For the Birds Radio Program: Eagle Nest
When a pair of Bald Eagles hatches out babies right along a busy highway, people notice. 4:02
For the past several weeks, drivers along Highway 61 between Duluth and Two Harbors have been delighting in an eagle nest in a huge pine right next to the road. The adults have been diligently incubating the eggs for over a month now, at least presumably, based on what people have been seeing. Drivers slowing down could observe an adult’s head sticking out above the enormous nest, and last week I heard a report that the adult was sitting up higher, continually looking down into the nest and seemingly helping a baby beneath, which probably must mean the babies are beginning to hatch. Eagles are very skittish birds, and it’s fairly miraculous that a pair is bringing off babies right on the highway—it certainly wouldn’t be worth the risk disturbing them just to check out what’s happening inside, so we’ll have to satisfy ourselves with guesses until a baby or two emerges in a month or so.
It takes about a month for an eagle egg to hatch, and over two more months for the nestlings to make their first flight. This is an intense time for the parents. Eagles lay from one to three eggs, usually two, and the adults seem almost to expect that the larger baby will bully, and perhaps even kill, the smaller. When food is plentiful, the adults can keep both babies well fed and the smaller can usually protect itself, but when the fishing is tough, the littler eaglet is doomed to provide a slim meal for its sibling, or simply to be trampled into the nesting materials. Perhaps the reason the adults sit by watching the sad spectacle is that they survived to reach adulthood only by partaking in such a grim activity themselves. But the adults do their best to feed both babies, lugging in fish as fast as they can pull them out of the water, or at least as fast as they can steal them from Ospreys, and sometimes two, and even more rarely three nestlings survive. Fish provide at least 70 percent of eagle baby food, but the parents bring anything else they can get, too, including a generous helping of duck. At first both parents tenderly cut their children’s meat, but as the babies get bigger and stronger, they start digging in themselves.
Few creatures are brave enough to come too close to a nest of eagles, but there are many records of Great Horned Owls nesting in abandoned eagle nests, and, amazingly, of these ferocious owls burrowing into the lower sticks of an active eagle nest and raising their own babies side by side with the eagles. One eagle was once found actually incubating a Great Horned Owl egg along with her own. This unfortunately happened during the museum age of ornithology, and in the name of egg collecting, they weren’t left for anyone to discover whether a baby owl could be successfully reared by an eagle.
Eagle nests near Lake Superior don’t have a good success record—those illiterate birds just can’t seem to understand fish consumption guidelines, and PCBs, mercury, and other heavy metals take a toll on the young. But since the Highway 61 eagles may well be river fishing as well as lake fishing, we can reasonably hope they’ll do okay. We won’t know for sure what’s going on in the nest for several weeks, when a baby or two starts climbing up higher in the nest. In a couple of months the young will start making tentative flights, and the parents will continue to nurture it as it starts taking fishing lessons. By summer’s end, though, the baby will be on its own, and next year if it happens to come home, the parents will drive it off their territory as they get back in gear to raise a new eaglet or two.