Birds are warm-blooded vertebrates, but more closely related to reptiles than mammals on the evolutionary pathway. Scientific research, including the discovery of Archaeopteryx, with its distinctively avian feathered wings, has revealed that birds are present-day relatives of dinosaurs. Birds are the only living animals with feathers, a unique adaptation that performs a number of life-sustaining functions beyond enabling flight. For a bird, maintenance of those feathers is so important that it warrants spending hours preening each day. Preening keeps the feather structure clean and intact and also allows feathers to retain the sheen and the brilliance of the color. Most birds apply uropygial gland secretions (preen oil) during preening for water repellency and control over feather-degrading bacteria.
IMPORTANT REMINDER – FEATHERS ARE PROTECTED
Due to this rigorous upkeep, the feathers that we received for this project from local wildlife rehabilitation organizations (Raptor Trust, Volunteers for Wildlife, USDA APHIS Wildlife Services) were in very good condition. As discussed in a previous post using unprocessed feathers is vital to the accuracy of our research. Commercially available white feathers are cleaned, bleached and often dyed, removing the natural preen oils and potentially altering the chemical structure.
For our cleaning study we chose downy body and contour feathers from the wing (primarily coverts, which conceal the base of the primary and secondary wing feathers) of the Mute Swan, from three specimens of which were salvaged and donated for the project by the Raptor Trust, Volunteers for Wildlife and the USDA APHIS Wildlife Services. Mute Swans (Cygnus olor) can have upwards of 25,000 feathers, the majority being soft, insulating downy feathers. In contrast, their contour feathers have interlocking barbules that give them their smooth surface and rigid structure allowing the bird to maneuver in flight. Contour feathers include flight and tail feathers and body feathers which cover the downy feathers on the bird’s outer body. As the outer layer, they are naturally exposed to the greatest amount of sunlight and general wear. [1]
The delicate structure of the wing coverts of the Mute Swan is representative of many feather types that one encounters when cleaning soiled feathers and bird taxidermy. We like them as well for our research as they are consistent in size and texture, flexible enough to be flattened for analytical measurements, and plentiful enough on the bird that it is feasible to collect the quantity needed for this project.
[1] For detailed information on feather morphology visit The Feather Atlas, created by the US Fish and Wildlife Service. It is a valuable resource which promotes feather identification, research, and appreciation by providing high-resolution scans of the flight feathers of North American birds.
The salvaged swan specimens were first placed in an ultra-cold walk-in freezer for several weeks in order to kill any potentially damaging pests. After thawing the specimens for 24 hours, we carefully and methodically removed the feathers and separated them by type and size. Most were plucked by hand, but some of the larger wing feathers were clipped.
The information we will acquire from these natural white feathers will help the Museum to better understand how to preserve the existing collection of scientifically valuable bird specimens, which are critical to ongoing biodiversity research and education.
Leslie Vilicich has been volunteering in the Natural Science Conservation department since May 2019 and officially joined the team in January 2020 in her position as pre-program intern for the IMLS funded feather research project
In Their True Colors 