The first sign of heat stress is typically panting (also referred to as open-mouth breathing). Panting birds will open their beaks, accompanied by rapid constriction of the throat muscles as seen in the video. Birds will also droop their wings to increase air flow (viewable in the first video). Panting is easily assessed using the transect method. While this measure is relatively rare, it is important to look for as heat stress can have long term physiological implications including death. Birds housed with outdoor access may be more likely to exhibit panting.