Saturday, March 31, 2012

Amphibious Nocturne (Symphony in F Major, 1st Movement)

I built a yard pond a few years ago.  Forty-four ninety pound bags of concrete mix, a few days to spare, a very sore back, and The Pond was on it's way.  It is still on its way -- I only work on it when I feel like it.  And the one thing I can't seem to complete in a timely fashion is installing the pump system for circulating flow.
But the frogs don't seem to mind that I have other priorities.  For the past couple of years, about 10 Northern Pacific treefrogs (Pseudacris regilla) have congregated here to carry out their annual reproductive symphony.  Treefrogs prefer still water for egg-laying, so if I do install the waterfall, they might not come back.

Pseudacris translates to "false cricket," and regilla means "regal" supposedly referring to the markings, though I am not sure which marking is considered regal.  They are a lot like crickets, only much louder.  At night the noise can be deafening, especially since it isn't far from our bedroom window.  But I like it. I know it is spring and longer days with more sun is on the way.

The males do the singing, and according to CaliforniaHerps.com, there are several main calls: diphasic or two-part calls, and monophasic calls, used when the lady frog is very close to committing.

Today, March 31, instead of beginning to prepare for the return to the classroom, I decided to begin documenting the development of their eggs.

Pacific treefrogs lay their eggs attached to pond bottom vegetation. Above are two clusters attached to a bit of straw that fell in the pond. Temporarily removing them gave me the closeup photo at right, then they were returned to the upper pool.

The pale areas are the yolk of what I think are fertilized eggs (I can't imagine that they wouldn't have been recipients of all that nocturnal passion).

It will take from 1-3 weeks for the tadpoles to hatch out, dependent on temperature. Right now it is about 12 degrees Celsius, but warmer temperatures should cause more rapid development.

Now if I can just find them again in a few days.





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