Because it certainly looks like this guy in Morro Bay is giving us one. (Photo from Preita's Flikr photostream).
By Daniela Ogden
November 03, 2011
A New Colony of Caspian Tern Decoys on Aramburu Island
Richardson Bay Audubon Center is attacting breeding pairs of Caspian Terns with these newly painted tern decoys—a strategy successfully used by previous tern relocation efforts.