Appreciating Natural Science in the Real World

Forrest M. Mims III

Great blue herons are usually reclusive creatures. When they are standing in a stock pond or a natural body of water, they are almost always alone.

The big birds are almost stately in appearance as they stand motionless while staring ahead or slightly downward. Their usual objective is to catch a fish, which they spear with their sharp beak.

It's difficult to get close to a great blue heron. Those that visit the Geronimo Creek where I reside launch into flight at the first sign of movement. Once I got within 30 meters (a hundred feet) or so of one perched in a tree on the San Marcos River in Central Texas.

Sometimes great blue herons enforce their lonely life style. Recently I was photographing hundreds of ducks, pelicans, sea gulls and shore birds at the Hans and Pat Suter Wildlife Refuge in Corpus Christi, Texas, when a great blue heron landed in an open space of shallow water.

Several white egrets were nearby, and one made the mistake of walking toward the bigger heron, which made some threatening gestures. When the egret held its ground, the heron spread its wings to their full six-and-a-half feet width and charged. The egret quickly flew away.

Before it charged, the ill-tempered heron directed some loud sounds toward the egret. A children's article on the Texas Parks & Wildlife web site describes the sound much better than I can: " Although a beautiful bird, the heron makes an awful "krarrrk" sound!"

This encounter was observed by the other egrets, which kept their distance as the great blue heron pranced back to its position in an open area of water.

Figure 1. A great blue heron (right) chases a white egret from its fishing spot in Oso Bay at Corpus Christi, Texas. Photograph by Forrest M. Mims III.

All this was so fascinating that I made a dozen or so photographs of the encounter. A large number of sea gulls perched in the water just off the beach were less impressed. They completely ignored the entire spectacle, which suggests that the great blue heron's irritability was well known to them.

Then suddenly it was the sea gull's turn, for the big heron began squawking and attacking them. A dozen or so gulls promptly moved out of the big bird's reach.

When the heron was satisfied it was lonely again, it stood as motionless as a statue and stared off into the distance.

After watching this spectacle, I did some research on the great blue heron. While some sources were very nicely written and full of facts, nothing I read conveyed the wonder of actually watching a heron staking out its territory. As Bill Hilton reminds us in his Hilton Pond column in each installment of The Citizen Scientist, the heron experience was a good example of how natural science can be observed firsthand in the real world without having to rely solely on the web and televised nature programs.

You can see great blue herons wading along the coast, in stock ponds and in shallow along rivers and creeks. They have long legs, and their neck is shaped like the letter S. They have a yellow beak and their head is gray and white. Their back is a more gray than the blue suggested by the name.

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The Citizen Scientist (05 February 2010).