A little falcon’s 60 000km journeyComment on this story
Above the birds gather. They come in high, gliding in on the last lifting thermals of the day.
Below Rina Pretorius stares up at the reeling columns of thousands and searches for the special one.
As the sky darkens the flocks draw closer to the line of pine trees in Allen Street, Newcastle. Then one by one the birds drop on to the branches where they will roost for the night.
Somewhere among all those birds is the last of the 10 special birds.
They were caught two years ago, fitted with matchbox-sized satellite transmitters and let go. Each had a different satellite-tracking number. This allowed a never-before peek at a 14 500km-long migration of Amur Falcons – pigeon-sized birds of prey.
Nine of the birds have vanished. Maybe some are dead. Maybe their transmitters have stopped working. But not 95778. Her transmitter is still pinpointing her journeys.She’s the bird Rina is looking for.
In two years 95778 has made four transcontinental trips, clocking a distance long enough to circle the Earth one and a half times. Now she is back where it all started.
“It would be like winning the lotto if I saw her,” laughs Rina.
Rina searches the sky.From a distance, she explains, the antenna that runs down the falcon’s back would make her tail appear longer.If she is close enough, Rina might spot the small satchel that holds the satellite transmitter.
In two years 95778 has travelled nearly 60 000km on a journey that has crisscrossed continents and oceans. “And that doesn’t take into account day trips when she heads off to catch a goggatjie. That is just awesome,” says Rina.
All this is thanks to the efforts of BirdLife Northern Natal, and two German birdwatchers, Professor Dr Bernd-Ulrich and Christina Meyburg.
Rina is no stranger to the long-distance flyers of the bird world. She is a bird ringer and has ringed thousands of migratory Barn Swallows.
At weekends Rina can be found out in the field minding her mist nets.
When time permits she will even squeeze in a few hours after a shift at the ArcelorMittal site in Newcastle.
Sometimes she finds a special bird entangled in her mist nets. In bird-ringing circles they are known as retraps – birds that already carry rings.
In February she netted a Barn Swallow that had travelled 8 522km from the spot where it was caught in Slovakia six months earlier.
In 2009 Bernd-Ulrich approached Rina’s bird club with an unusual request.
He wanted them to catch a migratory bird that usually flies so high that one had never been caught before in a bird ringer’s mist net.
Bernd-Ulrich knew Allen Street attracts the largest-known roost of Amur Falcons in the world.
Between November and April every year, more than 20 000 birds take up residence in a line of pine trees that run for about 400m along the street. The roost is just a two-minute drive from the Newcastle CBD.
With the help of Eskom and the local municipality, Rina and other members of BirdLife Northern Natal came up with a plan to snatch the falcons from the air.
Using long poles and a pulley system, the ringers were able to hoist the nets 10m into the air, and place them in-between the trees.
In December 2009 they netted their first Amur and a month later the Meyburgs arrived in Newcastle carrying with them 10 prototype transmitters.
Over two days in January, they were able to catch 10 suitable Amur Falcons that were heavy enough to carry the transmitters.
Days after their release, the transmitters were streaming data, and the Meyburgs were ready to chart the first Amur Falcon migration from SA to their breeding grounds in Mongolia.
From his PC in Germany, Bernd-Ulrich tracked the birds as they cut their way north first through Mozambique then Tanzania, then Somalia.
Then the surprise.
The birds changed bearing; heading north-east, they struck out over open sea.
For an average of two days the birds flew non-stop over the Indian Ocean.
The fastest and the one with the most endurance was bird 95773, which took off from the coast of Somalia, crossed the Indian Ocean and touched down only five days later, in Burma.
Their journey ended 14 560km away in Mongolia, where the Amur Falcons paired and bred.
Three months later the birds were back in SA and Rina again stared up at the flocks hoping to catch sight of one of her birds.
Time passed and one by one the birds disappeared from Bernd-Ulrich’s PC screen.
Three of the birds stopped transmitting soon after they were released in 2010.
“We just don’t know if it is just the transmitters that failed, or if the birds died,” Rina says.
As for 95773, that speedster who flew non-stop for five days from Somalia to Burma, her transmitter went dead in September last year.
By the time the Amur Falcons began their second journey, at the end of last year, only transmitter 95778 worked.
As 95778 winged her way south, she faced an unexpected danger.
En route to Newcastle, 95778 spent about a month in the Kruger National Park; one fix had her 2km from the Mozambique border. “She survived the cyclone that swept through Kruger. Sometimes rain can affect the way that they feed,” says Rina.
By early February Bernd-Ulrich informed Rina that 95778 had arrived back at the Newcastle roost.
Once again Rina had a chance of catching a glimpse of the bird.
And this time she had a plan. She’d use her ears, not her eyes, to find 95778.
Rina planned to eavesdrop on 95778’s transmitter. Paul Howey, the owner of the Microwave Telemetry company that manufactured the transmitters, told her that if she got close enough to 95778 with a hand-held walkie-talkie set to the right frequency, she might be able to hear her.
“He told me what I would hear is the sound of an old fax modem – that would mean she is near,” explains Rina.
The sound would be a series of electronic beeps so fast that they would last just a third of a second.
Because the solar panel on the transmitter had aged, she was told to try after a bright day.
Carrying a two-way radio, Rina headed out to the roost for her first try. She arrived as the birds returned from a day of foraging. In her hand she also carried a stainless steel pot lid.
Rina had been told that she could improve the reception of the radio by holding it in her hand, pressed against the lid – it works like a satellite dish.
She walked along the line of trees, up and down, again and again.
Nothing. Only the chatter of the roosting falcons in the branches.
Every day for the next week, Rina returned with the radio and her pot lid. Bernd-Ulrich had told her via e-mail that the bird was still at the roost. But the radio remained silent.
There were times when she must have walked right past the tree that held 95778.
As a last resort, Rina approached local radio ham operator Dave Fourie.
He had equipment and the know-how. Dave knew they had between five and 10 minutes every night. They had to time it when a satellite was either overhead or on the horizon.
“The transmitter would then send messages to the satellite every 70 seconds,” says Dave. “There is only a window period.”
On April 3, Rina and Dave met at the roost. The satellite, Rina had learnt from Bernd-Ulrich, would be over them at 9.06pm. To play it safe, they arrived early and Dave brought along two radio receivers tuned to different wavelengths.
They had the frequency, and Dave believed a good chance, to pick up 95778. 9pm came, then 9.30pm. Nothing. Just dead air on both radios.
“We thought maybe we got the times wrong,” says Dave.
The next evening Dave decided he needed more firepower. He opted to stay at home.
From his house he could see the roost, 1km away.
Dave aimed the antenna at the pine trees. He set the volume to high and waited.
Dave had the frequency, times when the satellite passed overhead and a bird kept returning to the roost.
Everything in place, locating the bird should be easy.
But days passed and the radios remained silent.
Something was wrong.
What Rina and Dave did not know was that 95778 wasn’t there. She had left.
Bernd-Ulrich sent an e-mail, but he sent it too late.
The e-mail said that 95778 had left Newcastle on April 1, two days before Dave and Rina headed down to the roost. The next day at midday she was 230km north of Volksrust.
Then she headed north, fast.
Her third trip to Mongolia carrying her special cargo had begun. From Bernd-Ulrich’s e-mails, Rina learnt that 95778 did the transoceanic crossing safely in three days.
His last e-mail told Rina that the bird had made it as far as Burma.
Soon she will be back at the breeding grounds and if the electronics she carries survive the rigours of a Mongolian summer, and her strength holds for another long-haul flight, then… just maybe.
This time Dave believes that if 95778 touches down again at the largest Amur Falcon roost in the world they’ll get her.
He has software now that tracks satellites, so he will know when 95778’s satellite is overhead. He will have the antenna aimed at the pine trees and the radios ready.
Rina will be listening, too.
“If she makes it five times, why not six… and now that we know how to work the radios, this time we will find her,” says Rina. - The Star