Shrike vocalization is so odd.  I had the opportunity some years 
ago to ask  Dr. Reuven Yosef from Eilat, who's done a fair amount 
of field research on shrikes, why they sing in the dead of 
winter, and he surprised me by saying that although he didn't 
know for sure, he thought it was a way of luring small songbirds 
within range by imitating fragments of their songs and calls.  Yikes!

Dr. Yosef's presentation of his research on shrikes is one of the 
most fascinating talks I've ever heard on any subject in my life. 
  Don't know if he ever gives it anymore, but if you should be 
somewhere he's supposed to talk on the subject, GO.


David Johnston wrote:

> This morning on Bonnyvale RD in W. Brattleboro I heard soft, short, sort of 
> trilly sounding vocalizations and looked up into a locust tree to see a N. shrike 
> sitting at the top vocalizing away. It is the first time I've ever heard one.
> Dave Johnston  1/25