There was a lovely segment on TV last night about swifts. Apart from being a jog to the fading memories of summer warmth, it was a fascinating insight into the mysterious evolutionary niche these birds inhabit.
They fly non-stop for several years, eating and sleeping on the wing, able to circle around and compensate for winds blowing them off course, even with half of their brain shut down. They cover thousands of miles in their lifetimes and no-one knows how they get enough calcium for their egg shells since the insects they eat don't contain enough.
Film from Oxford University Library showed a family of swifts in their nest in the roof. These birds can't walk or perch and they have virtually no neck muscles so they lie awkwardly on top of each other. They had a few parasites, called flat beetles, but no-one knows how the creatures get there since the birds never land except to breed.
Truly amazing.
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2 comments:
That is amazing. Incredible how they sleep on the wing.
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