The arrival of spring means the arrival of hundreds of cliff swallows to Thunder Valley Casino.
In years past, that meant months of treacherous ingress and egress for the resorts staff and patrons, who were forced to dodge liquid waste from the birds nesting on the eaves of the facility.
"They were everywhere. It was almost like an infestation," said Doug Elmets, a spokesman for the casino. "Something had to be done, not only to protect the swallows, but to protect the staff and the guests."
Now the migratory birds come and go - pun intended - with little notice from anyone. In 2008, the casino constructed a $500,000 multi-story structure in the northeast corner of its parking lot with a large overhang and lots of eaves - a gigantic birdhouse, but with no actual windows.
On Tuesday, despite gusty winds, the birdhouse - painted and constructed to look like other casino buildings - was atwitter with activity. Dozens of dried-mud nests lined each side of the three-story structure. Birds would gracefully darted into nests before re-emerging to forage the nearby grasslands for building materials or insects to eat.
The swallows build new nests each spring and fly south for the winter, said Tim Fitzer, a member of the Sacramento Audubon Society.
"They are probably all paired up and building nests," he said.
Elmets observed that the birds are quite industrious in collecting mud and other materials.
Building the birdhouse might have been more costly than the casino's tribal owners would have liked, but it was clear that something had to be done, Elmets said.
To encourage the birds to begin nesting at the new structure, away from the casino, a contractor lured them with swallow mating calls amplified by a boombox, Elmets said. He said the contractor drove back and forth playing the sounds until the birds began to use the new habitat.
"Once they made the migration - which was really quick - they decided this was their new habitat," Elmets said.
Once the birds moved, the casino spent hundreds of thousands of dollars installing netting to discourage the birds from building new nests under the eaves of the casino, Elmets said.
Since they are communal nesters, the birds construct their nests in close proximity to one another on the facade of the birdhouse.
"If you put something up, birds will take them," Fitzer said. "Birds are very receptive to whatever habitat you put out there."
Call The Bee's Ed Fletcher, (916) 321-1269. Follow him on Twitter @newsfletch.
Editor's note: An earlier version of this story incorrectly identified the birds nesting at Thunder Valley Casino as barn wallows. They are cliff swallows. Story was updated at 10:35 a.m. Wednesday, April 24.