West Nile Virus Still Impacts Birds

West Nile virus is an arthropod-vectored virus that was first identified in New York in 1999. Wild birds serve as the natural reservoir for the virus, with some species being more susceptible to disease than others.

The appearance of West Nile virus in Illinois occurred in 2001, with both birds and people becoming sick in the Chicago area. August 2002 brought the first central Illinois cases to local hospitals, as well as to the Wildlife Medical Clinic. Corvids, crows, and jays were known to be exquisitely sensitive to the virus, with many of these birds succumbing to the infection rapidly. However, some species of birds seemed resistant to the viremia, while others developed clinical signs but were able to recover.

Since 2002, the Wildlife Medical Clinic has seen numerous cases of confirmed and suspected West Nile virus infection. Most of the time, infected birds display signs of neurologic disease including inability to fly, head tilt, unsteady gait, and lethargy. These birds also have evidence that they are fighting systemic inflammation when evaluated through diagnostic tests. Some birds with West Nile virus infection also develop ocular disease with varying degrees of vision impairment. The only treatment for the virus is supportive nursing care to try to help the animal pull through, but the virus is very serious and can be fatal.


Crows are common victims of West Nile virus.

Although newspapers have slowed their reporting of West Nile, it is still very much present in our state and impacting wild bird populations. The Wildlife Medical Clinic has seen several suspected West Nile Virus cases this year. Many have been confirmed by the Veterinary Diagnostic Lab at the University of Illinois.

West Nile virus is spread by mosquitoes that have bitten infected animals or people. In humans, most healthy people do not show signs of illness. As the virus has become endemic, or established over time, both human and animal populations have developed a degree of immunity against the virus through previous exposure. This probable immunity has resulted in fewer clinical cases being reported annually as compared to when the virus emerged. However, local public health departments across Illinois still perform mosquito control and disease monitoring by submitting birds that have been found deceased to the Diagnostic Lab for testing. You can protect yourself from West Nile Virus by avoiding mosquito bites: stay indoors when mosquitoes are most active (at dusk), use mosquito repellent, and wear long sleeves and pants. Keep areas where water pools drained to prevent mosquito larvae from hatching.

If you see a bird on the ground in the same place for many hours, consider bringing it to the Wildlife Medical Clinic for care. A towel can be placed over the bird to calm the bird and help control the wings. The animal can then be scooped into a box for transport. Be careful and consider wearing a pair of thick garden gloves and a long sleeved sweatshirt to protect yourself against the beak and talons of large raptors. The animal will be accepted 24/7 at the Small Animal Clinic of the Veterinary Teaching Hospital at the University of Illinois College of Veterinary Medicine in Urbana.

—Erin Newman, 4th-year veterinary student

The Case of the Common Grackle

An example of a Common Grackle fledging

Guest post by second year veterinary student, Megan Stuart.

On a hot summer’s day in late May, a Common Grackle was found on a driveway in Springfield, Illinois and brought to the Wildlife Clinic as a healthy fledgling. Common Grackles are large blackbirds that have adapted well to city and surburban habitats, and are resourceful omnivores: in agricultural fields they’ll follow plows to pick out insects and mice, near marshes they will pick leeches off of turtles and wade into water to catch small fish, raid smaller birds’ nests to eat eggs and live birds, and can even use a special beak adaptation to saw into acorns and eat the insides! Adult Common Grackle males have brightly iridescent feathers of blue, purple, and bronze, but young Common Grackles do not show any sign of sexual dimorphism (distinct difference in size or appearance between the sexes of an animal in addition to difference between the sexual organs themselves), so volunteers are unsure of this fledgling’s sex.

The small fledgling received nestling care as often as possible for the first few days in the clinic to supports his growing body and nutritional needs – in some cases, volunteers will check on these young ones nearly 10 times per day! Once he had grown some more, he received little balls of food 5 times a day, and was promoted to mealworms once he showed signs of eating on his own. Since he was caged alone, the fledgling was given a mirror to encourage self-recognition, which he sat by all day and was even spotted playing with his reflection!

Towards the end of the Grackle’s stay, a fledgling American Robin came into the Wildlife Medical Clinic, and was placed in the cage so the grackle could have a feathered companion. Soon after, he was consistently eating mealworms on his own, and so the fledgling was transferred to a local, licensed wildlife rehabilitator to grow a little more before being released. All of the volunteers enjoyed working with adorable fledgling, who never turned down the opportunity to eat! He went from 48.8 grams to 89 grams while in the Wildlife Medical Clinic at the University of Illinois.

Summer at the WMC: Red-Tailed Hawk

Working in a wildlife clinic on a daily basis is an adventure, as you never know what you will be presented with. We take everything from a litter of baby bunnies to an emergency hit-by-car raccoon, so we always have to be prepared. The summer is a busy season. It is always bustling in the clinic and there are constant opportunities to try new things and to learn.

Interns are in the clinic almost every day, giving us the opportunity to follow cases from intake to the resolution of symptoms. It is one of the most rewarding feelings to get to release a patient you have worked with, which is exactly what I got to do for a juvenile red tailed hawk that came in this June.

The young hawk presented on June 5th with no obvious musculoskeletal abnormalities, but was very thin and dehydrated. Blood was drawn for diagnostic purposes, and showed that the patient had an active inflammatory process. He was offered food, but was not eating on his own. Due to the fact that he was so thin, we decided to tube feed him a liquid carnivore diet to make sure he could get the nutritional support that he needed. When volunteers tried to pass a feeding tube down his esophagus, they noticed that there was a mass in the back of the throat that made the tube difficult to pass and probably prevented the hawk from being able to swallow on his own.

There are a few things that can cause masses and plaques in the oral cavities of birds, and with a swab of the area, we were able to narrow it down. Our hawk had trichomoniasis, an infection caused by a small protozoan parasite. We started him on Metronidazole to help kill the parasites. The mass dislodged and was removed several days later, but our patient was still not eating on his own.

On June 21st, he was anesthetized for an endoscopy, which allowed us to get a good look at what was going on in his esophagus. There were open sores that were infected with different bacterial species, so the area was then treated like a wound. We gave him an anti-inflammatory medication, an antibiotic, a pain medication, and a medication to protect the ulcerated tissue from further damage.

Our hawk gained weight and started to become more lively. He would vocalize when bored or hungry, so volunteers had to come up with creative ways to keep him entertained. His mice were hidden in various items like kongs or hand made newspaper hides so that he would have to forage for food as a form of environmental enrichment.

Finally, on July 10th, our patient was ready to go back into the wild. He was eating on his own and gaining weight, and his throat looked great with no new evidence of infection and no return of his plaques. It was a warm, sunny evening, and with a little coaxing, our hawk flew away across a field and landed in a nearby clearing.

Katelyn Bagg, third-year veterinary student and one of the clinic’s full-time summer interns