Academic literature on the topic 'Birds Birds Feathers'

Using light microscopy, a method has been developed for the identification of feathers and feather fragments collected after collisions between birds and aircraft. Characters of the downy barbules of feathers are described for 22 orders of birds. The use of a key in combination with the macroscopic method of comparing feathers with bird skins in a museum collection results in identification to order or family level in 97% of the analysed bird strikes. Application of the method to other fields of biological research including taxonomy is discussed.

AbstractThe current study was designed to determine the concentrations of toxic metals (Ni, Pb and Cr) in feathers of birds collected from four regions of NE Pakistan. Feather samples of birds (House Crow, Common Myna and House Sparrow) were collected from different areas. Atomic absorption spectrophotometer was used to determine the concentration of metals in feathers. Analysis of the data revealed that concentrations of Pb and Cr were significantly different (p < 0.05) among bird species, whereas no difference (p > 0.05) was detected among bird species (house crow, common myna and house sparrow) for Ni. A significant difference was found for the concentration of Pb and Ni in all the four studied regions. Whereas, non-significant difference was found in all the studied regions for the concentrating of Cr. It was revealed that there is significant rising concentration of metals (Pb, Cr) in feathers of birds in Azad Kashmir.

Dinosaur fossils possessing integumentary appendages of various morphologies, interpreted as feathers, have greatly enhanced our understanding of the evolutionary link between birds and dinosaurs, as well as the origins of feathers and avian flight. In extant birds, the unique expression and amino acid composition of proteins in mature feathers have been shown to determine their biomechanical properties, such as hardness, resilience, and plasticity. Here, we provide molecular and ultrastructural evidence that the pennaceous feathers of the Jurassic nonavian dinosaur Anchiornis were composed of both feather β-keratins and α-keratins. This is significant, because mature feathers in extant birds are dominated by β-keratins, particularly in the barbs and barbules forming the vane. We confirm here that feathers were modified at both molecular and morphological levels to obtain the biomechanical properties for flight during the dinosaur–bird transition, and we show that the patterns and timing of adaptive change at the molecular level can be directly addressed in exceptionally preserved fossils in deep time.

A diverse array of birds apparently make mechanical sounds (called sonations) with their feathers. Few studies have established that these sounds are non-vocal, and the mechanics of how these sounds are produced remains poorly studied. The loud, high-frequency chirp emitted by a male Anna's hummingbird ( Calypte anna ) during his display dive is a debated example. Production of the sound was originally attributed to the tail, but a more recent study argued that the sound is vocal. Here, we use high-speed video of diving birds, experimental manipulations on wild birds and laboratory experiments on individual feathers to show that the dive sound is made by tail feathers. High-speed video shows that fluttering of the trailing vane of the outermost tail feathers produces the sound. The mechanism is not a whistle, and we propose a flag model to explain the feather's fluttering and accompanying sound. The flag hypothesis predicts that subtle changes in feather shape will tune the frequency of sound produced by feathers. Many kinds of birds are reported to create aerodynamic sounds with their wings or tail, and this model may explain a wide diversity of non-vocal sounds produced by birds.

Feathers serve a diversity of functions in birds and their continuous use and exposure to the environment requires a scheduled moult to maintain their full functionality. As feathers represent about 25% of a bird’s protein content, moult is expected to impose substantial energy and nutrient demands, but perhaps not to the extent reported. Energy conversion efficiencies for feather formation are among the lowest for any biological structure examined, but this assumes that increases in maintenance energy requirements (minimum resting metabolic rate (RMRmin)) during moult are predominately due to feather synthetic costs. We tested this assumption by comparing the RMRmin and protein turnover rates of House Sparrows (Passer domesticus (Linnaeus, 1758)) during peak moult and in a non-moulting cohort before and 12 days after having a similar amount of feathers plucked. Replacement of plucked feathers had no effect on metabolic rate, whereas RMRmin was 28% higher in moulting than in non-moulting House Sparrows. Protein turnover rates were lowest in non-moulting birds, but rate differences between non-moulting and moulting birds were threefold higher than those between non-moulting and plucked House Sparrows. Thus, the energy inefficiencies reported for feather replacement are mainly due to costs associated with coincident processes rather than being a direct cost of feather synthesis per se.

Variable feather overlap enables birds to morph their wings, unlike aircraft. They accomplish this feat by means of elastic compliance of connective tissue, which passively redistributes the overlapping flight feathers when the skeleton moves to morph the wing planform. Distinctive microstructures form “directional Velcro,” such that when adjacent feathers slide apart during extension, thousands of lobate cilia on the underlapping feathers lock probabilistically with hooked rami of overlapping feathers to prevent gaps. These structures unlock automatically during flexion. Using a feathered biohybrid aerial robot, we demonstrate how both passive mechanisms make morphing wings robust to turbulence. We found that the hooked microstructures fasten feathers across bird species except silent fliers, whose feathers also lack the associated Velcro-like noise. These findings could inspire innovative directional fasteners and morphing aircraft.

Feathers are complex integumentary appendages of birds and some other theropod dinosaurs. They are frequently coloured and function in camouflage and display. Previous investigations have concluded that fossil feathers are preserved as carbonized traces composed of feather-degrading bacteria. Here, an investigation of a colour-banded feather from the Lower Cretaceous Crato Formation of Brazil revealed that the dark bands are preserved as elongate, oblate carbonaceous bodies 1–2 μm long, whereas the light bands retain only relief traces on the rock matrix. Energy dispersive X-ray analysis showed that the dark bands preserve a substantial amount of carbon, whereas the light bands show no carbon residue. Comparison of these oblate fossil bodies with the structure of black feathers from a living bird indicates that they are the eumelanin-containing melanosomes. We conclude that most fossil feathers are preserved as melanosomes, and that the distribution of these structures in fossil feathers can preserve the colour pattern in the original feather. The discovery of preserved melanosomes opens up the possibility of interpreting the colour of extinct birds and other dinosaurs.

The geometry of feather barbs (barb length and barb angle) determines feather vane asymmetry and vane rigidity, which are both critical to a feather's aerodynamic performance. Here, we describe the relationship between barb geometry and aerodynamic function across the evolutionary history of asymmetrical flight feathers, from Mesozoic taxa outside of modern avian diversity ( Microraptor , Archaeopteryx , Sapeornis , Confuciusornis and the enantiornithine Eopengornis ) to an extensive sample of modern birds. Contrary to previous assumptions, we find that barb angle is not related to vane-width asymmetry; instead barb angle varies with vane function, whereas barb length variation determines vane asymmetry. We demonstrate that barb geometry significantly differs among functionally distinct portions of flight feather vanes, and that cutting-edge leading vanes occupy a distinct region of morphospace characterized by small barb angles. This cutting-edge vane morphology is ubiquitous across a phylogenetically and functionally diverse sample of modern birds and Mesozoic stem birds, revealing a fundamental aerodynamic adaptation that has persisted from the Late Jurassic. However, in Mesozoic taxa stemward of Ornithurae and Enantiornithes, trailing vane barb geometry is distinctly different from that of modern birds. In both modern birds and enantiornithines, trailing vanes have larger barb angles than in comparatively stemward taxa like Archaeopteryx , which exhibit small trailing vane barb angles. This discovery reveals a previously unrecognized evolutionary transition in flight feather morphology, which has important implications for the flight capacity of early feathered theropods such as Archaeopteryx and Microraptor . Our findings suggest that the fully modern avian flight feather, and possibly a modern capacity for powered flight, evolved crownward of Confuciusornis , long after the origin of asymmetrical flight feathers, and much later than previously recognized.

Birds in the cormorant (Phalacrocoracidae) family dive tens of metres into water to prey on fish while entraining a thin layer of air (a plastron film) within the microstructures of their feathers. In addition, many species within the family spread their wings for long periods of time upon emerging from water. To investigate whether wetting and wing-spreading are related to feather structure, microscopy and photographic studies have previously been used to extract structural parameters for barbs and barbules. In this work, we describe a systematic methodology to characterize the quasi-hierarchical topography of bird feathers that is based on contact angle measurements using a set of polar and non-polar probing liquids. Contact angle measurements on dip-coated feathers of six aquatic bird species (including three from the Phalacrocoracidae family) are used to extract two distinguishing structural parameters, a dimensionless spacing ratio of the barbule ( D *) and a characteristic length scale corresponding to the spacing of defect sites. The dimensionless spacing parameter can be used in conjunction with a model for the surface topography to enable us to predict a priori the apparent contact angles of water droplets on feathers as well as the water breakthrough pressure required for the disruption of the plastron on the feather barbules. The predicted values of breakthrough depths in water (1–4 m) are towards the lower end of typical diving depths for the aquatic bird species examined here, and therefore a representative feather is expected to be fully wetted in a typical deep dive. However, thermodynamic surface energy analysis based on a simple one-dimensional cylindrical model of the feathers using parameters extracted from the goniometric analysis reveals that for water droplets on feathers of all six species under consideration, the non-wetting ‘Cassie–Baxter’ composite state represents the global energy minimum of the system. By contrast, for other wetting liquids, such as alkanes and common oils, the global energy minimum corresponds to a fully wetted or Wenzel state. For diving birds, individual feathers therefore spontaneously dewet once the bird emerges out of water, and the ‘wing-spreading’ posture might assist in overcoming kinetic barriers associated with pinning of liquid droplets that retard the rate of drying of the wet plumage of diving birds.

Worldwide, bacteria are the most ubiquitous microorganisms, and it has been extensively demonstrated that migratory wild birds can increase bacterial global scale dispersion through long-distance migration and dispersal. The microbial community hosted by wild birds can be highly diverse, including pathogenic strains that can contribute to infections and disease spread. This study focused on feather and plumage bacteria within bird microbial communities. Samples were collected during ornithological activities in a bird ringing station. Bacterial identification was carried out via DNA barcoding of the partial 16S rRNA gene. Thirty-seven isolates of bacteria were identified on the chest feathers of 60 migratory birds belonging to three trans-Saharan species: Muscicapa striata, Hippolais icterina, and Sylvia borin. Our results demonstrate the possibility of bacterial transfer, including pathogens, through bird migration between very distant countries. The data from the analysis of plumage bacteria can aid in the explanation of phenomena such as migratory birds’ fitness or the development of secondary sexual traits. Moreover, these results have deep hygienic–sanitary implications, since many bird species have synanthropic behaviors during their migration that increase the probability of disease spread.

L'exposició a la contaminació ambiental és una de les principals amenaces per a la salut dels ecosistemes i les poblacions silvestres. L'estrès produït per la contaminació pot causar importants alteracions a la fauna, especialment als depredadors com les aus rapinyaires que, d'altra banda, s'utilitzen com espècies sentinelles del seu ecosistema. Comprendre el mecanisme mitjançant el qual els organismes fan front a l'estrès ambiental i s'adapten a un ambient canviant és crucial per a la seva conservació. Amb aquest propòsit, les hormones d'estrès (corticosterona en aus) s'han utilitzat com a biomarcadors d'estrès ambiental. La corticosterona és l'hormona resultant de l'activació de l'eix hipotalàmic-hipofisari-adrenal (HPA), element clau de la resposta d'estrès. L'activació d'aquest eix i el seu correcte funcionament permet als vertebrats mantenir l'homeòstasi i fer front a les pertorbacions del seu ambient. Per tant, detectar alteracions en el funcionament d'aquest eix (com és l'estrès crònic) pot ser utilitzar com un biomarcador de poblacions en risc i oferir informació valuosa sobre l'estat de l'animal i la seva eficàcia biològica. Les plomes són la única matriu capaç de proporcionar una mesura a llarg termini de corticosterona, i per tant de reflexar l'activitat de l'eix HPA, de manera retrospectiva i integrada en el temps. A més, aquesta matriu pot reflectir l'estat intern de contaminació d'una au, essent una eina molt útil per a la biomonitorització de contaminació ambiental. No obstant, al ser una matriu relativament nova, encara existeixen moltes incògnites metodològiques. A més, tot i que els contaminants tenen el potencial d'alterar l'activitat de l'eix HPA, hi ha molt poca informació al respecte. L'objectiu principal d'aquesta tesi és, per una banda, avaluar l'ús de les plomes per mesurar corticosterona com a biomarcador de la salut i l'eficàcia biològica de les aus, explorant alguns aspectes metodològics d'aquesta matriu, i per l'altra, avaluar l'aplicabilitat de les plomes per biomonitoritzar contaminació ambiental estudiant els efectes dels contaminants en la resposta adrenal d'estrès de les aus. Primer, vam explorar la idoneïtat de diferents tipus de plomes per mesurar corticosterona i contaminants ambientals. Vam comparar nivells de corticosterona entre plomes corporals i plomes primàries de vol, que són les més utilitzades en gairebé tots els estudis previs. Les plomes corporals van mostrar una menor variabilitat en els nivells de corticosterona, indicant que aquest tipus de ploma és més adequat per obtenir informació més específica en el temps i minimitzar factors de confusió. A més, es va descriure per primer cop que les plomes natals dels pollets són útils per biomonitoritzar contaminants, essent un nou mètode de mostreig no invasiu. En segon lloc, vam demostrar que els nivells de corticosterona en plomes cobertores són consistents i estables al llarg de la generació de la ploma, mentre que varien d'un any a l'altre indicant flexibilitat individual. A més, es va validar un protocol optimitzat per extreure corticosterona de les plomes de manera més ecològica i ràpida. En tercer lloc, vam observar que concentracions de corticosterona en ploma podien predir mortalitat i fallada reproductiva en el següent període, demostrant la utilitat potencial d'aquesta eina en programes de maneig d'aus. En quart lloc, es va mostrar com els contaminants més persistents influeixen l'activitat de l'eix HPA en aus de vida lliure, adultes o pollets, però no en aus en captivitat. Tot i la relació positiva entre contaminants i l'activitat adrenal, no es va observar que els contaminants afectessin el creixement dels pollets i, mitjançant l'avaluació de la dehidroepiandrosterona en plomes, vam observar una resposta adaptativa de l'eix HPA en adults. Finalment, es van explorar diferents factors fisiològics i metodològics que potencialment podien crear confusió. En general, aquesta tesi proporciona una evidència important de la solidesa i utilitat de les plomes corporales per avaluar nivells de corticosterona a llarg termini i la seva utilitat com a biomarcador de l'eficàcia biològica en aus, així com un avanç per comprendre els efectes de la contaminació ambiental sobre la resposta adrenal d'estrès en les aus rapinyaires.<br>La exposición a la contaminación ambiental es una de las principales amenazas para la salud de los ecosistemas y las poblaciones silvestres. El estrés producido por la contaminación puede causar importantes alteraciones en la fauna, especialmente en los depredadores como las aves rapaces, que además son utilizadas como especies centinelas de su ecosistema. Comprender el mecanismo mediante el cual los organismos hacen frente al estrés ambiental y se adaptan a un medioambiente cambiante es crucial para su conservación. Con este propósito, las hormonas de estrés (en aves la corticosterona) se han utilizado como biomarcadores de estrés ambiental. La corticosterona es la hormona resultante de la activación del eje hipotalámico-hipofisario-adrenal (HPA), elemento clave de la respuesta de estrés. La activación de este eje y su buen funcionamiento permite a los vertebrados mantener la homeóstasis y hacer frente a las perturbaciones ambientales. Por lo tanto, detectar alteraciones en el funcionamiento de este eje (como es el estrés crónico) puede ser utilizado como biomarcador de poblaciones en riesgo y ofrecer información valiosa sobre el estado de salud y eficacia biológica de los animales. Las plumas son la única matriz capaz de proporcionar una medición a largo plazo de corticosterona, y por tanto de reflejar la actividad del eje HPA, de manera retrospectiva e integrada en el tiempo. Además, esta matriz puede reflejar el estado interno de contaminación de una ave, siendo una herramienta muy útil para biomonitorizar contaminación ambiental. No obstante, al ser una matriz relativamente nueva, aún existen algunas incógnitas metodológicas. Además, aunque los contaminantes tienen el potencial de alterar la actividad del eje HPA, hay muy poca información al respecto. El objetivo principal de esta tesis es, por un lado evaluar el uso de las plumas para cuantificar corticosterona como biomarcador de la salud y eficacia biológica de las aves, explorando algunos aspectos metodológicos de esta matriz, y por el otro, evaluar la aplicabilidad de las plumas para biomonitorizar contaminación ambiental estudiando los efectos de los contaminantes en la respuesta adrenal del estrés de las aves. Primero, exploramos la idoneidad de diferentes tipos de plumas para medir corticosterona y contaminantes ambientales. Las concentraciones de corticosterona se compararon entre plumas corporales y plumas primarias de vuelo, que son las más utilizadas en casi todos los estudios previos. Las plumas corporales mostraron una menor variabilidad en los niveles de corticosterona, indicando que este tipo de pluma es más adecuado para obtener información específica en el tiempo y minimizar factores de confusión. Además, se describió por primera vez que el plumón natal de los pollos es útil para biomonitorizar contaminantes, siendo un nuevo método de muestreo no invasivo. En segundo lugar, demostramos que los niveles de corticosterona en plumas corporales son consistentes y estables a lo largo de la generación de la pluma, mientras que varían de un año al otro indicando flexibilidad individual. Además, se validó un protocolo optimizado para extraer corticosterona de las plumas de una forma más ecológica y rápida. En tercer lugar, observamos que concentraciones de corticosterona en pluma pueden predecir mortalidad y fallo reproductivo en el siguiente período, demostrando la utilidad potencial de esta herramienta en programas de manejo de aves. En cuarto lugar, mostramos que los contaminantes más persistentes influyen en la actividad del eje HPA en aves de vida libre, adultos o pollos, pero no en aves en cautiverio. Aunque se encontró una relación positiva entre contaminantes y una alta actividad adrenal, no se observó que los contaminantes afectaran el crecimiento de los pollos y, mediante la evaluación de la dehidroepiandrosterona en plumas, observamos una respuesta adaptativa del eje HPA en adultos. Finalmente, se exploraron diferentes factores fisiológicos y metodológicos que potencialmente podían crear confusión. En general, esta tesis proporciona una evidencia importante de la solidez y utilidad de las plumas corporales para evaluar niveles de corticosterona a largo plazo y su utilidad como biomarcador de la eficacia biológica en aves, así como un avance para comprender los efectos de la contaminación ambiental sobre la respuesta adrenal del estrés en las aves rapaces.<br>Exposure to environmental pollution has been one of the major threats for ecosystems and wildlife populations. Pollution stress can cause important alterations to wildlife, especially to top predators such as birds of prey, which have been widely used as important sentinels of their ecosystem. Understanding the stress-copping mechanism of organisms is crucial for species conservation. To this purpose, stress hormones (i.e. corticosterone in birds) have been used as biomarkers of challenging or stressful environments. Corticosterone is the endpoint of the hormonal cascade along the Hypothalamic-Pituitary-Adrenal (HPA) axis, which is activated under the presence of some stressors. The HPA axis is one of the main regulatory pathways birds use to deal with changes in the environment, and its effective functioning is imperative for maintaining homeostasis. Thus, detecting alterations in the HPA axis activity (i.e. chronic stress) can be used as a biomarker of populations at risk and offer valuable insights regarding population health and fitness. Feathers are the unique matrix able to provide long-term levels of corticosterone as an assessment of long-term adrenal activity with a retrospective insight. Furthermore, feathers can reflect the internal state of contamination, providing a valuable tool for biomonitoring environmental pollutants. However, as a relatively new matrix, feathers still present some methodological issues that need to be addressed for a proper interpretation of data. In addition, very little information exists on the influence of pollutants on the HPA axis activity. The present thesis aimed to evaluate, on one hand the use of feather corticosterone as a biomarker of bird fitness, addressing some methodological issues of this matrix, and on the other, evaluate the applicability of feathers to biomonitor environmental pollution exploring the effects of pollutants on birds adrenal stress response. First, we explored the suitability of different types of feathers to measure corticosterone and environmental pollutants. Corticosterone concentrations were compared between body feathers and flight feathers, which had been used in almost all previous studies. By showing lower variability, body feathers were found to be a more suitable type of feather to sample due to they provide more specific information in time and minimize confounding factors. In addition, nestling down feathers were described as a new non-invasive method for biomonitoring contaminants. Second, we demonstrated consistency and stability of feather corticosterone concentrations in body feathers over the same feather generation, while we found that levels differ from year to year indicating individual flexibility. Furthermore, we validated an optimized protocol for extracting corticosterone from feathers in a more timesaving and ecological way. Third, we observed that high concentrations of feather corticosterone predict mortality rate and reproductive failure the following seasons, demonstrating the potential utility of this metric in bird management programs. Fourth, we showed that the most persistent pollutants influenced the HPA axis activity of free-living birds, either adults or nestlings, but not captive birds. Interestingly, although a positive association was found between these pollutants and high adrenal activity, they were not observed to negatively affect growth development in nestlings, and through assessing dehydroepiandrosterone in feathers, we observed an adaptive response of the HPA axis in adults. Finally, we explored different potential biological and methodological confounding factors. Overall, this thesis provides important evidence for the robustness of body feathers to assess long-term levels of corticosterone and its usefulness as a biomarker of bird fitness, as well as a step forward for understanding the effects of environmental pollution on the adrenal stress response in birds of prey.

Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 59-60).<br>In nature, aquatic birds can interact with water without their feathers being easily wetted; some species dive tens of meters and emerge to spread their wings to dry. In past studies attempting to connect such ecological behavior and feather structure, the typical approach of microscopy has demonstrated the difficulty in characterizing specimens as delicate and complex as feathers by visual techniques alone. In this work, the question was addressed of how various species balance the wettability problem with the need to dive to various depths or to remain on or near the water surface as dictated by their feeding habits. Texture of wing feathers from six different species of aquatic birds was characterized by measuring contact angles and applying the previously developed framework of the effective spacing ratio, D*, and robustness factor, A*, according to the Cassie-Baxter relation for composite interfaces. This "effective microscopy" technique was successfully employed to assess the wettability and robustness of bird feather textures. The observable water-related behaviors of diving, wing-spreading, shallow foraging, and dabbling for the species studied were explained as partly determined by feather structure, exhibiting effective- D* analysis as an adequate technique for characterizing complex, textured surfaces, fabricated or natural.<br>by Jesus O. Guardado.<br>S.B.

Dominant white, a mutation of the I gene, leads to amelanosis and is common to many commercial breeds of fowl, including Pile Games, White Plymouth Rocks and White Leghorns. Despite much investigation on the cellular mechanisms of Dominant white, its mode of action is still poorly understood. The aim of this study is to elucidate the molecular basis of amelanosis in WPR X PG chickens by addressing the following two questions: are melanocytes present in the skin regions and feather follicles in normal numbers of 8- to 13-day white chick embryos? If melanocytes are present in normal numbers, are they unable to synthesise pigment because of a defect in melanocyte differentiation? Two approaches were used to answer the first question. MelEM, a monoclonal antibody, shown to react specifically to quail melanocytes, was found to be unsuitable for localisation of chicken melanocytes. Secondly, in situ hybridisation with tyrosinase and tyrosinase related protein-2 (TYRP2) probes was carried out to quantitate the number of melanocytes at different stages of development. The results indicate that tyrosinase - and TYRP2 -expressing melanocytes are present in 10-day white chick skin and feather buds in normal, if not greater numbers than in the control (Black Australorp) breed. This suggests that amelanosis is not due the failure of migratory melanoblasts to reach the developing feathers, nor is it due to the selective elimination of melanocytes during migration. The results further showed that with increasing developmental age (12- and 13-days), there is a decline in the number of tyrosinase - and TYRP2-expressing melanocytes in the white chick breed in comparison to the black breed. This suggests that white skin melanocytes either downregulate tyrosinase and TYRP2 gene expression yet remain viable, or they undergo cell death. At 17-days, the results showed an absence of gene expression in both the black and white follicles due to the normal process of feather development. Thus, although WPR x PG melanocytes are present in normal numbers in 10-day skin and feather follicles, they never melanise. To address this issue, black and white neural crest cells were cultured in conditions resembling their respective skin environments. Firstly, black neural crest cells grown in defined medium with either black or white skin extract were able to synthesise melanin. This suggests that white skin contains the appropriate signals necessary to induce melanogenesis of black melanocytes. This in turn suggests that the white melanocyte itself is intrinsically defective. To test this, white chick neural crest cells were grown in defined medium in the presence of black or white skin extract. The results showed that white cells were able to respond to signals in extracts of skin from both breeds and became melanised, suggesting that white melanocytes are not intrinsically defective. Due to the intricate nature of this study and subsequent experimental limitations encountered, these contradictory results could not be completely resolved. However, a testable model in which the I gene is postulated to encode c-kit is presented.

In Europe, in the Middle Ages, ostrich feathers were used for the decoration of military headgear, as a representation of the high lineage of the possessor and his military virtues. They were imported from the coasts of West Africa, from Egypt and Syria into Italian and Spanish ports and from there exported to England and continental Europe. Venice, at the end of the fourteenth century, began to color feathers and soon the new fashion was spread throughout Europe. During the fifteenth century, even women began to use ostrich feathers on their hats or in their fans. When European ships reached America, Central Africa and the islands of the Indian Ocean, a huge amount of exotic bird feathers became available and ostrich feather fad spread through the population.

Presently, all man-made aircraft are optimized for one specific flight regime. Commercial aircraft fly at a specific cruising altitude at which they are most efficient, and military aircraft, which require excellent performance in many flight regimes are designed to be ‘good’ at all of them. A new concept in aviation, morphing aircraft, or aircraft that can fully change their shape, will allow for optimization at nearly any flight regime. This concept has been millennia in the making, well before mankind. Looking to various bird species, tails and wings can completely change shape to optimize their morphology for a given flight regime. Raptors, especially, have mastered the air in that they must out compete and overcome other birds while hunting. For soaring, these birds spread their wings fully to maximize their lift to drag ratio and maintain a low energy, long endurance flight. To maximize speed in a dive they will bring their wings close to their bodies to minimize drag. This study seeks to quantify the aerodynamic properties of the wing. From bird wings the aerodynamic properties of shape changing elastic structures can be understood. The coefficient of lift versus angle of attack plot of a bird wing is not like that of a typical airfoil, it has no distinct point where the wing stalls, instead the bird wing will twist into the flow. Additionally, the induced drag of an avian wing is significantly less than the theoretical induced drag on a wing predicted by the aspect ratio. A flow visualization around the slotted wingtips of a bird reveals smooth streaklines near the primary feathers. These feathers are canted downward and accordingly generate lift in the thrust direction of the wing, which acts to reduce the induced drag on the wing.

This paper presents the development of a biomimetic closed-loop flight controller that integrates gust alleviation and flight control into a single distributed system of feather-like panels over the upper and lower surfaces. This bio-inspired gust alleviation system (GAS) mimics the techniques used by birds to respond to turbulent and gusting airflow. The GAS design replicates the profile of a bird’s wing through the installation of feather-like panels across the upper and lower surfaces of the airfoil, and replacement of the trailing-edge flaps. While flying through gusts, the flight controller uses a linear quadratic regulator to perform continuous adjustments to the local states through active deflection of electromechanical feathers. This system consequently offers a wide range of flap configurations that enable the vehicle to perform gust response maneuvers unachievable by standard aircraft. The GAS is developed using a 2D adaptive panel method that enables analysis of the airfoil’s aerodynamic performance during all flap configurations. The airfoil’s dynamic model is simulated to calculate the disturbances incurred during gusting flows. The flight controller tracks the vehicles velocity, angle of attack and position, and continuously performs adjustment to the orientation of each flap to induce the corrective responses to inbound gusts. The replacement of standard single trailing edge profile with the integration of a dual trailing edge (DTE) configuration offers a reduction of the aircraft’s deviation from the target flight path through the introduction of aero-braking during strong longitudinal gusts. The introduction of 6 additional surface flaps offers new flap configurations capable of minimizing the disturbances in the aircraft’s global states. Non-linear and linear dynamic models of the 8-flap GAS are compared to a traditional single control surface baseline wing and the DTE configuration. The feedback loops synthesized depend on the inertial changes of the global states; however, variations in flap configuration are compared. The integration of an 8-flap GAS provides enhancements to maneuverability and stability in turbulent intensive environments.

Even though Unmanned Aerial Vehicles (UAVs) operating at low Reynolds numbers are becoming common, their performance and maneuverability are still greatly limited due to aerodynamic phenomena such as stall and flow separation. Birds mitigate these limitations by adapting their wings and feather shapes during flight. Equipped with a set of small feathers, known as the alula, located near the leading edge and covering 5% to 20% of the span, bird wings can sustain the lift necessary to fly at low velocities and high angles of attack. This paper presents the effect on lift generation of different placements of a Leading-Edge Alula-inpsired Device (LEAD) along the span of a moderate aspect-ratio wing. The device is modeled after the alula on a bird, and it increases the capability of a wing to maintain higher pressure gradients by modifying the near-wall flow close to the leading-edge. It also generates tip vortices that modify the turbulence on the upper-surface of the wing, delaying flow separation. The effect of the LEAD can be compared to traditional slats or vortex generators on two-dimensional wings. For finite wings, on the other hand, the effect depends on the interaction between the LEADs tip vortices and those from the main structure. Wind tunnel experiments were conducted on a cambered wing at post-stall and deep-stall angles of attack at low Reynolds numbers of 100,000 and 135,000. To quantify the aerodynamic effect of the device, the lift generated by the wing with and without the LEAD were measured using a 6-axis force and torque transducer, and the resulting lift coefficients were compared. Results show that the location of the LEAD yielding the highest lift enhancement was 50% semi-span away from the wing root. Lift improvements of up to 32% for post stall and 37% for deep stall were obtained at this location, demonstrating that the three-dimensional effects of the LEAD are important. The lift enhancement was also more prominent on a finite moderate aspect-ratio wing (3D) than on an airfoil (2D), confirming that the LEAD is a three-dimensional device. Identifying the configurations and deployment parameters that improve lift generation the most is needed to design an adaptive LEAD that can be implemented on a UAV wing for increased mission-adaptability.

Following the current trend for developing biologically inspired flight configurations, flight control system for a transport type aircraft with no vertical tail and segmented main wing is to be developed. The transport configuration is inspired by the fact that birds do not have vertical tails and their wings have various trailing edge feathers that serve to form independent wing segments for roll and yaw control. An aerodynamic model for a generic transport aircraft, modeled after the Boeing 747, is obtained using NASA’s PMARC software. The aircraft is modeled with no vertical tail and the main wing has several independently controlled trailing edge segments. A flight control design will be carried out to satisfy roll and yaw moment commands. These moment commands might come from desired roll or yaw rate commands from the pilot. In addition, for increased performance, it is desirable to maintain a minimum drag configuration. This will result in a reduction in fuel usage for maximum range, endurance, or maximum flight speed. The final controller will provide main wing segment deflection commands designed to meet desired roll and yaw moment commands while attaining a minimum drag configuration.

Canada geese, snow geese, ducks, and American coots all have been implicated in agricultural crop and turf damage. Generally, goose, duck, and American coot damage to crops, vegetation and aircraft can be difficult to identify. Usually the damage to crops or vegetation shows signs of being clipped, torn, or stripped. Tracks, feces, or feathers found neat the damage can be used to help identify the species. Damage to aircraft is obvious if the bird is recovered, but if not, and only bird parts are recovered, a scientific analysis is required. Canada geese, snow geese, ducks, and American coots are federally protected by the Migratory Bird Treaty Act (MBTA), which stipulates that, unless permitted by regulation, it is unlawful to “pursue, hunt, take, capture, kill, possess, sell, barter, purchase, ship, export, or import any migratory birds alive or dead, or any part, nests, eggs, or products thereof.” Generally, geese, ducks, and coots can be hazed without a federal permit in order to prevent damage to agriculture crops and property with a variety of scare techniques. In most cases, live ammunition cannot be used.

The URL links to a website page in the Drexel Digital Museum (DDM) fashion image archive containing a 3D interactive panorama of an evening gown by French fashion designer Christian Lacroix with related text. This evening gown by Christian Lacroix is from his Fall 1990 collection. It is constructed from silk plain weave, printed with an abstract motif in the bright, deep colors of the local costumes of Lacroix's native Arles, France; and embellished with diamanté and insets of handkerchief edged silk chiffon. Ruffles of pleated silk organza in a neutral bird feather print and also finished with a handkerchief edge, accentuate the asymmetrical draping of the gown. Ruching, controlled by internal drawstrings and ties, creates volume and a slight pouf, a nod to 'le pouf' silhouette Lacroix popularized in his collection for Patou in 1986. Decorative boning on the front of the bodice reflects Lacroix's early education as a costume historian and his sartorial reinterpretation of historic corsets. It is from the private collection of Mari Shaw. The panorama is an HTML5 formatted version of an ultra-high resolution ObjectVR created from stitched tiles captured with GigaPan technology. It is representative the ongoing research of the DDM, an international, interdisciplinary group of researchers focused on production, conservation and dissemination of new media for exhibition of historic fashion.