Johannesburg - Meet Jonathan "Boeing" Seagull and his cousins "Antonov" and "Embraer".
These three grey-headed gulls have forsaken the maritime environment enjoyed by most of their brethren across the world – choosing instead to dwell far from the sea, close to the rich inland pickings of Gauteng.
But the presence of growing numbers of these gulls in the vicinity of the OR Tambo International Airport in Johannesburg - and the increasing risk of bird strikes – has resulted in three of the birds being captured and fitted with lightweight tracking devices.
The trio, a female and two males, whose comings and goings will be tracked by bird experts for the next several months, have been renamed after American, Russian and Brazilian aircraft manufacturers – Boeing, Antonov and Embraer.
BirdLife South Africa says the risk of collisions between birds and aircraft cost the international aviation industry millions of dollars each year, either from direct damage to aircraft from bird strikes, or indirectly, from delays caused by aircraft down time.
Now BirdLife, the Airports Company South Africa (ACSA) and Albert Froneman Consulting have launched a new project to get a better handle on the movement of grey-headed gulls which often congregate around OR Tambo airport in large numbers during the winter months while breeding on the surrounding pans and wetland areas.
BirdLife says OR Tambo International Airport has a world-class wildlife hazard management programme that is designed to mitigate the impacts that birds and other wildlife pose to arriving and departing aircraft.
This includes radar scanning, firing blank shotgun rounds into the air to scare birds away or deploying specially-trained sheep dogs to chase them away.
But, over the last 17 years, bird collision data has indicated that grey-headed gulls are an increasingly high risk species at the airport.
"As the gulls often congregate in large numbers near the periphery of the airport and occasionally venture onto the airfield, it is particularly difficult to mitigate the risks they pose as potential bird strike victims," says BirdLife SA chief executive Mark Anderson.
Dr Hanneline Smit-Robinson, Craig Natrass and Gail Schaum attach a tracking device and body harness to one of the grey-headed gulls near OR Tambo International Airport. ( Albert Froneman)
Using birds as trackers
Little is currently known about the movements of grey-headed gulls on both a local and seasonal scale, complicating plans to develop effective bird strike mitigation strategies.
Now, to gain a better understanding of the movements of these birds, a tracking study has begun.
After careful research and testing of harness design and fitting methods, three gulls were captured earlier this week and fitted with light-weight, solar-charged, tracking units to provide 15 minute point-locations throughout the day.
Once a better understanding of the grey-headed gull movements has been established, a new management strategy will be developed to reduce the risk that these birds pose to aircraft at OR Tambo International Airport.
Though most gull species are associated with marine environments, large numbers also move deeper inland to breed and roost in lake and wetland areas.
But it also seems that some of these inland gulls get fed up with the cold weather, smog and noisy traffic around Gauteng and head back for occasional seaside holidays.
This was demonstrated this week, when "Embraer" – just two days after being fitted with a tracking device – flapped hurriedly from Gauteng and made straight for KwaZulu-Natal.
Dr Melissa Whitecross of BirdLife said tracking data showed that Embraer had relocated already to Lake St Lucia in the iSiminagaliso Wetland Park, north of Richards Bay.
- From next month, members of the public will be able to follow the movements of the birds via maps on the BirdLife SA website: https://www.birdlife.org.za
