Mysterious White House lockdown caused by… birds?

Two days before millions of Americans were expected to feast on turkey for Thanksgiving, a flock of birds is theorized to have been responsible for the White House lockdown in the early hours of the morning on Nov. 26, 2019.

The White House was placed on lockdown between 8:30 and 9:15 a.m. because of an unauthorized aircraft flying in restricted airspace, according to reporters on the scene.

The North American Aerospace Defense Command, the US and Canada's first responder to an aerial threat, scrambled US Coast Guard helicopters to investigate the scene. No military fighter jets were dispatched, the US military spokesman Maj. Andrew Hennessy told The Washington Post.

By the time the lockdown was lifted, it was unclear what prompted the warning.

"Upon further investigation, we found there was no aircraft," Hennessy said, according to WRC-TV.

(Photo by Arttu Päivinen)

The WJLA reporter Sam Sweeney said the scare may have been because of a flock of birds. Birds are known to migrate south by way of the US Capitol in late October, according to The Washingtonian.

In an unrelated event several hours later, President Donald Trump pardoned one of two turkeys named Bread and Butter. The White House tradition dates back to President Abraham Lincoln in 1863. Trump ended up pardoning Butter, and Bread will also live the rest of its short life at "Gobblers Rest" on the Virginia Tech campus.

This article originally appeared on Business Insider. Follow @BusinessInsider on Twitter.