That means the flock of cormorants would have to move on.
People living here in Brandermill say they've heard the sounds wildlife officials have deployed recently to scare the invasive birds off.
"Kind of like a roll of thunder off in the distance," said David Skovranko, a fisherman.
"It's a really loud boom, not like fireworks or a gunshots, though,” said Brandermill resident Alison Velazquez. “It can be scary if you don't know what it is."
"Shoot a few in the air, then poof, a loud boom," said 12-year-old Daniel Elsakr. Wednesday little Daniel witnessed what was causing it. "I saw some guys shooting flares for birds, just in mid-air," he said.
Those guys were Woodlake and USDA officials doing some cormorant ‘cleansing.’ "They don't like the pyrotechnics so we shoot them off and scare them," said Natalie Perry, a member of Woodlake’s Environmental Committee.
The invasive species of migratory birds is known to excrete highly acidic dung, which can negatively impact water quality. That in turn would affect the trees around places like the Swift Creek Reservoir.
"These birds eat a pound of fish a day and they excrete that on trees, which covers the trees and isn't good for plant life," said Perry.
Skovranko lives near the reservoir and says he's happy to see something is being done about them. "These birds create havoc, a lot of mess," he said. "It's a humane way of getting them to not come back."
Crews were heard setting off pyrotechnics around five p.m. Monday. Experts say they do this later in the day since the birds are clumsy flyers and typically spend the night where they end up.