how many years can a bald eagle live
Bald eagle The average lifespan of bald eagles in the wild is around 20 years, with the oldest confirmed one having been 38 years of age.[107] In captivity, they often live somewhat longer. In one instance, a captive individual in New York lived for nearly 50 years. As with size, the average lifespan of an eagle population appears to be influenced by its location and access to prey.[108] As they are no longer heavily persecuted, adult mortality is quite low. In one study of Florida eagles, adult bald eagles reportedly had 100% annual survival rate.[8] In Prince William Sound in Alaska, adults had an annual survival rate of 88% even after the Exxon Valdez oil spill adversely affected eagles in the area.[109] Of 1,428 individuals from across the range necropsied by National Wildlife Health Center from 1963 to 1984, 329 (23%) eagles died from trauma, primarily impact with wires and vehicles; 309 (22%) died from gunshot; 158 (11%) died from poisoning; 130 (9%) died from electrocution; 68 (5%) died from trapping; 110 (8%) from emaciation; and 31 (2%) from disease; cause of death was undetermined in 293 (20%) of cases.[110] In this study, 68% of mortality was human-caused.[110] Today eagle-shooting is believed to be considerably reduced due to the species protected status.[111] In one case, an adult eagle investigating a peregrine falcon nest for prey items sustained a concussion from a swooping parent peregrine, and ultimately died days later from it.[112] An early natural history video depicting a cougar (Puma concolor) ambushing and killing an immature bald eagle feeding at a rabbit carcass is viewable online although this film may have been staged.[113]
Golden eagle Golden eagles usually mate for life. A breeding pair is formed in a courtship display. This courtship includes undulating displays by both in the pair, with the male bird picking up a piece of rock or a small stick, and dropping it only to enter into a steep dive and catch it in mid-air, repeating the maneuver 3 or more times. The female takes a clump of earth and drops and catches it in the same fashion.[2][48] Golden eagles typically build several eyries within their territory (preferring cliffs) and use them alternately for several years. Their nesting areas are characterized by the extreme regularity of the nest spacing.[92] Mating and egg-laying timing for golden eagle is variable depending on the locality. Copulation normally lasts 10–20 seconds. Mating seems to occur around 40–46 days before the initial egg-laying.[2] The golden eagle chick may be heard from within the egg 15 hours before it begins hatching. After the first chip is broken off of the egg, there is no activity for around 27 hours. After this period, the hatching activity accelerates and the shell is broken apart in 35 hours. The chick is completely free in 37 hours.[24] In the first 10 days, chicks mainly lie down on the nest substrate.[24] The eagles are capable of preening on their second day but are continually thermoregulated via brooding by their parents until around 20 days.[2] Within 10 days, the hatchlings grow considerably, weighing around 500 g (1.1 lb).[93] Around this age, they also start sitting up more.[24] Around 20 days of age, the chicks generally start standing, which becomes the main position over the course of the next 40 days.[24] The whitish down continues until around 25 days of age, at which point it is gradually replaced by dark contour feathers that eclipse the down and the birds attain a general piebald appearance.[2] After hatching, 80% of food items and 90% of food biomass is captured and brought to the nest by the adult male. Fledging occurs at 66 to 75 days of age in Idaho and 70 to 81 days in Scotland. The first attempted flight departure after fledging can be abrupt, with the young jumping off and using a series of short, stiff wing-beats to glide downward or being blown out of nest while wing-flapping. 18 to 20 days after first fledging, the young eagles will take their first circling flight, but they cannot gain height as efficiently as their parents until approximately 60 days after fledging. In Cumbria, young golden eagles were first seen hunting large prey 59 days after fledging. 75 to 85 days after fledging, the young were largely independent of parents. Generally, breeding success seems to be greatest where prey is available in abundance.[2]