Lewisville city officials have tried in recent years to build more tourist attractions. This spring, the city is making a point to remove one.

NATALIE CAUDILL/DMN

A great egret perches over ponds in Highland Village. Thousands of its cousins, the cattle egrets, swarmed Lewisville Lake Park in the past.

For the last two summers, thousands of cattle egrets have swarmed a forested area at Lewisville Lake Park next to a parking lot and soccer fields. It was a spectacle, white birds everywhere.

"It was amazing to see," parks director Bob Monaghan said. "People came out just to see them."

KYE R. LEE/DMN

At Lewisville Lake Park, this cannon, attached to a propane tank and sitting on a high platform, makes random booms to annoy cattle egrets, whose droppings kill trees. This and other noisemakers don't harm the birds.

But problems outweighed the benefit. Where there weren't birds, there were bird droppings – whitewashing foliage and killing dozens of trees. And a horrible stench wafted onto the athletic fields.

"They're very, very messy," said Keith Lockhart, an amateur bird-watcher from Highland Village who gives tours at Lake Park. "And the smell is so bad."

So, Mr. Monaghan bought a cannon. It attaches to a propane tank and sits on a platform high in the air. The cannon makes a loud boom at random intervals to annoy the birds; it doesn't harm them. The city also bought some pistol-like noisemakers for similar effect. Lewisville officials said they spent about $1,000 on the equipment.

Mr. Monaghan made sure his team was ready when the first egrets began arriving over Easter weekend from winter migration in Central America. Once the whole flock arrives and nesting begins, federal law prohibits any effort to disturb a migratory bird's habitat, even though egrets aren't endangered.

It appears the noisemakers worked. There weren't any egrets in sight Thursday afternoon. About a dozen returned Friday morning but were quickly chased off when park employees began firing the noisemakers.

"We've become a bigger nuisance to them than they are to us, so they left," Mr. Monaghan said.

Lewisville looked for ways to scare off egrets in the past, but Mr. Monaghan said the city hadn't acted early enough the last two summers.

Egrets are a fairly common problem across North Texas, one that frustrates homeowners and city officials who don't plan ahead. Lewisville learned from neighboring Carrollton's mistake that people can't mess with nesting egrets.

In 1998, Carrollton city workers bulldozed trees – with nesting egrets in them – at Josey Ranch Park. More than 300 egrets died. The city was fined $70,000 and paid $123,000 in veterinarian services.

In Lewisville Lake Park, the birds and their droppings are gone, but the egret effect remains. Empty nests are visible in almost every limb. And in one concentrated area, dozens of trees appear dead.

Mr. Lockhart said he's trying to track the egrets' relocation, but it appears they've yet to settle. Mr. Monaghan said he's heard of sightings in nearby Highland Village and Hickory Creek.

"They'll go bother someone else," Mr. Lockhart said.