Thursday, January 9, 2014

Wet Forest, Glacial Marine Drift and Kinglets

Right back out in the field after a bit of vacation. My first field visit was a nice mid to upper 30s and rain day in a forest underlain by glacial marine sediments - which meant lots of wet ground.

The glacial marine drift was deposited over large areas of northwest Washington during the late stages of the last glacial period approximately 13,000 years ago. The mass of glacial ice had depressed the local land surface downward in some areas hundreds of feet. When the ice began to retreat and thin, low areas in northwest Washington were flooded by sea water and the area was located below sea level with glacial ice floating on the sea surface above. As the ice melted sediment consisting mostly of clay and silt was deposited on the sea floor along with occasional sand, gravel, cobbles and boulders from the melting ice. The area has subsequently rebounded to its current elevation. Some minor reworking of the upper surface by wave action took place as the area was uplifted. The silt and clay soils have low permeability and water perches on top of the glacial marine sediments during periods of extended wet weather. 

The forest was full of small birds seeking insects and their path intersected mine. Apparently I was not viewed as a threat as they landed within feet of me, and for a second one alighted on the toe of my boot. They moved about quickly and the light was a bit dim so I did rather poorly with pictures (I could have turned on the flash, but I wanted to enjoy the little birds and feared the flash would scare them off).

I  determined this one as a golden-crowned kinglet

This one I think is female ruby-crowned kinglet
This ruby identification is mostly based on seeing one I thought was a male with its small ruby plumage and no black and white stripe. My two bird books suggest ruby-crowned should be off to the south this time of year, so my ID confidence (never real high) that it is a ruby is diminished.  


Upupaepops said...

Ruby-crowned are here year round

males hide their crown when not displaying, so this could be male or female.
watching a pair of Rub-crowned males bicker started me birdwatching

Geoffrey Middaugh said...
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Geoffrey Middaugh said...

I have never understood why the word "drift"? Were the sediments embedded in the "drifting" ice, or were they later deposited as river sediments?

Dan McShane said...

Thanks for the verification Upup.
As for drift, it kind of is a broad brush term to avoid specifics. The sediment in the glacial marine drift likely was falling out of the floating ice - certainly the occasion boulder would suggest that. There is some influence from inputs from glacial melt water rivers as well.