White Feathers Research Articles

Bacterial Degradation of Black and White Feathers

Bacterial Degradation of Black and White Feathers

Feathering in commercial poultry I. Feather growth and composition

Feather growth, structure and patterns of moulting are important characteristics of poultry in commercial environments. As the market age for broilers continues to decline, the “maturity” of feather cover becomes even more important for protection of the skin and underlying tissue. Feather growth begins at around day 5 of incubation while keratinisation is complete 2 – 3 d prior to hatch. Feathers do not grow randomly over the skin surface, but rather in distinct tracts, which cover at most 75% of the skin surface. Broiler chickens will have about 50 g of feathers by market age, although at this early age some feathers will have already been lost by sequential moulting. Although most modern strains of poultry have white or brown feathers, there are various colour schemes that are again dictated during embryo development. In a subsequent paper, we will detail factors affecting feather growth, moulting and the occurrence of various abnormalities.

BACTERIAL DEGRADATION OF BLACK AND WHITE FEATHERS

Abstract When feather-degrading Bacillus licheniformis is grown in culture, it secretes a keratinase that hydrolyzes the β-keratin matrix of a feather, thereby releasing oligopeptides that dissolve into the medium surrounding the feather and feather-degrading bacilli. These peptides absorb light passed through a sample of medium from which feather fragments, melanin granules, and bacteria have been removed by centrifugation. Samples of medium in which white, nonmelanic feathers are degrading absorb more light than samples of medium in which black, melanic feathers are degrading, which indicates that more oligopeptides are dissolved in medium surrounding white feathers than in medium surrounding black feathers. The differential absorption of light supports the conclusion that B. licheniformis degrades white feathers more rapidly than black feathers.

FEATHERS AT A FINE SCALE

IN 1668, ANTOINE von Leeuwenhoek improved the crude microscopes that were being produced in Europe to better study small biological objects (Madigan et al. 1997). Although von Leeuwenhoek's microscope revolutionized biology-giving credence to, among other things, the theory of the cell-the microscope's potential escaped the attention of most ornithologists. Since the late 19th and 20th centuries, a small group of researchers have used microscopes to study feathers (for historical reviews, see Fox 1976, Prum 1999); but it was only recently that a consideration of feathers (and the organisms that live on them) has been united with traditional studies of colors and structures on a macroscopic level. The result is a new appreciation of the importance of the bacterial flora of feathers and their potential to serve as a selective force that can affect the colors of feathers. Microbes were isolated from feathers more than 40 years ago (e.g. Gierl0ff et al. 1961; Pugh and Evans 1970a, b), but feather bacteria went largely unstudied until Burtt and Ichida (1999) isolated feather-degrading Bacillus spp. from the feathers of several species. Shawkey et al. (2003a) subsequently cultured 13 distinct isolates from the feathers of House Finches (Carpodacus mexicanus). More comprehensive surveys, using both culture-based and cultureindependent methods (see Amann et al. 1995 for a review of those methods and their importance in detecting microbial diversity), have revealed even greater microbial diversity on feathers (M. D. Shawkey et al. unpubl. data). Although it is now clear that feathers are capable of harboring a diverse microflora, the ecological role(s) of that microflora remain largely a mystery. Goldstein et al. (2004) improves our understanding of these roles. Using standard microbiological methods, they demonstrate that feather-degrading bacteria degrade unmelanized white feathers more quickly and completely than melanized black

The Value of Immaculate Mates: Relationships between Plumage Quality and Breeding Success in Shelducks

AbstractImmaculateness, a novel measure of bird plumage quality, defined as the regularity of the borders of a coloured patch of feathers, and the uniformity of the colour within the patch, tends to decline as a result of feather wear and damage. If it declines more quickly amongst birds in poor condition, it has the potential to act as an honest signal of individual quality and therefore be subject to social and sexual selection. We scored plumage immaculateness in shelducks Tadorna tadorna, based on the absence of white feathers in the red‐brown chest band and the evenness of the band's border. We monitored body condition and plumage quality in birds at feeding sites in the Severn Estuary (UK) during the early breeding season when females were forming eggs, and later in the season when chicks arrived. Drakes had more immaculate chest bands than ducks. At preferred feeding sites, drakes were more immaculate, and birds of both sexes were in better body condition. Birds with more immaculate plumage tended to mate assortatively at preferred sites and were more likely to produce a brood that survived the journey to the feeding areas. Immaculateness could therefore be an honest signal of parental quality. Although our evidence is only correlational, we suggest that plumage immaculateness indicates the ability to establish and maintain control over the best breeding sites and feeding territories in the face of competition with other shelducks.

The role of ultraviolet-A reflectance and ultraviolet-A induced fluorescence in the appearance of budgerigar plumage: insights from spectrofluorometry and reflectance spectrophotometry.

Fluorescence has so far been found in 52 parrot species when illuminated with ultraviolet-A (UVA) 'black' lamps, and two attempts have been made to determine whether such fluorescence plays any role in sexual signalling. However, the contribution of the reflectance versus fluorescence to the total radiance from feathers, even in the most studied species to date (budgerigars), is unclear. Nor has the plumage of this study species been systematically assessed to determine the distribution of fluorescent patches. We therefore used spectrofluorometry to determine which areas of budgerigars fluoresce and the excitation and emission spectra involved; this is the first time that such a technique has been applied to avian plumage. We found that both the yellow crown and (normally hidden) white downy chest feathers exhibit strong UVA-induced fluorescence, with peak emissions at 527 nm and 436 nm, respectively. Conversely, the bright-green chest and dark-blue tail feathers do not fluoresce. When comparing reflectance spectra (400-700 nm) from the yellow crown using illuminants with a proportion of UVA comparable to daylight, and illuminants with all UVA removed, no measurable difference resulting from fluorescence was found. This suggests that under normal daylight the contribution of fluorescence to radiance is probably trivial. Furthermore, these spectra revealed that males had fluorescent crowns with substantially higher reflectance than those of females, in both the UV waveband and at longer wavelengths. Reflectance spectrophotometry was also performed on a number of live wild-type male budgerigars to investigate the chromatic contrast between the different plumage areas. This showed that many plumage regions are highly UV-reflective. Overall our results suggest that rapid surveys using UVA black lamps may overestimate the contribution of fluorescence to plumage coloration, and that any signalling role of fluorescence emissions, at least from the yellow crown of budgerigars, may not be as important as previously thought.

The blood of our sons: men, women, and the renegotiation of British citizenship during the Great War

Introduction PART I: PROPAGANDA AND THE PUBLIC MIND The Rape of Belgium and Wartime Imagination The Making of Tommy Atkins: Masculinity, Propaganda and the Triumph of Family Values Redrawing the Boundaries of the Private Sphere: Patriotic Motherhood and the Raising of Kitchener's Armies PART II: SHAMING RITUALS AND SEXUAL IDENTITY The Order of the White Feather Conscription, Conscience, and the Travails of Male Citizenship 'Reinventing Womanhood: Sufragettes and the Great War for Citizenship PART III: THE CULTURAL CONSTRUCTION OF LAW The Power of Sacrifice: 'Physical Force' and Women's Work Votes for Whom?: The Ideological Origins of the Representation of the People Bill

White Plumage

Many birds with colored dorsal plumage have white underparts and among waterbirds extensive white plumage is common. Feathers are made of keratin, which is naturally transparent and colorless. They appear white because keratin foam or fibers scatter all frequencies of the visible spectrum. Colored feathers have keratin structures that reflect light selectively or mechanisms for depositing pigment within feathers. Color is not essential for flight, streamlining, insulation or waterproofing; some of the largest birds fly and breed successfully with all-white plumage. Adaptive scenarios concerned with camouflage, communication and thermoregulation have been based upon the visual properties of white feathers. These are discussed, but few examples are convincing enough to falsify the hypothesis that feathers may be white by default. Arctic land birds provide evidence for cryptic white plumage, but some white feathers are retained after they cease to be cryptic. White plumage also occurs in some tropical land birds.

Scare Tactics in a Neotropical Warbler: White Tail Feathers Enhance Flush–Pursuit Foraging Performance in the Slate-Throated Redstart (Myioborus Miniatus)

AbstractFlush–pursuit foragers use exaggerated and animated foraging movements to flush potential prey that are then pursued and captured in flight. The Myioborus redstarts comprise 12 species of flush–pursuit warblers found in montane forests of the American tropics and subtropics. All members of the genus have contrasting black-and-white tail feathers that are exposed by spreading the tail during animated foraging displays. Plumage pattern and tail-spreading behavior were examined to see how they affected flush–pursuit foraging performance of the Slate-throated Redstart (Myioborus miniatus) in Monteverde, Costa Rica. Although flycatching was the most common foraging tactic used by Slate-throated Redstarts, flush–pursuit foraging increased in both frequency and intensity when birds were feeding nestlings. Flush–pursuit prey attacks occurred more frequently following hops in the spread-tail foraging posture than hops in more typical warbler-like posture, suggesting that tail-spreading behavior assists in startling and flushing potential prey. The hypothesis that the white tail feathers enhance flush–pursuit foraging was tested by means of a plumage-dyeing experiment. After locating nests containing young 5–7 days old, I captured the male and female at the nest and assigned one member of each pair to the experimental treatment group; its mate served as a control. For experimental birds, a permanent marker was used to blacken the white tips of the three outer retrices. For sham-darkened controls, the naturally black tips of the three inner retrices were also “blackened”. Experimental birds with darkened tail feathers were significantly less successful in flush–pursuit foraging, showed a significantly lower overall rate of prey attack, and fed their nestlings at a significantly lower rate than did their sham-darkened mates. For experimental birds, only 7.6% of hops in the spread-tail posture were followed by an attack on a prey item, compared to 20.9% of hops for controls. These experimental results, similar to those obtained recently by Jabłoński (1999) for the congeneric Painted Redstart (Myioborus pictus), indicate that white tail feathers are critically important in startling potential prey and raise questions about interspecific and intraspecific geographic variation in plumage pattern in the genus.

THE COURTSHIP DISPLAYS AND SOCIAL SYSTEM OF THE WHITE-RUFFED MANAKIN IN COSTA RICA

We studied the relationship between group and individual display in the courtship and social system of the White-ruffed Manakin (Corapipo leucorrhoa altera) in the Atlantic slope foothills of Costa Rica. Between 20 April and 28 May 1989, we searched for display logs and conducted 358 h of observations focused on four display logs. We found logs owned by a single resident male in which activity was continuous, as well as logs and areas where displays were occasional. Six of the eight logs found in the study area were arranged in two clusters separated by about 300 m, although we also found a solitary log 200 m from the nearest active display site. The resident male was at his display site 40.7–93.7% of the time, mostly alone. Residents were visited by other males mainly before 08:00 and less frequently by females later in the day. Residents continually gave advertisement calls during the day and performed several visual displays, including an elaborate Flap-chee-wah in which the male would fly steeply upward from the display log to land explosively at high speed a few seconds later, instantly jumping while turning in the air to land facing the original landing point. Two of these displays culminated in copulations. Other common displays were a slow undulating Butterfly flight and Throat-flagging in which males slowly moved their heads, exposing the fully erected, contrasting white throat feathers. Males performed the displays alone, in the company of other males, or in the presence of females. We conclude that C. leucorrhoa displays in dispersed leks as found by other authors for C. gutturalis. Each log is owned by a single individual and the visits by other males may have a social function related to the establishment of a dominance hierarchy. We found important similarities between the two species of Corapipo and also with the genus Masius, which supports the proposed close relation between the two groups.

Testing homology of loci for two plumage colors, "lavender" and "recessive white," with chicken and Japanese quail hybrids.

Homology for two plumage color loci was studied by hybridization between chickens and Japanese quail. First, chicken-quail hybrids were produced from homozygous "lavender" chicken cocks and "bleu" Japanese quail, and all 30 hybrids had the same parental slate blue plumage color. On the other hand, no hybrids with this plumage were obtained out of 18 progeny from the same cocks and wild-type quail. These results show that the slate blue plumage color is determined by homologous loci in Japanese quail and chickens. Second, all (n = 25) chicken-quail hybrids hatched from homozygous "recessive white" cocks and "recessive white" (n = 8) or "wild-type" (n = 17) quail had the same pattern of plumage color, with white feathers on the ventral face and colored feathers elsewhere. These results indicate that the recessive white mutations are not homologous in Japanese quail and chickens.

UNUSUAL SUMMER PLUMAGE OF WHITE-TAILED PTARMIGAN

We observed two White-tailed Ptarmigan (Lagopus leucurus) in white winter plumage (basic) in Colorado during late July through August during 35 years of field study. Both individuals were adult (>2 yr of age) females; one was collected and the second examined and photographed. Examination of the plumage revealed that neither had molted from winter plumage into their nuptial (alternate) or postnuptial (supplemental) plumage. We speculate that retention of the white winter plumage was the result of failure of the pituitary and thyroid glands to secrete sufficient hormones to initiate replacement of white body feathers with normal breeding plumage feathers. Perhaps this failure of the pituitary and thyroid glands was not age related but instead gender related. Despite conspicuous white plumage during summer, behavior and survival of both birds appeared normal.

Petticoats and White Feathers: Gender Conformity, Race, the Progressive Peace Movement, and the Debate over War, 1895-1919.

Mustering Support for Gender, Culture, and Language To Re-educate the World: The Origins and Ideology of the Progressive Peace Movement The Progressive Peace Movement's March Toward Military Preparedness Doing Our Plain Duty: The Congressional Debate and the Pacifist Voice Women's Ways in War: The Feminist Pacifism of the New York City Woman's Peace Party Conclusion Selected Bibliography Index

Abstracts for Special Issue

Microbial biodegradation of waste feathers constitute an alternative to convert hard proteins into valuable products through non-polluting processes. The probiotic Bacillus subtilis FTC02PR1 demonstrated efficiency for degradation of feather meal, white feathers and melanized feathers. Only a few reports describe the microbial degradation of highly resistant melanized feathers. Human hair, a source of pure α-keratin, was poorly degraded. A keratinolytic protease produced by this strain was purified by liquid chromatography on Sephadex G-75 and DEAE Sepharose. The enzyme was characterized as a serine proteinase with approximately 30 kDa, and optimal activity at 60 °C and under a broad pH range 6.0–11.0). Thermal tolerance at 55 °C was significantly increased in the presence of manganese ions. This enzyme may be useful for hydrolysis of recalcitrant proteins. The production of keratinases by probiotic bacterial strains may concomitantly allow better use of keratin-based feeds, due to the possibility of diet supplementation with beneficial microorganisms.

Petticoats and white feathers: gender conformity, race, the progressive peace movement, and the debate over war, 1895-1919

Petticoats and white feathers: gender conformity, race, the progressive peace movement, and the debate over war, 1895-1919

Remembering the Great War - Sites of Memory, Sites of Mourning: The Great War in European Cultural History. By Jay Winter. Cambridge: Cambridge University Press, 1995. Pp. x + 310. $34.95. - Dismembering the Male: Men's Bodies, Britain, and the Great War. By Joanna Bourke. Chicago: University of Chicago Press, 1996. Pp. 336. $32.50. - “White Feathers and Wounded Men:

Remembering the Great War - Sites of Memory, Sites of Mourning: The Great War in European Cultural History. By Jay Winter. Cambridge: Cambridge University Press, 1995. Pp. x + 310. 32.50. - “White Feathers and Wounded Men: Female Patriotism and the Memory of the Great War.” By Nicoletta Gullace. Journal of British Studies36, no. 2 (1997): 178–206. - “Reconstructions: Prosthetics and the Rehabilitation of the Male Body in World War I France.” By Roxanne Panchasi. Differences7, no. 3 (1995): 109–40. - “Re-membering the Modern Subject: The Wounded Body and the Politics of Mourning, 1917–1937.” By Matthew Brady Brower. M.A. thesis, University of Colorado, 1996. - Volume 37 Issue 1

Restrictive

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White Feathers and Wounded Men: Female Patriotism and the Memory of the Great War

On August 30, 1914, Admiral Charles Penrose Fitzgerald, an inveterate conscriptionist and disciple of Lord Roberts, deputized thirty women in Folkstone to hand out white feathers to men not in uniform. The purpose of this gesture was to shame “every young ‘slacker’ found loafing about the Leas” and to remind those “deaf or indifferent to their country's need” that “British soldiers are fighting and dying across the channel.” Fitzgerald's estimation of the power of these women was enormous. He warned the men of Folkstone that “there is a danger awaiting them far more terrible than anything they can meet in battle,” for if they were found “idling and loafing to-morrow” they would be publicly humiliated by a lady with a white feather.The idea of a paramilitary band of women known as “The Order of the White Feather” or “The White Feather Brigade” captured the imagination of numerous observers and even enjoyed a moment of semiofficial sanction at the beginning of the war. According to the Chatham News an “amusing, novel, and forceful method of obtaining recruits for Lord Kitchener's Army was demonstrated at Deal on Tuesday” when the town crier paraded the streets and “crying with the dignity of his ancient calling, gave forth the startling announcement: ‘Oyez! Oyez!! Oyez!!! The White Feather Brigade! Ladies wanted to present the young men of Deal and Walmer … the Order of the White Feather for shirking their duty in not coming forward to uphold the Union Jack of Old England! God save the King.’”

Molt and the Basic Plumage of Male Harlequin Ducks

Using observations on 28 individually marked male Harlequin Ducks from mid-June until late November, we describe plumage changes which occur as individuals proceed from the alternate plumage through basic to the return of the new alternate plumage. We also describe the timing of these events, at the individual and population level. Conspicuous white tertial feathers which become visible early in the period of the basic plumage present a challenge to existing theories to explain the function of the drab basic plumage. We hypothesize that these feathers act as a badge of quality and are used as a sexual signal to other birds. Intra-sexual competition among males to assess the quality of rival males prior to subsequent pair formation is a proposed function of this feather badge.

Sexual selection in the northern pintail (Anas acuta): the importance of female choice versus male-male competition in the evolution of sexually-selected traits

We experimentally studied the relative importance of plumage, dominance status, and courtship behavior in determining male pairing success in the northern pintail Anas acuta and assessed whether these traits function in female choice, male-male competition or both. In an experiment (experiment IA) that eliminated the confounding effects of male-male competition and social courtship, females chose males with pure white breasts and colorful scapular feathers. When the same group of birds were free to interact (experiment 1B), male behavior was more important: females chose males that courted them intensely and were attentive to them, although preferred males again had whiter breasts and more colorful scapulars. In a second experiment (experiment 2), testing the effect of age on pairing success, females showed a significant preference for 2-year-old males over yearlings: 2-year-old males courted more and were more attentive to the female than yearlings; they were also more colorful than yearlings in a number of plumage measurements. Although males (in both experiments 1B and 2) were aggressive to one another while courting the female and dominant males were sometimes able to exclude subordinates from social courtship, contrary to expectation, we found no relationship between initial dominance rank and pairing success or dominance rank and age. In addition, dominance was not correlated with any of the morphological traits measured. Once chosen, however, subordinate males typically initiated fights with the higher-ranked male(s) and quickly achieved dominance. These results suggest that (1) females choose males based on a suite of morphological and behavioral characteristics, (2) male dominance relationships do not constrain active female choice, (3) a male's position in a dominance hierarchy is largely a result rather than a cause of female choice, and (4) female choice plays a more significant role than male-male competition in the evolution of several secondary sexual traits in male northern pintails.