11 March 2013 by Julienne du Toit

Lesser kestrel mysteries

Tens of thousands of pigeon-sized kestrels head to the Karoo every year from the Steppes and Kazakhstan, probably flying via Saudi Arabia. They’re easy to see, but for the most part, they are true Eurasian enigmas.

Lesser kestrels roosting in tall trees in the middle of towns. Picture Chris Marais

In October and November every year, tens of thousands of lesser kestrels leave their homes in Europe, Siberia and Kazakhstan and head south to insect-rich Africa.

A very large number of them, perhaps 60 000, choose to head for little Karoo towns like Hanover, Victoria West, De Aar, Vosburg and Philipstown. Here they seek out the tallest trees, usually bluegums or pines, and roost tightly together, each tree harbouring hundreds, sometimes thousands, of lesser kestrels.

They are no larger than rock pigeons. The females are an elegant fawn colour with dark brown markings. The males are more rufous, with grey heads and greyish wing feathers.

These kestrels are flight addicts. Once they’ve finished hawking for insects and mice from telephone wires and fence posts for the day, they come back to town, gliding and rising exuberantly on thermals until long after the sun has gone down and they are no more than dark silhouettes. And they’re gone long before dawn the next morning.

In the third week of January, when numbers are at a peak, volunteers head out to count them. The only time to gain a real idea of their numbers is first thing in the morning, as they leave their roosts. But truly, it is akin to mission impossible.

They give little or no warning before they burst out of the tree in an explosion of pale wings and feathers, wheeling around briefly before heading out into the veld.

Ronelle Visagie of the Endangered Wildlife Trust’s Birds of Prey Programme has to get up at 4am, and then stands among roosting trees with a battered old voice recorder in one hand and her binoculars in another.

I eavesdropped on her once in De Aar.

'Two thousand in the hospital tree. Three hundred from the tree in front of the school. Another thousand from a bluegum in the hospital grounds. Five hundred from the tree near the water tower...'

Each count is at best a guesstimate. They give little or no warning before they burst out of the tree in an explosion of pale wings and feathers, wheeling around briefly before heading out into the veld.

They really are mystery birds. It’s assumed that the Karoo’s lesser kestrels (which come here to eat insects, moult and get a little peace and quiet) come from the Steppes because a ringed lesser kestrel found in 1975 and another in 1983 came from Russia.

A decade later, a lesser kestrel ringed in South Africa was found by a prince in Saudi Arabia, which might be on their flight path. But that is the sum total of our knowledge on their origins.

The other mystery is why they prefer to roost in Karoo towns rather than in trees on quieter farmsteads. Do they find it easier to navigate their way back to a town? 

It’s March now, and they’re readying themselves to leave on their 10 000km flight back to their breeding grounds. You can still see them hawking for prey on the side of the road. In a few weeks, they’ll be gone, and the Karoo will look a little lonelier without them.

Category: Wildlife

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