The eyebrow is thought to shade the eye from the sun and provide some physical protection. Bald eagles take four or five years to reach adult plumage. Adults at 4 to 5 yrs. are identified by their white head and tail, solid brown body, and large, curved, yellow bill. Juveniles have blotchy patches of white on their underside and tail. Life span for eagles is up to 30 years in the wild, and longer in captivity.
Eagles usually start to breed at four to nine years of age.
Bald eagles nest in coniferous trees up to 82 feet high, and are monogamous. Eagles reuse nests, adding sticks and greenery each year. Eagles lay one to two eggs each breeding season during the spring when prey is most plentiful. Incubation is 31 to 45 days. Eagles live and nest near coastlines, rivers, lakes, wet prairies, and coastal pine lands in North America from Alaska and Canada south into Florida and Baja, California.