As of 2016, the oldest Great Blue Herons we know of in the wild lived to be at least 24 years, 6 months old. Yours may be the same bird, but remember that Great Blue Herons like to fish alone. Birds flying over that see one having luck on your dock may come down there occasionally when that one flies off, so you may actually be seeing more than one individual.
Or it may really be the same bird—the only way scientists can be certain is to mark the bird with a U.S. Fish and Wildlife Service numbered band and, sometimes, a colored leg or neck band, or wing tag, and check the color/number every time the bird is observed. Whether it’s one bird or more, it’s very exciting that you have such a reliable visitor!
Check out our All About Birds species guide for detailed information on North American Birds including information on longevity. You can also browse through The USGS Patuxent Wildlife Research Center’s Longevity Records of North American Birds.
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