If you see blue ribbons tied around tree trunks around town, you’ll want to look up.

It means there are white terns nesting in those trees.

The group Hui Manu-o-Ku is responsible for putting up those ribbons, mainly to let tree-trimmers know the birds are in there.

“As it turns out, the terns essentially breed year-round now, but the trees, of course, need to be trimmed, and it’s a pretty substantial fine if you disturb an active white tern nest,” said Rich Downs of Hui Manu-o-Ku. “White terns are nesting in the trees here in the Honolulu, Waikiki area, and this is the only place in the Pacific where they do that in an urban environment.”

The white tern is the official bird of Honolulu.

Its Hawaiian name, manu-o-Ku, translates to bird of Ku, the Hawaiian god of war.

Fines for disturbing these birds range from $250 to tens of thousands of dollars and prison time.Click here for more information.