Saturday, January 14, 2017

Program helps planes avoid ‘collisions’ with large birds near Dover Air Force Base

USDA wildlife biologist John Mogle and his dog Memphis work to keep birds and other wildlife away for the Dover Air Force Base. 

When birds collide in mid-air, it can be messy — especially if one of those birds is a C-5M Super Galaxy (America’s largest military cargo aircraft). Since these C-5Ms, and many other aircraft, take off and land around the clock at Dover Air Force Base (DAFB), there is a strong interest in making sure these collisions don’t happen.

This effort falls under the purview of the Bird/Wildlife Aircraft Strike Hazard (BASH) prevention program. The staff on base responsible for running this program are USDA wildlife biologist John Mogle and his trusty four-legged co-worker Memphis (a Labrador mix). The USDA, through an inter-agency agreement with various military branches, provides specialists like Mr. Mogle to military airfields to help control and disperse wildlife from landing strips to ultimately reduce the costs and incidence of what they call: foreign object damage (FOD).

Being right in the middle of the Atlantic Flyway, the East Ccoast’s bird migration route, just south of Bombay Hook National Wildlife Refuge, north of Prime Hook National Wildlife Refuge and practically on top of Little Creek Wildlife Area makes Dover Air Force Base a virtual magnet for migratory bird activity. Luckily, because of a late migration this year, the snow geese, which are ordinarily the base’s most pesky species, have been late in arriving. Once they did arrive there weren’t as many as last year, said Mr. Mogle.

“We do rough estimates each time we disperse a flock of them,” said Mr. Mogle. “Last year we were up around 300,000 snow geese for the season, but as of late December I estimated only 50,000.”

But the base can’t afford to let its guard down even for a moment, especially since cooler weather can easily send more snow geese into the flight path.
Prevention strategies

To limit the number of potential bird strikes, Mr. Mogle and the Dover Air Force Base use a number of different strategies:

•Fly time restriction

One of the simplest, but potentially most important, techniques the base uses is stalling flights when the bird traffic is at its highest.

“Sunrise and sunset are the worst times in terms of high traffic,” said Mr. Mogle. “We have a regulation that restricts the first 90 minutes after sunrise and the 30 minutes after sunset.”

He notes that there are some exceptions and special approvals that give this rule some flexibility. If Mr. Mogle notices a large flock on base or nearby, he can also call in to the tower and have flight temporarily restricted until the birds are cleared.

USDA wildlife biologist John Mogle sets up a Swedish goshawk trap next to his office on the Dover Air Force Base.

•Habitat removal

By default, Dover Air Force Base looks like a nice site to cluster for birds because large flocks are attracted to wide open fields. The base tries to make itself less charming in that respect. They limit standing water, remove “perch points” and maintain grass to specific heights.


If Mr. Mogle comes across birds on the airfield or nearby he’ll first try to spook them away. So he’ll radio in to the tower to make sure a plane isn’t about to land or take off and then deploy Memphis.

“He’ll be looking out the window when we pull up, he’s ready to go when I open the door,” said Mr. Mogle.

Memphis is a little over three years old. Adopted in Georgia, he was originally trained as a detection dog for the federal Chesapeake Bay Nutria Eradication Project. That effort was aimed at protecting the Chesapeake Bay wetlands by eradicating invasive nutria, which are small semi-aquatic rodents, from the Delmarva Peninsula.

Memphis took to his new job quickly though, Mr. Mogle said. He has a natural inclination to chase birds and learned the most important techniques early.

“He’s trained to follow me when I’m out in the field,” he added. “But also, he just follows the most important commands ‘come’ and ‘goose!”

Of the different dog breeds, Mr. Mogle said that Border Collies make especially gifted BASH dogs, but they are expensive — whereas Memphis, who is a rescued dog, was basically free.


Pyrotechnics are used to not only get the birds up in the air, but direct them as well. Mr. Mogle said he uses four types: “bangers, screamers, shell crackers or a CAPA pistol”.

Bangers and screamers do just as their names imply. Mr. Mogle uses these two types the most often. They are fired from a starter pistol and have a range of 50 to 60 yards.

“I use a banger to get the birds’ attention, then a screamer to sort of steer them if their headed away from where I want them to go,” he said.

Shell crackers are fired from a shotgun. They also make a loud bang, but have a bit longer range — about 100 yards. For the hard to reach birds, such as ones roosting in the middle of a field he can’t get to, Mr. Mogle uses a CAPA pistol — a loud pyro with a range of 1,000 yards.

“These are intended for range, but they’re expensive so we have to use them very sparingly,” he said.


For some birds that Mr. Mogle is required to catch and release, like red-tailed hawks and snowy owls, he employs traps.

“We set blackbird traps, and I also have a Swedish Goshawk Trap, baited with a live pigeon, that catches hawks and owls so we can band them and release them away from the base,” he said.

He’s required to put a special tracker on snowy owls he catches and make a report in a database that monitors their movements.

The long parked Air Mobility Command Museum airplanes are heavily populated nesting grounds for small birds like starling, sparrows and cowbirds. Mr. Mogle obtained a new type of small birdhouse trap he’ll be setting up soon to start reducing these populations.


Depredation, or shooting the birds, is a last resort for Mr. Mogle.

“We try non-lethal methods first, but if we have habitual offenders that are ritually coming back to the same spot we have to remove them,” he said.

Oftentimes, certain birds will become stubborn, refusing to leave. Mr. Mogle’s spooking methods will get them airborne, but they may only fly 100 yards away or return shortly after he leaves.

“With the snow geese, they get stressed out as it gets colder and they get really stubborn then,” he said. “They’re also operating under a safety-in-numbers mentality.”

•Cooperation with neighbors

The BASH program seeks to create a no bird “five mile bubble” around the base. This happens to include some land belonging to adjacent farmers and property owners. The air force has negotiated a contract with them that allows Mr. Mogle, sometimes in a limited capacity, to use his methods to spook birds on their property.

“Because we’re a government entity we had to have documentation saying that we were allowed on these peoples’ property,” he said. “We have contracts attached to the deeds that are renegotiated every five years, they basically spell out what we can and can’t do on the properties like using our dog or pyros.”

Zero tolerance for wildlife

BASH is the main component of Mr. Mogle’s job, but because the Air Force maintains a zero tolerance policy for wildlife in the base’s perimeters, he tracks and chases down a number of other animals too like fox, deer and turtles.

“Last year we had 12 deer on the airfield,” he said. “Some were hopping the fence, and others were coming up from underneath it. There’s a tidal drainage near one of the corners of the airfield and as the tide came in it would wash away some soil a leave a spot open for them.”

The spot in the fence was quickly patched with a new section of chain-link.

Mr. Mogle said the turtles start climbing out of the drainage ditches in the summer in large numbers and find their way onto the airstrip.

“It’s unbelievable how many snapping turtles we have come out,” he said. “The females want to go to higher ground to dig a hole an lay eggs.”

Although chasing out snow geese in the winter has Mr. Mogle the most busy, battling birds on base is a year-round affair. After the migratory birds like snow geese and Canadian geese head back north, osprey come up.

“In March, osprey arrive, and they’re a threat because they can get big,” he said. “We’ll also have a lot of nesting European starlings and Brown Headed cowbird.”

He noted that the interaction between these two birds is particularly interesting because cowbirds will often lay their eggs in starlings’ nests and then abandon them. The starlings will still raise the cowbird chicks though.

Although Mr. Mogle said some birds seem to pick up on the fact that the base is not a good place to hang out, at times the wildlife seems more interested in adapting to him rather than avoiding him.

“For the first time ever this year we found a few nests up in the tail of an active plane,” he said. “Starlings found a fold up there and made several nests in two separate planes — the nests even survived a few flights.”

Birds known for being particularly shrewd, like vultures and crows, recognize his vehicle and will often move away before he arrives and come back when he leaves. Foxes see him coming and will duck into low spots in the field so he can’t find them, he said.

Eagles are especially stubborn.

“We have permit to use pyros to scare them away, but they just don’t spook easy,” he said. “They get up and move maybe 100 yard and I constantly have to follow them around. They show up in October and we don’t have too many, I maybe saw 4 last year at one time. There are a few established nests in the area.”

Bird strike procedure

Despite the base’s best efforts, bird strikes still happen. According to the 436th Airlift Wing Safety office, over the last five years, the base has averaged about 38 strikes per year. However, most were non-damaging. For instance, in financial year 2016 the base reported 32 bird strikes, none of which resulted in damage.

Often, a bird strike will result in nothing more than a corpse on the runway or a smear on an airplane panel.

“The most frequently hit bird is a sparrow,” said Mr. Mogle. “It’s usually not an issue because they are so small. If I find pieces of a bird in the field I’ll record it as a glancing blow, but sometimes a sparrow will pass the exhaust of a plane and just drop dead and I’ll find the body whole.”

Occasionally, a pilot will hear or see a bird strike. Under these circumstances, they will notify maintenance when they land so they’ll know where to look. Sometimes though, a pilot won’t even know they hit a bird until a post landing inspection. This is when maintenance finds what’s known in the industry as “snarge” — a colorful term that mixes the words “snot” and “garbage”.

Sgt. Justin Petrosky, quality assurance inspector of the 436th Maintenance Group, said when his team discovers a bird strike they reach for a kit specifically designed to deal with the remains.

“The kit contains gloves, a plastic bag to put the remains in, alcohol pads and Q-tips,” he said. “I brief all bird strikes to the wing vice commander every quarter so he is aware of them.”

The snarge is so carefully removed and bagged up because it actually gets sent to the Smithsonian for analysis, said Mr. Mogle.

“It gets shipped to the bird ID lab down there so they can go through and do DNA testing on it,” he said. “This way, we can keep track of what types of birds are being hit and where they’re from to form better strategies.”

After the cleanup, Mr. Petrosky will inspect the impact site for damage. If the bird strike impacts the engine, he’ll inspect the inlet and associated parts. If the bird went into the core of the engine, he’ll inspect the inside through the use of a borescope.

“The most severe damage is usually a bent blade or bent Exit Guide Vane,” he said. “For the C-17, blades are replaced in sets of 180 degrees apart for equal weight distribution to ensure no vibration occurs in flight. A set of blades cost the USAF $1,500 and usually takes about 2 hours to replace for a total cost of $1,594.”

Mr. Petrosky estimates that 9 out of 10 bird strikes result in no damage — just cleaning and inspection.

Just how costly can a bird strike get?

The costs associated with supporting Mr. Mogle, Memphis, the maintenance crew’s procedure and any other BASH related work is considerable, but weighed against the potential of a catastrophic bird strike, it’s nothing.

It’s not inconceivable that a bird strike could bring an airplane down.

“The bigger the bird the more the damage usually,” said Mr. Mogle. “But if you’re flying through a dense flock, even small birds would be like bullets. A bad enough strike could certainly bring a plane down.”

In a catastrophic scenario like this, the lives of the crew, passengers and people on the ground would be at risk — to say nothing of the extensive property damage that would result. Luckily, this hasn’t happened at DAFB.

They’ve had their costly run-ins though. Wing safety reported that in the last 10 years, DAFB has only had three major bird strike mishaps. In each case, the aircrew was able to land safely. However, the aircraft in each incident sustained damage to an engine, which was costly. Spokesman for the base, SrA Aaron Jenne, said that the bird strike in 2006 cost the Air Force over $2.8 million, the one in 2008 cost $992,679 and the one in 2012 cost $666,517 in damages. He noted that two of the three mishaps involved snow geese and the other mishap involved Canada geese.


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