Dead Duck Found in Reflecting Pool: Experts Weigh In on 3 Potential Causes

A viral image of a dead duck found floating in the Lincoln Memorial Reflecting Pool has intensified scrutiny of the site's recent overhaul, with the cause of the bird's death still unclear amid ongoing concerns about water quality, chemical treatments, and environmental conditions.

The discovery of the dead duck comes amid broader concerns about the Reflecting Pool following its recent $14 million renovation, which included repainting the basin and refilling the water. Within days of reopening, the pool turned a murky green due to algae growth, while sections of the new coating reportedly began peeling into the water.

National Guard troops and police have tightened enforcement around the Reflecting Pool, warning visitors they could be detained for touching the water amid increased security following reported damage, ongoing cleanup issues and unverified vandalism claims.

While officials have not confirmed what killed the duck, several possible explanations have emerged. Crews recently treated the pool with hydrogen peroxide to combat an algae bloom, raising questions about whether chemical exposure could have played a role, though experts say the compound is commonly used in water management. Others have pointed to the presence of blue‑green algae or cyanobacteria, which can produce toxins harmful to wildlife during blooms. Some experts note the duck’s death could also be due to natural causes such as disease, environmental stress or separation from its brood.

Hydrogen Peroxide

Critics and some social media users have speculated that hydrogen peroxide added to the Reflecting Pool to combat algae could have contributed to the duck's death, though there is no evidence confirming a link. It is “unlikely” that hydrogen peroxide is the cause of death, Krysten Schuler, an assistant research professor of public and ecosystem health, and a wildlife disease ecologist for the Cornell Wildlife Health Lab, told Newsweek.

The chemical is commonly used to sanitize bird feeders and treat water in baths and ponds used by birds, Cornell University associate professor Maren Vitousek told Newsweek. It is not harmful at low concentrations.

“The peroxide levels in the Reflecting pool have been tested - they are safe and at the same level used in natural swimming pools,” a White House admin official told Newsweek.

Blue-Green Algae

One possible explanation raised by observers is the presence of blue‑green algae, also known as cyanobacteria, which can form in warm, stagnant water and, in some cases, produce toxins harmful to wildlife. While not all algal blooms are dangerous, large or concentrated blooms can pose risks to animals that ingest contaminated water.

In the case of the Reflecting Pool, reports of murky green water following the renovation have fueled speculation about whether these conditions could have affected the bird, though there is currently no evidence to confirm a link to the duck's death.

“Some birds seem to be more susceptible to the effects of cyanobacteria (also called blue green algae) than others, but mallards can be susceptible to avian vascular myelinopathy, a disease that is produced by a toxin that comes from cyanobacteria,” Vitousek told Newsweek.

Conducting a necropsy, or animal autopsy, is the only way to identify the true causes of death, Schuler told Newsweek, but if a toxin was present, she “would expect to see more dead wildlife.”

“Botulism, another toxin produced by the bacteria, Clostridium botulinum, has been identified previously in ducks dying on the reflecting pool,” Schuler said. “If there is only 1 dead duckling with many others surviving, it's not likely to be a systemic problem. It appears the situation is being closely monitored, so any additional deaths should have the carcasses collected and examined by trained wildlife health professionals.”

Natural Causes

Several experts told Newsweek that it’s entirely possible the duckling died of natural causes.

“Ducklings do regularly die of natural causes,” Vitousek said. “Getting too cold is a very common cause of death for ducklings, as their feathers are not yet fully waterproof. Ducklings can also die of starvation and disease, or be killed by unrelated adults. A necropsy would be the only way to know for sure.”

It is unclear if officials are pursuing a necropsy to identify the cause of death.

“Without a necropsy, it would be difficult to determine the cause of death of any individual duckling. Ducklings face a variety of natural and human-related risks, including nature predators, disease, weather exposure, injury, malnutrition, and hazards associated with urban environments,” a DC Bird Alliance spokesperson told Newsweek.

“One concern that has been documented at the Lincoln Memorial Reflecting Pool is that ducklings may follow their parents into the water but have difficulty exiting because of the pool’s steep sides. Measures that help ducklings safely leave the pool, including wildlife escape ramps, can reduce that risk and support local and migrating wildlife.”

Newsweek saw ducks and ducklings, all of them alive and well, swimming in the Reflecting Pool on Monday. It is unclear if there have been any other duck deaths since the discovery of the duckling over the weekend.

Contact Newsweek editors on this story: Jason Lemon and Sam Wilson.

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This story was originally published June 22, 2026 at 11:01 AM.