SEATTLE - No charges will be filed against two state troopers who clubbed three baby seagulls to death at Colman Ferry Dock in July, the King County Prosecutor's Office said Thursday.

The troopers, who provide security at the ferry terminal, said they were responding to complaints from ferry employees about aggressive seagulls who were dive-bombing ferry passengers and workers on July 15.

The troopers climbed to the roof of the terminal, where the birds were nesting, and killed three seagull chicks in an effort to drive away the aggressive adult birds that were harassing passengers.

No charges will be filed because the case does not fit the criteria for second-degree animal cruelty, the Prosecutor's Office said in a statement.

According to the Prosecutor's Office, the troopers did not "knowingly, recklessly or with criminal negligence inflict unnecessary pain or suffering upon an animal."

The troopers killed the young seagulls quickly by clubbing them over the head with their batons, and they took their actions "under color of state regulatory authority," the statement said.

The prosecutor also reviewed the case for a possible charge of unlawful taking of protected wildlife.

But that charge was rejected as well because it could not be shown that the troopers acted "with malicious intent or hunted without authority."

Normally, the U.S. Department of Agriculture or the Division of Wildlife Services are called in to handle problem gulls by dispatching chicks with CO2 gas or by shooting them in the head with an air rifle.

The troopers believed they were acting within State Patrol policy in destroying the gulls, but that conclusion was "misguided," the prosecutor's office said.

"The troopers used poor judgment, but there is no evidence to suggest that they acted with malice, which is requirement for criminal charges to be filed," the prosecutor's statement said.

"Rather, they were attempting, in a misguided way, to alleviate a genuine problem at the ferry terminal in a way that is generally consistent with how the problem would have been handled if the USDA or the Washington state Department of Fish and Wildlife had been called."

The two accused troopers, who are said to be 10- and 13-year veterans of the force, have been on administrative leave during the investigation.

They could have faced fines of up to $5,000 and up to a year in jail if they had been charged and convicted of animal cruelty.

The Washington State Patrol will conduct its own independent review of the incident now that the criminal investigation is complete.