Handling and Care of Dry Bird and Mammal Specimens
Conserve O Gram September 2006 Number 11/9 Handling And Care Of Dry Bird And Mammal Specimens
Introduction Organization Natural history specimens represent the bio- logical legacy of our predecessors. They are the Taxonomic arrangement tools used by researchers to assess how species are distributed in geographical and ecological There are a variety of schemes to organize bird time and space. How we care for these collec- and mammal specimens. They can range from tions today will directly affect their significance following a fully phylogenetic arrangement that and usefulness in the future. Some bird and organizes taxa to the subspecific level based on mammal specimens in North American collec- a recognized taxonomic authority to a simple tions are over two hundred years old. All speci- alphabetical arrangement by family or genus. mens, new or old, share common preservation The system followed should be logical, intuitive, and maintenance needs. The handling and care and efficient, and should allow researchers to of dry bird and mammal skins, skeletons, and easily find specimens of interest. Not all users parts is highlighted in this Conserve O Gram. of natural history collections are knowledgeable systematists, so base the scheme on how the Storage collection will be used and by whom. Always document the arrangement of the collection A well-sealed cabinet is the best protection and post a copy handy for researchers and staff. for bird and mammal specimens. The cabinet shields specimens from UV light, dust, pollut- Physical arrangement ants, insect pests and rodents, and moderates ambient temperature and relative humidity. Study skins of birds and mammals are gener- Always return specimens to the cabinet after ally placed directly in drawers or compartmen- use and close the doors after removing or talized in trays within drawers. Specimen trays installing specimens. Never leave the speci- provide a convenient way to sort specimens mens outside the cabinet overnight. Doing by sex, locality, species or subspecies. They so can expose them to damage by rodents or make it easier to remove a series of specimens insect pests such as clothes moths and dermes- at a single time for examination. All materi- tid beetles. Returning an infested specimen als should be “archival or museum quality”, a to a cabinet will expose the entire contents term connoting permanence and durability but to a potential insect infestation. For suitable for which there is no universally agreed-upon sources of vertebrate cabinets see Conserve O meaning (Cato et al. 2003). Ideally, drawers Gram 4/10. (if no trays are used) and trays should be lined National Park Service Conserve O Gram 11/9 Conserve O Gram 11/9 National Park Service
with unbuffered cotton blotter paper. This and “Covers” in Rose and Torres (1992). serves a variety of functions including reduc- ing movement of specimens when opening Bird eggs and nests: Eggs need protection and closing drawers, absorbing grease and oil from breakage and to ensure they do not roll. still remaining on the skin and thus prevent- Use polyester batting to wrap each egg and ing the staining of trays, and improving the then place in a box lined with polyester or museum staff’s ability to see specimen damage cotton batting for additional protection. Nests or insect frass resulting from an insect infesta- can be stored in boxes made of clear polysty- tion. Small birds such as hummingbirds are rene or archival board. See-through boxes or often stored in round plastic tubes due to their those with Mylar® windows are practical for fragile nature. Flat skins and tanned hides of viewing the contents without opening the con- large mammals such as mountain lions and tainer. For additional protection use a layer of foxes should be stored flat in drawers. A less polyethylene foam to line the bottoms of the preferable but more common practice is to nest boxes and secure each nest with a “ring” hang skins over padded support bars with the of unbuffered blotter paper. Other sugges- weight supported evenly. This can cause skins tions are found in Cato (1986). Eggs and nests to stretch no matter how much care is taken are usually stored separate from the skin col- with the skins. lection.
Mounted birds and mammals are usually Skulls and skeletons (osseous material) are stored separate from the dry skin collections. generally stored in vials or boxes. Vials can be They typically require more storage space due made of glass or polyethylene plastic (there to their irregular shape. If they are placed on are pros and cons to both), and can be round drawers in cabinets they will need additional or square (the latter shape prevents rolling). support to keep them from toppling over After prolonged exposure to some chemical when the drawer is opened. Frequently, they fumigants i.e., paradichlorobenzene (PDB), are stored on stationary shelves or specially vials made of polystyrene have been known to designed racks that accommodate differ- show signs of “crazing”, a type of deteriora- ent sized objects. If stored on open shelves tion that forms very fine cracks in the surface they should be protected with dust covers of the vial. Polyethylene caps or archival made from materials such as cotton or poly- foam rod plugs are preferred covers for vials ethylene sheeting. The dust covers protect- over corks because they reduce the amount of ing open shelving mount storage should be acidic wood products in natural history collec- opaque to add protection from light. Antlers tions. Containers should be large enough that and mounted heads of deer and elk can be specimens can be removed and replaced with- suspended from heavy gauge hardware cloth out damage. Bird skulls traditionally remain using padded supports. Do not drill holes in inside the skin; whole bird skeletons usually are the specimen to anchor it to support brackets stored separately from the skins to conserve because of the irreparable damage it causes. If space. The skins and skeletal components of space and materials are available, however, it mammals are usually stored together but in is preferable to store these specimens on open separate trays. A series of vials can be stored shelving or in closed cabinets. See additional in trays that either fit within the skin tray (but suggestions listed under “taxidermy mounts” not on top of specimens) or just outside the
2 Handling and Care of Dry Bird and Mammal Specimens Handling and Care of Dry Bird and Mammal Specimens 3 National Park Service Conserve O Gram 11/9 Conserve O Gram 11/9 National Park Service
tray. To keep vials from rolling in a tray, use specimen and support the rest of the specimen stable non-acidic products such as polyethylene with the other hand. The skins of small birds foam, not wood blocks or cork. The skulls and or those with long or very fragile legs are also skeletal elements of large mammals should be sometimes prepared with a support stick in stored in boxes or trays or on padded shelves. the middle of the body to provide extra sup- The cranium and mandible of the skull should port. Handle these birds by the support stick not be stored with the teeth in direct contact but because the stick is anchored into the skull. because this can cause breakage of the teeth. Take care not twist or twirl the specimen by It is preferable to store the skull and mandibles the stick as this can loosen the anchorage point with the teeth facing up; if stored so that the of the stick. Handle wings carefully taking teeth occlude, separate them with a padded care not to slide a wing along a surface against layer of polyethylene foam. the grain which might damage the feathers. Never handle specimens by the tags or labels. Handling After returning specimens to a cabinet, be sure Wearing gloves reduces the transfer of oils there is enough space between the top of the and dirt from individuals to specimens and specimen and the bottom of the drawer above vice versa. Cotton gloves are suitable when before sliding in the drawer. Tips of ears of handling recent collections but when handling some rodents are prone to sticking up and ears older specimens, those collected before the of lagomorphs (rabbits and hares) are espe- 1970s, latex or nitrile gloves are recommended. cially high and can be easily broken when slid- The insides of skins of many older specimens, ing in a drawer with inadequate clearance. particularly taxidermy mounts, were treated with arsenic and other insecticides, or pesti- Mounted specimens of birds and mam- cides and fungicides i.e., mercuric chloride, that mals are awkward and can be heavy to handle can leach through the cotton fibers, making alone. Ask for help when moving a large latex and nitrile a better choice. Research- mount and use carts with support straps when ers are required to wear gloves when working possible. Wear gloves when handling older in NPS collections, but for many non-NPS (collected before the 1970s) specimens because natural history collections there are no restric- of the past practice to treat the insides of skins tions. If gloves are not worn, wash your hands with arsenic or other chemicals to repel insect before and after handling any specimen. pests.
Skins: Handle bird and mammal skins one at Bird eggs and nests: Due to the fragility of a time by placing your hand around the main eggs, some museums allow them to be handled part of the body. Do not grasp the extremi- only in the presence of a curator or collection ties or other fragile parts of the body. Use manager. both hands for larger or heavy specimens or for large birds with spread wings or long legs Skulls and skeletons: These materials are or necks. Some rabbits and other long-legged fragile but hold up well if handled at the mammals are made into study skins with a thickest part of the bone. Use fine-pointed wooden dowel between the legs to help sup- forceps to pick up individual bones or bones port the legs. Grasp the dowel to pick up the from small specimens. Small bones and frag-
2 Handling and Care of Dry Bird and Mammal Specimens Handling and Care of Dry Bird and Mammal Specimens 3 National Park Service Conserve O Gram 11/9 Conserve O Gram 11/9 National Park Service
ments are easy to lose so take care to return blotter paper. everything you removed to its original, correct container. Check to see if bones are num- Once egg and nest collections are properly bered and, if not, do not remove contents prepared there is only minimal care that needs from more than one container at a time. By to go into these collections. The main care for placing bony elements on a sheet of paper or eggs is to make certain they are well protected box lid you can gently slide them back into from rolling. Egg and nest collections do have the container. The bony processes of small to be protected from excesses of light and mammal skulls, e.g., the zygomatic arches and humidity; too humid an environment can cause pterygoid processes, are especially fragile and mold growth or Byne’s Disease on eggs. can break easily if held too tightly between the fingers. Hold small skulls of bats, shrews, and Insect activity should be monitored regularly mice by grasping lightly between the top and by placing sticky traps throughout the collec- bottom of the skull or cradle them in a hand tion room. The data provide a useful record for examination. The skulls of certain families of pest trends, i.e., seasonality, abundance of birds, such as flycatchers, are fragile as part and diversity, etc. If rodent droppings are of the skull never fully ossifies. Handle these found in collection areas, it is preferable, and skulls with great care. more humane, to use live traps to capture and remove the rodents. Maintenance The single most important step in maintain- Collection staff can easily reduce the amount ing specimens is to inspect skins for the pres- of “maintenance” needed for specimens if ence of insect pests if a problem is suspected. “common sense” practices prevail from the Inspection is done by systematically lifting time the specimens arrive in the collection to each bird or mammal skin in a tray or drawer each and every time they are accessed. Ensure and looking for obvious signs of an infesta- that specimens are not brought directly into tion: clipped fur or feathers, insect frass, or a the collection unless they are determined to live insect (adult or larval form). The insect be 100% pest-free, and that specimens are frass of different species is diagnostic and can returned to the cabinet after use, and are never sometimes be readily identified, for example, left outside a cabinet overnight. clothes moth frass resembles coarse ground black pepper. All signs of an active infestation Apply good housekeeping rules to the collec- are easier to see if tray or drawer bottoms are tion space: regularly vacuum or damp mop light-colored or lined with white blotter paper. the floor and wipe the tops of cabinets and Specimens should always be inspected when- all work surfaces with a damp cloth to remove ever they are moved by museum staff. dust. Do not sweep as this only shifts dirt and dust. Inspect cabinets periodically to Despite our best intentions, specimens can get ensure the door fits tightly and closes properly. attacked by insect pests and at this point imme- Inspect gaskets for wear and replace when diate action is required. Method of treatment necessary (see guidelines in Raphael and Cum- depends on money, space, and resources avail- berland 1992). As tray liners or blotter paper able to the museum staff. Effective options become greasy or stained, replace with new are freezing, anoxic (low oxygen) treatment,
4 Handling and Care of Dry Bird and Mammal Specimens Handling and Care of Dry Bird and Mammal Specimens 5 National Park Service Conserve O Gram 11/9 Conserve O Gram 11/9 National Park Service
and isolation and monitoring. Here are a few 234 in Storage of natural history collections: ideas suggested sources of information: freezing and practical solutions (Rose, C.L., A.R. de Torres, procedures: Florian 1990; Strang 1997; Con- eds). Society for the Preservation of Natural serve O Gram 3/6; Anoxic treatment: Burke History Collections. 346 pp. 1996; Daniel 1995; Conserve O Gram 3/9; General treatments: Conserve O Gram 3/8. Rose, C.L., A.R. de Torres (eds). 1992. Storage of natural history collections: ideas and practical solu- Sources of Supplies and Equipment (can tions. Society for the Preservation of Natural include for the following products if this is History Collections. 346 pp. warranted: plastic specimen tubes, cotton blot- ter paper, Mylar-windowed boxes, polystyrene Strang, Thomas J.K. 1997. “Controlling insect boxes) pests with low temperature.” CCI Notes 3/3. Canadian Conservation Institute, Ottawa. References
Burke, J. 1996. “Anoxic microenvironments: a Cindy A. Ramotnik simple guide.” SPNHC Leaflet 1 (1):1-4. Soci- Museum Specialist ety for the Preservation of Natural History U.S. Geological Survey, Biological Resources Collections, Washington, D.C. Discipline Fort Collins Science Center Cato, P.S. 1986. “Guidelines for managing [Arid Lands Field Station, Museum of South- bird collections.” Museology No. 7. Texas Tech western Biology] University, Lubbock, TX. 78 pp. University of New Mexico Albuquerque, NM 8713 Cato, P.S., J. Golden, and S.B. McLaren (com- pilers and eds.). 2003. “MuseumWise: work- place words defined.” Society for the Preservation of Natural History Collections, Washington, D.C.
Daniel, V. 1995. Storage in low-oxygen envi- ronments. Pp. 147-155 in Storage of natural history collections: a preventative conservation approach The Conserve O Gram series is published as a reference on collections management and curatorial issues. Mention of (C. Rose, C.Hawks, and H. Genoways, eds.). a product, a manufacturer, or a supplier by name in this Society for Preservation of Natural History publication does not constitute an endorsement of that Collections. 448 pp. product or supplier by the National Park Service. Sources named are not all inclusive. It is suggested that readers also seek alternative product and vendor information in order to Florian, M-L. 1990. “Freezing for museum assess the full range of available supplies and equipment. inspect pest eradication.” Collection Forum 6 (1): The series is distributed to all NPS units and is available to non- 1-7. NPS institutions and interested individuals on line at
4 Handling and Care of Dry Bird and Mammal Specimens Handling and Care of Dry Bird and Mammal Specimens 5