The Shrike of uncertainly held onto his ambiguous identity by staying hidden or
moving on to better hunting grounds. I gave it a good shot having spent Sunday
morning and all Monday from daybreak to 4:00 PM canvassing the area but I was
skunked.
There are several articles on Shrike identification that may be of use to
folks who want to take a look at this identification problem. Probably most
have read them but they were new to me. See links below:
http://www.sibleyguides.com/2010/12/a-perplexing-shrike/
http://www.ofo.ca/site/page/view/articles.shrikeid
I am uncertain at this point on the identification and don't feel I really have
enough experience with Northern Shrikes to have a good sense of what separates
these two species. After reading Sibley's article about the New York Shrike I
realize these two species can - at times - be difficult to separate. Yes in all
honesty I am leaning towards Northern but it is incredibly easy to see what
one wants to see when birding. Perhaps if I lived further North where the
Loggerhead is the rarer of the two species my mind set would be completely
different. That said here are some points to consider:
1. Size of bill and bill hook. Both Shrikes have hooked bills but typically
Northern Shrikes are thought to have a more pronounced hook. However if you
read Sibley's article he states this field mark has limited usefulness in the
field. In Pittaway and King's ariticle the drawings of Northern Shrike all show
a more pronounced hook in my opinion. So this impression of a longer bill and
more pronounced hook may or may not be significant. Diane's photo appears to
show a fairly pronounced bill and hook.
2. Length of pale section of lower mandible is at least a third of overall bill
size on our Shrike of Uncertainty i.e. the Wolfe ridge Shrike. Typically this
is more likely to be true of Northern but apparently Loggerheads can show this
feature as well...see museum specimens in the following article .....
http://picasaweb.google.com/101683745969614096883/SpecimenExamples?gsessionid=gKnX-wBhzu1L7x3-0VT_pQ#5545727898467308530
3. Size of white patch at base of primaries looks very small on our mystery
Shrike. This feature points to Northern Shrike. So far I have not read
anything suggesting this mark is ambiguous but here the issue of mind set may
come into play. Also I have recently only read three articles on separating
the two Shrikes so it is entirely possible I am mistaken on this account.
4. Color of crown on Northern Shrike should be same color as back of bird. In
Loggerhead the color of the crown should be a bit darker and thus show more
contrast between head and white throat. Looking at Diane Lepkowski's photos I
struggle to ascertain which is the case. If you look at the right side of the
head in the photo the Shrike appears to have a darker crown but if you look at
the left side the crown appears overall to show a crown with little or no
contrast between crown and back. The problem here of course is created by a
shadow cast on across the right side of the bird which unfortunately also
partly appears to partly bleed on to the right side.
5. It appears to me that Diane's photos show white feathering across the base
of the bill which may point to Northern. On the other hand I don't really see
white above the eye which would point to Loggerhead.
6. Overall giss of the bird. Here I am way out of my league having seen only
one Northern Shrike and that was back in the 90s. That said most folks I have
heard from to date that have seen Diane's photo seem to think giss supports
Northern Shrike. That is my impression as well but again I may be seeing what I
want to see. Also one must try to account for the angle at which the bird
was photographed. Photo was taken looking from behind and up at about a 45
degree angle ( per photographer)
So where does this leave us? With a shy Shrike that really really needs a few
more photos!Otherwise we have been Sandplovered Regardless of the birds true
identity or the accuracy of the information I tried to relate from the
articles cited above, it was a fun chase. Fortunately as often happens
when one goes birding and doesn't see what one hopes to see we find a few
surprises to compensate for our misfortune..... In this case a very unusual
looking striped headed immature presumed Peregrine and the day's Mascot were
willing to act as substitutes for the Shrike.
See Flickr links below.
https://www.flickr.com/photos/34227153@N06/23609363090/in/dateposted-ff/
https://www.flickr.com/photos/34227153@N06/23816724161/in/dateposted-ff/
Ps, there is a link to the Shrike photos on the Shenvalbirds listserv.
best,
William Leigh leightern@xxxxxxx
Bridgewater, Virginia
