Yellow-vented Bulbul: Drying after the rain?

Lena Chow made an interesting observation on Yellow-vented Bulbuls (Pycnonotus goiavier) at Aljunied Park, Singapore one day in June 2006:

“…after a heavy downpour they fly out of a spot in the treetop for about 2 metres and immediately fly back into the same spot, repeating this for quite a while. It's quite a sight when a dozen or so bulbuls do this simultaneously, looks like a choreographed dance of sorts! I guess this must have something to do with drying themselves, but does anyone know if there's anything more to this behaviour? The other birds in the park are nowhere to be seen at this time." Our bird specialist R. Subaraj has this to say: “Most interesting observation. I cannot think of any other reason for this behaviour. You may be right in assuming that it has something to do with the drying process though we should continue observations on this ‘dance’ to see if there is more to it than meets the eye.”

Note: We need more observations by more birders before we can even try to understand this strange behaviour. So birders in the field, send in your observations.

Thank you, Lena, for this observation. Unfortunately we do not have an image of this aerial dance, so the above two have been provided by YC.