This week’s Wildlife Matters springs from a Curious North question.
Kaye Jaeger from the town of Crescent asks: We love the loons on our lake. We also love the eagle that flies over regularly. Is there anything we can do to prevent the eagle from eating the baby loons?
To respond to Kaye's question, the Masked Biologist contemplates the interactions of two charismatic Northwoods wildlife species: bald eagles and loons.
It can be a terrible feeling any time you watch one animal attack, kill and eat another animal. I’m not sure I can provide an answer that you will like, or that will make you feel any better, but I will try.
Loons and bald eagles are two of our most iconic, emblematic Northwoods birds species. Both have struggled with reduced populations in past years. Eagles suffered from significant impacts from dangerous pesticides, especially DDT. It took decades of dedicated effort to help bring them back. Loons accumulated heavy metals from consuming meals of fish, especially mercury and lead. Both are on the rebound, and both can be found frequenting our higher quality lakes across northern Wisconsin. Unfortunately, these birds cannot get along. While they are both predators, loons prey on fish and eagles prey on fish and other wildlife species including loons. Eagles will eat other waterfowl as well. In fact, I remember working on a large wildlife property in Kansas in the 1990s that hosted large numbers of migrating waterfowl. I saw bald eagle circling over a flock of ducks one day, and it harassed them enough to purposely flush the ducks into the air. Then it went into a power dive into the middle of the flock, knocking birds out of the air and down into the water. Then it picked up one of the ducks, flew to its perch and proceeded to tear it apart and eat it. I was amazed, and impressed. In the moment, it didn’t really occur to me to feel bad for the duck.
Through the years, I have seen a lot of predator prey interactions, or at least the aftermath of it. I found a spot where a wolf killed a deer, and all that remained were stomach contents. I routinely find a blood spot in the woods with only a few grouse feathers to tell the tale. In the moment, the life and death struggle must seem horrific and one-sided. Completely not fair. In fact, though, the attack is not intended to be savage or personal. When a predator is killing prey, it is usually for one of a couple of reasons. First, obviously, they are hungry and they eat meat. Second, they may have had their natural predatory instincts triggered by an animal that appeared weak, ill or injured. This is all about maximum return for minimum effort. An animal wants to kill its food without using up its energy or getting hurt itself. I have seen from time to time where a predator was killed by its prey. Only those that are most effective at killing without being killed will live to produce future generations.
Let me tell you another story, one I heard from a wildlife rehabilitator. There was a loon chick that was orphaned, and would need adults to care for it and teach it to evade predators and find food. The well-intentioned individual found another loon family and released the chick in proximity hoping the loons would raise it as one of their own. Well, that did not happen. The adult pair of loons attacked and killed that chick as the horrified person watched helplessly from shore. One could argue that this attack was more savage than that of an eagle picking a loon chick off the water for a meal, possibly to feed its own young. These loons were simply exhibiting territoriality to the death, as lakes that are well suited to raise their young on every year are worth fighting (and dying) over.
Loons and eagles are both protected by law. We cannot interfere with an interaction between these two birds not only because it is the law but because it is the natural order of things. The loons that dive at the first sign of danger will survive, and they will go on to raise offspring that dive to avoid eagles as well. Instinct can only carry a young bird so far; having the benefit of an experienced adult to teach them can mean the difference for future generations.
Striving to make new things familiar and familiar things new, this is the Masked Biologist coming to you from the heart of Wisconsin’s great Northwoods.
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