Naturespeak A naturalist's view of the world

March 23, 2008

Mergansers in the Hood

Filed under: Uncategorized — wykes @ 7:23 pm

  Hooded mergansers engage in up to 10 different distinct motions when performing their courtship dance, but I’d like to focus only their flashiest moves for now. These striking little fish ducks are migrating through at the present time and, like many of their fellow waterfowl travelers, they stop off to “rest” in our local waters.  Dressed in their finest and headed toward the main dance floor, the birds practice their steps along the way. Their performances are short but memorable.

  “Hoodies” are the smallest of the three species of mergansers that pass through the Great Lakes country.  They have the long serrated bill that is the mark of this peculiar trio of fish eating ducks also known as sawbills.  These birds dive and pursue their prey underwater and are specially adapted for precise water vision (able to change the refractive qualities of their eyes to see through the liquid element).  All these wonderful adaptive features aside, the entertainment qualities of this merganser are based solely on look’n good.

  It is the hood, or the crest, that is the best way to separate a male Hooded Merganser from the other types (take a look).  The white spot on the crest stands out like a beacon and serves to highlight the glowing yellow eyes and sharp black & white back feathering. The females (see here) are restricted to a duller palette of colors but have a nice cinnamon crest of their own.  

  My attention was drawn to a cluster of these birds as I passed an open patch of water framed by a wall of dead cat-tails. From a distance the only thing I could see was a set of 5 or 6 white dots milling about.  These dots turned out to be the raised crests of so many males trying to impress a single female in the center of the watery dance floor. A regular burst of guttural croaking cut through the airspace as the males vocalized their intentions.

  Each display sequence started with a male bird raising his hood as far as he could – beyond vertical and leaning forward like a punker’s Mohawk. As he jockeyed for position alongside the female he would inflate his throat and begin a series of three stiff head pumps. Like the rising action of car jack to each pull of the lever, the bird brings its chest higher out of the water with each forward pump. After the third, and hardest pump, the head is jerked back between the shoulders to the point where the beak is pointing straight up (here’s a drawing of one in the act of throwing his head back). To finish off this dramatic final move the bird lets out a rolling frog-like “Crooooooo” as the head is returned to its normal orientation and the chest is lowered back into the water.

  All this makes for a pretty impressive individual courtship display, but when several males are performing the same ritual at the same time the effect is downright theatrical. Many times two competing birds will mirror each other in choreographed sympathy. The dancing fervor would rise to a boiling pitch and then suddenly cease as the dance troupe would swim further down the cat-tail edge.

  The female is not a passive bystander in this dance.  She eventually shows her interest by responding with a similar set of spastic head pumps.  I did see the female in this bunch perform in the direction of one of the males, but she quickly cut off her reaction and swam away.

  At any rate, the dancing and crooning will continue throughout the remainder of the northward migration until the nesting location is reached – at which point the gals will have to make up their minds. Because all the males appeared to act with equal proficiency, I’m not sure how the female will ultimately make her final choice. Perhaps she’ll pick the one that is the most persistent, or that raises his crest the highest, or croons with the most amphibianistic qualities. It is also distinctly possible that the choice will be completely arbitrary. In this final matter, there is direct parallel with the human world.

 

1 Comment »

  1. The same thing happen in Louisiana this week, yes it was not has many but 500+ birds is a lot too. Just seems odd to me. I do live in AR and have never heard of anything like the things that have been happing here lately. A bunch of small earthquakes at least one a week (we don’t have them here), birds and fish dying in the masses. Who knows what else has or will happen…. I just hope they figure it out soon.

    Comment by Candida Orpen — January 4, 2011 @ 1:16 pm

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