Saturday, September 13, 2008

Chalklines

Seems to be have been a good season for Green Herons. Reports have abounded, and I've seen many this year in my wanderings. That's good. Nice to know this interesting little heron is seemingly holding its own.

Green Herons are one of my favorite birds. Discovering one is always a treat. Sometimes it is of a distant high-flyer, straight-lining it to some farflung destination. In flight, they suggest crows but have a different look due the thick scrunched up neck and a somewhat different wingbeat cadence. You can tell 'em a mile off and dazzle your friends with one of these extreme calls from afar.

Or you might be lurking about some shrubby wetland or wooded stream corridor, when suddenly KYOW! A Green Heron bursts forth from hiding, delivering its telltale piercingly metallic call.

Young Green Heron, showing the extensive neck streaking characteristic of juveniles. Photo taken at Sheldon Marsh State Nature Preserve.

As often as not, Green Herons will give you a visual interpretation of what they think of you, if you have the gall to shake them from their routine. Next time you flush one, watch. It's liable to expel a prolific stream of liquid chalky-white feces. Could be a ploy to quickly lose weight for the quick escape. Or it could be an avian salute; the equivalent of a raspberry. This interesting if not somewhat disgusting habitat led to the nickname "chalkline" for the bird. It is laying down a nasty white line of fecal chalk.

That isn't this species only nickname, though. Another, which I will leave you to decide the interpretation of, is "shitepoke". Still another is "fly-up-the-creek".

At one time, they were known as Green-backed Herons. This dates to when taxonomists considered our North American birds conspecific with birds of the New and Old World tropics. Now they are deemed separate. Ours is Butorides virescens; the tropical species is Butorides striatus, the Striated Heron. There is some debate about the legitimacy of this split, but what would ornithology or another other branch of natural sciences be if we knew everything absolutely.

A fine young specimen. Perhaps the most interesting behavior of Green Herons is their ability to use tools. That's right, they are are nearly as adept as a fisherman with tackle box when it comes to tricking fish into their reach. They take likely looking lures and drop them in the water to pull in small fish. Feathers are a commonly used lure, but they've been known to use everything from mayflies to bread crusts to berries. Woe to the foolish minnow that investigates this bit of shitepoke trickery. Green Herons can snap that coiled slinkylike neck out quicker than you can say sushi.This is breeding distribution of Green Heron in Ohio as delineated by the first Ohio Breeding Bird Atlas, 1982-85. You can see they are nearly everywhere, the most broadly distributed breeding heron in the state. Green Herons will breed on much smaller water bodies than will other herons, including little farm ponds and tiny creeks. Their nests won't win any architectural awards. A flimsy platform of sticks, that even a Mourning Dove might scoff at. Well, maybe not that bad but these aren't the Frank Lloyd Wrights of the bird world.

Here's data to date generated by the current Ohio Breeding Bird Atlas II. Not looking quite as robust as the first go-around, but not bad, and many more records will be added in the next two years of this atlas.

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1 comment:

Tricia said...

I would like to take credit for this but it came from the Zick. Shitepoke. Shite being the polite way to say sh*t and poke is a bag. Leave it to a Harvard grad to figure that one out :-)