Sand Martins carpeting the road (2 Viewers)

[lockbreeze926]

This was passed to me (not my text or question, nor obviously photo) -

"Sand Martins on the road in France. They roll around along our lane every year during autumn migration. Is this common behaviour? Why do they do it? It's above 30C, the roads are sticky, are they oiling their wings? Deterring ticks etc? Anyone know!?"

Several responses suggest it's the equivalent of various other species sunning to deter parasites, but apparently it happens every year, on the same spot (presumably at similar temperatures, though.)

Any advance on parasite deterrence?

 

[MJB]

This was passed to me (not my text or question, nor obviously photo) -

"Sand Martins on the road in France. They roll around along our lane every year during autumn migration. Is this common behaviour? Why do they do it? It's above 30C, the roads are sticky, are they oiling their wings? Deterring ticks etc? Anyone know!?"

Several responses suggest it's the equivalent of various other species sunning to deter parasites, but apparently it happens every year, on the same spot (presumably at similar temperatures, though.)

Any advance on parasite deterrence?

View attachment 1525433

I've seen them do this one warm August on cycle paths around Neusiedlersee in easternmost Austria.
MJB

 

[Jon Turner]

Nowhere near this scale, but I once slowed down for a group of about 15 Red-rumped Swallows on the road in Monfrague National Park in Extremadura.