Extreme heat events present a serious challenge to wildlife, and birds are particularly vulnerable to high temperatures. Unlike mammals, birds maintain a much higher internal body temperature, typically between 104 and 107 degrees Fahrenheit, meaning they have a smaller margin for error before overheating. This high metabolic rate means that when environmental temperatures rise, birds can quickly succumb to heat exhaustion or lethal heat stroke. Recognizing their limits and implementing simple preventative measures can make a significant difference in a heatwave.
Avian Thermoregulation
Birds are endotherms, meaning they must internally generate and regulate their body heat to maintain a constant core temperature. Since they lack sweat glands, they rely on a combination of behavioral and physiological mechanisms to shed excess heat. The primary method for evaporative cooling is through rapid, shallow breathing known as panting or gular fluttering.
Gular fluttering involves vibrating the floor of the mouth and throat (the gular region) to move air rapidly over moist membranes. This process efficiently dissipates heat through evaporation. Physiologically, birds also employ vasodilation, which increases blood flow to unfeathered areas like the legs, feet, and wings. By routing warm blood close to the skin surface, they use convection and radiation to transfer heat to the cooler air.
Behaviorally, birds seek out microclimates and reduce activity during the hottest parts of the day to conserve energy. They also spread their wings slightly away from their bodies to expose less-insulated flanks and allow air to circulate. While these mechanisms are typically effective, prolonged exposure to high heat, especially when combined with dehydration, can push a bird past its ability to cope.
Identifying Heat Stress in Birds
A bird’s normal cooling behaviors, such as light panting and holding the wings slightly open, should not be confused with distress. When these mechanisms fail, a bird will show signs of severe heat stress or heat stroke that require immediate attention. One of the clearest signals of danger is heavy, continuous open-mouth breathing that progresses beyond simple fluttering to labored gasping.
A distressed bird will often appear severely lethargic, listless, and unresponsive to its surroundings. It may be found on the ground, unable to fly or even stand, a state often described as “going to ground.” In the most severe cases of heat stroke, the bird may exhibit neurological symptoms like unsteadiness, severe head tilts, tremors, or seizures. If a bird allows a person to approach and handle it easily, it is likely in a state of shock or collapse and requires urgent intervention.
Providing Aid and Prevention
The most effective way to help birds during a heatwave is through preventative measures, primarily by providing accessible water and shade. Placing shallow containers of fresh water, such as a bird bath or a simple plant saucer, allows birds to drink and bathe. The water depth should be no more than one to two inches deep, and a rough surface or added stones prevents slipping and provides safe perching areas for smaller species.
Water should be changed daily, or even twice a day during peak heat, to keep it cool and prevent the growth of harmful bacteria. Creating shaded areas, especially near the water source, allows birds to rest without direct sun exposure, reducing their need for strenuous evaporative cooling.
If a bird is found collapsed and clearly suffering from heat stroke, the immediate action is to move it to a quiet, dark, and cool location, like a ventilated cardboard box. It is crucial to avoid forcing water into the bird’s mouth, as a stressed or weak bird can easily aspirate the liquid, leading to fatal pneumonia. Instead, gently moisten its feet and legs with cool (not ice-cold) water to help dissipate heat through vasodilation. After stabilization, the bird must be transported immediately to a licensed wildlife rehabilitation center, as they have the expertise to safely rehydrate and treat heat-related injuries.