Highly Pathogenic Avian Influenza

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Greater White-fronted Goose

By Dr. Guthrum Purdin, DVM

Avian influenza is a disease that has been infecting birds for over 150 years. The first documentation of the virus dates to 1878 in northern Italy, where it was described as a contagious disease affecting poultry. Historically avian influenza has had minimal impact on wild birds, but the most recent strain of the virus has had a detrimental effect on wildlife across the Americas. The disease is effectively 100% fatal for birds, and it has already caused the death of over 53 million wild and domestic animals in the United States alone.

The current strain of highly pathogenic avian influenza (HPAI) first arrived in North America late in 2021, appearing in eastern Canada. It was likely carried to Newfoundland from Eurasia by migratory waterbirds. Through 2022 it slowly made its way across the continent and the first west coast cases were found in Washington State late April/early May: a pair of Snow Geese and a Bald Eagle. By summer the contagion had reached the San Francisco Bay. Hundreds of wild birds are known to have died in the Bay Area, but fortunately for Southern California the southward advance of the disease was stalled there for the rest of the summer. HPAI does not tolerate hot, dry conditions well and last summer’s heat may have helped protect our local birds.

Although many domestic poultry flocks have been affected, an unusual aspect of this particular H5N1 variant of HPAI is that it particularly affects a wide range of wild birds. Some species can carry it without showing symptoms while others get infected and die quickly. In Washington State, for example, one lake experienced the deaths of hundreds of geese. Even worse, along the coast of Peru, which until now had been free of HPAI, over 22,000 pelicans and other seabirds were lost to the contagion in December. Other animals too can be affected, including harbor seals, bobcats, foxes, even a black bear recently tested positive in the Pacific Northwest.

The staff at the California Wildlife Center had been closely monitoring the inexorable advance of HPAI as it came relentlessly closer to Los Angeles. We learned everything we could from the experiences of other wildlife rehabilitation groups in affected areas of the US, as well as those in Africa and Europe who have been dealing with both this H5N1 strain and multiple other variants of HPAI for many years. Working with hospital staff, as veterinarian I put together a comprehensive set of protocols for how to respond, knowing that HPAI’s arrival in SoCal was inevitable. Of great importance was ensuring that HPAI positive animals not enter the general population of patients. If that happens, there is a high risk of it spreading through a busy wildlife hospital.

Now, when members of the public call about animal’s they’ve found, they’re asked a variety of questions to help identify possible HPAI patients. When they arrive on site, they’re met by volunteers and staff wearing protective gear who bring the new patient to a specially designated screening room separate from the rest of the hospital where they are carefully checked for signs of avian influenza. After initial HPAI screening, patients free of overt clinical signs get a follow-up exam in our ICU to determine what injuries or non-influenza illness led to being rescued and a course of treatment is determined. During this, they are again evaluated for HPAI, since sometimes symptoms that are not immediately obvious can be caught on this second intake exam, especially subtle signs like milky looking eyes or a tendency to act “switched off’, like they’re awake and standing but otherwise totally unresponsive to stimuli. After that they spend a day or two in strict quarantine and then a few days in isolation. HPAI is so virulent, that susceptible species usually present symptoms right away—however, in rare cases they may not show signs until later in care, hence the orderly set of exams and quarantine/isolation housing areas. This way we have a strong sense of a negative HPAI status before new admits are housed around patients already in care. Each area has disinfectant foot baths and appropriate levels of personal protective gear. Special foot coverings are worn when entering and leaving outdoor aviaries and caging to be extra careful, since animals housed outside could potentially be infected by HPAI positive birds flying overhead.

In September, the inevitable happened, and CWC got its first positive HPAI patient, a Canada Goose with the severe neurological and visual deficits that are classic for HPAI birds. The disease was identified during physical exam and this goose was humanely euthanized to alleviate their suffering. The diagnosis of HPAI H5N1 was definitively confirmed with the assistance of the California Department of Fish and Wildlife’s Wildlife Investigation Lab.

Throughout the greater SoCal area numerous other cases have been identified among migratory birds, especially geese and raptors. So far, the horrifying mortality events seen in Europe, Peru and the Pacific north coast have not occurred here and winter cases have tapered off.

CWC awaits the spring migration with trepidation, as birds already stressed by their far travels may be carrying HPAI back into our area. However, our hospital’s thorough and decisive biosecurity protocols, as well as the keen vigilance of the treatment crew, have served well in protecting the hospital from an onsite outbreak. Another hot, dry summer after the winter rains would, in this case, be an added boon.

What can you do to help prevent the spread of this disease?

  • If you handle birds, wash your hands carefully with soap and water.
  • Avoid any contact between domestic poultry and wild birds.
  • If you have outdoor chickens or other poultry, take down all bird feeders and bird baths.
  • In general, bird feeders & bird baths should be cleaned and disinfected at least once a week.
  • Keep pet birds indoors and away from other domestic or wild birds.
  • If you might be handling sick birds or other wildlife, wear appropriate protection (like masks, gloves, and eye protection).
  • Disinfect surfaces that have come in contact with birds or sick wildlife.

Backyard Birds

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Townsend’s Solitaire

By Denys Hemen, Hospital Manager

Having a yard is a privilege in the city. If you are fortunate enough to enjoy one at your home, it only takes a few minutes to put down your phone, be very still, and enjoy the nature around you. You may see tiny birds hiding in a bush, a squirrel high up in a tree, a soaring hawk or a gliding crow may pass overhead. Just going outside can bring you closer to nature. Nature is all around us and as humans develop lands farther and farther into open spaces, we are going to share our space more often with the creatures that live among us. One group of animals feeling the negative effects of human encroachment a little more than others are small songbirds. Most populations are on the decline and could use some help. Here are some easy ways to make your yard bird friendly and lend a hand to our feathered friends.

If you choose to have a bird feeder or waterer in your yard, please keep it clean. Take feeders down and discard leftover seed at least every two weeks, scrub with soapy water then rinse well. Make a solution of 9 parts water and 1 part bleach in a clean spray bottle and spray all parts. Leave the feeder sitting for ten minutes then rinse. Allow all items to air dry before refilling. If you provide water for wild birds the water should be changed daily, and the waterer should be sanitized in the same manner as the feeders every two weeks. If you ever see sick birds at your feeder, especially those with what looks like eye infections, take your feeder down, discard the seed, clean, sanitize, and leave it down for a week or two. Many bird diseases are easily transmitted through feeders and waterers.

Hummingbird feeders should be cleaned and sanitized every time they are refilled, which should be every 3-5 days to prevent mold from growing. Do not use detergent to clean, only use boiling water and a bottle brush. Sanitize the same way as previously described. The only formula that should be fed to hummingbirds is 4 parts water to 1-part white granulated sugar. Boil the water until the sugar is dissolved, then let the formula come to room temperature before refilling.

Planting native plants is a fun way to attract more birds to your yard. In Southern California, the fall and early winter are prime times to get native plants into the ground. Choosing which plants birds like best can be tricky on your own. At calscape.org, you can find plants that are native to your specific zip code. Descriptions are included of what each plant will attract- from bees to bugs, butterflies to birds!

If you have trees in or around your yard, try to “leave the leaves” as much as possible. Leaves provide cover for tiny insects that birds such as towhees and Northern Mockingbirds love to scratch around and hunt for. Fallen leaves also make excellent mulch for your native plants.

In the spring and summertime, quickly walk your yard to look for fledgling birds on the ground before letting your dog out. Many bird species have young that leave the nest before they can fly. These fledglings spend a few days on the ground before they build the strength to fly and are very vulnerable.

If you have windows that birds repeatedly fly into there are many ways to fix this issue. A great resource for remedies is abcbirds.org. Here you can find dozens of ways to “bird proof” your windows. From iridescent bird tape to streamers, all the items suggested by this non-profit organization have been tested and rated.

The last and most important way to make your yard bird friendly is to always keep your cats inside and never feed strays around your home. Outdoor cats kill over a billion birds in the US each year. Cats are the number one cause of the decline of native songbird populations.

If you ever find an injured bird, place the bird in a cardboard box that has air holes and is lined with a paper towel. Then take a picture for species ID by our staff later. Give our hospital a call at 310-458-WILD and we will be happy to help you.

Think Twice About Those Traps

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By Denys Hemen, Hospital Manager

Bewick’s Wren on fly trap

There are dozens of home pest control items available for purchase today at various home improvement retailers. From sprays to traps to zappers, humans have developed many creative ways to keep unwanted insects and rodents out of our homes. It is understandable for people to strive to keep the inside of homes free of unwanted creatures. Unfortunately, when these products move from indoor pest control isles to the outdoor gardening section in retail settings, this becomes a misguided and irresponsible action. Native and beneficial wildlife often become the unintended victims of these products. The worst items to place outdoors are poisons, glue traps, and snap traps.

When poisons are moved outside of the home, the number of non-target species that are affected increases exponentially. Poisoning rats and mice outside may lead to predator species like coyotes, bobcats, and raptors eating these sick and debilitated rodents that are easy to catch. Many health problems may arise, such as raptors losing the clotting ability of their blood and damage to the immune systems of coyotes and bobcats which may lead to severe break outs of mange. Such problems are seen inside of the hospital at CWC many times a year.

Glue traps, including sticky fly traps, used outside of the home draw in even more non-targeted animals. Sticky traps are a double whammy because the target species gets trapped in the goo and predators will go after it, entangling themselves in the sticky mess. The intention of the glue trap is to keep prey in place so that they slowly die of dehydration and starvation. Also, animals may accidentally get stuck while going about their natural ground or arial foraging routines. We have seen all types of animals stuck in these traps. Snakes, ground dwelling birds like towhees and wrens, mockingbirds, warblers, desert cottontails, and many other species have passed through the doors of our exam room with feathers, scales, or fur entangled in a sticky trap.

A very wide variety of domestic and wild animals are harmed by snap traps left outside. A rat snap trap has the potential to cause great injury to a curious cat or dog that may sniff around the bait. Wild animals fare even worse. Just last month we received an American Crow that had its beak shattered by a snap trap as well as a Barn Owl with a trap on its leg. Unfortunately, neither patient survived their injuries. An earlier snap trap victim, a Striped Skunk, was able to be treated and released with 51 days of medical care after getting his foot caught in a rat snap trap.

Coyote pup with mange

Please help protect our wild friends and never place poisons or traps outside of your home. We cannot prevent nuisance animals from passing through, but we can prevent them from wanting to stay and hang out! Some straightforward ways to keep unwanted rodents from chilling out in your yard or patio are to never leave fallen fruit from trees on the ground, bring cat or dog food inside, and keep all trash receptacles closed. If you ever find an animal stuck in a glue trap, do not try to remove them. For snap traps, if you can safely remove the trap without fear of the animal attacking you then do so. For suspect poisonings, as well as animals caught in glue traps and snap traps, contain the animal and trap in a box if you can do so without fear of the animal harming you. If you are fearful of the animal, call your local animal shelter for assistance. Call CWC immediately for assistance after containment in all instances.

The Winter Royals

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By Cori Carlson, Administrative Coordinator

Adult White-crowned Sparrow

White-crowned Sparrows are one of the many migrating bird species we see each year at California Wildlife Center. On average, we admit 10 of the large gray sparrows each year. As adults they are easily identified by the black-and-white stripes on their head and their pale pink or yellow beaks. These birds most often come to our facility after being caught by a cat or striking a window.

These sparrows tend to be generalists when finding a place to live. They are commonly seen in brushy areas and also in open grasslands. The birds migrate each year, living in the mountains during the summer and flying to the southwest lowlands in the winter. They start their migration south in September and return back north around April. At California Wildlife Center, we usually see the sparrow patients between October and May.

You will often see White-crowned Sparrows in flocks foraging on the ground near bushes and trees for safety. When you hear rustling on the ground it may be a White-crowned Sparrow scratching to find food. Similar to Towhee species, the White-crowned Sparrows can be heard rustling around on the ground, often called, “double-scratching.” They quickly hop backwards to flip over leaves and then pounce to catch insects.

While in care at CWC, our wildlife technicians provide the birds with enrichment, activities designed to mimic their wild environment. Some of the ways we do this is by adding familiar foliage to their enclosures and skewering a variety of berries on the branches to imitate how they forage. These birds eat a variety of seeds, insects and berries in the wild. At CWC, their diet consists of mealworms, a special Songbird mix and berries.

It has been said that the White-crowned Sparrows return to the same area each year so if you are lucky you might see the same birds year after year.

Two California Scrub-Jays Get a Second Chance

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By Kristen Kanatzar, Wildlife Technician

The Orphan Care Unit (OCU) is dedicated to the care of young, orphaned wildlife such as squirrels and finches. As they are found along the West Coast of the US, Canada, and Mexico, another species we care for in the OCU are nestling and juvenile California Scrub-Jays. One of our recent patients was a nestling scrub-jay that had most likely fallen out of their nest. On intake we found the bird to be in good health overall but with a head tilt. Head tilts are usually a sign of neurological damage and brain swelling. Although the exact cause of the injury was unknown, the patient most likely hit their head on a hard surface when they tumbled from the nest. We prescribed anti-inflammatories to help reduce the suspected swelling of the brain. These medications also provided the young bird with pain relief. The patient quickly started to improve, and within ten days the juvenile scrub-jay was no longer showing any signs of trauma. OCU continued to provide supportive care until they were old enough to survive on their own. After five weeks in care, the healthy bird was released back into the wild.

Juveniles scrub-jays are mostly gray in color with sections of blue on their tails and wings. They are significantly fluffier than adults as they still have their downy feathers that help keep them warm. As they get older, they shed these downy feathers, and they sleek down into their new adult plumage with the distinctive bright blue colors.

Juvenile California Scrub-Jay

Another California Scrub-Jay who recently came through our doors was suspected to have been caught in a glue trap. The fledgling bird was cared for in OCU, where they were stabilized before being cleaned. Technicians carefully removed the glue contamination with specialized solvents and warm soapy water. The washing process can be extremely stressful on wild animals, so technicians were only able to clean small portions of the feathers at a time. After about a week the scrub-jay was completely free of contaminations and was soon moved into an outdoor aviary. One month after being admitted to our facility, the California Scrub-Jay was ready for release.

Scrub-jays tend to live in coastal woodlands but can often be seen in urban areas and in people’s backyards. They are omnivores that tend to scavenge for food including fruits, insects, nuts, seeds, and small animals such as lizards and other hatchling birds. Being part of the corvid family, which includes crows and ravens, scrub-jays are highly intelligent and can often have a sneaky side.

We will frequently catch them in their enclosures playfully tossing mealworms around and helping feed each other. They will also take some of their food and attempt to hide it within the enclosure much like they would in the wild.

These two young birds were fortunate to make it to our facility. Through the hard work and dedication of the OCU staff and volunteers, these California Scrub-Jays got a second chance at life!

Don’t be a Birdglar!

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By Denys Hemen

House finch nest found with nests intact are prime candidates for re-nesting.

Each spring CWC gets hundreds of calls from the public regarding baby birds that have fallen from the nest. This can be a very stressful moment for everyone. Seeing a baby bird appearing “helpless” on the ground can induce panic. Being on the phone with the person who sees this baby bird on the ground can be even more panic inducing! So, stay calm and follow these guidelines if you encounter young birds on the ground.

Baby birds seem very delicate, vulnerable, and begging for your help, but not all of them need our attention. Some are fledglings and don’t need any assistance at all. These birds can perch, have most of their feathers, and some can even fly a little bit. It’s natural for most songbirds in our area to leave the nest before they can fly. Having 4 or 5 large baby birds in one nest is a sitting target for a predator. So, they disperse before they can even fly sometimes. This is a way of hedging their bets against a predator taking out an entire generation. If there are no injuries, it is best to leave these birds alone and let the parents continue doing their job. Keep pets and children away. And never, ever, ever leave your cat outside. Of course, if there are injuries to the bird, give us a call.

These fledgling Northern Mockingbirds would not need assistance if found uninjured.

Sometimes baby birds can use a hand. This is the case when the bird is a nestling or a hatchling. These birds are generally helpless. They are not very mobile, do not have their adult feathers yet, and are unable to perch. If the entire nest has fallen and you see the nesting material next to the baby birds, you can put the birds and the nest up someplace high in a tree closest to where you found them. The nest will likely need some extra support like a shallow Tupperware with lots of holes for drainage or a plastic berry clamshell. Be sure that whatever you use is about the same size as the nest. Form the nesting materials into a bowl shape inside your container. Now attach it to a sheltered limb by using some twist ties, wire, zip ties, or twine. Avoid using tape because the adult birds and the babies can get stuck to any exposed adhesive. Once the artificial nest is firmly attached to a nice shaded, unexposed limb you can carefully place the baby birds back in. Keep an eye out for signs of the parents returning to the nest but stay back as far as possible. Give it a couple of hours. If they do not come back, call CWC!

If you find one or two babies on the ground, but no nesting material, it is not advisable to try to create an artificial nest. For these animals, the original nest may still be in place. The parent is unable to sit on both the original and the artificial nest, leaving the babies out in the cold. Look carefully above you because the original nest can be very small and hidden in the tree. If you are able to locate it, the babies can be picked up and placed back in the nest. Be sure to check for any obvious injuries before doing this. Keep an eye on the area from afar for parental activity. If you see no activity for 2 hours or if the fallen babies have obvious injuries, call CWC.

Following all these steps can help more babies stay with their mothers in nature and avoid an unnecessary trip to a Wildlife Rehabilitation Center. Thank you for reading and please do not be a bird burglar.

Flocks of Finches

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By Dr. Guthrum Purdin, DVM

Photo by Dr. Guthrum Purdin, DVM

If you have a birdfeeder in California or have an eye for birds flittering by the side of the trail, you’ve seen House Finches. They’re small, lively, streaky grey birds; only about 21gm (0.74oz) on average. The males’ heads, chests, and shoulders are boldly colored red or reddish orange, looking like they’ve been dipping a little too deeply into somebody’s red wine! Last year, CWC received just over 300 of these little birds that had been rescued by the public, many of them babies still dependent on their parents (or we humans as substitutes…) for care.

Considering this species ranges so widely, from southern Canada, through the United States, and all the way to Central America, living in often harsh environmental conditions, you’d think they would be easy to raise — but you would be mistaken! Baby House Finches (or HOFIs) require very specific food and handling.

Most baby songbirds, regardless of what they eat as adults, are fed an insect diet by their parents. This is done because insects are high in protein — just the thing babies of any species need to grow. Adult HOFIs on the other hand, feed their chicks mostly seeds (including poison oak) and just 2% of the diet is insects. To match these nutritional needs, we mix together the formula diets of two different kinds of birds—those that eat only seeds and those that eat mostly animal protein. It took a lot of experimentation but this mixture provides exactly what HOFI hatchlings, nestlings, and fledglings need.

But that’s not all! Chicks energetically beg food from their parents from sunrise to sunset. Their one job is to eat and grow, and they take that very seriously! As long as it’s light in the room, someone must be ready to feed them. That’s every 30 minutes for hatchlings and every 45 minutes for nestlings and older. When you’ve got racks and racks full of hungry mouths cheeping and waving their yellow beaks & red mouths around, it’s exhausting to keep up. Fortunately, once the lights are out they go right to sleep. As long as they get a good meal before it’s dark, their metabolisms will slow, processing the formula through the night. When morning comes, it’s right back to work for everyone. House Finch parents work hard, and so do our staff and volunteers!

Relying on their parents to decide how much food they should eat, young HOFIs don’t know when they’re full and it’s time to stop begging. So, they beg and gape, gape and beg until their crops can become overfull and stretched out. A ‘crop’ is an out-pocketing of the esophagus at the base of the neck, used to store food between meals in some species. Birds that feed on sporadic food sources in the environment use crops to fill-up between foraging opportunities. But the chicks don’t know when enough is enough, so their crops can become stretched out with food and sit there becoming a petri dish for bacteria, yeast, and protozoal parasites. To deal with this we closely control how much they get at each feeding, checking crops before feeding a nest of hungry mouths. If a bird has slow crop clearance or looks “out of sorts” we take a sample of crop fluid, check it under a microscope, and assign the appropriate medication for whatever organisms may be freeloading in their crops.

So, ‘Don’t Feed Too Much’ is a major rule with HOFIs. Feeding too little is a different problem. If not enough food is given while they are growing, they can become weak and develop poor feathering that may never improve, leaving them flightless or unable to survive the chill of winter.

Photo by Dr. Guthrum Purdin, DVM

Hatchlings have no feathers except a few whisps on their heads and are kept warm by their parents until they grow feathers. Consequently, housing is a warm incubator unit for the youngest HOFIs. Once feathered, nestlings are okay for room temperature housing. A fledgling will hop out of the nest, but still can’t quite fly. They want to be away from the nest as soon as they can because nests are at higher risk of predator attacks. Unfortunately, kindhearted people sometimes find these flightless youngsters and think the parents have abandoned them. If you see a cheeping, feathered little grey bird like this, watch it from a distance. Chances are the parent is just out of sight waiting to feed the little one.

At this stage we offer them a tempting selection of chopped greens and seed. Their beaks are still soft, and they aren’t experienced in how to shell seeds, so the greens, like broccoli florets, are the first thing they’ll eat. An adult may shell and swallow a seed in less than a second, while a fledgling may carry a seed around for 20 minutes, practicing handling (beaking?) techniques.  In the wild, once fledglings start to fly, they follow their father closely for a few weeks learning what to eat. In human care, as they make the transition to independence, teenage HOFIs have to learn to feed themselves and we are there to support them while they finish growing up.

Only a few short weeks after hatching, they’re self-feeding and ready for the aviary. We raise groups together and after they’ve had some time to exercise and stretch their wings, the whole group will be returned to the wild together — a brand new flock like a busload of teenagers heading off to college.

Dr. Guthrum Purdin, DVM, co-authored the chapters covering House Finches and Blackbirds in the text Hand-Rearing Birds, 2nd Edition, which is an indispensable resource for rehabilitators and other animal care professionals. He also co-edited Topics in Wildlife Medicine Vol. 4: Orthopedics, in which he co-wrote chapters covering fracture repair in songbirds, doves, and hummingbirds.

What Was ICU Up To In 2021?

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By Jenn Guess, Development Manager

Photo by Cambria Wells

2021 was quite a year here at California Wildlife Center (CWC). This past year we had 4,013 animals come to our facility. Our Wildlife Technicians are directly responsible for the care of our patients and every patient that came through our doors was assessed by the technicians in the Intensive Care Unit (ICU). Animals were carefully examined to determine the best course of action for rehabilitation. Sometimes it was as simple as providing fluids and moving the patient to our Orphan Care Unit for supportive care. For adult animals, it was often more complex.

Our ICU technicians didn’t stop after the initial intake exam. They were responsible for the daily care and rehabilitation of thousands of patients during 2021. This was a huge undertaking, especially considering that we continued to operate with minimal help due to the persistence of Covid-19. Our technicians provided extensive wound care, splinted fractures, and administered a complex array of medications to treat infections, reduce swelling, and provide pain management.

Photo by Brittany Moser

Coronavirus did not slow down the influx of new animals showing up each day. Our busiest day was May 31st, where ICU technicians received 42 new patients in one day. The second busiest day was April 26th, with 40 new patients. We always know that Spring and early Summer are the most hectic months there at CWC. From April through June we admitted 1,771 patients, 44% of all animals received for care in 2021. Overall, we saw an increase in the number of patients from 2020. We admitted over 200 more patients in 2021, compared to the previous year. Since opening our doors in 1998, the need for care has increased steadily every year except 2020 (likely due to the arrival of Covid).

Photo by Jenn Guess

Technicians saw a variety of animals this past year, with 160 different species making their way through our doors. The five most common patients that the ICU technicians examined were, in decreasing order, Eastern Fox Squirrels, Mourning Doves, House Finches, Mallards, and American Crows. Some of the more uncommon species were a Red-breasted Sapsucker, Lesser Scaup, Black-throated Gray Warbler, Western Pond Turtle, and an American White Pelican.

Now that it’s Winter, the ICU technicians are eagerly preparing for the next busy season. In addition to an endless list of smaller tasks, they are deep cleaning the ICU kitchen, repairing enclosures, and reorganizing supplies, all while continuing to perform daily intake exams and care for existing patients on site. It’s a job that is never done, and CWC is very fortunate to have a staff of dedicated technicians who are up for the challenge.

A Great Horned Owl Flies Free

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By Guthrum Purdin, DVM

Photo by Guthrum Purdin, DVM

This Great Horned Owl was brought to CWC from West Valley Animal Control one afternoon back in late September. There was no history to go with the transfer, why she had come into care was unknown. What was immediately apparent however, were abrasions on the bird’s cere (the base of the upper beak) and, although the talons could still grip, she was dehydrated and unable to stand. The wounds were cleaned and subcutaneous fluid given to rehydrate the bird.

In addition, nonsteroidal anti-inflammation medication was started. This was done to control possible pain, but even more importantly because head trauma was strongly suspected. A head injury, such as being hit by a car, can cause inflammation and swelling in the brain. Symptoms of brain swelling can take a few days to manifest, and that’s what we saw happening to this owl. Although able to stand on the second day in care, she was staring off into the distance as if unaware of what was going on around her, until she was actually touched by a caregiver. Her right wing was drooping with no injuries found by palpation or x-rays.

Then, two days later, she started spinning in circles. This worsened over the next few days. At any stimulus, the owl would start turning to the left, spinning repeatedly, over and over. Her pupils were very different sizes (called anisocoria), the left much larger than the right. The right eye would focus on moving objects, but the left would not, seemingly blind. Things were looking grim for the owl, and we feared she was not going to recover. When our veterinarian looked at her, he found the eyes were structurally normal, with no outward sign of injury; the problem seemed completely associated with her brain. Head trauma can cause “central blindness,” where the eyes are structurally normal, but there is damage to the visual centers of the brain. More promisingly, the owl would occasionally stop spinning and make the loud “beak clattering” noise that Great Horned Owls do to show aggression and as a warning to strangers to “back off!” Despite her cerebral compromise, she was self-aware enough to warn her caregivers to be wary. Now, when touched, she’d turn to bite. She always missed but was determined to try!

Treatment continued, and we monitored her carefully. If she could see people, she’d start spinning, but if left alone, would stop and relax. After about two weeks, the owl was eating on her own, no longer requiring being hand fed. Her eyes still had anisocoria, but less dramatically. When trying to bite, the owl now could snap down on what she aimed at—caregivers beware! The drooping wing had been wrapped until now, but that was no longer needed.

A few days later, the owl was moved to a shady, quiet, small aviary to allow more space and peace for recovery. The owl immediately went up to the low perches provided and settled in. Medication could be given in the food, and she was left in peace as much as possible. The owl still spun to the left when approached on the first day in the small aviary, but finally stopped for good by day two.

Photo by Guthrum Purdin, DVM

Improvement was gradual. Initially, flight was unusually noisy when taking off. This is a serious problem for owls. They rely on flying almost silently when hunting. Owls have specialized feathers that allow them to fly noiselessly. This enables them to descend on their prey without being detected. For this to work, the wings must be held at the proper angle. As this owl slowly regained normal use and positioning of her wings, flight became stronger and quieter. She initially would tire quickly after being moved to a large, flight training aviary. Staff and volunteers would go out and gently encourage flying, thus building up her strength and endurance.

It took weeks, but her pupils returned to normal. The owl was able to avoid objects placed in the aviary, fly silently, and land normally. But could she see well enough to hunt? During a “live prey test,” the owl swooped down, catching her dinner immediately after staff closed the aviary door. Feeding herself would be no problem; she was ready at last to return home! After nearly two months in care, this Great Horned Owl was returned to where she had originally been found.

When she first arrived, it really looked like the owl wouldn’t make it. Thanks to our dedicated staff and volunteers using their experience and attention to detail, this bird was given every opportunity to improve. Thanks also to the owl herself, for her fierceness and resilience. She’s out there somewhere right now, living wild and free.

A Raven’s Journey to Recovery

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By Cambria Wells, Wildlife Technician Supervisor

Wildlife rehabilitation is often a story of collaboration. This is even more true when a species requires intensive or specialized care. California Wildlife Center (CWC) has a large service area and is the only facility in Los Angeles County permitted to rehabilitate Ravens and Crows, and therefore receives relatively high numbers of them each year. For that reason other wildlife rehabilitators will sometimes transfer young corvids, the family name encompassing Crows, Ravens, Jays, and Magpies, to join our groups of fledglings as a measure to prevent them becoming habituated to human care. One of these birds has been a favorite patient of CWC staff and volunteers this summer. Originally found in a rural area in Central California, Common Raven 21-2166 was treated for a fracture of his tibiotarsus, a leg bone. Once stable enough to travel, he hitched a ride with transporters to his destination here at our facility for long term care.

Common Raven

Common Raven 21-2166 with his “buddy”
Photo by Cambria Wells

Since 21-2166 was already an older bird and at risk of habituation to human care, staff paired him as quickly as possible with other Raven “buddies.” Then, the group was set aside in a smaller enclosure for evaluation in order to ensure they would be self-feeding and free of parasites before getting access to a large flight pen. 21-2166 quickly became known for his sweet habit of asking for food like a younger bird, not for himself, but to feed to his new friends. This highly affectionate and social Raven thrived in the presence of his own species, allowing us to provide care while keeping his behaviors closer to that of a bird being raised in a wild setting.

In the wild, corvids like Common Ravens and American Crows spend their days in activity foraging for food, engaging in complex social behaviors with their family group, and interacting with other species. They are known to raid nests, scavenge for carrion, craft and use tools, and even steal food from other foraging animals in order to survive. 21-2166 and his “buddy” were provided large numbers of objects to investigate, manipulate, and destroy to ensure they would focus on enrichment and learn skills for survival.

Common Raven

Common Raven 21-2166 admiring his destroyed box
Photo by Cambria Wells

Staff at CWC gives every animal, whether a new intake or a transfer, a full exam on arrival and regular checkups. This is critically important as sometimes new health issues develop in captivity. Raven 21-2166 required extensive care. Before his arrival at CWC and during transfer, he once again fractured his left tibiotarsus. During treatment for that left leg, his habit of leaning on his right led him to develop an early case of “bumblefoot,” a form of dermatitis common in birds on perching of the wrong size, which left a wound in the middle of his other foot. By the end of his visit, this Common Raven received not so common care including almost the full range of what CWC can provide; radiographs under sedation, cage rest, pain medication, antibiotics, treatment for gastrointestinal parasites, anesthetized wound care, bandage changes, small aviary residence, large flight pen residence, hand-feeding, daily enrichment, re-wilding and more! If this care were provided in isolation to such a young animal, 21-2166 likely would have been unable to be returned to the wild due to his attachment to humans. At CWC, our summer group of young Ravens means we can avoid that unhappy ending and aim for the best outcome.

Providing the medical and husbandry care to get these animals prepared for release is only possible due to the efforts of a large staff and volunteer force whose absolute focus is the return of birds like 21-2166 to their native habitat. Any juvenile Common Ravens and American Crows admitted to CWC are raised by the Orphan Care Unit. As early as 7:30 in the morning we begin their hand-feeding every 45 minutes, and feed until the sun sets in the evening, a total of around 12 hours of feeding. Nestling birds are kept incubated under close observation in the Orphan Care Unit main room until fully feathered. At this point, in order to provide the best environment for them to grow, they are moved up to a special room set aside just for Crows and Ravens. By release, our young corvids have received up to five months of daily attention from veterinary staff, and devoted husbandry care totaling about 2,500 hours of volunteer time. Corvids make up a heavy proportion of our most involved cases, most satisfying releases, and some of the dearest patients to our hearts.