A Southern California Edison biologist brought a rare patient to California Wildlife Center (CWC) this March – a young native Pocket Mouse. This small mammal can be found in chaparral and grasslands from the San Francisco Bay area to Baja California. Brownish gray in color with white bellies, large ears and hind feet, the mouse has a distinctive fur-tipped tail.
Birds live by their feathers. They need them to keep warm, to stay dry in the rain and most of all, they need them to fly. There’s a rhythm to molts during which old feathers are shed and new ones grow. If a feather breaks or is damaged, the bird is stuck with it until its next molt. When multiple flight feathers are broken, flight may be impossible. For these birds, unable to find food or escape predators in the wild, life is at an end.
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?
Dr. Guthrum Purdin, Veterinatian
Desert Cottontail Release, Photo by Brittany Moser
Late in January, a Desert Cottontail Rabbit was found with his head stuck under a fence and brought to a local vet clinic. The doctors there gave him some IV fluids and he was quickly transferred to our wildlife hospital’s ICU. When the Cottontail first arrived at CWC, he was highly stressed and disoriented with a swollen face. There was also a small wound behind the left ear. Initially looking very ill, the Rabbit was given oxygen and moved to a warm incubator until stable enough for a thorough exam.
Rabbits have very sensitive, fragile skin and getting trapped like this can be very damaging. The pressure directly injures skin and muscle cells, but even worse, it restricts blood flow which can lead to a spreading necrosis or death of the surrounding tissue. It may take several days for the full extent of the injury to develop. Antibiotics, pain control, and anti-inflammatory medication were started, the wound was cleaned and dressed. By this time, he was standing and looking much brighter. The Cottontail was set up in a comfortable warm enclosure for the night and we settled in to wait and see how the injury would progress.
By the next morning, his appetite was great. He was up and alert, and actively trying to run away from his caregivers—just like a Rabbit is supposed to. As the days passed, and as feared, the injury behind the ear got larger and two big new wounds developed on the middle of the head and the back of the neck. The original wound was especially deep, and there was concern the Rabbit might lose his ear. During surgery, the dead tissue was all removed and afterwards, pain control meds increased.
Fortunately, rabbit skin, while fragile, heals incredibly fast. The wounds were cleaned and disinfected at first daily, then every other day, then once every three days. The Cottontail was scarfing up his food, scampering away when people checked on him, and generally looking like everything was normal, despite the severity of his injuries. It took less than four weeks for this rabbit to go from looking like he was at death’s door to being fully recovered and able to be released. Amazing! If you find yourself in Woodland Hills and see a Desert Cottontail Rabbit out nibbling grass in a field, it might be this very one. Good luck, little bunny…and stay clear of fences!
By Dr. Stephany Lewis, Veterinarian
A Wren stuck to a glue trap
Photo by Samantha Orzech
Every year, California Wildlife Center receives approximately twenty animals that have been caught in glue traps, or “glue boards:’ Some glue traps come as strips or tubes that are hung up to catch flying insects, while others are placed on the ground to catch crawling insects and rodents. Glue traps are used as a method of pest control, but unfortunately, these traps are indiscriminate. CWC most commonly receives small songbirds that have been caught in these traps, but we also see lizards, snakes, small mammals, and even small hawks and owls who have suffered from traps. Most of these animals eat insects and rodents, so these traps end up eliminating the most natural form of pest control!
When an animal gets caught in these traps, sadly their death is not quick and painless. They suffer for hours or even days, as they struggle and slowly die of exhaustion, hunger, and thirst. As they struggle to escape, they will often sustain painful injuries. Bird feathers also become severely damaged and mangled from the glue. If not discovered and freed from the trap quickly and carefully, the animal will die.
If an animal becomes stuck to a glue trap, they always need professional medical treatment. If you find a live animal caught in a glue trap, we do not recommend that you attempt to free the animal yourself. Without proper care and training, it is possible to injure animals even more while attempting to free them. Simply place a box with ventilation over the animal and keep it in a quiet and safe place while you contact your local wildlife rehabilitation center and transport the animal to receive help.
A Cooper’s Hawk covered in glue from a trap
Photo by Stephany Lewis
When we receive animals caught in glue, we carefully remove them from the glue with the help of a small amount of oil. In some cases, we may sedate the animal for this process to help alleviate stress and minimize struggle. The animal is then assessed for injuries and feather damage, and provided fluid and nutritional support, as well as pain medications and antibiotics if necessary. We wait several days before removing the remaining glue off their feathers, fur, or scales to ensure that the patient is stabilized before starting this process, because being washed is extremely stressful for a wild animal. For this reason, sedation or anesthesia are typically provided for the patient during the washing process. The glue is removed with a small amount of canola or a soy-based oil. The oil then must be washed off with dish detergent in warm water. The animal is dried and placed in a warm incubator to recover. Once the animal is clean and dry, they are moved to an outdoor enclosure to ensure that they can exercise and fly and can be acclimated prior to release.
There are many ways you can help wildlife avoid this situation! Please never use glue traps, sheets, or boards, and work with a reputable pest control company that does not use glue traps or poisons. A responsible pest control company will focus on natural and humane exclusion and deterrent methods and create a pest management plan that is best for the health of your family, pets, and wildlife. Educating your friends and family about the dangers of inhumane pest control methods is also an easy and important way for everyone to help our wildlife.
Join us each week as we look at different areas of California Wildlife Center. This week, enjoy a peek inside the Intensive Care Unit!
Each video comes with a children’s activity. Click here for a hidden picture seek and find.
By Dr. Stephany Lewis, Veterinarian
On the morning of December 30th, CWC received an adult female Red-Tailed Hawk from Newbury Park with evidence of anticoagulant rodenticide toxicosis (rodenticide poisoning). Raptors are exposed to rodenticides by ingesting poisoned rodents, and it leads to an inability to clot their blood, resulting in massive and often fatal blood loss. Our Hawk patient had multiple bruises on her body, was actively bleeding through a tiny puncture wound on her toe, and was severely anemic. We performed a crude test that quickly helps support a diagnosis of anticoagulant rodenticide toxicosis; we pulled a small amount of blood from the bird and placed it in an additive-free tube. Normally, a Hawk’s blood should clot within 2-5 minutes in the tube; our patient’s blood did not clot until the next day!
Hawk 3859 receiving a blood transfusion, photo by Cambria Wells
I decided to attempt a treatment that I had not performed since I was a dog and cat veterinarian; I opted to give this bird a blood transfusion. For a blood donor, we used another systemically healthy adult female Red-Tailed Hawk who had been in our care for about two months, but still had at least a few weeks to go in her rehabilitation process. She was briefly placed under anesthesia, and a unit of blood (which for her size is about 10 mL) was drawn from her jugular vein into a syringe with a special anticoagulant in it commonly used for blood transfusions. Our donor bird recovered extremely well, and no negative effects from the blood donation were seen.
Our recipient bird had a catheter placed into her right ulna. For birds, intraosseous catheters (catheters placed into the bone) tend to be more reliable than intravenous catheters since bird veins are very small and fragile, and the medullary cavity (marrow) of most bones (except the “hollow” ones that are continuous with their air sacs) are directly connected with their blood vessels.
Dr. Lewis administering blood transfusion, photo by Cambria Wells
The blood was slowly given through a blood filter and into the intraosseous catheter. The Hawk began to perk up towards the end of her blood transfusion and started to nibble at the line, so we placed a falconry hood to keep her calm and keep her from fussing with her catheter and line. She completed her blood transfusion without any complications and was administered fluids for the rest of the day through her catheter. Her catheter was removed that evening. We also started her immediately on vitamin K, which is an antidote to this type of rodenticide.
The next morning, I received a message from one of our technicians describing this bird as “salty.” And indeed she was! She was bright, alert, quite feisty, and significantly less anemic! I had never seen such marked improvement so quickly in a patient suffering from rodenticide. From then on, her recovery was smooth sailing; she was able to live in one of our outdoor flight pens while completing her therapy, and the vitamin K was just hidden in her diet. The vitamin K is always administered for a full month, until the rodenticides should have cleared the body. Her anemia quickly resolved, and her blood was able to clot normally after discontinuing the vitamin K. After a couple of weeks reconditioning in our largest flight pen, she was successfully released back into the wild!
The blood transfusion recipient the next day, photo by Dr. Stephany Lewis
We were all so happy to have had such a successful outcome for this patient; however, many carnivores suffering from secondary rodenticide toxicosis do not have positive endings. CWC receives between 20 and 40 cases of secondary rodenticide poisoning yearly, and the success rate historically has been less than 10%. Almost all these patients perish in the first 12 hours, which is before our vitamin K therapy is able to take effect and stop their bleeding. In this case, the whole blood transfused not only provides life-saving oxygen and nutrients to their cells, but also replaces some of their clotting factors that have been inactivated by the rodenticide, so they can immediately stop the bleeding that is occurring. This is very helpful while we wait for the vitamin K antidote that we give to take effect, which takes 12-24 hours.
Our hope is that with this treatment, our success rate for patients suffering from these poisons will increase. The only challenge may be finding a readily available donor bird, as bird blood cannot be effectively stored for any significant amount of time. However, birds do not have any naturally occurring antibodies to blood types, so we can safely give a blood transfusion without typing or cross-matching and can even give blood from one completely different bird species to another without risk of a serious transfusion reaction. Though the best thing for our patients is for rodenticides not to be used at all, so they never need a transfusion in the first place! Please use poison-free alternatives for rodent control to protect all of our native carnivores!
Support CWC’s treatment of rodenticide-poisoned Hawks. Donate to the Have a Heart for Hawks campaign at cawildlife.org, mail in the enclosed envelope, or call us at (310) 458-9453, ext. 101.
By Dr. Stephany Lewis, Veterinarian
California Quail
Photo by Cambria Wells
Since May of 2018, Southern California, as well as parts of Arizona and Utah, have been impacted by a disease called Virulent Newcastle Disease (VND). Formerly known as Exotic Newcastle Disease, VND is an extremely contagious and deadly viral disease of birds. This virus can potentially infect humans but causes only mild conjunctivitis (inflammation around the eyes) and flu-like symptoms that resolve on their own without treatment. This disease primarily impacts poultry species, but no humans have been infected by eating poultry products.
The nervous and respiratory systems are most commonly affected in birds infected with VND. Clinical signs in infected poultry can include sneezing, coughing, nasal discharge, swelling around the eyes, depression, twisting of the neck, difficulty walking, and diarrhea. However, some birds may exhibit sudden death without any preceding clinical signs. Conversely, it is also possible for birds to be infected and shedding the disease without any signs of illness, particularly in psittacine birds (parrots). Some parrots can shed the virus for over a year. The virus is shed in respiratory secretions and feces of infected birds, and can be transmitted via contaminated people, feed, or equipment, as well as directly bird-to-bird.
Mourning Doves
Photo by Cambria Wells
Sadly, there is no cure for VND, and prevention is only possible with stringent biosecurity measures. The California Department of Food and Agriculture (CDFA) have put in place strict quarantine and other biosecurity regulations, which can be found on their website at cdfa.ca.gov. These regulations have been significantly impacting both the commercial poultry industry, as well as backyard poultry owners within the quarantine zones of LA, Riverside, and San Bernardino counties. These regulations have also impacted us here at California Wildlife Center. Some of the regulations put forth by both the CDFA as well as California Department of Fish and Wildlife include prevention of the movement of wild poultry species if they have been housed at the same facility as domestic poultry species. Wild poultry species that we treat at CWC include Mourning Doves, Ducks, Geese, Band-Tailed pigeons, and Quail. Every year we have many patients transferred to us by LA county animal shelters; however, because these facilities house domestic poultry, they have not been allowed to transfer us any wild poultry species. Staff and volunteers who own birds at home also have had to practice some biosecurity measures, such as changing shoes and clothes.
Over 400 cases of VND have been confirmed, and over 1.5 million poultry have died or been euthanized due to the outbreak, but no new cases have been confirmed since August 30, 2019. For now, it is still important for everyone working with birds to continue practicing enhanced biosecurity, as the virus will remain in the environment for several more months, but hopefully, no new cases will be detected, and the disease is soon eradicated.
By Dr. Stephany Lewis, Veterinarian
This winter, CWC admitted an adult male Red-Shouldered
Red-Shouldered Hawk
Photo by Johanna Molina
Hawk after he was found on the ground in Santa Monica, too weak to fly. On physical examination, his only injury was a very small laceration on his toe, only about 5 mm in length, yet his feathers were completely soaked with blood and the laceration was actively bleeding. The mucous membranes in his mouth were pale white, and he was so weak that he couldn’t stand, wouldn’t open his eyes, and was barely responsive to external stimuli. A small amount of blood was collected from the bird for some basic bloodwork. He was found to be severely anemic, with 5 times less red blood cells than normal.
Sadly, those of us working in wildlife rehabilitation know that there is only one thing that could cause these clinical signs in a bird of prey. This bird was suffering from anticoagulant rodenticide toxicosis. Anticoagulant rodenticides are rat poisons that cause death to rodents by preventing their ability to clot their blood. Non-target species, such as Hawks, Owls, Bobcats, Coyotes, and Mountain Lions are exposed to these compounds by ingesting the rodents that have eaten these poisons. The poisons do not kill the rodents immediately, but rather slowly weaken them and make them easier prey. Some of these compounds, such as brodifacoum, difethialone, and bromadiolone, are known as “second generation anticoagulant rodenticides”. These compounds were invented in the 1970s in response to rodents becoming resistant to the “first generation” compounds, such as warfarin. One of the differences between the first and second generation rodenticides is also what makes the second generation compounds so much more dangerous for wildlife; they last for a very long time in the body. This means that non-target wildlife species can ingest multiple small doses over long periods of time until they build up levels high enough that they are no longer able to clot their blood. This has disastrous consequences. Animals can bleed into their lungs, causing severe distress, as well as into their brains, eyes, joints, and muscles, causing severe pain and permanent disabilities. Or, like our Red-Shouldered Hawk patient, they can lose all of their blood through what should be an inconsequential wound. Additionally, Bobcats and Mountain Lions are believed to suffer deleterious impact on their immune systems due to chronic exposure to these poisons, making them more susceptible to illness and death from infectious diseases such as mange.
Luckily for our Red-Shouldered Hawk patient, there is an antidote to these poisons, and it is just a simple vitamin, vitamin K. This treatment needs to be given daily for four weeks. Additionally, he received fluid therapy for the first week (a blood transfusion would be the preferred treatment but is unfortunately not an option for our unique patients). This bird actually had a catheter placed into a bone in his wing to quickly replenish blood volume and blood pressure after such drastic blood loss.
Forty-three days after he arrived, our Red-Shouldered Hawk had normal bloodwork, was well-conditioned, flying beautifully in one of our flight pens, and ready to be released! This was a wonderful outcome for this patient, but sadly most of the rodenticide victims who come to us are not as lucky. Because they arrive very late in the course of their illness, the majority of them pass away in the first 24 hours, before our vitamin K therapy has had time to work. Every patient who passes away due to rat poison is submitted for examination by biologists at the California Department of Fish and Wildlife to confirm the cause of death and aid research proving how damaging these poisons are to our native wildlife. The exposure frequency of wildlife to these compounds continues to be astounding, despite previous legislation made to limit their use. Scientists continue to detect these compounds in anywhere from 79 to 100% of animals tested, and in many cases, 3 – 6 different compounds are detected in the same individual.
Anticoagulant rodenticides pose a substantial and far-reaching threat to wildlife and ecosystem health. A California bill, AB1788, has reached the State Senate, and if passed will greatly restrict use of these poisons in our state. CWC is so grateful for everyone who has been working tirelessly to get this bill passed, and we hope you join us in urging your senator to pass this important legislation! Our wildlife deserves poison-free food!
By Dr. Stephany Lewis, Veterinarian
This Mule Deer buck had a plastic pipe stuck on his leg. Photo by Heather Henderson
This fall the California Wildlife Center was given a unique opportunity to help a Mule Deer buck who had gotten PVC piping entrapped on one of his legs. A caring citizen named Brenda Robinson contacted our hospital manager, Denys Hemen, regarding this buck in need of help. The buck spent much of his time with a herd at the Getty Villa, and a few days prior Brenda had noticed that the animal had gotten a piece of white PVC piping trapped just above his hoof. He was licking at the area and had begun to limp on the leg. Brenda was worried that this animal was in pain and would eventually be weakened to the point that he could fall prey to coyotes or mountain lions known to be in the area.
After learning of the situation, Denys and I visited with Brenda at the Getty Villa to observe the Deer and see if it would be feasible for us to help the animal. Brenda knew exactly where the herd would be throughout the morning, and he was so accustomed to her presence that we were able to observe him from a reasonable distance. We were excited to be able to potentially help this animal, and after organizing with biologist Amelia Viera at the California Fish and Wildlife Service, we were scheduled to return on the morning of October 30th to sedate the Deer and remove the plastic pipe from his leg.
The morning of October 30th, the group of us involved in the procedure as well as grounds crew at the Getty Villa, met just before sunrise to discuss the plan of action. Immobilizing an adult Deer in the field requires quite a bit of preparation, and it’s extremely important that everyone involved knows each step in the procedure, what to expect, what could go wrong, and what their responsibilities are.
The deer was sedated so the pipe could be removed. Photo by Heather Henderson
The grounds crew quickly located the buck for us, and I was able to get into a position to successfully dart the animal. Our dart gun at CWC is a simple carbon dioxide-powered rifle (sort of a glorified blowpipe), and the darts are pressurized with air so that when the needle enters an animal’s skin, a rubber sleeve is pushed off small holes on the side of the needle, and the drugs are quickly injected right after impact. The Deer was darted in the hindquarters with a combination of sedatives, half of which were reversible, and the other half were short-acting. He trotted off a few meters after darting, but we were easily able to watch him as the sedation was taking effect. His close-knit herd stayed by his side the entire time until I approached. About 15 minutes after darting, the buck laid down, and we were able to safely approach him. We protected his eyes with lubrication, blindfolded him and placed cotton in his ears to decrease stress and make him less reactive. He was held in a safe position and his vital signs were monitored by Denys and Maria Jose Lopez Jara, a visiting veterinarian from Chile.
Staff was able to remove the restrictive pipe from the Deer’s leg. Photo by Stephany Lewis
The PVC pipe was quite tight around the Deer’s leg, around the pastern area, which is just above the hoof and below the fetlock joint. It has caused several large wounds on the leg around its entire circumference, but none so severe that we did not think he could recover once it was removed. Heather Henderson, our marine mammal stranding coordinator, removed the pipe with a coping saw, starting between the pipe and the leg and sawing outward to avoid causing further trauma. The wounds were clipped of dirty hair, cleaned, flushed, and an antiseptic ointment was applied. The buck then received an injection of a long-acting antibiotic, a pain medication, and reversal of the sedation.
It took just over a half hour after reversing the sedation for the buck to start to stand and walk on his own. While he was recovering, one of his herd-mates, a little doe, came to check on him! He spent most of the rest of the day relaxing with his herd, but has since been up and about, no longer in pain. We are still receiving updates from Brenda, and the buck is doing fabulously! We are so thrilled to have been able to help this animal, and hope this serves a reminder to everyone to please be neat and remove your trash!