From A to Z Wildlife Rehab Quandaries and Conundrums

Aardvark to Zebu: Wildlife Rehab Quandaries and Conundrums

Good Housekeeping

The rescuers of a mourning dove they found under a chair on their back porch approach a wildlife center. They are initially skeptical of the standards of the facility after observing that the building is an old mobile home and the outdoor caging looks homemade. However, the rescuers are pleased when they enter – the facility appears tidy and smells clean. They are greeted by a volunteer who is entering information on a well-kept log, and another volunteer busily mopping the hall in front of a closed door marked “Infirmary.” The volunteer at the desk puts on gloves and takes the bird into a room adjoining the lobby marked “Intake: Rehabilitators Only,” notifying a woman donning a lab coat that a new patient has arrived.

In another location, a rescuer confidently takes a nest of baby squirrels into a building that looks like a veterinary clinic with a large “Wildlife Rehabilitation Center” sign. She is not greeted, so she calls for attention down a dark hall. The building smells of animal waste. A volunteer appears from a room containing several animals in cages, eating a sandwich. There are what appear to be feces on her sleeve, and her shoes are caked in mud. The volunteer puts the squirrels in a box and puts them in a closet with other boxes, and asks the rescuer to fill out a form that looks to be smeared with blood stains before shutting the door behind her.

While these examples may seem like a lesson in first impressions, the purpose is anything but. Busy wildlife rehabilitators often rely on support volunteers to perform “busy work,” such as cleaning cages, sweeping, mopping, and doing the laundry. However, these activities are just as important as delivering medical care to wildlife patients. A healthy wildlife rehabilitation facility is not characterized by the structure of the workplace. In fact, it is a comprehensive zoonoses prevention plan that deserves more than relegating tasks to volunteers.

Zoonoses are infections that pass from animals to humans. A majority of existing zoonotic infections are associated with domestic animals (pets, farm animals, etc.) and are well-known, predictable, and curable. However, zoonoses associated with wildlife can be vague in presentation and life-threatening. Prevention of zoonotic disease consists of measures taken to reduce the risk of transmission of disease.

Personal habits eliminate or provide a barrier against zoonoses, including hand washing and use of personal protective equipment (PPE) such as gloves, gowns, masks, and special clothing. It is important to remove PPE after use to prevent them from becoming fomites (inanimate objects that harbor a pathogen, only to be transmitted to a person who touches the item later). Take gloves off immediately after touching an animal to avoid transmitting pathogens from the gloves to other objects. Remove outer clothing (such as lab coats or shoes) after caring for an animal or its environment and wash them separately from other clothing. Because of the large number of pathogens that can be spread through the fecal-oral route of transmission, human food and beverages must be stored and consumed in an area away from the animal care areas.

The process of cleaning and disinfecting removes zoonotic pathogens from the environment. Cleaning is the most basic step. It involves removal of trash and debris from the area (“tidying”), changing soiled bedding and caging, dirt or contaminants from surfaces, and washing food and secretions from feeding utensils (including syringes and feeding tubes).

Disinfecting is a chemical method to eliminate pathogens from objects. Disinfecting must always be preceded by cleaning because most chemicals are inactivated by organic material. Disinfection is complete once the surface has been thoroughly air-dried.

Similar to the fact that there is not a single medication that cures every illness, there is not a single disinfectant that eradicates every pathogen. Selecting a product for disinfecting is not easy. Consulting veterinary practices for advice is as necessary a component for managing the physical environment as is assuring animal treatment protocols are correct.

Cleaning occurs on a frequent basis to prevent zoonotic diseases from gaining a hold on the care environment. However, disinfecting is done based on the area or item. For instance, feeding utensils can be cleaned between uses on the same animal, but must be disinfected after the last use of the day. Caging may be cleaned daily, but disinfection is required when the enclosure is heavily contaminated or after the occupant is moved out of the cage. Despite having the best intentions and practice, humans can spread pathogens during daily activities in the rehabilitation center. Using disinfectants to mop floors on a daily basis greatly reduces this risk.

So, just as a wildlife rehabilitator would never neglect the care of an animal, never neglect the care of the workplace. The prevention of zoonoses is rooted in the cleaning and disinfecting of the facilities and equipment of the wildlife rehabilitation center. Consistent application of the steps of a comprehensive zoonoses prevention process supports the overall mission of wildlife rehabilitation. At the same time, this purposeful work by dedicated support volunteers provides a great first impression for rescuers who bring in the patients.

Urban Predators


In the US, it’s fairly common to see whitetailed and blacktailed deer, coyotes, and all sorts of mesopredators in and around the city.  A recent National Geographic article mentioned the increased urban appearance of apex predators like cougars.  The article made me think “what does this mean for rehab”?  My only experience with an apex in the city had a tragic end.  It was a timber wolf that was shot for being too close to a mall.  How can rehabilitators assist in preventing human wildlife conflict with this new influx of predators?

Here are some thoughts from IWRC members:

Ned Bruha: The article in Nat Geo, just like their TV programming, is following suit with so many others who have the power to help instead of hinder animals. They have found that If they talk about, film, and add drama to wildlife dilemmas, they make more money. Wildlife and larger predators will always adapt and overcome. If you feed them, they will come.

Rehabilitators will continue to do gratis rehabilitation to “nuisance” and federally protected animals with personal and donated money, while the state and fed wildlife dollars will continue to go towards anything but helping wildlife that is in true need of rehabilitation. Because of this, it is even more important to screen calls to see if animals truly do need a rehabber’s assistance… those first 3 young raccoons sure look cute and inviting in the spring, but how much time and money can you save by explaining to the caller how to keep them with their real mother? The same goes with calls from people afraid about larger predators. Many times, they are raiding garbage cans, hunting at bird feeders and eating pet food left outdoors along with the cat or dog at the outdoor food bowl – often times, these are avoidable situations.


Kevin Bertoli: There is no way we can stop the influx of wild animals into our neighborhoods, short of our own retreat from THEIR habitat. I don’t see that happening, so it is inevitable that they will continue to be destroyed. Rehabbers can assist in slowing this process if they work in conjunction with their local Wildlife Officers and assist in either notifying them, or working with local law enforcement to quickly incorporate sedation and humane removal when a threat arises. This would mean organizing local vets, animal control, wildlife officials and those able to keep the necessary drugs and equipment on hand ready for immediate response.


Up For Discussion – Nonnative Species


Virginia Opossum (Didelphis virginiana) is non-native in British Columbia, Washington, Oregon, and California. Photo Credit L Reed

Up For Discussion

The upcoming issue of JWR will feature a Letter to the Editor questioning the ethics of treating and releasing non-native, invasive species. In this particular case, the species in question is Virginia opossums in California (introduced in 1910, according to Jameson & Peeters (California Mammals, University of California Press, 1988)). But rehabilitators across the U.S. are familiar with the dilemma of caring for European starlings and English (house) sparrows. And this concern is not limited to North America. In Australia the problem may be European rabbits, red foxes, and cane toads. Africa’s invasive species include the crab-eating macaque, grey squirrels, and Canada geese; the grey squirrel has also been introduced to central Europe, along with California quail and the bullfrog.  Add to the list beaver in South America, raccoons and nutria in Asia.

Rock Pigeon (Columba livia) Photo Credit Bob Elko

Some rehabilitators believe that when an invasive species arrives for treatment the most humane and ethical protocol for all parties is to euthanize the animal. They may point out that rehabilitators have enough trouble garnering respect from the more established wildlife professions without engaging in activities that undermine efforts to support native wildlife populations. Others argue even an exotic species offers an opportunity to educate the public—about empathy AND environmental issues. Then there is the very practical concern over possible bad PR for a rehabilitation organization that depends on donations to operate getting “caught” euthanizing some of its patients simply because they are not deemed “worthy” of care.

Obviously, this is an enormous issue that needs to be faced and discussed by the wildlife rehabilitation community.

What are your thoughts on this matter?

What is the most important issue for rehabilitators to address—the health of the individual, the health of the population, or the health of the ecosystem?

Do you (if home-based) or your organization (if affiliated with a rehab center) have an established protocol for dealing with non-native wildlife species?

If so, what is it, and how did you come to this decision?

If not, why not?

Submit your responses to Kieran Lindsay, JWR Editor at

Thoughts on Imprinting vs Socialization

Aardvarks to Zebu: Post 2

Every so often we choose a challenging rehabilitation question and poll two to four experts on the topic.  This time, we chose “Explain the difference between an imprinted or socialized animal, or are they the same thing?” and asked it of a behavioral scientist who works at an education and behavioral research facility with captive canids.  If you have your own burning question, email me at  The question just might find its way into a future post!


Aardvarks to Zebu:

Wildlife Rehabilitation Quandaries and Conundrums


Explain the difference between an imprinted or socialized animal, or are they the same thing?

Pat Goodman – Wolf Park

ABSTRACT:  Imprinting and Socialization are closely connected behavioral events.  Imprinting occurs during a limited period of time, typically for a short period after an animal is born or hatched.  It has a profound effect on the young animal as it matures, determining to what species the infant will show social behavior, and sometimes determining from what species the animal chooses its mates.  Knowledge about imprinting is necessary in captive breeding programs if the animals so reared are to be able to choose and mate normally with their own species rather than choosing individuals of the same species as their foster parents.


While there will be variation depending on the species in question, socializing an animal means to rear, or interact with it in such a way that it can use its repertoire of social signals with other animals.  One of the prerequisites for socialization to a species other than its own is a reduced flight distance from that species.   Usually an animal is socialized to its own kind by interacting with its parent or parents, and other members of its social group.  As it matures, its experience and skills in social interaction expand to include others besides its parents and its siblings or other age mates.  Sometimes an animal acquires the ability to respond to the social signals of animals not of its own species, typically through either rearing by foster parents of a different species, or, later in life, repeated exposure and opportunity for non-damaging interactions with another species.

Often socialization to species other than its own is best begun when the animal is very young.  Socialization to humans later in life can be more stressful and risky for the animal and human involved, and the range of the social repertoire that the animal shows to humans may be only a fraction of what it would show to its own kind.  Wolf Park’s bison, for example, are somewhat socialized to humans through repeated contact paired with special food such as apple slices or sweet feed, and the opening of gates to greener pastures.  We do not make attempts to socialize them extensively.  They do a little bit of greeting occasionally, sometimes solicit food, and sometimes warn or threaten us.  Their social signaling to us is limited compared to the social signaling between us and the wolves.

Imprinting is not, itself, socialization, but it may determine what a young animal becomes socialized to.  Imprinting takes place during “critical periods” in the development of an infant animal.  Often this period starts very shortly after it is born or hatched.   During this time, the infant learns very quickly and very thoroughly to recognize a blueprint for a parental figure.    Once this sensitive period is over, socialization to other species, while theoretically still possible, tends to be more labor intensive, less complete, or even impossible given the limitation of resources in the real world – time and skilled caregivers.  It also tends to be less effective, less enduring, and may involve more hazards to the animal being socialized and the one doing the socializing.  Successful socialization to an animal of a different species, or even its own species, once the sensitive period for imprinting is past, may involve isolating the subject from its own species, and making it dependant on a member of another species for all its social contacts.

In some species this early imprinting also affects mate choice later on, if, in addition to recognizing its parent, the young animal learns to prefer an animal matching its parent’s blueprint as a mate when it matures sexually.  Typically it does not imprint on its individual parent as a future mate, but will prefer an animal of the same species as its parent.  If it has a foster parent not of its own species, it may reject mates of its own kind when it is an adult, and court members of the same species as its foster parents.  Some newly hatched birds can even imprint on inanimate models as parental figures.

In precocial species, which can run around shortly after birth, the infants often show a readiness to follow something that moves in their immediate vicinity.  An infant can develop a strong interest in an object and then be less interested in other objects to imprint on.  Often this attachment can be enhanced by food rewards.   Normally such reinforcement is provided by the mother, who may also reward infants with warmth and pleasant social touch.

The length of this sensitive period varies according to species, and to some extent, on the particular circumstances.  According to the Oxford Companion to Animal Behavior (David McFarland, editor, p. 303) “Domestic chicks kept in groups cease to follow moving objects 3 days after hatching, but chicks reared in isolation remain responsive for much longer.  In natural conditions the young birds would become imprinted upon one another; chicks and ducklings tend to stay close together, even in the absence of a parent.”

As young animals develop, they often begin to explore, and at some point many of them show signs of neophobia, fear of novel things.  This fear can interfere with the young animals’ abilities to form attachments to other animals, including humans.  At Wolf Park we discovered that we must take wolf pups away from their mother and start hand-rearing them at 10 to 14 days of age.  It is not enough to leave them with a wolf mother who will permit trusted humans to visit daily and handle the pups.  The mother-reared pups will show some shortened flight distance from us as they mature but they will not show much of their social repertoire to us and they will not solicit many affiliative interactions; rather, they tend to stay out of reach.  If, however, we take the pups away from the mother, but keep the litter together, so that they get near constant contact with their own litter mates for wolf –to-wolf socialization, and give them about 2000 human hours of social contact, which takes more than one human, starting from their removal from their mother at 10 to 14 days old, until they are 16 weeks old, we have wolves who will be able to show the full repertoire of social behavior to their own kind and almost their full repertoire of social behavior to humans as well.

Historically, researchers studying the biology of behavior used imprinting to do experiments that required cross fostering, producing young that were thoroughly socialized to a species not their own.  Once these young animals were mature they were willing to mate with members of their foster species, and, in turn their offspring often demonstrated which behaviors were inborn, and which behaviors were learned during individual development.  Such research was done a lot with birds, which often imprint on their foster parents’ species as future mates.  Such sexual imprinting seems to happen less often with mammals, according to the Oxford Companion to Animal Behavior, but it can occur.  Wolf Park once received a wolf pup rejected by his mother, and also he was the only survivor of his litter.  Reared in a children’s zoo until he was five months old he had plenty of exposure to humans, but no experience of canines until he came to Wolf Park.  I do not recall him ever showing courtship to other wolves, though several of our females found him attractive and courted him.  He preferred to court humans, and vigorously rebuffed female wolves.

To sum up, imprinting is a type of learning restricted to certain periods very early in the development of animals.  During these sensitive, or critical, periods, an animal’s preferences for social companions, and mates may be determined and it may be difficult, or impossible to change them later in life.  In some species, food preferences, and preferences for a certain kind of habitat may also be established very early in life.  Animals may be able to imprint on more than just one species.  Konrad Lorenz and his students were able to “infiltrate” their goose flocks and study the birds’ behavior at very close quarters by imprinting goslings on humans as well as on geese.

At Wolf Park, whose founder, Dr. Erich Klinghammer, regards Lorenz as a friend and mentor, we do something similar with wolves.  Since our wolves are not candidates for release in the wild, and so need not be fearful of humans for their own safety, this type of rearing facilitates our husbandry procedures throughout their lives.  It makes additional environmental enrichment opportunities available, since some of our routine maintenance can be a social occasion in which the wolves participate willingly.  It reduces the stress of being in captivity and contained in fairly close proximity to the visiting public.  Routine care, and even some emergency medical care can be accomplished without tranquilizer guns, nets, etc.   If a wolf is driven from its pack, or if it outlives its pack members and we cannot provide it with another compatible wolf as a companion, humans may be that wolf’s only source of friendly social interaction, especially for social touching.

Imprinting does not guarantee that a wolf will always be safe and easy to handle.  It does result in a wolf that is typically open to life – long learning about, and, we hope, improvement of its social skills with humans.  This openness is achieved and maintained by carefully monitoring our interaction history with wolves, use of some classical and operant conditioning, and attempting to understand their physical perceptions and emotional states, plus their individual developmental and history of personal experience with humans and their environment.

Up For Discussion – “Do as I say”

The Issue:

Wildlife rehabilitators have long understood the need to educate the public about appreciating and living in harmony with wildlife. Moreover, rehabilitators have ready access to non-releasable animals who can help put a face on some abstract concepts and drive home an important message. In fact, it’s often the chance to meet a wild animal “up close and personal,” rather than the educational theme of the program, that draws a crowd. And that’s fine, because if we’ve done our job well, they’ll leave having been enlightened as well as entertained.

Still, nearly everyone who’s stood before an audience—be they preschoolers, millennials, Gen-Xers, boomers, or the greatest generation—with a wild animal has had to deal with the dreaded question: “Can I keep one as a pet?”

Of course, this is not the message intended to deliver, but can you blame them? There you are, standing in front of a bunch of envious people holding a cool creature who looks pretty calm and healthy, so obviously it does pretty well in captivity… we really shouldn’t be all that surprised when they wonder, “how come you can do it while telling me I can’t?” If only there were some way for wildlife educators to avoid or overcome this hazard of using live animals in education programs.

The Question:

How do you avoid sending a “do as I say, not as I do” message with your captive education program animals?
What’s your opinion?  Email your thoughts and experiences to for potential inclusion in an upcoming JWR issue.

Aardvarks to Zebu: Post 1

Hello!  We have a new column here at IWRC.  Each month we will choose a challenging rehabilitation question and poll two to four experts on the topic.  In this, our first post, we chose the question “Would you release a one-eyed diurnal raptor?” and asked it of three long time raptor rehabilitators, Louise Shimmel, Randie Segal, and Marge Gibson.  If you have your own burning question, email me at  The question just might find its way into a future post!


Aardvarks to Zebu:

Wildlife Rehabilitation Quandaries and Conundrums


Would you release a one-eyed diurnal raptor?

Louise Shimmel – Cascade Raptor Center

No – with very few exceptions.  Turkey vultures, perhaps – though there’s increased risk of them being hit by a car on their blind side.  They are already clumsy getting off the ground, losing even a couple of seconds of awareness of the approach of a predator or car could be fatal.  However, since they are often on the ground in the company of others who could provide an early warning system, I would definitely consider releasing a one-eyed turkey vulture (we don’t get black vultures, and I know little about them).  I once thought harriers might be possible, but have had only one with an eye injury that was otherwise releasable, and she definitely ran into things.

I know of one case of an immature bald eagle in Alaska.  She did not have the personality for life in captivity, so it was decided to try releasing her down in the Skagit Valley of Washington, with telemetry.  The Seattle zoo and Washington DFW followed her for a couple of years, as I understand it, and she was eating more carrion than normal, but she did survive.  I tried it once with an adult female red-tailed hawk, on the assumption that she knew how to hunt, she probably had a mate to help feed her part of the year, she’s also a carrion eater.  She apparently did fine through the summer, either from a mate providing food and/or abundant prey or carrion – but she came back in starving, once the weather turned in October.  My main concern is the loss in the field of vision, especially for the falcons who hunt at speed and need particularly good depth perception.  Even more critical would be eyesight for the accipiters, who are not only hunting at speed but maneuvering through cover at the same time.  So, my basic response is no – a one-eyed diurnal raptor is not releasable.


Randie Segal – Wind River Wildlife Rehabilitation Center

First, it would depend on the age of the bird. If it is a young bird (hatch year), then I would be very hesitant. I would be concerned that the bird is too naive to be successful without his depth perception . I would evaluate the bird with the same methods as an older bird. An older bird with more experience, I would be more likely to consider release. The experience of the bird could be enough to compensate for the loss of depth perception.I would suggest flying the bird with a Falconer or watching carefully in a large flight to see if the bird is hitting his perches with regularity. We also would want to know how alert the bird is in his surroundings.This way you could evaluate the effects of the depth perception loss. If you add live prey and the bird kills repeatedly, the bird would be released to enjoy life in the sky.


Marge Gibson- Raptor Education Group Inc

In most cases, I would not.  However, as in other aspects of wildlife rehabilitation, it is hard to use a “cookie cutter” approach to this question.   It is good to think the question through for each patient. That way you will understand the issue thoroughly and feel satisfied in your decision on your patient’s behalf.

Your decision to release a one-eyed raptor depends on many things, including the age of the raptor, species, the type of injury or disease that caused the blindness, and even the habitat and climate zone in which  the raptor lives.  Ultimately the bird’s ability to hunt and demonstrate depth perception accurately in a large flight, will give you your answer.   We have admitted raptors owls, buteos and eagles that have old injuries to their eyes.  If they were in good weight when admitted and doing well in the wild, we may consider releasing them again. Admittedly, one-eyed patients released to the wild at R.E.G.I. are a low percentage.

It is important to begin with a basic premise, that your patient with one eyed blindness will have a shorter expectancy if released to the wild than a raptor with prefect vision.   If your patient has adjusted well to captivity and will be placed in a terrific education facility, consider that option first for your patient.  If the bird is not comfortable in captivity, the following list may help with your decision:

1. Was the injury to the eye only or was head trauma part of the initial injury?  One-eyed blindness may be only part of a larger diagnosis when head injury in the cause. Head injuries complicate existing blindness.  The bird is not generally a candidate for release.

2. Is the blindness caused by West Nile Virus?  Blindness caused by WNV is not always detectible by an eye exam.  WNV can compromise the area of the brain that controls vision. This condition may deteriorate over time.  The eye itself may appear quite normal.  Typically, a raptor affected by WNV blindness will run into things in a flight, not hit perches accurately or land short of a target.  A bird of this description should never be released to the wild.

3. Does the bird hold its head in a natural manner or is it tipped to one side?  Head injuries can affect not only the brain and eyes, but the auditory system as well. A bird with previous head injuries may hold its head in an unusual position. This patient should not be considered releasable both for medical reasons and for natural behavior (posture) which is important in the wild.

4. Will your patient be released in an area without severe weather conditions?   If you live in the far north and your patient is not a migratory bird, do not release it to the wild.  Eyes and the surrounding socket area loose tissue, fat padding and circulation after a traumatic injury or enuculation surgery.  The fore-mentioned problems make the area subject to pain and frostbite in severe temperatures.  If you cannot assure your patient will have temperate weather in which to hunt and utilize carrion do not release it.

5.  Young birds that have never hunted before their eye injury should not be released. The one exception is if the bird was first flown by a falconer for a year or more and proved itself to be a skilled hunter.

6. Was the patient older, had a healed eye injury and previously adjusted to hunting with its disability?  Does the patient have a mate?  An older patient that has learned to hunt successfully with its disability was in good weight and feather condition when admitted, is a candidate for release.

We have released one-eyed raptors and through banding records found, they lived many years in the wild with their disability.   Studies have shown one-eyed raptors eat more carrion than wild birds of their same species.  Our banding results indicate one-eyed birds often lose their life when hit by car or attacked by other predators.  Videos exist of both adult Bald and Golden Eagles on active nests where one parent bird has a blind eye.  It is assumed the eagles were already a mated pair when one was injured and developed one-eye blindness.   Most biologists assume a one-eyed bird would not be “selected” as a mate over a bird without a disability.

One-eyed blindness is a serious disability for a raptor.  In most cases, it is not a good option to release them back to the wild unless a special circumstance exists.


Up for discussion – Rehabilitation Permit Fees

Up For Discussion – Rehabilitation Permit Fees

The Federal Aid in Wildlife Restoration Act (aka Pittman-Robertson Act, passed by the U.S. Congress in 1937, provides a mechanism for collecting and distributing federal aid to states for management and restoration of wildlife through an excise tax on sporting arms and ammunition. States contribute matching funds—collected primarily through the sale of hunting and fishing licenses–to receive this aid primarily. The Act offered states their first source of income for enforcement of wildlife laws, for habitat protection, and for many other conservation programs, creating Departments of Natural Resources (DNRs) as we know them today. Consequently, it gave hunters a powerful voice within the agencies… and that’s the primary reason they supported the legislation.

The idea of charging a fee for rehabilitation permits arises periodically, especially when agency budgets are being squeezed—and not just in the U.S.. Rehabilitators who are against permit fees argue that, unlike recreational resource users, they provide a free and yet valuable service to both the public and to the agencies; therefore, even a small fee for rehabilitation permits is an unjust burden on a group that is already making sacrifices for the good of wildlife, the public, and the state agencies that oversee their work. Those who support permit fees argue that the benefits to gained are worth the relatively small cost—“legitimization” of rehabilitation, a stronger voice within the agencies, and a source of funds to support research using the data collected on annual reports.

The Question: Should rehabilitators support annual permit fees?

Let your voice be heard in the Journal of Wildlife Rehabilitation’s upcoming issue. Send your thoughts on this issue to:  Replies may be edited for space and clarity. Please respond by 6pm EDT Wednesday, April 7.