[Birdtalk] yet another Shrike

[Kristin Purdy]

Doug,

Congrats on another life bird. I agree with your assessment that this one is 
a Northern Shrike. I'd add a caution, however, about using the white rump to 
distinguish between the two species since pale Loggerheads can also have a 
pale rump.

The field mark that serves me well and tells me to look for the 
corroborating markings is the black mask. Northern Shrikes have a thinner 
black mask and the black eye tends to bump up into the crown. The feature 
shows nicely in some of the profile images you shot and it's visible at a 
distance. Loggerheads have a thick black mask and the eye is almost entirely 
contained within it, not producing the bump up into the gray crown. Once the 
mask has caught your attention, you can look for other differences between 
the two to confirm your ID.

I also caution anyone interested in the differences between shirkes not to 
be mislead by two notes in Sibley regarding the hook (or lack thereof) at 
the end of a shrike's bill. On the Loggerhead, Sibley says "stubby bill 
without obvious hook at tip" and on the Northern, "large bill without 
obvious hook". I've never seen a shrike of either species that doesn't have 
an obvious hook at the tip of its bill. The closest any bird has come was a 
juvenile Loggerhead, who was young enough not to have developed a strong 
hook yet. This issue has lead people astray many times.

Congrats again on your Northern Shrike.

Kris
  ----- Original Message ----- 
  From: Doug Roberts
  To: Bird Talk
  Sent: Saturday, March 01, 2008 9:53 PM
  Subject: [Birdtalk] yet another Shrike


  Hi,
  Yet again I've found another Shrike, this time at Farmington may, near the 
Nature center. It was some distance away, so the picture quality is not so 
good. It seems to me that this is a Northern Shrike, not a Loggerhead. The 
rump looks white to me. What do you all think?
  Thanks,
  Doug Roberts
  See pics at:
  http://trailgeezer.smugmug.com/gallery/4437840_pT3f4/#260776515



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