The afternoon of 18th October 2008 was excessively hot at the Chinese garden in Jurong and Choo Teik Ju a.k.a. choo caught sight of a Grey Heron (Ardea cinerea) cooling off (above left).
Lee Tiah Khee has similarly caught a Blue-tailed Bee-eater (Merops philippinus) cooling off in the image on the right (above).
Yes, birds cool off by panting. Opening its mouth allows evaporation to take place over an increased area. And evaporation cools the body. At the same time water vapour from the lungs and air sacs evaporates, adding to the cooling effect.
Herons indulge in gular fluttering, opening their mouth wide and at the same time fluttering the thin gular membranes of the throat. This exposed a large featherless area to moving air.
Cormorants, pelicans, owls and nighthawks similarly indulge in gular fluttering, although the gular sacs of the first two groups are more prominent.
Image of heron by Choo Teik Ju and of bee-eater by Lee Tiah Khee.
This post is a cooperative effort between www.naturepixels.org and BESG to bring the study of bird behaviour through photography to a wider audience.