Thursday, March 5, 2015
What is a Blood Feather?
Depending on size, species and age, birds may have between 940 (hummingbird) and 25,216 (swan) feathers. Each of these feathers is molted and replaced on average every six months.
Feathers on a bird are not evenly distributed. They grow in distinct tracts or lines called pterylae, inbetween areas of bare skin called apteria. The apteria help cool the bird. Apteria vary in size and are typically covered with contour, or body feathers, that overlap the apteria. Because of the effects of water on feathers and ultimately on body temperature, water birds have small apteria and penguins have almost none.
New feathers emerging on the head of an African grey parrot. (photo: Dawn Trainor Griffard)
As a bird molts a feather, the new emerging feather pushes up into the base of the older feather, eventually forcing the older feather out of the follicle (place of feather growth) altogether. As a new feather grows into place, it is nourished with blood by a small artery, which allows for its growth.
The growing sheath the new feather, along with the feather itself, is formed of keratin – just like human fingernails. The growing sheath is semi-sharp and hard enough so it can press through the epidermis (outer layer of skin). During a heavier molt, this is the part of the process that makes our companion birds a little uncomfortable and crabby. It’s probably an annoying and itchy process!
Actively growing primary flight feather with a blood supply (photo: Dawn Trainor Griffard)
Before the new feather erupts from the growth sheath, it’s referred to as a “pin” feather until the keratin sheath falls off or is removed, and you can see the actual feather. As the feather grows the protective sheath either sloughs off or is preened off by the bird. When a feather completes its growth, the blood supply to the feather stops.
Problems can arise when a feather is accidentally damaged during its growth period. If a blood feather is damaged during its development, it can bleed profusely, endangering the health of the bird. Birds with actively bleeding blood feathers must be attended to immediately. However, only intervene if the feather will not stop bleeding. Usually the broken blood feather bleeds a little, then stops bleeding on its own. Then the body usually stops blood flow to the feather, the bird preens the broken feather out, and a new feather starts to grow. It’s most important to figure out how the bird broke the feather and make sure it doesn’t happen again.
Microscopic view of the “birth” of a feather (photo: Dawn Trainor Griffard)
If the bleeding will not stop, the blood feather is either carefully trimmed or completely pulled out – the latter of which is probably a painful procedure as the feather is often attached to a bone, so removal must be done expertly and quickly.
If the damage is slight yet the bleeding won’t stop, you can stop it with cornstarch and/or direct pressure. However, care must be taken that the feather does not receive further damage. In almost all instances the bird would have to be restrained for this procedure, so letting the bird’s body naturally take care of the broken blood feather is best.
Through its daily preening, the growth sheath is removed by the bird itself or a conspecific – usually the mate. In captivity, the bird’s keeper can often gently remove those growth sheaths the bird cannot reach (like on the back of the head), as long as the bird tolerates being touched.
At the World Bird Sanctuary our birds are fed nutritious diets and are monitored very closely to ensure that the molting process goes smoothly. If we see that one of our birds is having a problem with a bloodfeather or that a growth sheath is not being shed, we can step in and intervene to ensure the health and comfort of our birds.
Submitted by Dawn Trainor Griffard, World Bird Sanctuary Naturalist