The Academy of Natural Sciences of Drexel University has one of the 10 largest and most taxonomically diverse collections of birds in the world. Our Ornithology Department has over 215,000 study skins from over 7,000 species of birds.
The Specimen Preparation Process
The preparation of bird specimens is vital for preserving them for long-term use. We expect that specimens prepared today will last for centuries. In fact, there is material in our collections from the mid-1700s. Important ancillary materials from the specimens, such as tissue samples and ectoparasites are also collected for further study. We can use these specimens and their ancillary materials to answer numerous ecological, evolutionary, and environmental questions. For example, specimens can help us to analyze how species evolve over time, how environmental changes affect biodiversity, and why some species have gone extinct or have become endangered.
The preparation process can take anywhere from a few hours to multiple days depending on the species, its body size, and the condition of the specimen. Before we start removing tissue, we collect information about the physical features such as species, weight, color of eyes, bill, and feet if noted when fresh, and information about the presence of molting feathers. We also note collector information like where and when a specimen was found, who found the specimen, and the cause of death.
Once we record all of these data in our notebook, we are ready to begin to remove the skin from the carcass of the bird. We start by making a short incision down the breast with a scalpel. This allows us to begin to separate the skin from the body by peeling it away from the muscle below it. When the skin has been separated sufficiently to expose joints such as the wings, we reach in with scissors and forceps to cut bones and remove muscles. Ultimately, we peel away the entire skin with feathers remaining attached and remove the carcass, which we then dissect to take additional data.
Through the dissection, we take tissue samples, which are stored in the museum’s frozen tissue collection. We also note information about the gender, age, and stomach contents based on the dissection and description of internal organs. All of this data is recorded in the preparation notebook and then transcribed to a tag that is ultimately tied to the specimen.
After the dissection of the carcass, we continue to prepare the skin for stuffing by removing excess fat from the skin and the remaining muscles attached to the wings and legs, making sure to keep the ends of the wings and leg bones. Then, we finish skinning out the head by inverting the skin over the head and cutting the back of the skull to remove the brain and eyes.
Once all soft tissues and fat have been removed and we are left with just the inside out skin, we turn the skin back inside in, so the feathers are again on the outside. We tie the wing bones together to keep the wings tight to the back. Next, we use cotton to stuff the eyeball sockets and place a cone of cotton in the body cavity to give it the natural shape of a bird. After the body is stuffed, the midline is sewn together and the stitches are easily concealed by the feathers. Similar to the wings, we tie the legs together. To finish the specimen preparation, we pin the bird to a board and allow it to dry in this position.
Specimen preparation is not only about aesthetics, but also function. A well prepared specimen will not only look like the bird when it was alive, but it will be structurally strong, which will allow it to be measured and studied for centuries. The goal is to tuck in fragile structures like wings and legs as to minimize things that may break off when handled.
After a skin is prepared and the data tag tied to its legs, the specimen is ready for accession into the collection. The data in the notebook and on the tag is entered into the collection database and the specimen is “filed away” into the collection cases based on the species taxonomy and by the region from which it was collected. The study skins are kept in sealed metal cabinets in a temperature controlled environment.
You Can Help
If blood and guts does not sound like your forte, there are many ways to get involved! Often people come across deceased birds that have struck windows or buildings. If you have a plastic bag or storage container you can individually bag each bird. It is important to make note of information like the date and time it was found, the exact location where it was found, the species, and of course who found it (You!). Just be sure that the bird is not heavily decomposed yet.
You can also participate as a community scientist monitor for our Bird Safe Philly Project (see Community Monitoring Instruction and iNaturalist project at the Bird Safe Philly website.) You can also find detailed instructions and times for specimen drop-offs in the Community Monitoring Instructions PDF. If you can’t make it during those times, you can put the bird in your freezer to help preserve it and arrange for another drop off time. This is important work and is vital to further our understanding of birds. It can’t be done alone and we depend on the public to help us with this important research.
By Jenna Souto
Ornithology Laboratory Assistant Co-op