MARICOPA — When duck carcasses started rising to the surface of a lake at the Lakes at Rancho El Dorado neighborhood in Maricopa, the residents were first to step up and rescue the remaining living ducks from the lake.

“We’re not happy with it at all with how the homeowners association is handling and the cleanup of the lake,” resident Christine Holtz said.

The official statement from the subdivision HOA’s board of directors said that since July 29, at least two dozen deceased waterfowl had been removed from the community lake at Rancho El Dorado III.

“The Association and its lake maintenance vendor, Arizona Lake and Pond, have been in contact with Arizona Game and Fish to investigate. The Association is awaiting the results and will respond accordingly to the recommendations it receives. In the meantime, residents have been asked not to feed the ducks or other waterfowl,” the statement said.

Residents and the Arizona Department of Environmental Quality were the first to contact the Arizona Game and Fish Department regarding their concerns for the dying ducks at the lake. The AZGFD then sent out a biologist to collect the ducks to examine the incident.

The ducks were then sent out to the Liberty Wildlife Conservation Center, and eventually to the National Wildlife Health Center in Madison, Wisconsin, for testing.

“Testing is being done at the moment, and the results should be in by the end of the week,” said Anne Justice-Allen, a veterinarian at AZGFD. “What we found when we took a look at the location was that 30 ducks, and four (other) birds, had died.”

Based on the signs, they suspect avian botulism — a disease caused by bacteria in the environment that produces toxins under certain conditions such as organic material in the soil — may be the answer to the dying ducks.

“Sometimes it’s associated with fish dying, along with snails,” Allen said.

The disease causes the oxygen to go low and produce the toxins to which the ducks at lakes are exposed. The ducks become weak, paralyzed and drown, eventually causing them to die.

With avian botulism, there are usually several days of mortality and the continuation will depend on how much water is toxic to begin with, according to Allen.

“It kind of has to run its course. But it helps to have all of the dead ducks be removed and all of the dead vegetation be removed,” Allen said.

The disease is not a rare sighting, as the department sees similar incidents every year in the Phoenix area. It is said to be associated with water plants in the lake as well as the warm temperature of the water.

“A lot of the lakes around Phoenix have fountains in them to incorporate more oxygen,” Allen said. “Warm water cannot hold oxygen as much as cold water.”

In regards to helping the living ducks in the area, Allen suggested residents take them in or to Liberty Wildlife Conservation Center.

“To help out the remaining ducks, keep them warm and fed, offer them water and keep them out of the pond,” Allen said.

The incident is familiar to those who reside in the area, as thousands of fish died last year from the same neighborhood.

“This past spring into summer we have been dealing with awful flies, midge flies and rats in some areas, more pests in general,” Holtz said. “Now our ducks and waterfowl, storks, sandpipers, magpies and more are mostly dead. The previous company, H2ology, that took care of our lake was fired, along with a new HOA management company being brought in after that happened.”

The confirmed cause of the incident is to be announced later this week.