piezoelectric mechanoreceptor leverages feather-based vibration structures and flexible piezoelectric materials to refine and augment mechanoreception via coupled oscillator interactions and robust microstructure adhesion. Utilizing convolutional neural networks with the grey wolf optimizer, we develop tactile perception of airflow velocity and wing flapping frequency proprioception. This method also senses pitch angle via airflow direction and detects wing morphology through feather collisions. Our low-weight, accurate perception of flapping-wing robot flight states is validated by motion capture. This investigation constructs a biomechanically integrated embodied perception system in flapping-wing robots, which holds significant promise in reflex-based control of complex flight maneuvers and natural bird flight surveillance.

The genetic basis of the kakapo structural color polymorphism suggests balancing selection by an extinct apex predator.

The information contained in population genomic data can tell us much about the past ecology and evolution of species. We leveraged detailed phenotypic and genomic data of nearly all living kakapo to understand the evolution of its feather color polymorphism. The kakapo is an endangered and culturally significant parrot endemic to Aotearoa New Zealand, and the green and olive feather colorations are present at similar frequencies in the population. The presence of such a neatly balanced color polymorphism is remarkable because the entire population currently numbers less than 250 birds, which means it has been exposed to severe genetic drift. We dissected the color phenotype, demonstrating that the two colors differ in their light reflectance patterns due to differential feather structure. We used quantitative genomics methods to identify two genetic variants whose epistatic interaction can fully explain the species' color phenotype. Our genomic forward simulations show that balancing selection might have been pivotal to establish the polymorphism in the ancestrally large population, and to maintain it during population declines that involved a severe bottleneck. We hypothesize that an extinct apex predator was the likely agent of balancing selection, making the color polymorphism in the kakapo a "ghost of selection past."

Metals and other trace elements in plasma and feathers of seabirds breeding in Svalbard.

We assessed the concentrations of metals and other trace elements in two of the most common seabird species breeding on Svalbard, the black-legged kittiwake (Rissa tridactyla) and the Brünnich's guillemot (Uria lomvia). Both of these species feed mostly on fish and crustaceans but have different foraging strategies, kittiwakes being surface feeders while guillemots are divers. We investigated the concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb), selenium (Se) and zinc (Zn) in the plasma and body feathers of black-legged kittiwakes (n = 17), as well as in the body feathers of Brünnich's guillemots (n = 13). Samples were collected from adult birds at two time points, one week apart during July 2017 in Kongsfjorden, Svalbard. Of the non-essential trace elements, As was found at the highest median concentration at both the first (56.23 ng/g ww) and second (39.99 ng/g ww) sampling timepoints in the kittiwake plasma. When separating for the sexes, as well as sampling time, males sampled at the first sampling time point had significantly higher concentrations of As (median at 0.087 ng/g versus 0.039 ng/g) and Se (median 0.26 ng/g versus 0.16 ng/g) compared to males sampled at the second time point. There was no significant difference in plasma concentrations between females at first and second sampling time points. Kittiwake feathers contained significantly higher concentrations of As, Cd and Hg than guillemot feathers, while guillemot feathers had significantly higher concentrations of Cu, Pb and Zn. However, of the non-essential elements in both kittiwake and guillemot feathers Hg was found with the highest median concentrations at 5160 and 1080 ng/g, respectively, thus in kittiwakes exceeding the level of 5000 ng/g associated with adverse effect (e.g., impaired reproduction). Levels of Hg and Se found in the kittiwake feathers were higher than previous studies on seabirds in the Arctic.

Investigation of Glandula Uropygialis in Different Avian Species Using Morphometric and Histological Methods.

The aim of this study was to identify the glandula uropygialis's macroanatomical and histological structure in male and female birds (stork, goose, eagle, pigeon, crow and sparrowhawk) that belong to different populations. A total of 58 specimens were used in the study. The study materials were delivered to our laboratory by nature conservation and national parks, and no animals were euthanised for this study. The longitudinal and transversal lengths, dorsoventral heights and feather length of the glandula uropygialis and papilla uropygialis were measured with a digital calliper. Haematoxylin-eosin and Masson trichrome staining were performed for histological examinations. The shape of the glandula uropygialis was found to be pear-shaped in pigeons and sparrowhawks, heart-shaped in geese, kidney-shaped in eagles and oval-fascule-shaped in storks. In the crow, the shape of the glandula uropygialis was different from the other species in that it was located dorso-caudally. Histomorphological examination of the glands of these species revealed that the gland generally consisted of two lobes, right and left, surrounded by connective tissue from the outside. The parenchyma of these lobes consisted of tubulo-alveolar secretory glands with a radial arrangement from the periphery to the centre. The glands within the lobes differed from the periphery to the centre and although the general histomorphological appearance was similar between bird species, some differences were observed between species. Similar stromal structure was observed in all bird species evaluated in the study. However, the reticular connective tissue forming the roof of the gland was found to be more developed in pigeons, especially in Masson's trichroma staining. The degenerative layer in the glands was more prominent in the eagle, followed by the goose and crow. Although a common general histological structure was observed among bird species, simple histomorphological differences were found between these formations, but no differences were found between the sexes. The results obtained will be compared with the findings of the aves class and will provide a data source for this special gland specific to birds. It is thought that the results obtained may help to determine the functional properties of the gland and contribute to the science of ornithology.

Characterization of a Bacterial Keratinolytic Protease for Effective Degradation of Chicken Feather Waste into Feather Protein Hydrolysates.

BACKGROUND: Chicken feathers contribute to large quantities of keratinaceous wastes that pose serious environmental problems and must be catered to properly. Chicken feathers are also a potential source of vital proteins, peptides, and amino acids, which could be used as low-cost animal feeds. Therefore, there has been increasing interest in keratinase-producing microbes for reprocessing and using keratinous biomaterials. METHODS: Among the five isolated keratinolytic microorganisms, one microbe, Bacillus XT 01, produced a significant amount of enzyme activity, which was partially characterized. The potential of this protease-producing microbe was investigated for converting feather keratin waste to valuable protein hydrolysate. RESULTS: Maximum keratinase production was observed after 5 days of incubating Bacillus XT 01 at an optimum temperature of 45 °C and pH 8.5. Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) and zymogram of ammonium sulfate precipitated culture supernatant showed the presence of several proteolytic enzymes with molecular weights between 30 and 60 kDa. The Bacillus strain caused almost complete feather degradation (98%) after 7 days of incubation at 45 °C in a shake culture medium. Antioxidant and reducing activities of the feather protein hydrolysate (FPH) elevated with increased cultivation time. Investigation of the effect of feather protein hydrolysate on plants indicated improved plant growth regarding the agronomic parameters, such as plant height, number of trifoliate leaves, number of pods, pod length, number of seeds per pod, and root length, which increased by 30.84%, 49.32%, 70.90%, 53.27%, 60.03%, and 54.71%, respectively. CONCLUSIONS: The prospective of Bacillus XT 01 for degrading feather waste keratin to highly valued hydrolyzed feather protein offers effectiveness in the poultry industry and ultimately decreases environmental pollution hazards.

A sex chromosome polymorphism maintains divergent plumage phenotypes between extensively hybridizing yellowhammers (Emberiza citrinella) and pine buntings (E. leucocephalos).

Under allopatric speciation, populations of a species become isolated by a geographic barrier and develop reproductive isolation through genetic differentiation. When populations meet in secondary contact, the strength of evolved reproductive barriers determines the extent of hybridization and whether the populations will continue to diverge or merge together. The yellowhammer (Emberiza citrinella) and pine bunting (E. leucocephalos) are avian sister species that diverged in allopatry on either side of Eurasia during the Pleistocene glaciations. Though they differ greatly in plumage and form distinct genetic clusters in allopatry, these taxa show negligible mitochondrial DNA differentiation and hybridize extensively where they overlap in central Siberia, lending uncertainty to the state of reproductive isolation in the system. To assess the strength of reproductive barriers between taxa, we examined genomic differentiation across the system. We found that extensive admixture has occurred in sympatry, indicating that reproductive barriers between taxa are weak. We also identified a putative Z chromosome inversion region that underlies plumage variation in the system, with the 'pine bunting' haplotype showing dominance over the 'yellowhammer' haplotype. Our results suggest that yellowhammers and pine buntings are currently at a crossroads and that evolutionary forces may push this system towards either continued differentiation or population merging. However, even if these taxa merge, recombination suppression between putative chromosome Z inversion haplotypes may maintain divergent plumage phenotypes within the system. In this way, our findings highlight the important role hybridization plays in increasing the genetic and phenotypic variation as well as the evolvability of a system.

New Bacillus paralicheniformis strain with high proteolytic and keratinolytic activity.

Bacillus paralicheniformis T7, which exhibits high proteolytic and keratinolytic activities, was isolated from soil in Kazakhstan. Its secreted proteases were thermostable and alkaline, demonstrating maximum activity at 70 °C and pH 9.0. The proteases and keratinases of this strain were sensitive to Ni2+, Co2+, Mn2+, and Cd2+, with Cu2+, Co2+ and Cd2+ negatively affecting keratinolytic activity, and Fe3+ ions have a strong inhibitory effect on proteolytic and keratinolytic activity. Seven proteases were identified in the enzymatic extract of B. paralicheniformis T7: four from the serine peptidase family and three from the metallopeptidase family. The proteases hydrolyzed 1 mg of casein, hemoglobin, gelatin, ovalbumin, bovine serum albumin, or keratin within 15 s to 30 min. The high keratinolytic activity of this strain was confirmed through the degradation of chicken feathers, horns, hooves, wool, and cattle hide. Chicken feathers were hydrolyzed in 4 days, and the degrees of hydrolysis for cattle hide, wool, hoof, and horn after 7 days of cultivation were 97.2, 34.5, 29.6, and 3.6%, respectively. During submerged fermentation with feather medium in a laboratory bioreactor, the strain secreted enzymes with 249.20 ± 7.88 U/mL protease activity after 24 h. Thus, B. paralicheniformis T7 can be used to produce proteolytic and keratinolytic enzymes for application in processing proteinaceous raw materials and keratinous animal waste.

Influence of migration range and foraging ecology on mercury accumulation in Southern Ocean penguins.

In order to evaluate mercury (Hg) accumulation patterns in Southern Ocean penguins, we measured Hg concentrations and carbon (δ13C) and nitrogen (δ15N) stable isotope ratios in body feathers of adult Adélie (Pygoscelis adeliae), gentoo (Pygoscelis papua), and chinstrap (Pygoscelis antarctica) penguins living near Anvers Island, West Antarctic Peninsula (WAP) collected in the 2010/2011 austral summer. With these and data from Pygoscelis and other penguin genera (Eudyptes and Aptenodytes) throughout the Southern Ocean, we modelled Hg variation using δ13C and δ15N values. Mean concentrations of Hg in feathers of Adélie (0.09 ± 0.05 µg g-1) and gentoo (0.16 ± 0.08 µg g-1) penguins from Anvers Island were among the lowest ever reported for the Southern Ocean. However, Hg concentrations in chinstrap penguins (0.80 ± 0.20 µg g-1), which undertake relatively broad longitudinal winter migrations north of expanding sea ice, were significantly higher (P < 0.001) than those in gentoo or Adélie penguins. δ13C and δ15N values for feathers from all three Anvers Island populations were also the lowest among those previously reported for Southern Ocean penguins foraging within Antarctic and subantarctic waters. These observations, along with size distributions of WAP krill, suggest foraging during non-breeding seasons as a primary contributor to higher Hg accumulation in chinstraps relative to other sympatric Pygoscelis along the WAP. δ13C values for all Southern Ocean penguin populations, alone best explained feather Hg concentrations among possible generalized linear models (GLMs) for populations grouped by either breeding site (AICc = 36.9, wi = 0.0590) or Antarctic Frontal Zone (AICc = 36.9, wi = 0.0537). Although Hg feather concentrations can vary locally by species, there was an insignificant species-level effect (wi < 0.001) across the full latitudinal range examined. Therefore, feeding ecology at breeding locations, as tracked by δ13C, control Hg accumulation in penguin populations across the Southern Ocean.

Design, development and characterization of a chimeric protein with disulfide reductase and protease domain showing keratinase activity.

Keratin is one of the major components of solid waste, and the degradation products have extensive applications in various commercial industries. Due to the complexity of the structure of keratin, especially the disulfide bonds between keratin polypeptides, keratinolytic activity is efficient with a mixture of proteins with proteases, peptidases, and oxidoreductase activity. The present work aimed to create an engineered chimeric protein with a disulfide reductase domain and a protease domain connected with a flexible linker. The structure, stability, and substrate interaction were analyzed using the protein modeling tools and codon-optimized synthetic gene cloned, expressed, and purified using Ni2+-NTA chromatography. The keratinolytic activity of the protein was at its maximum at 70 °C. The suitable pH for the enzyme activity was pH 8. While Ni2+, Mg2+, and Na+ inhibited the keratinolytic activity, Cu2+, Ca2+, and Mn2+ enhanced it significantly. Biochemical characterization of the protease domain indicated significant keratinolytic activity at 70 °C at pH 10.0 but was less efficient than the chimeric protein. Experiments using feathers as the substrate showed a clear degradation pattern in the SEM analysis. The samples collected from the degradation experiments indicated the release of proteins (2-fold) and amino acids (8.4-fold) in a time-dependent manner. Thus, the protease with an added disulfide reductase domain showed excellent keratin degradation activity and has the potential to be utilized in the commercial industries.

Impact of a 15% spirulina (Limnospira platensis) dietary inclusion on productive performance and meat traits in naked neck and fully feathered slow-growing broiler strains.

Global population is rising, leading to higher demand for meat and concerns on environmental and economic impacts of conventional feedstuffs that corn and soybean meal have. Recently there has been a shift towards more sustainable feedstuffs such as Spirulina (Limnospira platensis) due to its nutritional value and ability to be produced locally. Consumer awareness prompts shifts towards free range poultry production but presents environmental challenges due to climate change. The naked neck (Na) gene, which reduces feather coverage, and enhances growth under adverse conditions offers a possible solution for improved welfare and efficiency. This study aims to investigate the impact of a diet with 15% Spirulina inclusion on growth performance, carcass traits, and meat quality of two slow-growth broiler strains: naked neck (NN) and fully feathered (FF). Forty, 1-day-old male broilers, 20 per strain, were randomly assigned to either a control or a diet containing 15% Spirulina, housed individually in cages and fed ad libitum for 84 d. Growth, carcass, and meat traits were evaluated. Results indicated that animals fed a control diet generally outperformed those fed a Spirulina diet in final body weight (BW), average daily gain (ADG), feed intake (FI), and feed conversion rate (FCR) (P < 0.001). Additionally, Spirulina incorporation led to an increase in the length of the gastrointestinal tract and digesta viscosity in the duodenum plus jejunum (P < 0.05). Although there were no significant differences in breast muscle yield between dietary groups, SP-fed broilers had higher yellowness (*b) values in meat (P < 0.05). Except for the decrease in water holding capacity (WHC) observed in the NN group animals (P < 0.05), there were no significant differences between the strains for the remaining meat quality traits (P > 0.05). The 15% Spirulina inclusion increased the concentrations of n-3 polyunsaturated fatty acids (PUFA) (P < 0.0001) in breast meat and decreased (P < 0.0001) nutritional ratios. Overall, under thermoneutral conditions, animals from the NN strain showed negative effects on growth parameters. Spirulina inclusion improved certain aspects of breast meat quality, particularly fatty acid profiles.

A selection breeding pattern for sexually dimorphic breast plumage color in Guangxi Yao chickens.

The breast plumage color of Guangxi Yao chickens shows obvious sexual dimorphism, with roosters showing black and black with red, and hens displaying partridge and red. Black plumage in roosters is considered a sign of quality, necessitating the purification of plumage color. Here, we developed an effective method based on genetic variations within MC1R and plumage characteristics. We clarified the distribution of 5 single nucleotide polymorphisms (SNP) and 3 haplotypes (H1, H2, and H3) of MC1R gene, and revealed potential associations between haplotype H1 and black breast plumage in the F2 resource population derived from a backcross between Guangxi Yao and Yellow chickens. Subsequently, using H1/H1 diplotype roosters and hens to construct families (n = 1,244) notably increased the proportion of offspring with black plumage. Further analysis suggested that red plumage in hens may be the putative phenotype of black plumage in roosters, driven by haplotype H1 of the MC1R gene, as verified by genotype and phenotype analysis. As expected, we found that almost all male offspring of hens with red breast plumage showed black plumage. In short, we established a selection pattern based on the combination of black-plumage roosters and red-plumage hens can significantly purify the sexually dimorphic plumage color and improve the efficiency of breeding programs in Guangxi Yao chickens. Our findings provide a novel technical framework to accelerate the breeding process for plumage trait in poultry.

Genome-wide association study reveals 2 copy number variations associated with the variation of plumage color in the white duck hybrid population.

Plumage color is an intuitive external poultry characteristic with rich manifestations and complex genetic mechanisms. In our previous study, we observed that there were more dark variations in plumage color in the F2 population derived from the hybridization of 2 white duck varieties. Therefore, based on the statistics of plumage color of 308 F2 populations, we further used the resequencing data of these individuals to detect copy number variations (CNVs) in the whole genome and conducted genome-wide association studies (GWAS) to determine the genetic basis related to plumage color traits. The CNV detection revealed 9,337 CNVs, with an average length of 15,950 bp and a total length of 142.02 MB, accounting for approximately 12.91% of the reference genome. The CNV distribution on the chromosomes was relatively uniform, and the number of CNVs on each chromosome positively correlated with the length of the chromosome. In the pure black plumage group, 2,101 CNVs were only identified, and 1,714 were specifically identified in the pure white plumage group. Ten CNVs were randomly selected for validation using quantitative real-time PCR, and 9 CNVs had the same CNV types as predicted, with an accuracy of 90%. Based on GWAS, we identified 2 CNVs potentially associated with plumage color variations, with the associated CNV regions covering 9 genes. Enrichment analysis of these 9 candidate genes showed significant enrichment of 3 pathways (ribosome biogenesis in eukaryotes, RNA transport, and protein export) and 17 gene ontology terms. Among these, VWA5A can downregulate MITF by binding to the regulatory factors SOX10. The occurrence of CNV may indirectly contribute to duck plumage color variation by affecting the regulatory factors of the switch gene MITF in the melanogenesis pathway. These findings have improved the understanding of the genetic basis of duck plumage color variation and have been beneficial for developing and using plumage color traits in subsequent poultry breeding.

New findings on the genetic basis of feathered legs in chickens: association of CUBN gene mutations with feathered-leg phenotype.

Chickens are the most thoroughly domesticated vertebrate species, and after long-continued natural and artificial selection, they now show rich phenotypic diversity. In particular, feathered legs present in domestic chickens are a characteristic that is carefully selected by advanced breeders. Previous studies have identified the key mutations responsible for feathered legs on chromosomes 13 and 15; however, not all chickens can be easily distinguished based on these two markers. In this study, whole-genome resequencing of 29 Bamaxiaogu chickens (BXCs) yielded 12,201,978 valid single-nucleotide polymorphisms (SNPs) and 2,792,426 valid insertions and deletions (InDels). Population structure analysis based on SNPs revealed that the test samples came from the same natural population. Based on these findings, we used an SNP- and InDel-based genome-wide association study (GWAS) to investigate the genetic basis of feathered legs in chickens. GWAS results revealed that 2 SNPs located in the introns of cubilin (CUBN; SNP1, chr2:19885382T>A) and recombinant Ras suppressor protein 1 (RSU1) genes (SNP2, chr2:20002551G>A), as well as an InDel (InDel1, chr2:19884383TG>T) on CUBN, were all significantly associated with the presence of feathered legs. Diagnostic testing demonstrated that SNP1 effectively differentiated between chickens with feathered legs and those with clean legs (leg without feathers) within the BXC population and may thus be considered an effective marker of feathered legs in BXC. In contrast, other loci did not show the same discriminatory power. This study not only presents a new variant of feathered legs but also provides valuable novel insights into the underlying mechanisms of variation in the feathered-legs trait among chickens.

Birds display remarkable diversity in the distribution and morphology of scales and feathers on their legs. However, the genetic and developmental mechanisms controlling this diversity are complex and remain largely unknown. Feathered legs are a phenotypic trait of domestic chickens, which have undergone intense selection. Previous studies have shown that the 2 major loci controlling feathered legs are located on chromosomes 13 and 15. In this study, we used a single-nucleotide polymorphism- and insertion and deletion-based genome-wide association study to elucidate the genetic basis of feathered legs in chickens. Additionally, we report a novel mutation in the cubilin gene associated with feathered legs in Bamaxiaogu chickens.

Inorganic Characterization of Feeds Based on Processed Animal Protein Feeds.

The potential of utilizing inorganic constituents in processed animal proteins (PAPs) for species identification in animal feeds was investigated, with the aim of using these constituents to ensure the quality and authenticity of the products. This study aimed to quantify the inorganic content across various PAP species and assess whether inorganic analysis could effectively differentiate between PAP species, ultimately aiding in the identification of PAP fractions in animal feeds. Four types of PAPs, namely bovine, swine, poultry, and fish-based, were analyzed and compared to others made up of feathers of vegetal-based feed. Also, three insect-based PAPs (Cricket, Silkworm, Flour Moth) were considered in this study to evaluate the differences in terms of the nutrients present in this type of feed. Ionic chromatography (IC) was used to reveal the concentrations of NO3-, NO2, Cl-, and SO42-, and inductively coupled plasma optical emission spectroscopy (ICP-OES) to detect Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Si, Sr, Ti, and Zn. The application of multivariate chemometric techniques to the experimental results allowed us to determine the identification capability of the inorganic composition to identify correlations among the variables and to reveal similarities and differences among the different species. The results show the possibility of using this component for discriminating between different PAPS; in particular, fish PAPs are high in Cd, Sr, Na, and Mg content; swine PAPs have lower metal content due to high fat; feathers and vegetal feed have similar Al, Si, and Ni, but feathers are higher in Fe and Zn; and insect PATs have nutrient levels comparable to PAPs of other origins but are very high in Zn, Cu, and K.

IN VITRO LIFE HISTORY OF LIPEURUS TROPICALIS (INSECTA: PHTHIRAPTERA: ISOCHNOCERA) INFESTING GALLUS GALLUS DOMESTICUS (AVES: PHASIANIDAE).

The ischnoceran louse, Lipeurus tropicalis, which normally infests Gallus gallus domesticus, was subjected to in vitro study (35 ± 1 C, 75-82% relative humidity, on a feather diet). The life table was computed, and its intrinsic rate of natural increase (r) was calculated using the data from in vitro experiments. The value of the intrinsic rate of natural growth (r) is 0.032. Given this rate, a population of L. tropicalis should double after 21.66 days, indicating that it is a moderately paced breeder.

Diet and between-tissue isotope comparisons reveal different foraging strategies for age and sex of a Saffron Finch (Sicalis flaveola Linnaeus, 1766) population.

Measuring stable isotopes in different tissues offers the opportunity to provide insight into the foraging ecology of a species. This study aimed to assess how diet varies between yellow females, yellow males, and dull individuals of a Saffron Finch (Sicalis flaveola) population. We measured δ13C and δ15N in blood over a year, and in different feathers, to estimate seasonal consistency of resource use for each category. We conducted this study in a private farm in the Central Brazilian savannas. We sampled 195 individuals in seven field samplings between January 2017 and March 2018. The mean blood δ13C values were similar among yellow females, yellow males and dull individuals, indicating that this population of Saffron Finch predominantly accesses similar resources throughout the year, with a predominant C4 signal. Although Saffron Finch is considered a granivorous species, the mean δ15N values found indicate that both adults and juveniles also incorporate in their tissues some invertebrate. The slight isotope-tissue difference between feathers and blood is similar to the reported in previous studies and may reflect tissue-to-tissue discrimination. The isotopic space of yellow males was greater than that of yellow females and dull individuals, indicating greater dietary diversity due to greater inter-individual variation in diet. In Saffron Finch, which delays plumage maturation, competition-driven partitioning of food resources seems essential in driving carotenoid-based plumage coloration between age classes and sexes.

Effect of different LED light colors on welfare, performance, some behavioral patterns, and blood parameters of Muscovy ducks.

BACKGROUND: The current study was conducted to assess the impact of different LED light colors on welfare indicators in Muscovy ducks. These welfare parameters encompassed growth performance, specific behaviors, tonic immobility (TI), feather score, haematological, and serum biochemical parameters. Eighty-four healthy unsexed Muscovy ducklings aged two weeks were randomly assigned to four groups (3replicates/group; each replicate contains 7 birds) based on different LED light colors. The first group was raised under white light, the second under red light, the third under blue light, and the fourth under yellow light. To assess the impact of various LED light colors on welfare, growth performance indicators (body weight, body weight gain, feed intake, and feed conversion ratio) were measured. Behavioral patterns including feeding, drinking, standing, walking, sitting, feather pecking, and other activities were recorded. Tonic immobility test (TI) and feather condition scoring were conducted at 3, 6, and 10 weeks of age. At the end of the study blood samples were collected for hematological and serum biochemical analyses. RESULTS: The results revealed that using blue, yellow, and red colors had no adverse effect on the final body weight of the ducks (P > 0.05). Unlike to red light, blue light significantly reduced feather pecking, TI time and cortisol concentrations and improved the feather condition score (P ≤ 0.05). CONCLUSIONS: The current findings suggest that the application of blue light effectively improves welfare indices and has no detrimental impact on the growth performance of Muscovy ducks thereby positively contributing to their welfare.

Size differences among canaries, goldfinches and allies may explain correlated evolution of song and colour.

Sexual signals such as colour ornamentation and birdsong evolve independently of each other in some clades, and in others they evolve positively or negatively correlated. We rarely know why correlated evolution does or does not occur. Here, we show positively correlated evolution between plumage colour and song motor performance among canaries, goldfinches and allies, associated with species differences in body size. When controlling for body size, the pattern of correlated evolution between song performance and colour disappeared. Syllable diversity was not as strongly associated with size, and did not evolve in a correlated manner with colour. We argue that correlated evolution between song and colour was mediated by large size limiting song motor performance, likely due to constraints on the speed of moving heavier bills, and by larger species having less saturated plumage colour, possibly due to life-history traits of larger birds (e.g. longevity, stable pairs) contributing to weaker sexual selection. Results are consistent with the hypothesis that correlated evolution between sexual signals is influenced by how, in a clade, selective pressures and constraints affecting each type of signal happen to be co-distributed across species. Such contingency helps explain the diversity in clade-specific patterns of correlated evolution between sexual signals.

Feather mercury content of grey-faced petrels (Pterodroma gouldi): Relationships with age, breeding success, and foraging behaviour, in known age individuals.

Seabirds have been touted as excellent bioindicators of mercury pollution. We utilised grey-faced petrel (Pterodroma gouldi) feathers to assess interannual differences in total mercury (THg) concentrations in adults (2020-2021) and chicks (2019-2021) breeding in the Auckland region of New Zealand. For adults, we also correlated feather THg with bird age (3-37+ years) and breeding outcome (i.e., Non breeder, Egg failed, Chick reared) recorded for that season i.e., 2020 and 2021. Interannual differences in chick feather THg were matched with bulk stable isotopes (δ13C, δ15N) to map the influence of adult foraging behaviour on chick feather THg values. Adult feather THg levels were similar across the years investigated i.e., mean ± S.D. 38.2 ± 12.8 (2020), and 39.5 ± 14.7 (2021) ug g-1 (some of the highest THg values recorded for seabirds). A slight, but significant decrease in THg accumulation was evident as age increased but feather THg had no significant influence on breeding outcome. Interannual differences in chick feather THg concentrations were 7.78 ± 1.6 (2019), 4.23 ± 1.45 (2020) and 6.97 ± 4.41 (2021) µg g-1, (p < 0.01); and correlated with a significantly lower δ13C value i.e., -17.2 ± 0.4 ‰ (2019), -17.8 ± 0.3 ‰ (2020) and -17.6 ± 0.2 ‰ (2021). This suggests that the lower feather THg values in 2020 chicks resulted from more oceanic, rather than shelf-edge, prey being consumed by chicks that year. Values of δ15N in chick feathers remained consistent among years i.e., 15.2 ± 1.2 ‰ (2019), 15.2 ± 0.2 ‰ (2020) and 15.3 ‰ (± 0.4). Due to these interannual differences, we recommend using grey-faced petrel chicks to monitor Hg pollution over adults. Chicks are also subject to cultural harvests by Maori communities, offering partnership opportunities to generate mutually beneficial information streams for Maori communities and scientists alike.