Great horned owls seem to be the most long-living owl in North America. Among all owls, they may outrank even the larger Eurasian eagle owl in known longevity records from the wild.[4] Two owls on record that were banded as nestling were recovered 21 years and 4 months later and 22 years and 2 months later, respectively. However, one great horned owl banded at an unknown age was recovered 28 years and 7 months after the initial banding is the oldest owl ever recorded in North America.[223] A more typical top lifespan of a great horned owl is approximately 13 years old. The maximum lifespan reported in captivity was 38 years of age was considerably less than the unconfirmed maximum captive age of 68 years (by far the longest for any owl) for an eagle owl.[6] In general, great horned owls are most vulnerable in the early stages of life, although few species press attacks on the owl's nests due to the ferocious defensive abilities of the parents. Occasionally, nestlings and fledglings will fall from the nest too early to escape or to competently defend themselves and have then fallen prey to foxes, bobcat, coyotes, or wild or feral cats. Occasionally raccoons and American black bears consume eggs and nestlings from tree nests and Virginia opossum may take the rare unguarded egg. Unconfirmed predation on ledge nests in the northern regions by wolverines, canada lynx and foxes may have occurred.[4][10] Crows and ravens have been reported eating eggs and small nestlings. This can normally only happen when owls are driven from the nest by human activity or are forced to leave the nest to forage by low food resources but on occasion huge flocks of crows have been able to displace owls by harassing them endlessly.[5][10] In one case, a large murder of crows seemingly determined to displace an incubating female from great horned owls in order to feed on the owls' eggs were dissuaded by her mate, who sat tightly on his perch and turned sharply to face each crow as it attempted to approach, causing each crow to withdrawal until the corvids finally gave up and left after a long period of harassment.[29] Harris's hawks and red-tailed hawks have been reported to prey on nestling great horned owls.[84][224] In general, great horned owls rarely engage in siblicide, unlike many other raptorial birds. Siblicide occurred at 9 of 2,711 nests in Saskatchewan.[67] Most cases where young owls are killed and/or consumed by their siblings or parents appear to occur when the nestling is diseased, impaired or starving or is inadvertently crushed.[75] Adults generally have no natural predators, excepting both North American eagles and other owls of their own species.[5] A case where a ferruginous hawk attacked an adult great horned owl in an apparent predation attempt (given the time of year) was observed, although the hawk apparently failed to even maim the owl.[225] An “adult-sized” great horned owl was found dead during the winter apparently having been victim to a Red Fox, although the nature of the confrontation was unknown (the author opining that the owl was grounded for some reason) and the owl was left intact.[226]