KC Tsang was at Turf City on the morning of 7th January 2008 “observing a flock of swiflets and swallows flying back and forth catching insects in mid air.
“I was tracking one of them with my camera, and taking pictures of them flying.
“However, this is one photo that had captured one very unusual behaviour of the bird. It was that the bird was able to fold itself and reach its rump to scratch it in flight, and in midair… (I use the word scratch for lack of a better term) and continued flying without falling out of the air . Amazing!”
Swifts (Family Apodidae), that include swiftlets and needletails, are among the most aerial of birds. They regularly feed on the wing, sometimes even copulate in midair. What is extraordinary is that they even indulge in aerial roosting, although this has been proven with certainty only for the Common Swift (Apus apus).
If these birds can sleep when flying, it is no small feat to scratch while in the air.
On the other hand swallows (Family Hirundinidae), while highly aerial, often land on branches, utility wires, etc. where they can indulge in preening and scratching in the comfort of the perch.