BASH program works to keep critters, aircraft apart

Published May 18, 2012
By Mike W. Ray
Tinker Public Affairs

TINKER AIR FORCE BASE, Okla. -- A common refrain heard at Tinker is that birds and aircraft don't mix.

Keeping the two separated can be quite a challenge, for at least two reasons, John Krupovage, Natural Resources manager in the 72nd Air Base Wing Civil Engineering Directorate, related. First, Oklahoma lies in a corridor traveled twice a year by more than 10 million migratory birds flying south in the fall and north in the spring. In addition, because of protective environmental laws and restoration programs, many bird populations are increasing.

Four-legged critters also are a concern at Tinker, which is why this base -- in fact, the entire Defense Department -- has a Bird/Wildlife Aircraft Strike Hazard program, said Regi Davis of the 72nd ABW Safety Office.

The program here is a team effort that involves Base Operations in the 72nd Operations Squadron, the base Safety Office, the U.S. Department of Agriculture's Wildlife Services, CE's natural resources and pest management groups, all flight organizations, plus VQ-3 and VQ-4, two Navy units at Tinker -- "anybody with anything to do with flying operations," Mr. Davis said. "We also coordinate with Midwest City, Del City and Oklahoma City," he added.

Collectively they monitor bird flyovers and landings at or near Tinker -- Lake Thunderbird at Norman and Lake Stanley Draper a mile from Tinker AFB are favorite waterfowl rest stops, Mr. Davis noted. Air Force personnel also monitor fencelines, to detect attempts to breach the perimeter by animals such as coyotes, skunks, raccoons, deer and feral dogs and cats.

Wildlife pose a variety of challenges at Tinker. A common problem is birds that fly inside buildings such as Bldg. 3001. Tinker, site of the headwaters of three creeks, has beavers, which typically aren't a problem unless they try to dam up a drainage culvert or damage an ornamental tree, Mr. Krupovage said. The Tinker Golf Course is inviting to Canada geese, "which see it as a water and food source, and a nesting and rearing area for their young," Mr. Davis said.

That's why Tinker contracts with the USDA's Wildlife Services to provide animal damage management.

"They have the expertise in this field," Mr. Krupovage said. "They handle those sorts of problems throughout the state and the nation. And they have access to the most current scientific data through the USDA National Wildlife Research Center, which is a federal institution devoted to resolving problems caused by the interaction of wild animals and society."

Since 1989, CE's Natural Resources function, Virginia Tech and Southern Illinois Universities and others have conducted wildlife inventories to determine what wildlife occurs on or migrates across the base. Additionally, USDA's Wildlife Services conducts daily surveys to monitor wildlife activity to reduce real or potential human health and safety hazards and damage to government property, Mr. Krupovage said. BASH is an integral element of that process. "Our goal is to manage and sustain health wildlife populations without creating aircraft hazards," he said. "The bottom line is to ensure we maintain a safe flying environment."

Tinker logs an average of 3,000 aircraft sorties per month, Mr. Davis said, so bird migration patterns are critical. Approximately 15 years ago a TC-118 aircraft was damaged when it hit four 1-pound ruddy ducks, but the plane landed without incident.

Depending upon food sources and weather conditions, birds sometimes will "stage," Mr. Krupovage said. While working their way south or north, they may hang out in our area for several days or weeks before moving on.

When birds stage in this area, Wildlife Services personnel haze them -- with pyrotechnics, clappers, flares, and sometimes firearms -- to scare them away.

"We remove them lethally when necessary," Mr. Davis said.

However, "Federal law requires non-lethal means as the first measure of control," Mr. Krupovage said. "If hazards persist, lethal means may be employed."

For example, several thousand egrets established a nesting colony one year on privately owned land near Tinker, and the birds crossed the flight line daily, Mr. Krupovage recalled. After the birds flew south for the winter, the U.S.D.A. contacted the landowner and paid for modification of the egrets' habitat -- a non-lethal control strategy; as a result, the site was no longer appealing to the birds when they returned the following year, and they nested at another site away from the base.

A similar event occurred in 1991, two years after year field monitoring started at Tinker AFB. Among other things, a biologist discovered a flock of 800 red-wing blackbirds roosting daily in cattails in a drainage ditch on the airfield along the west side of Bldg. 3001. The channel was lined with concrete, which eliminated the cattails, and the birds moved on.

Squadron, wing and group commanders at Tinker determine what restrictions to impose on their aircraft when large numbers of birds are prevalent in the area.

During Bird Watch Condition Moderate, operational flying unit commanders establish specific limits on the numbers of practice takeoffs and landings, based on aircraft size and mission priorities, Mr. Davis said.

Migrating birds tend to take off around sunrise and land for the night around sunset, so between Sept. 15 and Nov. 15 each year, he said, Bird Watch Condition Moderate is established by Air Force bases from one hour before and after sunrise and sunset. "The theory is, there will be fewer bird strikes if fewer airplanes are flying when birds are also flying at the same altitudes around air fields," Mr. Davis said.

When Bird Watch Conditions are rated severe, Mr. Davis said, "You have to have a really pressing reason -- such as war -- to fly, because the risk of a bird strike is extremely high."

These coordinated efforts apparently are proving successful. During the first six months of fiscal year 2012, from Oct. 1, 2011 through April 27, 2012, only three bird strikes were reported out of 16,000 sorties, Mr. Davis said. In fact, he said, it has been "a long time" since Tinker had a bird strike that caused severe aircraft damage.

That's quite an accomplishment, considering the number of birds that pass this way.

Several flocks of pelicans flew through here just recently; those birds weigh 10 to 30 pounds and can have wingspans of over 9 feet, and their flocks often number 100 to 300 birds, Mr. Krupovage said. And gulls migrate through Tinker in the spring and fall by the thousands, he said.

The sheer number of birds is not the only factor to consider. When a heavy rain occurs, insects come out and earthworms come to the surface -- and the birds follow. Also, to a bird, wet concrete may look like a lake or pond or an inundated mud flat. In combination, these situations can create significant localized bird hazards on the runways.

Not all birds are a hazard to Tinker aircraft, Mr. Krupovage said. Cardinals, for instance, have a limited home range and prefer wooded areas (such as the 150-acre Urban Greenway) over clear spaces (such as the airfield). Based on 20 years of records, a cardinal has never been struck by an aircraft in the Tinker area.

Wildlife biologist