Avian Blood and Circulation
Birds possess a complex circulatory system that efficiently transports blood. Their blood consists of red blood cells, white blood cells, and thrombocytes suspended in plasma. Red blood cells carry oxygen, while thrombocytes aid in blood clotting to stop bleeding. A four-chambered heart pumps these components through arteries, which carry oxygenated blood, and veins, which return deoxygenated blood.
Unlike mammals, avian red blood cells and thrombocytes are nucleated. Their circulatory system is highly efficient, adapted to meet high metabolic demands, particularly for flight. Their heart rate is often higher than in mammals, reflecting this demand. Birds have a small total blood volume, typically 6% to 10% of their body weight. For instance, a 100-gram bird has about 10 milliliters of blood.
This limited blood volume means that even a minor loss can quickly become significant, leading to serious complications such as shock or anemia. Feathers can effectively hide wounds, making it difficult to assess bleeding externally. The rapid metabolism of birds also contributes to the swift onset of shock when blood loss occurs, underscoring the urgency required in such situations. Any observed bleeding warrants immediate attention.
Common Causes of Bleeding in Birds
Bleeding can arise from various incidents, with external injuries being a frequent cause. Collisions with windows, fans, or other objects can result in cuts, bruises, or severe trauma. Predator attacks from animals such as cats or other birds often cause lacerations and puncture wounds. Sharp objects, like exposed wires or broken cage parts, can also lead to accidental injuries and blood loss.
Another common source of bleeding is a broken blood feather. Blood feathers are new, growing feathers that contain a blood supply within their shaft. If one of these developing feathers breaks, it can bleed profusely because its internal blood vessel is still active. This bleeding is often alarming due to its volume but can sometimes be addressed with first aid.
Internal bleeding is less commonly observed but equally serious. This can result from blunt force trauma, such as a severe fall or impact, leading to organ damage like a fractured liver, spleen, or kidney. Signs of internal bleeding might include weakness, swelling, or blood in droppings, though it is challenging for a layperson to identify. Trauma remains the most common cause of hemorrhage.
Recognizing and Responding to Bleeding
Identifying bleeding requires careful observation, as feathers can mask injuries. Signs include matted or visibly wet feathers, the presence of blood on surfaces, or a visible wound on the bird’s body. An injured bird might also exhibit general weakness, lethargy, rapid breathing, or signs of shock, such as being unresponsive or having difficulty moving. If you suspect a bird is bleeding, approach calmly to avoid further stress.
If you find a bleeding bird, prioritize safety for yourself and the bird. Gently approach the bird, ensuring it cannot fly away or harm itself or you. If handling is necessary and safe, use a clean cloth or towel to gently restrain the bird, careful not to restrict its breathing. Apply gentle but firm pressure directly to any visible wound with a clean cloth or gauze for several minutes to stem blood flow. Do not wipe the area, as this can dislodge clots and restart bleeding.
After addressing immediate bleeding, place the bird in a quiet, dark, warm environment, such as a ventilated box lined with a soft cloth. This minimizes stress and prevents hypothermia, which can worsen shock. Do not offer food or water unless instructed by a professional, as a bird in shock may aspirate.
The next step is contacting a local wildlife rehabilitator or an avian veterinarian immediately. These professionals possess specialized knowledge and equipment for avian care, which differs significantly from mammal care. Prompt professional intervention is important due to the bird’s small blood volume, high risk of shock, and susceptibility to infection. Attempting self-treatment without professional guidance can unintentionally cause further harm or delay life-saving care.