The Everett Police Department said the crows, which live in a tree next to the north precinct office, have been dive-bombing officers for the past few days, The (Everett) Daily Herald reported Monday.
Everett police Lt. Bob Johns said he recently "got zinged" by the birds.
"They're like velociraptors," he said.
Police said one officer attempted to ward off the crows using the siren in his patrol car and the birds responded by covering the cruiser in their feces.
Ruth Milner, a biologist with the state Department of Fish and Wildlife, said crows are often aggressive this time of year because they are "defending their nest."
Milner said the crows may be targeting the police officers because of their matching uniforms.
"If your cops have done something that (the crows) perceive as a threat, they could be keying in on them because they're all wearing the same kind of uniform," she said.