On a recent feedlot tour, a group of foreigners expressed surprise at the huge numbers of starlings in the yard. "What's their average daily gain?" quipped one visitor.

Regular, open supplies of grain and water found in feedyards are natural congregation points for pigeons, starlings and other blackbirds. The noisy, hungry invaders can become so numerous that some might wonder as to the crop being raised - cattle or birds.

Besides being a nuisance, birds are expensive. One feedlot manager estimates his feed loss to birds at $5,000 per day, says Rick Gilliland, district supervisor for USDA's Animal and Plant Health Inspection Service (APHIS) Wildlife Services.

The birds pass by the steam-flaked corn in favor of the ration's other nutrients. The economic loss is magnified by the loss of nutrients to the cattle feeding at the bunk.

More problems occur at the water troughs, where birds can pass on coccidiosis and salmonella to cattle as well as to personnel who clean the troughs.

And that doesn't take into consideration the perception of potential clients who see a black cloud of blackbirds flying from a feedlot. Finally, there's the cost of directing personnel, private industry or APHIS' Wildlife Services to attack the problem.

Control Possible The good news is that control is possible through an integrated management approach to controlling birds.

"An integrated management approach includes a mix of control options," Gilliland says. "There is no silver bullet and no single control."

Although the effectiveness of different controls varies depending on the numbers of birds attacking a feedlot, each method has proved effective in an integrated approach.

To begin bird control, feedyard managers have the option of contacting a pest control operator (PCO), which includes all private companies, or APHIS' Wildlife Services. Many states have different regulations regarding use of approved and legal methods. Feedyard managers can receive information on the best approach by contacting APHIS' operational support staff at 301/734-7921.

An integrated bird control program includes avicides, pyrotechnics, habitat management and electronic devices.

* Avicides. In high infestation areas of 100,000 birds or more, avicides are the recommended control method.

In some states, PCOs use Avitrol (Registered Trade Mark), which is considered a technical bait. That means the active ingredient is mixed with feed in the trough. Birds that eat Avitrol begin to squawk and fly erratically. Most eventually die. But their behavior often scares the other birds away.

Most other avicides are limited to use by APHIS' Wildlife Services. Among the most effective has been Starlicide Technical(Registered Trade Mark), otherwise known as DRC1339.

"APHIS developed this avicide," Gilliland says, "and it has a limited shelf life. It isn't put in the ration, but on bait such as corn chops in the alleys. It's proven very effective. Birds die at their roost sites one to three days after eating it." Use of this avicide, again, is subject to state regulations.

One benefit of DRC1339, he says, is that it's highly selective, only affecting blackbirds. Other, more desirable species are unharmed if they eat it.

The best time to attack birds is during the poorest weather. Under blue skies and warm weather, birds prefer to eat the feedbunk grain. With snow on the ground and temps in the 20s, birds will gravitate toward food in the alleys.

"We had good results with a north wind and the temperature about 22 degrees F," Gilliland says. "Since DRC1339 is not labeled for use in pens, we put the bait in the east-west alleys that provide the birds shelter on the south side from the north wind. They were almost standing on each other's shoulders. On different days, we had between 10 to 50 percent reduction."

Noise Control * Pyrotechnics. Any type of exploding device should be used in conformance with local laws, regulations and ordinances. In some cases, particularly in feedyards with low infestations, pyrotechnics have been effective.

The problem, Gilliland says, is birds habituate themselves to the devices. He's seen some cases where birds sit on the devices even as they go off.

The shells are propelled by 12-ga. shotguns or 15- or 17-mm pistols. The latter two have limited range. The disadvantage is that feedlot personnel must manually discharge the shells, thus tying up valuable labor.

Firecrackers also have been effective when lighting a fuse rope at one time. For yards just noticing a bird problem, these approaches can be effective, Gilliland says. "The birds could leave and not come back," he says. Feedlot cattle are initially bothered by the noise, but they become habituated. After a while, the noise is no more disruptive than a passing feed truck.

Another positive is that pyrotechnics disrupt the birds and give feedlot personnel a chance to evaluate the infestation, which could lead to other control methods.

Other Controls * Habitat Management. In Gilliland's experience, starlings have flown 23 miles from state-owned land to dine on a feedyard's grain supply. But if a feedyard manager has the rights to close-by land, he can modify the environment to discourage birds.

The approach varies by species, but thinning or pruning vegetation to remove protective cover can discourage roosting. North Dakota sunflower growers use helicopters to spray herbicides in order to remove cattails where redwing blackbirds congregate.

Although all habitat management requires personnel, it usually produces a more lasting effect than other methods and is less expensive in the long run.

* Electronic Devices. Electronic and broadcasted calls have also proven effective in limited circumstances. APHIS' Wildlife Services provides information on commercial sound generators. The sounds disperse birds, but aren't a permanent control device.

Other devices with limited effectiveness include whirling novelties, flashing lights, smoke, water sprays, tethered balloons and hawk silhouettes.

The price of controlling birds can be costly. Avicides are expensive. So are personnel assigned to fight the flocks of birds that eat for free. But the end result can be higher returns and fewer problems with cattle.