There is nothing like a bit of alfresco dining, sitting out in the open air, enjoying the food and the sunshine (or snow…)

A flock of seagulls or crows, and a minefield of duck droppings can really spoil the vibe.

Not to mention those of us who have seen Alfred Hitchcock’s The Birds, and are terrified by the sinister motivations of birds in close proximity with humans.

Costco has for a long time had a serious bird problem at its Issaquah store’s outdoor foodcourt.

Panicked customers and filthy tables even drove the store’s managers to install a sound system which played predatory bird calls, in the hope this would keep the winged-beasts away.

Mostly, it kept the customers away.

But now, thanks to an Everett company specializing in movie effects, the Costco foodcourt may have found an answer to the problem – a fog machine that emits a fine mist of grape seed extract.

According to Costco Food Service Manager Jason Clark, the grape seed mist irritates the lungs of small birds, though it is almost undetectable to humans.

“What we typically hear from our customers is that it smells like fruit,” he said.

“It is so fine though that it doesn’t affect the taste of their food, or do anything to their clothing.

“One customer said it smelt like blueberries, another said it reminded her of popsicles.”

Clark said the mist had been about 90 percent effective in keeping the birds away.

“The ducks still waddle in, and I have to get out there and chase them away,” he said.

Crawford International Theatrical Corporation (CITC) has for many years provided haze, mist and snow effects for the entertainment industry and retail business.

The problem of how to keep birds away from public spaces like outdoor restaurants and stadiums provided them with a new use for their technology.

According to the owner of CITC, Gary Crawford, the idea was launched when he read that the doctor who patented the grape seed extract was saying that if that extract could be reduced to a micro-fluid, and sprayed in a thin mist, then it would very effectively deter birds.

The fog and haze machines were adapted, and now CITC, through partner company Bird Buffer, supplies outdoor venues across the world with such devices, including 40 Costco stores, a Barnes and Noble store in Seattle, and the City of Seattle trash depot.

Crawford said the mist only affects birds in flight, as it needs to be sufficiently inhaled by the birds’ rapid breathing.

“The birds that are in flight will be effected, and they must have the freedom to leave, so they are not harmed in any way,” he said.

“It will not affect roosting birds, or those that are just standing around.”

The mist irritates the birds’ trigeminal nerve.