Owner Comments:
With our next modern dinosaur, we’re going to get semi-aquatic! It’s time to splash around with the Great Blue Heron, species name Ardea herodias.
The Great Blue Heron is the third largest extant heron, after the Goliath Heron and the White Bellied Heron. The Great Blue Heron has a head to tail length range from 3 to 4.5 feet, a wingspan from 5.5 to 6.6 feet, a height from 3.75 to 4.5 feet and a weight from 4 to 7.9 pounds. The Great Blue Heron gets its name from its bluish-grey flight feathers. The grey part of the coloration is pigment derived, but the bluish hints are due to structural pigmentation. Our eyes see the bluish hints due to the way light refracts through the feathers. No theropod dinosaur, either known only from fossils or extant, has been discovered that can produce blue pigments.
Other coloration on Great Blue Herons includes red-brown thighs, a paired red-brown and black stripe up the flanks, a rusty grey neck with black and white streaking down the front and a nearly white face. Mature herons also have long plumes on the lower neck with additional plumes on the lower back during their breeding season. There is also an all-white population of Great Blue Herons in Florida and the Caribbean that is so strikingly different in appearance than other Great Blue Heron populations that these individuals were considered a separate species for years. There is currently an ongoing scientific debate whether this is true or not.
Great Blue Herons range across North America, though some populations may overwinter in northern South America as well. The northernmost and some eastern populations are migratory in the winter but not all populations migrate. It is actually not how the temperature affects the birds that spurs migration as Great Blue Herons are extremely hardy and cold resistant. It’s whether or not they have unfrozen flowing bodies of water to hunt in or not over the winter. Great Blue Herons can call almost any body of water home, provided they have prey and nesting grounds.
Great Blue Herons are predatory. They mainly prey on small fish, though they will also consume invertebrates, small amphibians, small mammals and small birds and other small reptiles. They mainly hunt by wading in the water, finding prey by sight and spearing it with their long, pointed and very sharp beak. Since they eat small prey, they typically swallow their prey whole. Great Blue Herons are typically solitary hunters, but they will occasionally hunt in groups when there is a large school of fish or some other gathering of a large group of prey animals. Great Blue Herons also exhibit considerable adaptability in their hunting strategy, with behaviors ranging from floating on the surface of the water and spearing prey, jumping in the water to ambush prey, hovering over the water and capturing prey and diving head first into the water to ambush prey
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Like the Marabou Stork, Great Blue Herons breed in colonies but these colonies are far less terrifying. These colonies, called heronies, are established in are that are difficult to reach on foot in order to protect the eggs and young from mammalian predators. Other waterbirds and even some raptors will also breed in these heronies for the protection they offer. While most raptors can easily fight off any mammalian predators threatening their young, the herony offers an environment where they don’t even have to worry about it. This symbiotic community makes the eggs and chicks of all involved quite safe. Unlike raptors, which mate for life, Great Blue Heron pairs are only monogamous for a single breeding season. They almost always choose different mates each season.
Great Blue Herons lay between three to six eggs asynchronously at two-day intervals and hatch asynchronously after being incubated for around 27 days each. Both parents incubate the eggs and care for the young. The young are fed by the parents by regurgitating food and there is some aggression and competition among the chicks, which can end in siblicidal behavior, though it is more common that all chicks survive but the oldest grows more quickly. Great Blue Herons grow quickly; by the time they are 45 days old, they weigh 86% of their adult weight. At the age of between 55 and 80 days, Great Blue Herons take their first flights. They stay with their parents for around 3 more weeks after this and then disperse on their own by the following winter. Great Blue Herons live for around 15 years.
Given its large size, strength and very long and sharp beak, a full grown Great Blue Heron has few predators. The only predators a full grown Great Blue Heron really has to worry about are Golden Eagles and Bald Eagles over the course of most of their range and American Alligators and American Crocodiles in the southern portion of their range. Young herons may be preyed upon by Red-Tailed Hawks and Harris Hawks as well. Raccoons, Turkey Vultures, Common Ravens and Black Bears will consume heron eggs when the opportunity presents itself, which is pretty rare. Full grown Great Blue Herons are very strong and will defend themselves ferociously if they are in danger. The Great Blue Heron is one of the few animals that has been seen successfully fighting off a full grown Golden Eagle, which is absolutely amazing when you think about the power and hunting prowess of the Golden Eagle.
The Great Blue Heron has a special place in my heart. Last year, I was having a somewhat bad time with things. One day, I came home and I went to get the mail out of our mailbox and I saw one of these guys standing in a creek near our house. He just stood there while I watched him and glanced at me but he didn’t fly away. He seemed to know that I meant him no harm and that I just wanted to watch him. He just kept looking for fish for a bit while I watched him. After a few minutes, there apparently weren’t any fish in the creek to his liking, so he glanced at me again and flew off to better hunting grounds. This heron immediately snapped me out of my bad mood and put a smile on my face. This interaction has always stuck with me and is a constant reminder of how amazing all living things are and how they deserve our admiration, care and respect.