BROOKLINE — Twenty birds have been rescued from the Muddy River in Brookline and taken for medical treatment after heating oil leaked into the water from a storm drain, officials said Monday.
The leak, which was reported around noon on Sunday, appeared to come from a storm drain near Leverett Pond. The state Department of Environmental Protection, which is investigating the source, estimated that less than 100 gallons of oil was released, officials said.
Katrina Bergman, president of the New England Wildlife Center, said a dozen birds had been brought to the center’s medical facilities, and eight more were being taken there for treatment, with more expected.
“Part of the problem is that they can fly a little bit, so it’s hard to kind of capture all of them,” Bergman said. “But one of the most important things is, we’re telling the public, please don’t try to help, because it stresses the birds out and could kill them.”
Bergman said rescuers will be preserving some feathers from a few of the birds as evidence, in case they’re needed for any legal proceedings or litigation related to the spill.
Zak Mertz, the wildlife center’s chief executive, said, “We’re seeing a lot of impacted waterfowl, mostly ducks and geese.”
“Our crews have been working to scout the river,” Mertz said. “Our goal today is to try to get the most heavily impacted birds — the ones with the most oil on them that are the most critical condition.”
Wearing white hazmat suits, a team from the wildlife center worked to rescue birds from the river. The team has been using nets, boats, and towels to rescue the birds “with the least amount of stress possible,” Mertz said.
“If we need to, we may be able to use something like a net gun, but we’re really trying to avoid that, because a lot of these birds are in pretty critical condition,” Mertz said. “We really want to make sure we’re doing it in a way that isn’t causing them more harm. If you chase a bird around, it can still fly. Especially when it’s got oil in its mouth and lungs, you may be causing it enough damage where it could actually kill the bird.”
The birds are transported in containers lined with oil-absorbing pads.
The wildlife center team, a group of veterinary technicians, began their rescue efforts on Sunday afternoon and treated the birds until midnight at the center’s hospitals in Weymouth and Barnstable. The team returned to the river Monday morning.
Mertz said the rehabilitation process will take three weeks to a month. The birds need to be stabilized, given antibiotics, and put under veterinary supervision for “quite a while” before they can be released, Mertz said.
“Rescue is just a small piece of the equation,” Mertz said. “The washing process itself can take two hours per bird, and once you do that, you get all the oil off, you realign the feathers, and then it takes time for those birds to reapply their own natural oils,” Mertz said.
Mertz said the team will return to the river throughout the week.
Meaghan Still, a member of the wildlife center’s team, said the birds are not used to being handled and rescuers are trying to be as gentle as possible.
“We’re covering their eyes so they don’t get super stressed out,” she said. “We’re putting them into carriers, and then they’re going into the van directly to the hospital so there aren’t any middlemen.”
Kerry Batchelder, another veterinary technician, said the birds are given time at the hospital to “decompress before we start doing any intense procedures.”
“We do triage them real quick and make sure that they have fluids and food, and then they’re resting and de-stressing before we do anything further,” Batchelder said.
Wildlife center personnel have been working with the Boston Parks and Recreation Department, MassWildlife, and the state Department of Environmental Protection, which activated its emergency response team. DEP and its contractor, Clean Harbors, deployed floating barriers and absorbent materials along a one-mile stretch of the river to contain and manage the spill, state officials said.
People who see injured wildlife are encouraged to call the wildlife center’s hotline at 508-362-0111.
Emily Sweeney can be reached at emily.sweeney@globe.com. Follow her @emilysweeney and on Instagram @emilysweeney22. Sabrina Lam can be reached at sabrina.lam@globe.com.