How and why do flocks of birds collide with aeroplanes?

Thousands of planes are struck by birds in midair every year. Can people be hurt and how can we prevent it from happening?

birds with aeroplane in background
Thousands of birds collide with planes each year [File: Petros Karadjias/AP Photo]

For people who are fearful of flying, midair turbulence or cabin panels blowing off an airliner are probably among the more frightening things they might imagine happening. But did you know that colliding with a flock of birds is also a major aviation hazard?

A Virgin Australia flight on June 18 was forced to make an emergency landing in New Zealand after one of its engines caught fire due to a suspected bird strike.

In April, 39 flamingos were killed when they collided with an Emirates passenger jet shortly before it touched down in Mumbai on India’s west coast. Exactly one year previously, activists had warned against the construction of a second major airport for Mumbai – Navi Mumbai International Airport, due to be completed in 2032 – because of its proximity to two bird sanctuaries and the feeding grounds of several species of migratory birds, including flamingos.

In airports near coasts, wildlife activity may be higher than inland ones, putting birds and planes at higher risk of ill-fated encounters. Bird strikes, as these incidents are known, are common.

How did the Emirates plane hit the flock of flamingos? 

The Emirates Boeing 777 aircraft hit a flock of flamingos about 300 metres (1,000ft) above the ground on May 20. Later that same night, a group of children in Ghatkopar, a suburb in Mumbai, reported finding flamingo carcasses on the road.

While 29 dead flamingos were found that night, another 10 were discovered the next morning, according to a report in the Indian Express newspaper, which quoted a forest official.

The airline confirmed the incident two days later.

“The aircraft landed safely, and all passengers and crew disembarked without injury. However, sadly, a number of flamingos were lost, and Emirates is cooperating with the authorities on the matter,” a spokesperson told the Reuters news agency.

The aircraft was damaged, and the return flight, which had been scheduled to depart for Dubai the same day, was cancelled, the spokesperson added.

What is the risk of birds colliding with aircraft?

More than 14,000 bird strikes are reported each year in the United States alone, according to the Federal Aviation Administration. In 2022, the United Kingdom’s Civil Aviation Authority reported nearly 1,500 bird strikes over the year.

A study carried out in 2020 by German researchers at the Delft University of Technology and the Netherlands Institute of Flight Guidance at the German Aerospace Center, looked at the rate of bird strikes per movements of aircraft in several countries around the world. It found Australia had the highest bird strike rate – nearly eight for every 10,000 aircraft movements. The US had the lowest at 2.83.

Bird strikes rarely occur at higher altitudes. Collisions tend to occur when planes are in the same space where birds usually fly, such as when aircraft are approaching, landing at and departing from airports.

Waterfowl, gulls and raptors are the most common types of birds to come into contact with planes in the air, according to reports collected by the Bird Strike Committee based in the US.

What causes bird strikes?

Several factors put birds at risk of colliding with aeroplanes.

Birds are naturally attracted to habitats that are often located around airports, such as open fields, wetlands and bodies of water that serve as feeding and nesting grounds.

For instance, flamingos commonly live in large, shallow lakes and lagoons that can be close to land selected for the construction of coastal airports.

Although inland airports have less bird activity, even water pooling on uneven pavements can be enough to attract them.

Many birds are migratory. As a result, their flight paths can intersect with air traffic routes, especially during migration seasons when they make long journeys to travel between breeding and feeding grounds.

Birds often fly in flocks, which increases the likelihood of multiple fatalities in the event of a collision.

Have people been injured or killed in bird strikes?

A particularly deadly incident occurred in October 1960 when Eastern Airlines Flight 375, a Lockheed Electra plane, was hit by birds. Just 20 seconds after takeoff from Boston Logan International Airport, a large flock of European starlings struck the plane’s engines. The aircraft lost power and crashed into Boston Harbour, killing all but 10 of the 72 people on board.

In 1988, 35 of the 104 people on board an Ethiopian Airlines Boeing 737 aircraft were killed when it crashed after several birds flew into its engines during takeoff from Bahir Dar, Ethiopia.

Over the past 31 years, bird strikes have caused the deaths of 292 people around the world.

Injuries can occur as well. In 2009, US Airways Flight 1549 made an emergency landing in the Hudson River after hitting a flock of Canadian geese shortly after takeoff. The plane’s engines sucked in the geese after impact and lost power. Although 100 people on board were injured, all 155 passengers and crew were rescued by boats. The incident later became the subject of a Hollywood film, Miracle on the Hudson, starring Tom Hanks.

A decade later, in 2019, a Russian passenger plane struck a flock of gulls and had to make an emergency landing in a cornfield near Moscow. The event became known as the “Miracle over Ramensk“. Seventy-four of the 233 passengers on board suffered minor injuries.

Pelicans are a type of waterfowl that often collide with planes in the US [File: Rogelio V Solis/AP Photo]

Can bird strikes damage planes?

In most collisions, birds hit the windscreen of an aircraft or fly into engines, which can sometimes result in an emergency landing or, in rare cases, a crash.

Even a strike that has not caused obvious damage can reduce engine power and add to operating costs.

From 2013 to 2018, bird strikes caused $340m of damage to aircraft, according to an analysis by the Allianz Global Corporate and Specialty insurance company.

The firm reported that insurers received more than 900 bird-strike-related claims during those five years to cover the costs of repairing damaged engines and airframes, which include mechanical structures such as wings. The average claim was for $368,000 while some were in excess of $16m.

Can bird-plane collisions be prevented?

Because many bird strikes occur near airports, airport authorities and managers can reduce the risk of collisions through bird management and control. This involves first using a radar system to detect their presence.

As well as using better detection systems to alert pilots to adjust their flight paths, several techniques can be employed to scare away birds. Bird distress signals, decoy animals or using sounds and lights are some of the ways in which birds can be directed away from planes close to an airport.

Additionally, conservationists also advocate for the creation of safe migratory corridors for birds. These are networks of connected habitats that are created after identifying common migratory routes. They provide access to necessary resources such as food, water, and resting areas and help maintain biodiversity.

In some cases, these wildlife corridors are naturally existing, protected areas. In others, habitats that have become fragmented by human activity can be reconnected.

Source: Al Jazeera and news agencies