Wildlife experts are advising Whidbey Island residents to avoid feeding Bambi as a precaution against a deadly deer disease that has been spreading on nearby Fidalgo Island.

Although automobiles have long been the leading cause of deer deaths, Matthew Hamer, a state Fish and Wildlife biologist covering Island County, said something else has been killing Whidbey’s black-tail deer population this year.

He has received at least eight reports of suspicious deer deaths on Whidbey in 2021, the majority of which were determined not to be roadkill.

Since June, a highly contagious viral infection known as adenovirus hemorrhagic disease, or AHD, has been reported on Blakely, Henry, Lopez, Orcas, San Juan, Shaw and Stuart islands. It spread to Fidalgo Island in July.

A case of AHD has not yet been documented on Whidbey Island, but Hamer acknowledged that it’s possible that the virus, which only affects deer, may have spread here.

Symptoms of AHD include foaming at the mouth and diarrhea, which can be bloody. Several deer outside of Oak Harbor were displaying those symptoms in June and were promptly tested for the disease.

“Much to my surprise, they tested negative,” Hamer said. “The cause of death was undetermined.”

Hamer is asking people who notice sick deer with these symptoms to use the reporting tool on the state Fish and Wildlife website, wdfw.wa.gov/species-habitats/diseases.

Samples from various organs are collected from dead deer; there is about a 24-hour window between the animal’s death and its decomposition to test it for AHD.

“There’s no doubt that that short timeframe is definitely a challenge to collect tissue samples that would be suitable,” Hamer said.

Deer pass the disease through bodily fluids, such as blood, feces, and most commonly, saliva. It has been suspected that airborne transmission of AHD might also be possible.

He recommends not feeding the deer, as a congregation could further the spread of the disease.

“Social distancing definitely applies to deer as well,” Hamer said.

There is no treatment or vaccine available for the disease.

“More than likely, nature’s going to have to take its course,” he said.

There are other reasons to avoid feeding the ungulates. Besides AHD, Hamer said the higher mortality rate of deer on Whidbey could be because of rumen acidosis, a condition deer can develop after eating foods that are high in carbohydrates, such as corn or fruit. The rumen, which is the deer’s stomach, turns overly acidic in response. The acidity leaks into the bloodstream and causes death.

Cyanide poisoning from eating too many cherry pits has been documented in Port Townsend deer, and it could also be a cause of death for the Whidbey deer as well.

Hamer said people tend to feel bad for the deer during warmer temperatures and want to feed them or give them water. During a drought especially, forage conditions are not ideal and availability of water can be harder to come by, which also might lead to death.

He noted that it will be interesting to see how hunting season is affected. While eating venison from a deer with AHD poses no risk to hunters, he said it is recommended that hunters leave the entrails of the animal behind to limit the spread of the disease, in the event that the deer was carrying AHD. The preferred method of disposal for the entrails is to bury them, which limits scavenging.

There is some indication that things might be getting better. Reports of deer deaths have waned on Orcas and San Juan islands. Likewise, Hamer said reports of dead does and bucks on Whidbey have decreased significantly during the last couple of weeks.

“We are definitely asking residents to keep an eye out and report what they see, and we will respond,” he said.

Diane Jhueck, a South Whidbey resident, said she has about 20 deer come through her yard from the forest behind her. She hasn’t personally noticed any sick deer, but she has suspected that speeding, more than anything, has been playing a role in their sudden deaths.

On East Harbor Road, near where she lives, there is a 25 to 35 mph speed zone. She has observed people often going 50 mph or more.

“There are a number of families with young kids in this same stretch of road, so these deaths add to increased worry for them as well,” she said.