Down Feathers Research Articles

Description of natal down of the ostrich (Struthio camelus) and comparison with common quail (Coturnix coturnix): Developmental and evolutionary implications.

Natal down is a feather stage that differs in both form and function from the definitive feathers of adult birds. It has a simpler structure that has been speculated to be similar to the body coverings of non-avian dinosaurs. However, inference of the evolution of natal down has been limited by our understanding of its structural variation in extant birds. Most descriptive work has focused on neognathous birds, limiting our knowledge of the full diversity of feathers in extant taxa. Here, we describe the natal down of a post-hatch ostrich (Struthio camelus) and compare it to that of a post-hatch quail (Coturnix coturnix). We confirm the presence of featherless spaces (apteria) in S. camelus and the lack of barbules on the tips of natal down in both species. We also find differences between dorsal and ventral natal down structures, such as barbule density in S. camelus and the extent of the bare portion of the barb in both species. Surprisingly, we do not find that the neoptiles of either species follow the ideal morphologies for increasing insulation. Finally, we hypothesize that the different barb types present in S. camelus natal down result from a large addition of new barb ridges during development, which is not known except in feathers with a rachis. These results have implications for our understanding of how structure informs function and development in understudied feather types, such as those shared by non-avian dinosaurs.

Symbiosis between Cretaceous dinosaurs and feather-feeding beetles

Extant terrestrial vertebrates, including birds, have a panoply of symbiotic relationships with many insects and arachnids, such as parasitism or mutualism. Yet, identifying arthropod-vertebrate symbioses in the fossil record has been based largely on indirect evidence; findings of direct association between arthropod guests and dinosaur host remains are exceedingly scarce. Here, we present direct and indirect evidence demonstrating that beetle larvae fed on feathers from an undetermined theropod host (avian or nonavian) 105 million y ago. An exceptional amber assemblage is reported of larval molts (exuviae) intimately associated with plumulaceous feather and other remains, as well as three additional amber pieces preserving isolated conspecific exuviae. Samples were found in the roughly coeval Spanish amber deposits of El Soplao, San Just, and Peñacerrada I. Integration of the morphological, systematic, and taphonomic data shows that the beetle larval exuviae, belonging to three developmental stages, are most consistent with skin/hide beetles (family Dermestidae), an ecologically important group with extant keratophagous species that commonly inhabit bird and mammal nests. These findings show that a symbiotic relationship involving keratophagy comparable to that of beetles and birds in current ecosystems existed between their Early Cretaceous relatives.

Identification of Goose Down and Duck Down using Infrared Spectroscopy and Multivariate Analysis

Identification of Goose Down and Duck Down using Infrared Spectroscopy and Multivariate Analysis

Microscopic Analysis of the Plumulaceous Feather Characteristics of Cathartiformes and Accipitriformes in North America

ABSTRACT Although variation in microscopic plumulaceous (downy) feather characters is known to be useful in taxonomic identifications of birds, the conserved characters unique to most avian orders remain understudied. We examined plumulaceous feather characters (morphometric and observed pigmentation patterns [qualitative]) within three avian families (Cathartidae, Pandionidae, Accipitridae) occurring in North America that often require taxonomic identification based on incomplete or fragmentary remains. We found significant quantitative differences among these three families for measurements of barbule length, node width, average number of nodes per barbule, and internode length. We observed additional differences in pigmentation patterns and spine distribution at nodes. Differences in pigment patterns and intensity are diagnostic for distinguishing Black Vulture (Coragyps atratus) from Turkey Vulture (Cathartes aura) within Cathartidae. Further observed differences of a higher percentage of spined structures present at node junctions along the length of barbules are diagnostic of Pandionidae. Within Accipitridae, pigmentation patterns and pigment intensity separate Swallow-tailed Kite (Elanoides forficatus) and White-tailed Kite (Elanus leucurus) from all other taxa; and barbule length, together with average nodes per barbule is unique to Northern Harrier (Circus hudsonius) in the families examined in this study. Although significant differences in a combination of microscopic feather characters among species were seldom observed in this study, family level differences were consistently documented. Results support the use of a suite of microscopic characters in combination with macroscopic feather features, geographic distributions, molecular methods, and other circumstantial evidence to aid in the identification of species of birds from feathers.

Artificial Superhydrophobic and Antifungal Surface on Goose Down by Cold Plasma Treatment

Plasma treatment, especially cold plasma generated under low pressure, is currently the subject of many studies. An important area using this technique is the deposition of thin layers (films) on the surfaces of different types of materials, e.g., textiles, polymers, metals. In this study, the goose down was coated with a thin layer, in a two-step plasma modification process, to create an artificial superhydrophobic surface similar to that observed on lotus leaves. This layer also exhibited antifungal properties. Two types of precursors for plasma enhanced chemical vapor deposition (PECVD) were applied: hexamethyldisiloxane (HMDSO) and hexamethyldisilazane (HMDSN). The changes in the contact angle, surface morphology, chemical structure, and composition in terms of the applied precursors and modification conditions were investigated based on goniometry (CA), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR), and X-ray photoelectron spectroscopy (XPS). The microbiological analyses were also performed using various fungal strains. The obtained results showed that the surface of the goose down became superhydrophobic after the plasma process, with contact angles as high as 161° ± 2°, and revealed a very high resistance to fungi.

FIRST DESCRIPTION OF THE NEST AND NESTLING OF WHITE-BANDED TYRANNULET Mecocerculus stictopterus (TYRANNIDAE)

We provide the first descriptions of the nest and nestlings of White-banded Tyrannulet Mecocerculus stictopterus, only the second nest description for this genus of small Andean flycatchers (Tyrannidae). We found a single nest with newly hatched nestlings in early November, near Papallacta, northeastern Ecuador. The nest was an open cup composed of lichens and mosses, bound together with spider webs and saddled over a small branch. The natal down of the nestlings was bicolored, creating a camouflaging, sun-dappled effect.

A novel method to optimise the utility of underused moulted plumulaceous feather samples for genetic analysis in bird conservation

Non-invasive sampling methods are increasingly being used in conservation research as they reduce or eliminate the stress and disturbance resulting from invasive sampling of blood or tissue. Here we present a protocol optimised for obtaining usable genetic material from moulted plumulaceous feather samples. The combination of simple alterations to a ‘user-developed’ method, comprised of increased incubation time and modification of temperature and volume of DNA elution buffer, are outlined to increase DNA yield and significantly increase DNA concentration (W = 81, p < 0.01, Cohens’s d = 0.89). We also demonstrate that the use of a primerless polymerase chain reaction (PCR) technique increases DNA quality and amplification success when used prior to PCR reactions targeting avian mitochondrial DNA (mtDNA). A small amplicon strategy proved effective for mtDNA amplification using PCR, targeting three overlapping 314–359 bp regions of the cytochrome oxidase I barcoding region which, when combined, aligned with target-species reference sequences. We provide evidence that samples collected non-invasively in the field and kept in non-optimal conditions for DNA extraction can be used effectively to sequence a 650 bp region of mtDNA for genetic analysis.

Thermal insulation and morphology of natural and synthetic filled outdoor sportswear by repeated water washing and dry cleaning

PurposeThe purpose of this paper is to examine the thermal insulation and water vapor transmission rate (WVTR) according to the type of the filling material, and compared the thermal insulation in the dynamic state considering actual wearing conditions.Design/methodology/approachThe thermal insulation and WVTR were evaluated in a standard state depending on the type of filling material (goose down (GD), duck down (DD), Thinsulate700 (T700), Thinsulate600 (T600) and Polyester (PET)), and the changes in thermal insulation were examined by measuring the microclimate in the case of an environmental change from a high temperature to a low temperature. In addition, the clumping of filling material and the changes in the thickness/weight depending on the laundry process were observed, and the relationships with the thermal insulation were analyzed.FindingsThe results showed that for natural filling materials (GD and DD), the thermal insulation deteriorated significantly due to changes in the thickness/weight after laundering ten times, and water washing was more appropriate than the dry cleaning. On the other hand, the artificial filling materials (T700, T600 and PET) showed a relatively smaller difference, except for clumping, when they went through more dry cleaning or water washing cycles compared to the natural filling materials.Originality/valueThe results showed that the laundry methods have different effects on the damage to the filling material, the change in thermal insulation, and the change in the comfort-related physical property. Therefore, it is important to select the optimal laundry method depending on the filling material.

Regulatory Differences in Natal Down Development between Altricial and Precocial Birds

Regulatory Differences in Natal Down Development between Altricial and Precocial Birds

Assessment of the non-woven, goose down and duck down as thermally insulating materials for the clothing protecting against cold

PurposeThe purpose of this paper is to compare morphological and physical features of three kinds of materials intended for the insulating layer in the clothing protecting against cold – high-bulk non-woven, goose down (GD) and duck down (DD).Design/methodology/approachComparison of thermal performance of developed textile systems with the non-woven, GD and DD content was based on basic biophysical properties related to comfort sensations of the user such as thermal resistance, water vapor resistance and air permeability. In this study, light microscopy and scanning electron microscopy methods were employed to visualize the surface and internal structure of non-woven, GD and DD samples.FindingsThe paper indicates the advantages and disadvantages of each of selected insulating material. For the down samples, significantly higher thermal resistance in a dry state than for the non-woven samples can be achieved. Meanwhile, textile systems with the non-woven provide lower value of water vapor resistance. The selected textile systems for the research were characterized by a comparable air permeability.Originality/valueThis paper allows for an evaluation of high-bulk non-woven, DD and GD samples in terms of providing optimal thermal performance in clothing protecting against cold.

A phylogenetic comparative analysis reveals correlations between body feather structure and habitat

SummaryBody feathers ensure both waterproofing and insulation in waterbirds, but how natural variation in the morphological properties of these appendages relates to environmental constraints remains largely unexplored. Here, we test how habitat and thermal condition affect the morphology of body feathers, using a phylogenetic comparative analysis of five structural traits [i.e., total feather length, the lengths of the pennaceous (distal) and plumulaceous (proximal) sections, barb density, and pennaceous barbule density] from a sample of 194 European bird species.Body feather total length is shorter in aquatic than in terrestrial birds, and this difference between groups is due to the shorter plumulaceous feather section in aquatic birds. Indeed, a reduced plumulaceous section in feather length probably reflects the need to limit air trapped in the plumage to adjust the buoyancy of aquatic birds. In contrast, the high pennaceous barbule density of aquatic birds compared to their terrestrial counterparts reflects water resistance of the plumage in contact with water.Our results show that birds living in environments with low ambient temperature have long plumulaceous feather lengths, low barb density, and low pennaceous barbule density. Data also suggest that plumage probably has limited function in reducing the heat absorption of species living in hot environments.Our results have broad implications for understanding the suite of selection pressures driving the evolution of body feather functional morphology. It remains to be tested, however, how other feather traits, such as the density of plumage (feathers per unit area) and the relative number of different feather types, for example downy feathers, are distributed amongst birds with different water resistance and thermoinsulative needs.Alay summaryis available for this article.

Regulatory Differences in Natal Down Development between Altricial Zebra Finch and Precocial Chicken

Birds can be classified into altricial and precocial. The hatchlings of altricial birds are almost naked, whereas those of precocial birds are covered with natal down. This regulatory divergence is thought to reflect environmental adaptation, but the molecular basis of the divergence is unclear. To address this issue, we chose the altricial zebra finch and the precocial chicken as the model animals. We noted that zebra finch hatchlings show natal down growth suppressed anterior dorsal (AD) skin but partially down-covered posterior dorsal (PD) skin. Comparing the transcriptomes of AD and PD skins, we found that the feather growth promoter SHH (sonic hedgehog) was expressed higher in PD skin than in AD skin. Moreover, the data suggested that the FGF (fibroblast growth factor)/Mitogen-activated protein kinase (MAPK) signaling pathway is involved in natal down growth suppression and that FGF16 is a candidate upstream signaling suppressor. Ectopic expression of FGF16 on chicken leg skin showed downregulation of SHH, upregulation of the feather growth suppressor FGF10, and suppression of feather bud elongation, similar to the phenotype found in zebra finch embryonic AD skin. Therefore, we propose that FGF16-related signals suppress natal down elongation and cause the naked AD skin in zebra finch. Our study provides insights into the regulatory divergence in natal down formation between precocial and altricial birds.

ケリの初毛羽を用いたCHD遺伝子による性判定

ケリの生活史や繁殖生態を理解するためには，成長段階の早い時期からケリ雛の性別を知る必要がある．本研究では，簡便かつ確実なケリ雛の性判定法を確立するために初毛羽の基部からのDNA抽出を試みた．その結果，初毛羽からPCR増幅に十分量のDNAを得ることができた．加えて，この方法により京都府南部における17巣30個体のケリ雛の性を，雌14個体，雄16個体に判別することができた．即ち，初毛羽からのDNA採取の手法は簡便であるだけでなく，雛へのストレスを軽減する手法として有効であることが示された．

Fractal Model for the Effective Thermal Conductivity of Goose Down Assembly

Fractal Model for the Effective Thermal Conductivity of Goose Down Assembly

Fractal Characteristics for Goose Down Assemblies as Porous Media

In this paper, the fractal characteristics of goose down assembly are described by determining the pore area fractal dimension and the tortuosity fractal dimension. The goose down assembly, filled with mass of down fibers and pores, is loose and ductile. The pores are varying shapes and sizes, and distribute unevenly. Firstly, micro computed tomography is used to observe the internal microstructure of down assembly without destructing the original assembly shape. The derived computed tomography images of down assemblies with various volume fractions are then treated by two-value method. The measurement verifies that the porous structure of down assembly possesses typical fractal characteristic, and the pore area fractal dimensions D f are determined by the box counting method. According to the capillary principle the tortuous flow path in down assembly is simulated, and the fractal dimension of the tortuous flow path D T is also calculated by the same way. The results indicate that the pore area fractal dimensions decrease and the tortuosity fractal dimensions increase gradually as the volume fractions V f of the assembly increase.

A preliminary report on the development of young Indian Eagle Owl Bubo bengalensis (Franklin, 1831) in and around Puducherry, southern India

Morphometric, weight and photographic data on the growth patterns of young Bubo bengalensis was obtained in three areas in and around Puducherry. We continuously monitored and observed the growth patterns of nine chicks in total between 10 and 60 days after hatching. Among the morphometric variables, bill and wing chord length showed a mild yet steady increase throughout the observation period, while tarsus length displayed a steep increase till the 20th day, fluctuated till the 40th day and then increased marginally till the 60th day. Body mass showed a steady increase before reaching a plateau between 35 and 45 days, after which only a marginal increase was observed. Chicks were born with whitish natal down. The prejuvenile moult occurred around the 14th or 15th day. Full juvenile plumage was attained by the 35th day and persisted even after 60 days. Morphometric data showed a marked variability, and in this context, ageing of nestlings based on measurements alone may not be accurate and must be complemented with feather moult patterns.

Explanation of the Fractal Characteristics of Goose Down Configurations

Goose down has superior thermal insulating properties as a filler material used widely as an insulator in textile products. Its particular “tree” structure is expected to attribute greatly to this insulating property. In this paper, fractal structures of the down “tree” are observed using scanning electron microscopy (SEM), and the configuration characteristics of goose down are described quantitatively by local fractal dimensions. From two expects, the local fractal dimensions were calculated both theoretically and experimentally, revealing its value to be very close to the golden mean, 1.618. This near-optimal fractal dimension may be attributable to the excellent thermal insulation of goose down assembly, and the potential applications of such a fractal structure are also discussed.

Discrimination Between Goose Down and Duck Down by Fourier Transform Near-Infrared Spectroscopy

The percentage of duck down in goose down products is an important index in international trade. The traditional method for distinguishing between goose down and duck down uses a microscope and visual appraisal. However, there are some problems with this method, such as limited samples and low accuracy. In this study, all samples (n=140) were divided into four groups, according to different proportions of goose down and duck down. A near-infrared (NIR) method combined with chemometrics was used to discriminate among them. A spectrum of each sample was acquired by a NEXUS intelligent FT-IR spectrometer using diffuse reflectance mode. Chemometrics methods, including principal component analysis (PCA) and discriminant partial least squares (DPLS), were used to analyze the spectra obtained. Various pre-treatments such as multiplicative scatter correction (MSC) and derivatives were also used to improve the model. PCA was used to distinguish between pure goose down and pure duck down. Results of PCA show that samples were divided completely into two groups without overlap except for one outlier. The DPLS method was used to distinguish among the four groups. The DPLS method based on the derivative could increase the predictive precision of the model (r-values increase from 0.528 to 0.999), but the robustness of model was not satisfactory. Pre-treatment with MSC could improve the model in this aspect. The result shows that NIR is a fast and effective method for discrimination between goose down and duck down, even in mixtures.

Structures and Properties of the Goose Down as a Material for Thermal Insulation

As a natural filling material, the goose down is well known for its superior thermal insulating properties and is widely used as an insulated filling material for winter outerwear and quilters. However, our understanding of the material is so poor that we still cannot fully explain the mechanisms or the sources for its high thermal insulation. This paper reports an extensive investigation of the chemical compositions, morphological structure and the physical properties, pertaining to thermal resistance of the down and down assemblies compared with other fiber assemblies. Detailed experimental work and data analysis were conducted on the properties influencing the thermal insulation of the down.

Differences in Plumulaceous Feather Characters of Dabbling and Diving Ducks

AbstractAbstractWe examined variation in five microscopic plumulaceous (downy) feather characters of eighteen species of dabbling (Anatini) and diving (Aythyini, Mergini) ducks to quantify the differences between these tribes, and to explain how the plumulaceous feather ultrastructure in ducks may be influenced by different ecological requirements. Over 75% of the variation in feather characters among these ducks was explained by the first two components of a principal components analysis (PCA). Component 1 explained 51% of the variation and was positively correlated with the characters that quantified the number of barbules with expanded nodes and the number of expanded nodes on barbules. The microscopic feather characters of dabbling ducks (Anatini) have triangular-shaped, expanded nodes on most proximal barbules, whereas diving ducks (Aythyini and Mergini) lack expanded nodes on some barbules. Anatini also have a greater density of expanded nodes per barbule, wider nodes, shorter distance between expanded nodes, and longer barbule length. Further analysis of node density across all taxa showed that as dive depths increase, the number of expanded nodes per barbule decreases, and in the deepest divers many of the barbules completely lack expanded nodes. The significantly greater density of expanded nodes in dabbling ducks suggests that the downy nodes may function to trap more air. Diving species have fewer expanded nodes, less buoyant plumage, and are more efficient at foraging in deeper water than dabbling ducks.