Oh, wait. It was built in 1971. That explains everything. :-D
Lewis County has several roadside oddities so after doing a search I came up with the answer to your question Bill.
The viewers of Evening Magazine, a KING 5 show that airs out of Seattle, chose Yard Bird as the winner in that category for the Best Northwest Escapes 2011 edition. There are funding efforts to restore the bird as after 40 years sections of it have deteriorated. A benefit concert was held this past summer, June 25, 2011, featuring members of the Ventures and the Kingsmen. Lieutenant Governor, Brad Owen, who also plays in a band made an appearance as part of the back up.
As for what it ran up against? Other Northwest icons more than likely. If this were a Lewis County contest it would square off against the Centralia Art House, which the owner is in process of dismantling, or the Winlock Egg, and possibly the Gospodor Monuments.
In other news I have a Yard Bird refrigerator magnet.
:-D Definitely a landmark, but who voted? And what did it run against?