Feathers

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Contributors: Molly Gleeson; Renée Riedler; Yuri Yanchyshyn; Elena Best
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Copyright: 2012. The Objects Group Wiki pages are a publication of the Objects Specialty Group of the American Institute for Conservation of Historic and Artistic Works. The Objects Group Wiki pages are published for the members of the Objects Specialty Group. Publication does not endorse or recommend any treatments, methods, or techniques described herein.

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THIS ENTRY IS A DRAFT

Materials and technology

Materials

Feathers are the unique epidermal growths of birds, which allow for flight and provide insulation and waterproofing, environmental protection, and allow for display and camouflage. Like hair and horn, feathers are made of keratin. For the purposes of conservation documentation, preventive care and treatment, it is useful to become familiar with some of the basic terminology used to describe feather parts, types, location and color.

Feather parts

• Calamus: the hollow inner portion of the feather shaft that lacks barbs and attaches to the skin; sometimes called the quill

• Rachis: the solid upper portion of the feather shaft, to which the barbs are attached

• Vane: extends from each side of the rachis, made up of interconnecting barbs

• Barbs: individual parallel strands or branches extending laterally from the rachis

• Barbules: lateral, hair-like branchlets extending from the barbs

• Barbicels: hooks that cover barbules and that interlock with each other upon contact

Feather types

• Contour: These feathers make up the majority of feathers visible on a bird. They typically have a stiff shaft that extends their entire length and a vane on each side of the shaft. Also called pennaceous feathers.

• Semiplume: In appearance, semiplumes fall between contour feathers and down feathers, combining a large rachis with downy vanes, due to the fact that the barbs lack barbules. Semiplumes are distinguished from down feathers in that the rachis is longer than the longest barbs.

• Down: Fluffy feathers that appear to lack structure. The barbs of these feathers lack barbules, and the feather shaft is either reduced in length or missing altogether.

• Filoplume: Simplest type of feather, consisting primarily of the rachis with little to no barbs.

• Bristle: Highly specialized, small contour feathers which lack barbs on the outermost part and have a stiff rachis.

Feather locations

• Remiges: Flight feathers on the wing. Outer wing feathers (primaries) are pointed and have a distinct narrowing in the posterior vane, called a notch. The inner wing feathers are called secondaries.

• Rectrices: Flight feathers on the tail. The outermost tail feathers are asymmetrical with a narrow outer and broad inner vane. Towards the center of the tail the feathers are more symmetrical.

• Coverts: Feathers that border and overlay the edges of the remiges and rectrices on both the lower and upper side of the body.

• Afterfeather: Much smaller feathers attached to the lower shaft of some contour feathers; resemble the main feather.

Feather color

Hill et al. 2006

Identification

The identification of bird species from feathers and feather fragments is most challenging. Variation in color, size and shape occurs not only among families but also within individual species. Nevertheless there are similar characteristics that cross species and family, therefore morphology, size, color and color pattern contain valuable information. See Scott et al. 2010; Trail 2003.

The identification of bird species from feather fragments like barbs, barbules, nodes and pigmentation pattern (forensic feather identification) requires extensive training in microscopy. See Dove et al. 2010.

Deterioration

Clothing moth larval case on feather. Photo by Renée Riedler.

Insect damage

Feathers are susceptible to attack by insects and other pests, especially those that feed on protein-based materials. While still on the living bird, feathers can be damaged from feather lice and mites. Once incorporated into artifacts, feathers may be damaged by a variety of insects, including clothing moths and carpet beetles. In both clothing moths and carpet beetles, it is the larvae that cause damage.

Insect damage is found on feathers in the form of losses to the shaft and barbs, grazing on the shaft and barbs, and webbing, cases and frass left behind on the feathers and surrounding materials.

Mechanical Damage

Feathers sustain mechanical damage both while on the living bird and after the feathers have been harvested and incorporated in an artifact.

Mechanical damage that occurs on the living bird includes fault bars and vane loss from fault bars. Fault bars are narrow, translucent bands caused by defective barbule formation, often caused by stress in the bird. Within a fault bar, the barbules are either aberrant or missing entirely. These translucent bands are susceptible to feather breakage and can leave a feather with more than one fault bar with the appearance of a serrated edge.

Other types of mechanical damage seen on feathers include unlocked barbs and abrasion, bends, breaks on both the shaft and the vanes.

Conservation and care

This information is intended to be used by conservators, museum professionals, and members of the public for educational purposes only. It is not designed to substitute for the consultation of a trained conservator.

• To find a conservator, please visit AIC's Find a Conservator page.
  

Preventive conservation

Please refer to the Objects wiki article on Preventive Care for recommended general practices.

Interventive treatments

Cleaning

Both wet and dry methods may be employed to clean feathers though special care must be taken to ensure that the fragile barbs are not distorted or broken.

Effective dry-cleaning methods include using an air puffer to blow off dirt, gentle brushing with synthetic or squirrel hair brushes, or gentle vacuuming with a Velux-covered, small attachment, though it should be noted that Velux may leave behind fibers visible in UV.

Wet cleaning carries a risk of color change and distortion but may be necessary on heavily soiled feathers. Some proposed methods include odorless mineral spirits and ethanol. Deionized water is an option but can cause barbule deformation in highly degraded feathers.

Initial studies have been conducted regarding the impact of various cleaning methods on feathers (Elkin, Sybalsky, Paulson and Waller 2023).

Aesthetic reintegration

Feathers, like other keratinaceous materials, are susceptible to light damage and often fade over time.

Some methods to restore color include the use of Golden’s Qor Modern Watercolor. These are pigment-loaded paints bound in Aquazol that can be solubilized in ethanol. Qor watercolors do not transfer when dry, can be diluted and offer a range of colors. Testing shows that Qor may not be fully reversible, and different concentrations may cause clumping or uncontrolled wicking into the rachis.

Colorfin’s PanPastels are also an effective colorant. They can be applied dry and blended in situ, avoiding exposing the feather to moisture. They, too, are not reversible though with effort can be reduced somewhat through vacuuming through a clean cloth.

A third method has shown some success – the use of Kremer’s XSL Pigments. These are micronized pigments that can be mixed with water instead of a binder, and they can be applied with airbrush or brush. It should be noted that the use of water may damage the feather, and that occasionally, these pigments gave uneven coverage. Full reversibility is not possible.

In detail discussion of feather colorants can be found on the American Museum of Natural History’s website under “Feathers and Fur” (AMNH 2024).

References

American Museum of Natural History. 2024. "Feathers and Fur." https://www.amnh.org/research/science-conservation/material-type/feathers-and-fur

The Cornell Lab of Ornithology. All About Birds

Dove, C.J., Koch, S.L. 2010. Microscopy of Feathers: A practical Guide for Forensic Feather Identification. Journal of American Society of Trace Evidence Examiners 1(1):15-61.

Elkin, Lisa, Julia Sybalsky, Michaela Paulson, and Robert Waller. "Using Digital Capture and Multi-Criteria Decision Analysis to Rank the Impact of Cleaning Processes on Feathers." ICOM-CC, 2023. Accessed October 17, 2024. https://www.icom-cc-publications-online.org/5592/Using-digital-capture-and-multi-criteria-decision-analysis-to-rank-the-impact-of-cleaning-processes-on-feathers.

Hill, G.E., McGraw, K. J. eds. 2006. Bird Coloration. Mechanisms and Measurements, vol. I. Cambridge, MA: Harvard University Press.

Scott, S. David and Casey McFarland. 2010. Bird Feathers: A Guide to North American Species. Mechanicsburg, PA: Stackpole Books.

Trail, P.W. 2003. Identification of Eagle, Feathers and Feet. Identification Guides for Wildlife Law Enforcement No.3. Ashland, OR: USFWS, National Fish and Wildlife Forensic Laboratory.

Trail, P.W. 2003. Identifying the Flight Feathers of the Large Macaws. Identification Guides for Wildlife Law Enforcement No. 4. Ashland, OR: USFWS, National Fish and Wildlife Forensics Laboratory.

Further reading

Identification of Materials

• Identification Guide to Decorative Feathers of Pheasants, Chickens, Turkeys and Related Birds - http://www.lab.fws.gov/idnotes/_PheasantFeathers_final.pdf.

• Miscellaneous Wildlife Identification Notes and Guides: tusks, bones, fake ivory, bear claws, rhino horn, various cat pelts, various bird feathers, sea turtles - http://www.lab.fws.gov/idnotes.php

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