01/13/1997

State's Wild Birds Face Strong Risk of Tick Paralysis This Winter

AUBURN, Ala. - As the temperature drops this winter, Alabama's wild birds will face an increased risk of paralysis and death caused by a type of tick that feeds only on birds, warns an Auburn University entomologist who has studied the bird tick since 1986.

Bird ticks feed on their feathered hosts throughout the year, but when the parasitized birds are stressed by freezing-cold temperatures, they can fall victim to a potentially lethal paralysis, said Gary Mullen, an AU professor of entomology. Mullen's research indicates that outbreaks of tick paralysis occur every three years, and the next outbreak is due this winter.

"Birds can withstand the effects of tick paralysis if they're in good shape, but after a few days of very severe low temperatures, tick-infested birds could begin to succumb to paralysis," Mullen said.

Birds are attracted to feeders after cold snaps because they need more food to survive. It is here that homeowners and bird-watchers are likely to notice unusual activity in birds or find dead birds with attached ticks, he said.

"People will see birds with impaired flight or birds that are unable to walk," Mullen explained. "They may be staggering. They may flop their wings, unable to fly any appreciable distance. They may seem lethargic or just sit on the ground with their feathers fluffed.

"If the tick is not removed, the paralysis will progress until an affected bird dies of respiratory failure," he added. "However, removing the ticks will commonly result in a prompt and total recovery if symptoms haven't progressed too far."

Mullen said he has seen cases in which a bird recovered within 15-30 minutes of the tick's removal. In other cases, the recovery has taken hours. But once the birds reach the point where they are unable to stand at all, there is less chance of recovery. "If a tick is present, it's usually conspicuous -- attached around the head," Mullen said "By the time the bird shows signs of impaired mobility, the tick is usually quite engorged and difficult to overlook."

Mullen said that Alabama homeowners and bird-watchers can play a vital role in his bird tick study. Anyone who finds a tick-infested bird that is paralyzed or dead should call him at (334) 844-2554. His studies require identification of affected birds, examination of dead birds and examination of living ticks removed from birds. Mullen said he would like to recover any ticks or dead birds found in the Lee County area. For cases outside the local area, or if the researchers are unable to come in person, instructions on tick removal and detailed case information can be exchanged over the phone.

"After removing any ticks attached to the bird, you should place the bird in a covered container, such as a box or cage until they recover," Mullen said. "Identify and release birds that recover. Contact with the birds or ticks poses no human health threat."

Mullen warned that the tick must be removed properly to avoid breaking off its mouth parts. It is best to firmly grasp the mouth parts with tweezers placed as close to the bird's skin as possible. Then, slowly and steadily pull the tick out without twisting. Ticks can be kept alive by placing them in a zip-lock bag with a slightly moist paper towel.

Mullen said he has documented tick paralysis in 17 species of birds in Alabama, mostly song birds. The five most common are house finches, common grackles, chipping sparrows, yellow-rumped warblers and dark-eyed juncos. Mullen found that tick paralysis seems to occur on a three-year cycle. He has documented cases in the winters of 1987-88, 1990-91 and 1993-94, but no cases were seen in the intervening years. Likewise, no cases were seen in the winters of 1994-95 and 1995-96, but so far this winter four confirmed and one suspected case of tick paralysis have been documented in Lee and Tallapoosa counties.

Tick paralysis is caused by a toxin secreted in the tick's saliva, possibly the byproduct of some microscopic organism inhabiting the tick's salivary glands. Discovering the exact cause of tick paralysis, as well as investigating why the problem occurs on a three-year cycle, determining why some bird ticks cause paralysis and others do not, and gaining a better understanding of the bird tick's life cycle are among the goals of Mullen's study.

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Office of Ag Communications & Marketing

Auburn University College of Agriculture
Alabama Agricultural Experiment Station
3 Comer Hall, Auburn University
Auburn, AL 36849
334-844-4877 (PHONE) 334-844-5892 (FAX)

Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu
by Robyn Hearn

Jan. 13, 1997