Conservation Challenges
© AMNH Feathers and fur are vulnerable to damage caused by any of the ten Agents of Deterioration. They can show color loss and fading due to light exposure, embrittlement and structural instability from poor environmental conditions in storage, distortion from insufficient housing or unsafe handling practices, and they can act as a food source for pests like moths or rodents. When they are incorporated into composite objects like taxidermy mounts, additional challenges may present themselves. Bird and mammal taxidermy contain both organic and inorganic components like preserved animal skin, fur, feathers, claws or horns, and internal mannikin materials like metal, clay, or plaster. Composite objects respond to environmental changes and other agents in dissimilar, and potentially incompatible ways.
Setting Preservation Priorities
To inform projects intended to advance the preservation of our collections, we often survey the physical condition of a group of objects or storage environments. In efforts to advance standards of practice at the AMNH and beyond, we also typically rely on community surveys that capture the experience and judgement of other professionals and stakeholders. This approach ensures that our research goals are centered on concerns that reflect common needs.
Research into conservation methods for fur and feathers was heavily informed by a condition survey of the AMNH Mammalogy Department taxidermy holdings; and two widely-distributed online community surveys about preservation practices for fur and feather objects.
Collection Survey: Mammal Taxidermy
In 2015-2016, AMNH conservators performed a condition survey of the taxidermy holdings in Mammalogy collection storage. The mounts were originally constructed for exhibition, but for a variety of reasons were removed from display. The primary goal of the survey was to deepen our understanding of the historic and modern materials and techniques used in creating these objects, and the common condition issues affecting them. We evaluated a total of 635 mounts using temporary examination stations and a custom-built File Maker Pro database, observing the condition of both the animal materials (hide, fur, antlers, teeth) as well as the materials added by the taxidermist (paint, armature, eyes, display base materials). Here’s what we found:
- 20% of the specimens were judged to be in Poor condition (Specimens requiring extensive and time-consuming interventive treatment due to structural instability of the internal armature, large splits in the skin, extreme loss, obvious fading from light exposure, etc.)
- 52% were judged to be in Fair condition (Specimens with obvious condition issues to address but would not take a significant amount of time to treat, such as small losses in prominent places, matted fur, and thick dust accumulation.)
- 25% were determined to be in Good condition (Specimens requiring minimal treatment to repair small splits in the skin, fill small areas of loss, etc. These types of minor condition issues may not be perceptible to the visitor but need to be corrected to represent the species.)
- 3% were in Excellent condition (Specimens that did not require any conservation treatment.)
The most common issues among all categories were splits in the skin and losses (of any material on the mount), followed by detached or loose (but not lost) fragments. These prevalent condition issues appear to have generally resulted from insufficient storage conditions. Dust accumulation and accretions, as well as fading, were also seen, though were not as prevalent and most likely a result display conditions.
As we began working toward developing best methods for remediating these condition challenges, we recognized that others in our professional community have worked through similar challenges and have valuable experience to share. What solutions have they determined work well concerning conservation and preservation of taxidermy, and of equal importance, what failed?
Community Surveys
Mammal Taxidermy and Fur
This 2017 online survey solicited responses from professionals who work regularly with mammal taxidermy collections, and included an audience of conservators, taxidermists, and museum preparators from five different countries (primarily the US and UK) and represented a variety of institution types.
Respondents discussed their experiences with taxidermy, noting condition issues similar to those observed in the AMNH collection. Splitting of the skin and hides was the most common issue for both specimens in storage and on display; fading of fur from light exposure was a top issue for taxidermy on display; and pest damage was common for specimens in storage.
Respondents ranked materials they “regularly”, “sometimes”, and “do not often” use for cleaning fur, stabilizing splits in the skin, filling losses throughout a mount, and recoloring fur. Through write-in responses, they described specific techniques in detail. These methods were gathered and implemented in our lab on test pieces to determine working properties, efficacy, and efficiency, then selectively used in conservation treatment of collection mounts. The purpose of this was not to standardize treatment materials and techniques, as treatment decisions must be dictated by the individual needs of an object by virtue of its composition, use, and historic, scientific, or artistic significance. Instead, the survey provided a starting point – a list of techniques that have been found effective on mammal taxidermy mounts. This informed our research concerning the restoration of faded fur, and our development of training resources for basic care and cleaning of mammal taxidermy.
Bird Taxidermy and Feathers
A second community survey developed in 2019 to support research focused on the conservation of feathers probed deeply into people’s current practices, practical and ethical concerns, and observations related to cleaning, pesticide use, and approaches to color loss for bird taxidermy and other feather objects. We publicized widely and heard from nearly 100 professionals from thirteen countries including conservators, collection managers, preparators, curators, taxidermists, and researchers most of whom work with collections of indigenous objects and taxidermy used in display, research, and education.
Respondents described common damages they observed in feathers, including dust accumulation, broken and disengaged barbs and barbules, whole or partial feather losses, and pest damage. They revealed in detail the wide diversity of treatment solutions used in collection care, as well as the ways that we as a community prioritize and evaluate outcomes. The resulting dataset was massive and offered strong direction for our experimentation.
Again results of the survey were not used to identify standard procedures. Instead, they guided the development of a research program in which cleaning methods, pesticides, and recoloring materials could be systematically compared to better understand their impacts on feathers.
Removal of accumulations of loose particulates is a primary concern of those caring for collections of feather objects, most often driven by the understanding that these materials to contribute to degradation over time, and to a lesser extent by the desire to restore the feathers’ natural appearance and physical properties, or remove residual pesticides. The importance of giving consideration to the potential removal of residues from past cultural use is recognized by most caretakers, and there is a smaller but very significant number of people who give similar thought to naturally occurring preen oils.
Survey respondents described approximately twenty dry cleaning methods and sixty wet cleaning methods that they use or have used to clean feathers. They discussed different equipment combinations, cleaning solutions, applicators, rinsing and drying techniques, commenting extensively on their experiences, both good and bad. While some methods were clearly preferred by most people, other methods were equally favored and avoided due to concern about their potential for causing damage, illustrating the difficulty of assessing risk in cleaning.
More than one in five respondents to our survey reported seeing damage in feathers that they attribute to the use of pesticides. Paradichlorobenzene, naphthalene, dichlorvos (DDVP) and mercuric chloride were most commonly associated with damages. Interestingly many people consider damage to include not just stains, crystalline deposits, discoloration, changes in gloss, and embrittlement, but also odor and latent toxicity that may make an object inaccessible to researchers.
However nearly half of respondents expressed concern that a link between pesticides and damage in their collections may exist, but that they cannot assuredly relate cause and effect. Indeed much of our current understanding of how pesticides impact feathers remains anecdotal. In part this is likely due to the fact that pesticide exposure often takes place over long periods of time, so any resulting damage would occur gradually. And the nature of some damages attributed to pesticides (fading, embrittlement) may be difficult to distinguish from the impacts of other agents, such as light exposure. The impacts of pesticide use on feathers can be challenging to isolate and monitor, but there are sufficient reports of damage that caution is recommended until further research on this question is available.
Though restoring feathers through the direct application of colorants would be considered controversial in many collections, it is more widely accepted for taxidermy. This reflects an acknowledgment that exhibiting faded mounts does not reflect the naturalistic appearance of the species, which is generally prioritized in the display of natural history specimens, and may be considered misleading or contrary to artistic intent.
Past recoloring efforts in taxidermy collections are fairly common, varying greatly in the quality of their execution as well as their longevity. While some have been successful, in other cases heavy applications of paint have caused barbules to adhere, inhibiting normal maintenance. Some people caring for these collections have also reported uneven aging of original pigmentation versus recolored areas, transfer of loose pigments, and difficulty blending colors. In one case overpaint was applied to a specimen of research value, obscuring taxonomically significant features.
Of those currently caring for collections containing feathers, at least one in five executes or oversees this type of restoration, most commonly with dry pigments. Though these treatments were considered successful at least part of the time, these respondents spoke to the difficulty of removing recoloring materials, of recreating or maintaining the translucency and gloss of the original feathers, and to the tendency for applied colorants to interfere with barb engagement.