I used to keep rescued captive cockatiels. When they became old and needed to be kept inside or in sheltered aviaries in winter, I did a lot of things to try and achieve stable temperatures in sun, indoor or out. When I messed up and it became too hot for them, (and they are an Australian species, so one would think built for quite warm temps), they would start to gape, ie breathe with their mouths open, and I dont think they could have sustained those conditions (which I amended immediately).
So I am distressed to hear of wild birds panting. Unlike a dog, I do not think it is a sustainable cooling mechanism for birds, who in general need to conserve energy, esp. when not able to feed adequately and frequently, I think?
Does anyone know whether this panting is sustainable in any species of birds? Perhaps birds that feed infrequently, eg raptors perhaps?