just think of how wild birds would act in the very hot times of the day, first of all you will not see too many flying about to gather food, they do most of there feeding in the morning and evening whilst it is cooler, they have the shade of bushes and trees that they will hide in getting air around them even with little breeze, they mainly stay near a source of water, our birds are very similar, they eat in the morning rest during the day, if we are not around and eat later when it is cooler, during the warm times if they get hot they will stay put and rest, its best to have a gentle breeze to keep the air circulating, away from the sunlight coming through glass windows, close the curtain on the side the sun is shinning. provide plenty of water, you may find your bird will bath itself, if you notice that your bird is panting then it is best to increase the air circulation