Moulted Feathers Research Articles

Mercury Contamination in Idaho Bald Eagles, Haliaeetus leucocephalus

Because mercury contamination is potentially threatening to bald eagle (Haliaeetus leucocephalus) populations, we collected molted feathers at nests to determine the level of contamination in bald eagles in the state of Idaho, USA. Eagle feathers contained measurable amounts of cadmium (Cd), chromium (Cr), selenium (Se), lead (Pb), as well as mercury (Hg). Cadmium, Cr, Se, and Pb levels averaged 0.17, 4.68, 2.02, and 1.29 mg/kg dry weight, respectively, and were at or below concentrations indicated as causing reproductive failure in bald eagles. Mercury contamination was found to be the highest averaging 18.74 mg/kg dry weight. Although a concentration of only 7.5 mg/kg dry weight Hg in bird feathers can cause reduced productivity and even sterility, all of the eagles we sampled bred successfully and the population of bald eagles continues to grow annually throughout the state.

Molted Feathers as a Source of DNA for Genetic Studies in Waterbird Populations

The determination of genetic parameters for most waterbird populations presents considerable challenges because these species frequently breed in inaccessible locations which preclude capture of nesting pairs. The application of non-invasive sampling techniques, such as the collection of molted feathers in the field, could represent an appealing strategy to overcome the above cited problem. Here, the feasibility of sampling molted feathers collected in Brazilian populations of the Roseate Spoonbill (Platalea ajaja; N = 94) and the jabiru Stork (Jabiru mycteria; N = 10) for genetic studies was evaluated. Each feather yielded high quality DNA with a concentration 1.25 times higher than that obtained from feathers from similar sized birds from other groups. Amplification of a 390– 396 bp fragment for molecular sexing and 11 microsatellite loci was successful. The average percentage of positive PCRs (i.e. those that yielded products) among all Roseate Spoonbill loci and samples was 95.5%. The sampling approach appears suitable to gather genetic information in natural populations of these waterbirds and can be applied to other similar species.

On the Uniqueness of Color Patterns in Raptor Feathers

For this study, I compared sequentially molted feathers for a few captive raptors from year to year and symmetrically matched feathers (left/right pairs) for many raptors to see if color patterns of sequential feather pairs were identical or if symmetrical pairs were mirror-image identical. Feather pairs were found to be identical only when without color pattern (e.g., the all-white rectrices of Bald Eagles [Haliaeetus leucocephalus]). Complex patterns were not closely matched, but some simple patterns were sometimes closely matched, although not identical. Previous claims that complex color patterns in feather pairs are fingerprint-identical (and therefore that molted feathers from wild raptors can be used to identify breeding adults from year to year with certainty) were found to be untrue: each feather is unique. Although it is unwise to be certain of bird of origin using normal feathers, abnormal feathers can often be so used.

AN IMPROVED EXTRACTION METHOD TO INCREASE DNA YIELD FROM MOLTED FEATHERS

To assess the value of molted feathers as a noninvasive source of DNA for genetic studies of Northern Goshawks (Accipiter gentilis), we isolated and quantified DNA from molted feathers and compared yields across five feather types. We also compared PCR success across the same five feather types using five microsatellite genetic markers of varying size. In addition, we compared DNA yields from a commonly used extraction method versus one we modified to increase DNA yield. Results indicated molted feathers provided on average 24 ng μl−1 of DNA, which is a relatively high DNA yield compared to other noninvasive tissue sources. Tail feathers yielded significantly more DNA than primary, secondary, and smaller feathers, yet all feather sizes produced equally high rates of PCR success. Although our modified extraction method increased the time required for processing feathers, it resulted in significantly higher yields of DNA as compared to the unmodified protocol.

High error rates for avian molecular sex identification primer sets applied to molted feathers

Molted feathers are becoming increasingly important as a source of DNA for identifying the sex of individuals, and accurate methods for molecular sex identification are needed. Three molecular sex identification primer sets have been developed for use in nearly all nonratite birds, but performance of these primer sets has not been evaluated for molted feathers. For two species of birds, the Ring-necked Pheasant {Phasianus colchicus) and the Scarlet Macaw {Ara macao), we evaluated success and error rates among primer sets using DNA from molted feathers and assessed the percentage of times an incorrect sex would be assigned when analyses are completed in duplicate. Amplification success rates differed among the primer sets for both species, ranging from 67.5% to 89.2% {P = 0.0002 and 0.009), and error rates were high, ranging from 1.9% to 24.2%. Success rates and error rates were not consistent between species and among primer sets. To improve the accuracy of molecular sex identification tests when using molted feathers, we suggest determining acceptable confidence levels in the accuracy of sex assignment, conducting pilot tests to evaluate the performance of different primer sets, and using high-resolution electrophoresis systems to increase detection of errors. SINOPSIS. Tasa alta de error para identificar el sexo usando t?cnicas moleculares con conjutos de sebadores, aplicados a plumas mudadas Las plumas mudadas se est?n convirtiendo un una fuente importante de ADN para identificar el sexo en aves. No obstante, se necesitan m?todos m?s precisos para la identificaci?n molecular del sexo, cuando se utilizan fuentes no invasivas de ADN. Se han desarrollado tres m?todos moleculares para el sexado utilizando sebadores (primers) que son aplicados a aves que no son rat?tidos. Sin embargo, la confiabilidad de los conjutos de sebadores no ha sido evaluada utilizando plumas que hayan sido mudadas. Evaluamos el ?xito y tasa de error, entre conjuntos de sebadores, utilizando el ADN contenido en plumas mudadas de individuos de Phasianus colchicus y Ara macao. Las tasas de ?xito de amplificaci?n entre conjuntos de sebadores, para ambas especies de aves, variaron de 67.5% a 89.2% (P = 0.0002 y 0.009) y las tasas de error fueron altas con un rango de 1.9% a 24.2%. Las tasas de ?xito y las tasas de error no fueron consistente entre las especies y entre conjuntos de sebadores. Sugerimos establecer un m?todo riguroso, para fuentes no invasivas de ADN, a modo de incrementar la precisi?n en la identificaci?n del

Large-Scale Movements and Habitat Characteristics of King Eiders Throughout the Nonbreeding Period

AbstractAbstractKing Eiders (Somateriaspectabilis) breeding inwestern Canada and Alaska molt wing feathers andspend the winter in remote areas of the Bering Sea,precluding direct observation. To characterizetiming of migration and habitat used by King Eidersduring the nonbreeding period, we collectedlocation data for 60 individuals (27 femalesand 33 males) over three years from satellitetelemetry and utilized oceanographic informationobtained by remote sensing. Male King Eidersdispersed from breeding areas, arrived at wing moltsites, and dispersed from wing molt sites earlierthan females in all years. Males arriving earlierat wing molt sites molted flight feathers at higherlatitudes. Distributions of molt and winterlocations did not differ by sex or among years. Ofthe variables considered for analysis, distance toshore, water depth, and salinity appeared to bestdescribe King Eider habitat throughout thenonbreeding period. King Eiders were located closerto shore, in shallower water with lower salinitythan random locations. During the winter, lower iceconcentrations were also associated with King Eiderlocations. This study provides some of the firstlarge-scale descriptions of King Eider migrationand habitat outside the breeding season.

Application of molted feathers as noninvasive samples to studies on the genetic structure of pigeons (Aves: Columbidae)

The application of molted feathers as noninvasive samples for studies on the genetic structure of pigeons (Aves: Columbidae) was examined using a newly developed universal primer set for the hypervariable left domain of mitochondrial control region, SXL0 and KXH5. The feathers of pigeons with downy barbs are easier to find and identify than those of smaller species. Thirty-four feather samples from eight taxa, which included five species from three distant genera, were used to test the universality of the primer set and the intraspecific variability of the target region. Approximately 500 base pairs of the target region were able to be amplified and sequenced for 33 samples from all eight taxa. For most of the multisampled taxa, the target region was highly variable, and was suitable for studies on genetic structure. The use of molted feathers along with this universal primer set would be a powerful tool to overview the genetic structure of pigeon species, because of its easy and noninvasive sampling method and readiness for subsequent genetic analysis.

Prebreeding moult, plumage and evidence for a presupplemental moult in the Great Knot Calidris tenuirostris

We studied the prebreeding moult and resulting plumage in a long‐distance migrant sandpiper (Scolopacidae), the Great Knot Calidris tenuirostris, on the non‐breeding grounds (northwest Australia), on arrival at the staging grounds after the first migratory flight (eastern China) and on or near the Russian breeding grounds (Russian data from museum specimens). We show that breeding plumage scores and breast blackness were affected not only by the increase in moulted feathers but also in the wearing down of overlaying pale tips of fresh feathers. Birds migrating from Australia and arriving in China had completed or suspended moult, but more moult must occur in Asia as Russian specimens had moulted more of their mantle and scapular feathers. Russian birds had significantly more red feathering on their upperparts than had birds in Australia or those arriving in China. The increase in reddish feathers cannot by accounted for simply by continuation of the prealternate moult. Instead, a third, presupplemental moult must occur, in which red‐marked feathers replace some scapular and especially mantle feathers that were acquired in a prealternate moult only 1–3 months earlier. Great Knot sexes show little size and plumage dimorphism, whereas two other sandpipers that have supplemental plumages (Ruff Philomachus pugnax and Bar‐tailed Godwit Limosa lapponica) are thought to be highly sexually selected. Bidirectional sexual selection may therefore be involved in the evolution of a supplemental plumage in Great Knots.

Avian assimilation and dispersal of carbon and nitrogen brought ashore by breeding Westland petrels (Procellaria westlandica): a stable isotope study

AbstractOnly a small proportion of the marine nutrients brought ashore by breeding colonial seabirds is retained in colony soils. However, means by which these marine nutrients can be dispersed to the wider terrestrial ecosystem have rarely been identified. In this study, moulted feathers from Hemiphaga novaeseelandiae (an endemic pigeon; n=9) and Gallirallus australis (an endemic flightless rail; n=3) and from a Procellaria westlandica (Westland petrel) colony were analysed for 13C and 15N enrichment. Potential diet items from both the colony and a control location were also analysed, and their contributions to the diets of H. novaeseelandiae and G. australis calculated. Hemiphaga novaeseelandiae assimilated marine N but not marine C, and showed a wide range in the significance of different diet sources. Food for most H. novaeseelandiae came from within the colony, implying minimal transport of marine nutrients to the wider terrestrial environment. All G. australis food came from within the colony, but 29–39% was from petrel tissue, or invertebrates feeding on petrel material. Thus, both H. novaeseelandiae and G. australis assimilated nutrients brought ashore by P. westlandica, but neither was shown to disperse the nutrients much beyond the petrel colony. However, birds that are now locally extinct may have dispersed marine nutrients more widely. Future research should focus on the consequences of restoring these species to petrel colonies as part of attempts to re‐establish the functioning of pre‐human ecosystems in New Zealand.

An overlooked DNA source for non‐invasive genetic analysis in birds

Non‐invasive sampling is a useful tool for genetic analyses of endangered and/or elusive species, but it is often inapplicable due to the low quality and quantity of the DNA obtained. In this study we show that the blood clot located in the superior umbilicus of the feather shaft is a better source of DNA than the previously used tip samples from moulted feathers. We found that feather clots from museum specimens provided results nearly as good as footpad and better than those from the more commonly used museum skin snips. Feather clots proved to be a good source of DNA for genetic analysis that will significantly facilitate genetic monitoring of wild bird populations.

Noninvasive genetic analysis in birds: testing reliability of feather samples

AbstractNoninvasive samples are useful for molecular genetic analysis of free‐ranging animals. I tested whether moulted feathers collected in the field are a reliable source of DNA for genotyping microsatellite loci. I prescreened extracts for DNA quantity and, using only samples with higher amounts of DNA, obtained reliable genotyping results. Polymerase chain reaction (PCR) amplification success was higher from extracts of plucked feathers than moulted feathers. DNA quantity in larger feathers was higher than that in smaller feathers. This study clearly demonstrates that moulted feathers could be used for genetic studies in birds.

Stress during feather development predicts fitness potential

Summary Measures of the quality of an individual are important in the study of proximate and ultimate factors in biology. Records of developmental history are particularly desirable, as many phenotypical traits are influenced by conditions during growth. Conspicuous irregularities in feathers, known as fault bars, result from a variety of stresses that occur during feather growth. The frequency of fault bars was evaluated on primary and tail feathers (grown 1 year previously) of 1919 adult American kestrels from a breeding population in Canada (1990–97). Most (91·5%) birds exhibited some fault‐barring, although females had significantly more feathers with fault bars than males (17% vs. 14%, respectively). Body size, intensity of haematozoan infections and leucocyte differentials were all unrelated to fault bars; however, birds with many fault bars were in poor body condition during prelaying (males) and incubation (males and females). Individual kestrels tended to be consistent in the number of feathers with fault bars from year to year. The percentage of feathers with fault bars was not associated with the timing of arrival in spring or prey abundance per territory; however, birds of both sexes with many bars were less likely to breed. Birds paired non‐randomly, as mates tended to have a similar frequency of fault bars. Males and females with many bars had significantly later clutch initiation dates, but there were no negative consequences regarding clutch size or egg size. Female kestrels with many fault bars had lower survival probabilities. Both sexes were also less likely to be recaptured in years following initial banding if they had many bars, suggesting that they were more likely to emigrate from the study area temporarily. Fault bars on feathers appear to be indicative of an individual’s susceptibility to stress, and are useful in predicting components of fitness. The use of fault bars is a promising tool as they are easy to evaluate and can be assessed on live or dead birds, on moulted feathers and on individuals repeatedly over time.

Habitat selection and use by a hybrid of white and Tibetan eared pheasants in eastern Tibet during the post-incubation period

We investigated habitat selection and use by a recently discovered hybrid of the white eared pheasant (Crossoptilon crossoptilon) and Tibetan eared pheasant (Crossoptilon harmani) in the forests of eastern Tibet (93°39'E, 32°24'N) during the post-incubation period in 1995. The frequency of encountering molted feathers was used as an indicator of the relative abundance of eared pheasants in order to analyze patterns of habitat selection and use. Forests on south-facing slopes, dominated by the hollyleaf-like oak (Quercus aquifolioides) and Tibetan juniper (Sabina tibetica), were the habitats preferred by eared pheasants. North-facing slopes with coniferous forest, which is the most preferred habitat of eared pheasant species in other areas, were completely avoided, probably because moisture-heat conditions there are beyond the birds' physiological tolerance. We conclude that climatic conditions are the main determinant of macrohabitat selection by eared pheasant species. In preferred habitats, oak and juniper woodland accounted for a larger proportion of home ranges of family flocks. Daily movements of a flock might cover a large altitudinal range, from the base of the mountain to the area above tree line, with an apparent preference for sites that can be used for foraging and dusting.

Habitat selection and use by a hybrid of white and Tibetan eared pheasants in eastern Tibet during the post-incubation period

We investigated habitat selection and use by a recently discovered hybrid of the white eared pheasant (Crossoptilon crossoptilon) and Tibetan eared pheasant (Crossoptilon harmani) in the forests of eastern Tibet (93°39'E, 32°24'N) during the post-incubation period in 1995. The frequency of encountering molted feathers was used as an indicator of the relative abundance of eared pheasants in order to analyze patterns of habitat selection and use. Forests on south-facing slopes, dominated by the hollyleaf-like oak (Quercus aquifolioides) and Tibetan juniper (Sabina tibetica), were the habitats preferred by eared pheasants. North-facing slopes with coniferous forest, which is the most preferred habitat of eared pheasant species in other areas, were completely avoided, probably because moisture-heat conditions there are beyond the birds' physiological tolerance. We conclude that climatic conditions are the main determinant of macrohabitat selection by eared pheasant species. In preferred habitats, oak and juniper woodland accounted for a larger proportion of home ranges of family flocks. Daily movements of a flock might cover a large altitudinal range, from the base of the mountain to the area above tree line, with an apparent preference for sites that can be used for foraging and dusting.

Sex identification in birds

Visually identifying the sex of a bird can be difficult. It cannot be done in half the world's species when they are adults, and virtually none can be sexed as chicks. Despite this, the sex of a bird is vital for aviculture, scientific research, and conservation. Over the years, surgery and chromosome inspection have been used for sex identification. At present, these techniques are being eclipsed by the use of DNA. DNA can be used because a male bird has two Z sex chromosomes, whereas the female has a Z and a W. Consequently, the presence of a W unique DNA sequence will identify a bird as female. However, the isolation of a W-linked marker can be laborious. This is being remedied through the use of two DNA amplification reactions, known as random amplification of polymorphic DNA (RAPD) and amplified fragment length polymorphs (AFLP). Unfortunately, the markers they yield are often nonfunctional DNA. This type of DNA is a mild parasite and makes up about 95% of the genome. It also evolves rapidly so that a test based on such a sequence will only work in a single species or a few close relatives. More recently, a W-linked gene has been found. This is named CHD1-W, and it evolves far more slowly than nonfunctional DNA. It can be used to sex all birds, barring ratites such as the ostrich. The technique is simple, cheap, and effective. To conclude, DNA sex identification is demonstrated in three situations: an experiment that has shown that birds can control the sex of their offspring; a race to identify the sex of the last wild Spix's Macaw from moulted feathers; and as a valuable aid to breeding in zoos.

An association of mangrove mutation, scarlet ibis, and mercury contamination in Trinidad, West Indies

An unusually high incidence of mutations in a local population of red mangroves on the island of Trinidad was associated with locally elevated mercury levels in the underlying sediments. This restricted mercury contamination surrounded a large roost of scarlet ibises. Molted feathers of ibises using the roost had high concentrations of mercury, which were probably acquired by the birds during their annual migration to wetlands in South America contaminated with run-off from gold mining operations. Decades of molted feathers accumulating around the roost apparently has created the local contamination problem.

Behavioural development in groups of pen‐housed pullets in relation to genetic strain, age and food form

1. Behavioural development in groups of 8 pullets kept in pens with litter floors, and fed on either mash or pellets, was studied from 0 to 10 weeks in a White Leghorn X broiler (F2) hybrid line (experiment 1) and from 0 to 24 weeks in Hisex, White Leghorn and Brown Leghorn strains (experiment 2). The aim was to identify precursors of feather pecking and cannibalism. 2. Rates of body weight gain were consistently greater with pellets than with mash in both experiments. In experiment 2, the onset of lay was at 17 weeks of age in Hisex, 21 weeks in White Leghorns and 23 weeks in Brown Leghorns. 3. Persistent feather pecking, which was not seen in experiment 1, developed in 2 of 12 groups (one Hisex and one White Leghorn, both fed on pellets) in experiment 2, and was studied in detail at 23 and 24 weeks. The more damaging pecking in the Hisex group was followed by cannibalism in the same group. 4. Based on the (often inconsistent) effects of genetic strain, age and food form on behaviour diat were observed, a working hypothesis was constructed to account for the aetiology of feather pecking and cannibalism in situations where there is floor litter. 5. An age‐related decline in one or more foraging activities may coincide with increases in preening and non‐damaging pecking at other birds. Consumption of litter particles and moulted feathers may be reinforcing. Dustbathing may enhance the stimulus value of litter particles when they are contrasted against background plumage colour. This may direct pecking towards the backs of birds, where feathers as well as litter particles may be removed and eaten. Regular pecking and feather removal may lead eventually, after the onset of lay, to vent pecking and cannibalism. This sequence of events may be more likely in groups where activity levels are high.

The demand for feathers as building material by woodland nesting birds

The demand for feathers as a nest-building material was investigated by placing feather patches in woodland and garden sites between January and June 1993 and March and April 1994. The first of 18 species to breed in the area which use feathers in their nests was the Long-tailed Tit. The feather requirements of this species are known to far exceed that of the other species. Long-tailed Tits were shown to forage actively for feathers up to 115 m from the nest but possibly not as far as 200 m. Patches generally remained untouched during the 24-h exposure but when detected were typically heavily exploited. Complete disappearance of feather patches occurred sporadically right to the end of the study. The woodland contained only a low standing crop of moulted feathers and it is concluded that natural feather patches resulting from kills are important for birds who need this nest material. It is suggested that Long-tailed Tits may be attempting to avoid competition for feathers by nesting early.

The Extinction of the Egret

IT will be remembered by those who are interested in the protection of the white heron that the feather dealers have urged that the breeding haunts, or garzeros, of these birds are guarded, and that the moulted feathers are picked up from the ground. From information which has been sent to me from the National Association of Audubon Societies, based on the sworn testimony of a man who has been personally engaged in feather collecting in Venezuela, it appears that while a few moulted feathers, worth possibly a fifth of the value of those taken from living birds, are collected, there is not the slightest foundation for the statement that the breeding places are protected for the purpose.