[Tweeters] Odd Marsh Wren behavior

[Jack Stephens]

At Juanita Bay Park yesterday, I was able to follow a Marsh Wren as it 
worked the edge of the lake gleaning for food. Suddenly it stopped, 
cocked its head to one side, and held that position for several minutes. 
It as notable how still it was compared to its usual level of activity. 
I assume this is a defensive posture, all the better to see predators 
overhead, but it something I have never seen a bird do before. Below is 
a picture of what I am trying to describe. Any ideas on what it was doing?

Thanks

Jack Stephens
jstephens62 at comcast.net
Edmonds, WA

http://www.flickr.com/photos/jrs_eons/6911169238/in/photostream