‘Bird Kingdom speedsters’ threatened with extinction as their food sources threatened
There is an ornithological mystery that confuses scientists.
Yellow-billed kites aren’t known as the speedsters of the bird kingdom. Rather, they seem to spend their days lazily gliding over the thermals in search of something to eat.
But all is not what it seems.
Not so long ago, it was discovered that a yellow-billed kite had traveled quickly to Rwanda from South Africa.
“So he went right outside Pietermaritzburg to Hoedspruit (Limpopo) in one day. And then the next day, from there to the top of Zimbabwe in this corner with Mozambique. And then straight on to Rwanda. So huge distances, ”says Professor Colleen Downs of the School of Life Sciences at the University of KwaZulu-Natal.
Now the question is, did the bird receive assistance from a high altitude jet stream in its intra-African migration? Or was this bird’s journey unusual compared to others of its species?
Until recently, birders were unable to glimpse the long-haul flights of birds. The flyways had to be reconstructed from the sightings and the strange bird found that had been previously banded.
Today, smaller and smaller trackers tell where birds go and how they get there.
The yellow-billed kite that Downs and his team were tracking had a tracker that carries a SIM card and uses cellular technology.
As part of their ongoing study, they have installed tracking devices on eight other yellow-billed kites and will publish their results soon.
Trackers are now placed on even smaller birds. Just over a week ago, researchers at Lund University, Sweden, revealed in the Journal, iScience, a study they had done on common swifts.
These small birds with their long back wings are known to spend up to ten months of the year in continuous flight. They even sleep while flying.
They migrate to sub-Saharan Africa in the summer and have also been seen flying over Joburg.
Swifts were also believed to be able to travel long distances quickly. But what the scientists found was astonishing. These birds traveled an average of 570 kilometers per day. The maximum distance recorded in the study was over 830 kilometers per day for nine days.
“We found that Common Swifts nesting in the northernmost part of the European breeding range are making the fastest swift migrations recorded so far, exceeding expectations,” says Susanne Åkesson of Lund University. . “The Swifts appear to achieve these high speeds for substantial distances – averaging about 8,000 kilometers one way – in the spring using a mixed migration strategy, with stopover refueling and a flight and forage strategy, this which means they feed and feed a little each day.
Åkesson and his colleagues used tracking technology that geolocates using light to track birds.
As these birds return to their breeding grounds each year, they have been able to recover many trackers.
The study suggests that swifts could predict the weather, so the winds will help their flights.
“They seem to schedule their departures for the migration, so that the winds will be favorable for the coming flight period. This means that they don’t react directly to local winds, but what they expect to find along the route over the next few days, ”she said, explaining that the birds could do so by measuring the atmospheric pressure associated with weather conditions.
As the stalkers shrink their size even further, Downs believes they’ll be able to delve into the secret lives of even smaller birds.
“Are these little brown guys coming from Siberia to Africa, like some of the Reed Warblers. So we have data ringing, people called it in Siberia. And then we caught them here in Pietermaritzburg. So when they come in the summer, I think these distances, and given their size, will be really spectacular. That’s once we get some sort of transmitter small enough to accommodate them, ”says Downs.
The advantage is that the information gleaned from these tracking devices could help conserve some of these bird species.
Researchers studying the common swift have expressed concern that the bird’s dependence on insects could put them at risk, due to the use of pesticides by humans. And climate change could influence weather conditions and winds, which could impact their migration routes.
But the trackers of the future will not only reveal the lives of migratory species in the bird kingdom.
Bird banding also raised a few other little mysteries. One concerns a cape with white eyes, a bird that at first glance seems to jump from one garden to another.
“We rang a white eye in Pietermaritzburg and they found it in Ladysmith (a distance of 170 km). So some of the little things that we don’t even realize are moving, ”says Downs.
The Saturday Star