Feathers and flight are the primary facets of bird rehabilitation that make it uniquely more difficult than mammal rehabilitation. Feather condition is as critical during the course of release for birds as is the ability to fly. Any type of damage to the feather structure will impede a bird's ability to fly, waterproof, and thermoregulate. In short, birds with compromised feather condition will have a low survival ratio following release.
Birds regulate their body temperature using feathers; they fluff their feathers to trap air inside the layers, which provides additional insulation. If there are breaks in this "suit" of insulation, the bird's ability to maintain it's body temperature is greatly impaired.
Birds preen to tighten the weave of their feathers, then add a thin layer of oil which acts as hairspray to keep it in place. This process waterproofs them, which causes water to bead off their feathers. In the case of waterfowl, this process makes them bouyant. A released bird that is not waterproofed would be grounded following a rain and unable to fly, making it vunerable to predation. Waterfowl that are not waterproofed are at risk of drowning (ALWAYS bring a net when releasing waterfowl - just in case).
Each feather on a bird's wing serves a specific function in flight. These feathers are critical for obtaining lift (height), speed and for the tight manuevers necessary to escape from predators. Tail feathers have similiar tasks. Releasing a bird with wing or tail feather damage is comparable to releasing a mammal with a compromised limb.
To further compound the problem, the majority of birds have only one annual molt. Waiting for new feather growth is unrealistic in most cases. Isolating the problem is sometimes as difficult as finding a solution. By starting with feather quality, we can be break it down into several categories, which will help to possibly identify the cause and the steps necessary to correct the problem.
- Feather Lice/Mites - Lice are difficult to see, but make the ends of all feathers look sheered. The lice themselves look like flattened houseflies and are more prevelant on larger birds. Mites are pin-sized parasites that are common on all species of birds. They are difficult to find when in small numbers, but usually not missed when they completely infest a bird. Feather damage by mites is minimal, but the feathers will have a dirty or unkempt appearance. Holding the bird in a white towel for a few minutes will usually reveal the mites. Both lice and mites can cause substantial feather damage, and both can be treated using kitten flea powder. Using a toothbrush, lightly brush powder into the feathers on the head and neck area. Do this first, otherwise the insects will migrate there looking for places to hide. Next lightly dust the bird's body, including the underside of the wings and vent area, with the powder. Wrap the bird loosely in a small handtowel (with it's head exposed) for 10 minutes. If the bird was housed in a cage or with cagemates, both will also need treatment to prevent reoccurence. A bird that is preening regularly is usually able to keep mite numbers in check. A mite infestation is a sign that other problems exist. Both mites and lice can cause anemia and appropriate treatment should be provided as well.
- Housing - too often, caging that is too small or inappropriate for the species will cause ragged feathers. Seagulls and ducks left in carriers too long will get "split ends". As will woodpeckers that are left in wire cages without suitable logs. Songbirds will run back and forth along cages, slowly wearing away tips of their flight and tail feathers. It is important to provide ample perching/clinging areas in a cage that is suitable for the bird's size.
- Bacteria - Bird feathers naturally contain bacteria. Not only is access to sunlight necessary for vitamin D3 synthesis, sunlight has been shown to inhibit feather-degrading bacteria1.
Dirty incubators and housing only contributes to more bacteria on birds' feathers.
Birds that are grounded in aviaries due to wing injuries or existing feather damage, or housed for extended periods in carriers would be more prone to higher levels of feather bacteria.
Birds that are compromised and do not regularly preen risk degradation of feathers.
The quality of soil in our aviaries may actually impede reconditioning of feathers. We can speculate that access to clean water sources for bathing, direct sunlight rays for sunning, fine dirt for dusting, quality soil in our aviaries, etc may all play critical roles in feather quality and may be vital in controlling feather-damaging bacteria and improving overall feather quality.
- Housing - again, the wrong type of housing can result in plenty of feather problems. This is also very common when a bird is compromised and has difficulty getting around, especially with wing wraps. If a compromised bird has limited mobility but is still very active, provide extra perches low in the cage so that it can move from one to the next without going to the bottom of the cage. Nighttime "visitors" to the aviary can also cause night flight, which causes the birds to injure themselves as well as break feathers during their panic.
- Nutritional - very rarely will an adult bird that is housed correctly begin unexplainedly breaking off feathers. This is a much more common complaint with juvenile birds that are being prepped for release in aviaries. The new stresses they place on their feathers in flight cages is devastating if they did not receive the appropriate diet while being reared. Before taking any corrective action for feather condition, it is imparative to provide the appropriate diet for a minimum of 2 weeks. In other words, don't start pulling feathers before the bird has had access to essential nutrients. Otherwise, you will only encourage more weak and brittle feathers to grow (and they too will break off). In the unlikely scenario that it was a nutrient absorption problem, you will need to find alternate sources of the same nutrients.
- Access to bathing water/water quality Dirty water bowls are equivalent to taking dirty baths. Birds need access to clean water for bathing several times a day. Hard water can leave mineral deposits on feathers. For water birds, residual oil in their pools from fish provided as food can contaminate feathers. Overcrowding and aggressive cagemates can also impede bathing.
- Underlying condition - A healthy bird knows that preening is essential to survival. If a bird is not preening, it will be necessary to completely re-screen the bird for illnesses or injuries that were previously missed. The primary cause of this type of problem lies with internal and external parasites. If everything else checks out physically, get a fecal done.
Discoloration, Weak, or Missing Feathers
- Nutritional - Again, this is a common complaint with juvenile birds. Feathers with clear thin stripes, white feathers or exposed skin surfaces are nutritionally related. Before taking any corrective action for feather condition, it is imparative to provide the appropriate diet for a minimum of 2 weeks. In the unlikely scenario that it was a nutrient absorption problem, you will need to find alternate sources of the same nutrients.
Since the majority of feather damage during rehabilitation is caused by housing or nutrition, it is always necessary to correct those issues first before tackling the feathers themselves. Housing suggestions are provided below, but nutritional recommendations are species-specific and require research on your part.
- Provide ample perches and landings.
- If birds are "pacing" and causing wear on their feather tips, line the inside of the wire with a tangle-free cloth.
- Provide "ladders" to higher perches for birds that are wing-wrapped or unable to fly, which will prevent jumping (which breaks more feathers). This has been the most effective method we have found for those "ping-pong" birds that had broken off all their flight or tail feathers but still insisted on attempting to roost high.
- Sometimes moving the bird to a smaller cage until new feather growth begins helps.
- Provide high roosting areas and visual screens to limit night flight if night time visitors to the aviary are a problem.
- The substrate in your aviary should be cleaned regularly. The bacteria in the dirt could actually contribute to feather deterioration and breakage, especially in non-flighted (grounded) birds. See below
- This is extremely stressful on the birds and should only be done if a small number of primary feathers are damaged.
- On full flight and tail feather damage, it is best to do every other primary feather then repeat with the remaining feathers 4 weeks later.
- Firmly place your thumb and forefinger over the skin where the feather connects. With your other hand, use hemostats or tweezers to grasp the shaft of the feather at the point closest to the skin. In a very quick motion, give a very firm tug with the hemostats while still holding the skin with the other hand firmly in place. New feather growth should appear in 2 weeks and be complete in 4 weeks
- Feather imping is an option to consider for: birds that can remain in your care until new feathers grow, birds that do poorly in captivity and need to be released quickly, or birds that can fly but are missing a few flight feathers. The possiblity exists that the donor feather could fall out, so it is not a recommended technique to facilitate release on flightless birds.
- The broken or damaged feathers on the bird need to have at least 1/3 of their shaft still intact.
- An industrial strength epoxy or cement should be used. Household adhesives and hot glues can deteriorate when exposed to the elements.
- See these sites for more information:
Take this one step further...
Many, if not most, birds have damaging bacteria in their plumage. An in vitro test using cultured samples of collected bacteria completely degraded chicken feathers within a matter of days. "Assuming that wild birds are vulnerable to some level of bacterial damage, two fitness consequences could result. First, the insulative efficiency of the plumage could be hampered, causing thermoregulatory stress and a consequent reduction in body mass and survival. This chain of events has been well documented in the case of damage to plumage by feather-feeding lice (Booth et al. 1993, Clayton et al. 1999). A second fitness consequence of feather damage might be a reduction in aerodynamic efficiency. Bacterial damage could interrupt the airflow over the surface of the plumage of a flying bird, particularly given that bacteria are abundant on distal regions of the feathers (Muza et al. 1999). Furthermore, bacteria could weaken feathers, leading to increased breakage that would compound the thermoregulatory and aerodynamic problems just described. Burtt and Ichida suggest that ground and water birds have more bacteria than aerial or canopy birds because transmission of bacteria is enhanced near the ground or around water. "
Nine of 11 samples of feather-degrading (keratinolytic) bacteria were identified as Bacillus licheniformis, one as B. pumilus, and one as a Bacillus of undetermined species.
"Molt may play a ... role in helping birds to rid themselves of bacteria. Other behavior such as anting, dusting, sunning, and insertion of green vegetation in nests also might defend against bacteria. The most relevant evidence so far is work by Clark and Mason (1985) showing that plants inserted in the nest by European Starlings (Sturnus vulgaris) inhibit the growth of bacteria in vitro." It has also been suggested that the oil that birds distribute on their feathers contains certain antibacterial/antifungal qualities.
"Anting behavior, long postulated to control ectoparasites, may reduce bacteria by allowing birds to acquire antibiotic secretions from the metaplural glands of ants (Ehrlich et al. 1986). Dusting and sunning also may play a role in microbial defense by making the plumage too dry to support bacteria."
**References: http://pica.wru.umt.edu/Auk/ABS1162.HTML#clayton.orv FEATHER-BUSTING BACTERIA. Dale H. Clayton The AUK Vol. 116 No. 2 April 1999
OCCURRENCE OF FEATHER-DEGRADING BACILLI IN THE PLUMAGE OF BIRDS. Edward H. Burtt, Jr. and Jann M. Ichida http://pica.wru.umt.edu/Auk/ABS1162.HTML#burtt.art 1 http://www.academia.edu/download/33400807/Saranathan_and_Burtt_2007.pdf