01/27/2026
Let’s chat about one of Nature’s incredible architects that is a source of pride and admiration of many people:
Meet the bald eagle (Haliaeetus leucocephalus), a large bird of prey native to North America. This sea eagle’s range includes most of Canada and Alaska, all of the contiguous United States, and northern Mexico. This opportunistic carnivore is found near large bodies of open water with an abundant food supply and old-growth trees for nesting.
Let’s talk about those nests!
In contrast to most other raptors, bald eagles are early breeders. They complete their nest construction and/or remodeling in December-early January. Eggs are generally laid in January-March. Incubation usually takes place betwen March-May depending on the laying date. Eggs hatch from early February to early May, and the young fledge from late June to early July. For this reason, their nests must be more winter durable than other birds of prey.
Bald Eagle nests are the largest of any bird in North America! Nests are built of branches and used repeatedly, with the couple adding new material added each year. This layering process may eventually yield nests that exceed 13’ deep, 8.5’ across, and weigh as much as a ton! Most nests are used for less than 5 years, as they collapse in storms or break the branches supporting them by their sheer weight. There is one nest in the Midwest that was monitored and occupied continuously for at least 34 years! Most eagle couples will eventually build backup nests just in case their primary nest succumbs to storms or tree breakage.
Groovy fact #1: immature Bald eagles obtain much of their food by scavenging carrion or kleptoparasitism (stealing prey from other predators). Experience tends to shift this practice to hunting live prey as adults.
Groovy fact #2: Bald eagles are sexually mature at 4-5 years of age (this is also when the head feathers turn white). Bald eagles have high mate fidelity and generally mate for life. If a mate dies or disappears, the survivor will choose a new mate. A pair that has repeatedly failed in breeding attempts may split and look for new mates.Bald eagle courtship involves unique calls and flight displays by the males. A mature mated pair will defend a territory of 3/4-1.5 mile around their nest area.
Groovy fact #3: there is a widely circulated story that aging eagles rip off their beaks and talons to "rejuvenate" and live for another 30 years. This fake viral “Rebirth of the Eagle" tale claims that at the age of 40, an eagle’s beak becomes too bent, talons too long, and feathers too heavy to hunt, forcing it to fly to a mountain, rip out old feathers, and smash off its beak and talons to grow new ones. Eagles do NOT do this. If an eagle lost its beak, it would be unable to eat, resulting in starvation. Eagle beaks are made of keratin (like fingernails) and grow continuously throughout their life. They rub their beaks on rocks to shape them, not break them off. This myth is often shared as an inspiring story about personal transformation or letting go of the past to gain new life, but it has no basis in biology. I have unsuccessfully refuted this ridiculous wildlife myth too many times to count.
Photos taken by Carol Garrison. The fledgling in the nest was photographed at the John Bunker Sands Wetland Center. In 2022, the well known pair had a single offspring that died at just a few days of age. Much to everyone’s surprise, a second nest was observed and there was another clutch of eggs! The offspring in the photo successfully fledged the backup nest in late spring. The eagle pair returned to their tower nest the following November. The other pictures were taken during trips to Alaska.
