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Swifts (1 Viewer)

It's Tut have very fond memories of family holidays in Blakeney N. Norfolk of groups of shifts flying down the High Street. A true sound of summer, with their distinctive screaming sound as they hunted flying insects. Sometimes they were called devil birds because of this. I have a copy of "Swifts in the Tower" by David Lack, a classic book. One of my favourite birds and the real sound of summer - early May to early August.
 
They are a dull yet fascinating bird to me, dull in that they are always brown sillouettes, fascinating in the way they are up there unseen, yet when seen are amazing to watch. If I'm in the back garden and put my binoculars on a plane heading to Heathrow, quite often in summer a couple of swifts come into the view so high up that I hadn't spotted them.
 
I visited Malaysia periodically over the last few years and we stayed at a resort hotel close to the old airport at Subang. In the evenings we could lie on deck chairs beside the pool to relax and watch the tropical thunderstorms grow while enjoying the warmth of the local weather. In the sky above was a constant too-ing and fro-ing of swarms of swifts and swiftlets. The swifts hardly ever flap their wings just gliding in the thermals, whereas the swiftlets flap rapidly, glide, flap rapidly in quick succession. I never tired of watching them and wondered just how many insects are in the skies above KL for such a mass of birds to be constantly present and it didn't seem to matter what time of the year we were there. It's worth pondering their ability to see, mentally process the trajectory of their prey, then manoeuvre to intercept and gather in their mouths at the high speeds that they fly. No wonder they duck and dive so rapidly. I'd love to be able to put a 'g-meter' on them so see what sort of 'g's' they are pulling and what the roll rate they can achieve when banking to turn in such tight corners. As pilots we can sustain about 6 'g' with a 'g-suit' and a modern racing aeroplane can roll about 470 degrees per second... it would be interesting to see what these birds are achieving. Even so they are compelling watching for their mastery of flight. Like most birds they are adapted aerodynamically to their environment and you'll notice that swifts and swiftlets generally have anhedral wings... i.e., the wings sit below the horizontal. Aeronautical things have two choices; either controllability or stability; dihedral gives stability whereas anhedral provides controllability, no doubt why swifts and swiftlets are designed as such. However birds, unlike aeroplanes have an amazing ability to change their structure to suit the circumstance they are in.

Kind regards Chris

https://www.ararelitus.com/birds-1
 
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