Bald eagles are normally seen as strong and powerful birds. They can fly long distance, hunt fish and survive in difficult weather conditions. So when a bald eagle is found with anemia, many people may wonder how such a powerful bird can develop this health problem.
Anemia happens when the eagle does not have enough healthy red blood cells or when the blood cells are not carrying enough oxygen through the body. Anemia is not usually a disease by itself. In most cases, it is a sign that some other serious problem is happening inside the bird.
In bald eagles, anemia can be caused by blood loss, destruction of red blood cells or the body not producing enough new blood cells. It is not always caused by iron deficiency like many people commonly think.
Lead Poisoning
Lead poisoning is one of the major health threats faced by bald eagles. These birds are hunters, but they also eat dead animals whenever food is easily available.
Sometimes an eagle may feed on the remains of a deer or another animal which was shot using lead ammunition. Very small pieces of the lead bullet can remain inside the meat. The eagle may not notice these fragments and can swallow it along with the food.
Once lead enters the eagle’s body, it can damage the organs and affect the production of healthy red blood cells. It may also interfere with hemoglobin, which is needed for carrying oxygen.
A bald eagle suffering from lead poisoning may become weak, stop eating, lose balance or have difficulty in standing and flying. In serious cases, the poisoning can damage the brain, heart, eyes and other important organs also.
Rat Poison and Internal Bleeding
Rat poison can also cause anemia in bald eagles. The bird may not directly eat the poison. Instead, it may catch or eat a rat, mouse or another animal which already consumed the chemical.
Some types of rat poison stop the blood from clotting properly. Because of this, the eagle may slowly bleed inside its body. There may not be any major wound visible from outside, but the internal blood loss can become very serious.
When the eagle continues losing blood, the number of red blood cells will reduce. This may eventually lead to severe anemia, weakness and even death if treatment is not given.
Injuries and Physical Trauma
Bald eagles can suffer injuries after being hit by vehicles, colliding with power lines, fighting with other birds or getting shot.
Sometimes the injury may look small from outside, but there can be heavy bleeding inside the body. Any serious blood loss can quickly lower the eagle’s red blood cell count.
Even after the bleeding is controlled, the eagle may remain anemic for few days because the body need time to produce replacement blood cells.
Wildlife veterinarians normally perform blood tests on injured eagles to check how much blood was lost and whether the bird requires additional treatment.
Blood Parasites
Certain parasites can enter the bloodstream of bald eagles and damage their red blood cells. These parasites may be spread through biting insects such as black flies.
One blood parasite known as Leucocytozoon toddi has been found in bald eagle nestlings. Many infections may remain mild, but a serious infection can cause weakness and anemia.
Young eagles may be more affected because their immune system is still developing. An eagle which is already weak, injured or poorly fed may also find it difficult to fight the infection.
Serious Infections and Long-Term Illness
Sometimes a bald eagle may become anemic even when it is not losing blood. This can happen when the body stops producing enough new red blood cells.
Long-term infections, inflammation, organ damage, toxins and poor nutrition may affect blood-cell production. Kidney, liver or bone marrow problems can also be checked by veterinarians when the cause is not immediately clear.
In some cases, the eagle may be suffering from more than one health issue at the same time. For example, an injured eagle may also have lead poisoning and may not have eaten properly for several days.
Because of this, finding the exact cause of anemia can be little difficult.
Signs of Anemia in Bald Eagles
An anemic bald eagle may look very weak and tired. It may sit in one place for long time and may not try to fly away when humans come near.
Other possible signs include:
- Difficulty in flying
- Loss of balance
- Pale mouth tissues
- Drooping wings
- Rapid breathing
- Loss of appetite
- Unusual tiredness
- Difficulty in standing
These symptoms can also be caused by poisoning, infection or injury. So a blood test is required to confirm whether the eagle is anemic.
Veterinarians may perform a complete blood count, lead test, blood smear, clotting test and X-ray. The treatment will depend on what is actually causing the anemia.
Can a Bald Eagle Recover From Anemia?
A bald eagle can recover from anemia when the main cause is found and treated early. An injured eagle may require fluids, medicine, oxygen, proper food and treatment to stop bleeding.
Eagles suffering from lead poisoning may need special medicines which help remove lead from the body. Birds exposed to rat poison may require vitamin treatment and care for internal bleeding.
Severely anemic birds may sometimes require a blood transfusion. However, recovery depends on how much damage has already happened and how quickly the eagle receives veterinary care.
