Discussion of Washtenaw Co. WESA - 22 Sep 2004
22 September 2004 Discussions regarding Western Sandpiper ID
Birders,
Well, unlike Matt Hysell, I can't claim technical difficulties, but I can
whine about having 90+ disiscoped images to sort through, many now in the trash. Thanks again to Matt for letting me use his scope for a few photos yesterday, some of which are among the 14 now on my website at: http://www.amazilia.net/images/Birds/Shorebirds/WesternSandpiper.htm.
Well, unlike Matt Hysell, I can't claim technical difficulties, but I can
whine about having 90+ disiscoped images to sort through, many now in the trash. Thanks again to Matt for letting me use his scope for a few photos yesterday, some of which are among the 14 now on my website at: http://www.amazilia.net/images/Birds/Shorebirds/WesternSandpiper.htm.
And, unlike John Lowry, I'm not worried about "stirring up some scat". I
can't think of a better place for a discussion of a difficult ID of a rare
bird to take place than BIRDERS. So, I guess I'll start off with a few
points. Note that the photos on my website are numbered to make it more convenient for referencing in any discussion. Some good discussion has already gone on behind the scenes, and I'd like to encourage more discussion in this forum.
can't think of a better place for a discussion of a difficult ID of a rare
bird to take place than BIRDERS. So, I guess I'll start off with a few
points. Note that the photos on my website are numbered to make it more convenient for referencing in any discussion. Some good discussion has already gone on behind the scenes, and I'd like to encourage more discussion in this forum.
As Matt has noted, the reference material doesn't seem to be quite clear on what the scapular feathers should look like in a juvenile Western Sandpiper. The Hayman shorebirds book shows the UPPER scapulars in Western as having dark crescents, or "anchors" with rufous at the base and white fringes, and in Semipalmated as having all dark centers with duller rufous edges. Also, in the text, it is mentioned that such "anchors" can be found on the LOWER scapulars in both Western and Semipalmated.
Sibley, on the other hand, shows an identical pattern on the upper scapulars for both species, with the rufous shown brighter for Western. Sibley also shows (and points out) clear "anchors" on the lower scapulars for Western, and shows more blob-ended thick central streaks (or sub-terminal spots?) for Semipalmated. Who's right?
The Washtenaw County bird shows dark-centered, rufous-edged upper
scapulars, and gray lower scapulars with broad central streaks, ending in a blob, or perhaps somewhat anchor-like at certain angles.
scapulars, and gray lower scapulars with broad central streaks, ending in a blob, or perhaps somewhat anchor-like at certain angles.
In Hayman, some variations in bill length are shown, and from what I see the Washtenaw County bird is very near the upper limit for Semipalmated, but perhaps not outside the range for Semi. It would be nice if the bill were a couple millimeters longer, just for comfort :-)
OK. Now its your turn :-) Fire away!
Allen Chartier
amazilia1@comcast.net
1442 West River Park Drive
Inkster, MI 48141
Website: http://www.amazilia.net
Michigan HummerNet: http://www.amazilia.net/MIHummerNet/index.htm
amazilia1@comcast.net
1442 West River Park Drive
Inkster, MI 48141
Website: http://www.amazilia.net
Michigan HummerNet: http://www.amazilia.net/MIHummerNet/index.htm
A forward from Caleb Putnam which I think answers the question I posed
with regards to the birds scaps (though I do have an old photo in the
main section of my website that looks to me to be a juv Western with the
rare(?) illustrated pattern). I'm comfortable after reading this with
the scapulars being consistent with the rest of the bird as a Western.
with regards to the birds scaps (though I do have an old photo in the
main section of my website that looks to me to be a juv Western with the
rare(?) illustrated pattern). I'm comfortable after reading this with
the scapulars being consistent with the rest of the bird as a Western.
Matt
>Macklin/Allen/ and Matthew-
> I am following the mich-chat musings on the possible WESA via Jack
Siler's website- great discussion! A couple things came to mind which I
wanted to mention to you three. I am not a mich-chat member, so feel free to forward any of my comments to the listserv.
> My main point: Hayman et al are inconsistent in their treatment of
the upper scap pattern of juv WESA, and this has confounded the discussion. For juv WESA Hayman et al only illustrate a rare upper scapular pattern (bases largely rufous, fringes white), and fail to illustrate the most common pattern (black centered with rufous fringes as in the SESA illustrations 190e and 190g). The facing text says that only "Some [WESA], as depicted, show internal chestnut on upper scapulars like breeding adult" and the text on page 368 describes the upper scapular pattern of juv WESA as "centered black and fringed rich rufous", totally different than anything they illustrated for that species. This pattern is perfecly normal for WESA, and I have seen it in the field [in Montana] many times. However, it is also shown by some bright SESA (eg. Paulson page 250 top bird), so I think this mark is at best equivocal in this case.
> Overall, my view is that your bird very probably is WESA. The fact
that several upper scapulars and mantle feathers have already been replaced with formative-generation feathers also favors WESA, though probably is not diagnostic.
> Thanks for the great photos and discussion. I look forward to
further dialogue.
>Cheers,
Siler's website- great discussion! A couple things came to mind which I
wanted to mention to you three. I am not a mich-chat member, so feel free to forward any of my comments to the listserv.
> My main point: Hayman et al are inconsistent in their treatment of
the upper scap pattern of juv WESA, and this has confounded the discussion. For juv WESA Hayman et al only illustrate a rare upper scapular pattern (bases largely rufous, fringes white), and fail to illustrate the most common pattern (black centered with rufous fringes as in the SESA illustrations 190e and 190g). The facing text says that only "Some [WESA], as depicted, show internal chestnut on upper scapulars like breeding adult" and the text on page 368 describes the upper scapular pattern of juv WESA as "centered black and fringed rich rufous", totally different than anything they illustrated for that species. This pattern is perfecly normal for WESA, and I have seen it in the field [in Montana] many times. However, it is also shown by some bright SESA (eg. Paulson page 250 top bird), so I think this mark is at best equivocal in this case.
> Overall, my view is that your bird very probably is WESA. The fact
that several upper scapulars and mantle feathers have already been replaced with formative-generation feathers also favors WESA, though probably is not diagnostic.
> Thanks for the great photos and discussion. I look forward to
further dialogue.
>Cheers,
Caleb G Putnam
Grand Rapids, MI
larus10@hotmail.co
Grand Rapids, MI
larus10@hotmail.co
Birders,
Great discussion! We should definitely have more of these here, or even at a state-wide level as in Ohio and Indiana...Regarding the bill of the Washtenaw bird, I agree that it is good for Western in several ways. I believe it is at or near the very upper limit for Semipalmated as far as length goes, but there are some other features that also suggest Western. In my photo #1, you can see three distinct bill shapes. The Least Sandpiper is showing a thinner-based, slightly drooped, somewhat tapered bill which is classic for the species. Likewise, the Semipalmated Sandpiper is showing a bill that appears nearly uniform throughout its length, is fairly straight (and short), and with a rather blunt rounded tip. Again, this is typical for the species. The Western is showing a thicker-based bill, longer than the others, with a slight droop, and a tapered tip, quite normal for the species. The shape of the Western's bill is shown best, perhaps, in my photo #3. Note that I did have another similar photo where the bird had a water droplet at the tip of the bill, which exaggerated the impression of a droopy bill (use caution here!), but
Great discussion! We should definitely have more of these here, or even at a state-wide level as in Ohio and Indiana...Regarding the bill of the Washtenaw bird, I agree that it is good for Western in several ways. I believe it is at or near the very upper limit for Semipalmated as far as length goes, but there are some other features that also suggest Western. In my photo #1, you can see three distinct bill shapes. The Least Sandpiper is showing a thinner-based, slightly drooped, somewhat tapered bill which is classic for the species. Likewise, the Semipalmated Sandpiper is showing a bill that appears nearly uniform throughout its length, is fairly straight (and short), and with a rather blunt rounded tip. Again, this is typical for the species. The Western is showing a thicker-based bill, longer than the others, with a slight droop, and a tapered tip, quite normal for the species. The shape of the Western's bill is shown best, perhaps, in my photo #3. Note that I did have another similar photo where the bird had a water droplet at the tip of the bill, which exaggerated the impression of a droopy bill (use caution here!), but
from the other photos it is clear that the slight droop is real. Another
old reference of mine, "Guide to the identification and ageing of Holarctic
Waders" by Prater, Marchant, and Vuorinen (1977, by British Trust for
Ornithology) discusses another bill feature of peeps. There is a diagram on page 84 showing the bills of Western, Semipalmated, Red-necked and Little Stints from above. The bill of Semipalmated is shown as broadened at the tip, while that of Western is more tapered. In my photo #2, you can see the broader tip of the Semipalmated, while in Photo #7 you can see the tapered tip of the Western. This book is more of a banding reference, and gives some good information, including measurements of bills, wings, and tarsus by age and sex. I won't bore you with those! It does not, however, discuss much regarding plumage characters.
Regarding the scapular pattern, it is clear that the details of these
feathers are important in identification. It is also clear that there is
some variation (big surprise!). I know I have personally seen juvenile
Semipalmated Sandpipers (with "classic" bills) with a rufous scapular bar
about as extensive as in the Washtenaw bird, but with the rufous not quite as richly colored. Again, it would help the comfort level to have a more boldly marked individual to work with!
I've done a Google search for photos of juvenile Western Sandpiper on the internet, and got about 18 matches. A few images are of birds being
discussed, as we're doing here, so are probably better not referred to.
Most are taken in places where the species is common, and also these birds are showing even slightly longer bills than our bird.
old reference of mine, "Guide to the identification and ageing of Holarctic
Waders" by Prater, Marchant, and Vuorinen (1977, by British Trust for
Ornithology) discusses another bill feature of peeps. There is a diagram on page 84 showing the bills of Western, Semipalmated, Red-necked and Little Stints from above. The bill of Semipalmated is shown as broadened at the tip, while that of Western is more tapered. In my photo #2, you can see the broader tip of the Semipalmated, while in Photo #7 you can see the tapered tip of the Western. This book is more of a banding reference, and gives some good information, including measurements of bills, wings, and tarsus by age and sex. I won't bore you with those! It does not, however, discuss much regarding plumage characters.
Regarding the scapular pattern, it is clear that the details of these
feathers are important in identification. It is also clear that there is
some variation (big surprise!). I know I have personally seen juvenile
Semipalmated Sandpipers (with "classic" bills) with a rufous scapular bar
about as extensive as in the Washtenaw bird, but with the rufous not quite as richly colored. Again, it would help the comfort level to have a more boldly marked individual to work with!
I've done a Google search for photos of juvenile Western Sandpiper on the internet, and got about 18 matches. A few images are of birds being
discussed, as we're doing here, so are probably better not referred to.
Most are taken in places where the species is common, and also these birds are showing even slightly longer bills than our bird.
Regarding the upper scapulars, there are photos of birds that show both an entirely dark center
http://people.cornell.edu/pages/rrf3/nj/western_sandpiper.html
http://www.ofo.ca/photos/wesaho.jpg
and photos that show an "anchor" pattern
http://www.birdphotography.com/species/wesa.html
Some are in-between
http://www.geocities.com/tgrey41/Pages/WesternSandpiperp.html,
http://www3.sympatico.ca/jeaniron/Western.htm,
http://homepage2.nifty.com/stints/calidris/western-jA.html
Regarding the lower scapulars, again there are photos that show clear
"anchor" patterns
http://www.birdphotography.com/species/wesa.html
http://homepage2.nifty.com/stints/calidris/western-jA.html
http://www.ofo.ca/photos/wesaho.jpg
and those that show broad, blob-ended streaks similar to our bird
http://www.geocities.com/tgrey41/Pages/WesternSandpiperp.html
http://people.cornell.edu/pages/rrf3/nj/western_sandpiper.html
http://www.ofo.ca/photos/wesaho.jpg
and photos that show an "anchor" pattern
http://www.birdphotography.com/species/wesa.html
Some are in-between
http://www.geocities.com/tgrey41/Pages/WesternSandpiperp.html,
http://www3.sympatico.ca/jeaniron/Western.htm,
http://homepage2.nifty.com/stints/calidris/western-jA.html
Regarding the lower scapulars, again there are photos that show clear
"anchor" patterns
http://www.birdphotography.com/species/wesa.html
http://homepage2.nifty.com/stints/calidris/western-jA.html
http://www.ofo.ca/photos/wesaho.jpg
and those that show broad, blob-ended streaks similar to our bird
http://www.geocities.com/tgrey41/Pages/WesternSandpiperp.html
I have not seen any photos of juvenile Semipalmated that show quite the same kind of markings on the lower scapulars as on our bird. They are closer to Western, though again they aren't "classic" anchors. The lower scapulars that are showing only narrow dark shaft streaks are probably freshly replaced first basic feathers, not juvenile scapulars.
I think Macklin's point about a clean white breast is a good one, though I
think that Semipalmated could sometimes be this clean. Several of my photos of our bird show very fine streaks on the sides of the breast, which to me look more like Western than Semipalmated, but that is purely my own judgment, not based on any published infomation.
I think Macklin's point about a clean white breast is a good one, though I
think that Semipalmated could sometimes be this clean. Several of my photos of our bird show very fine streaks on the sides of the breast, which to me look more like Western than Semipalmated, but that is purely my own judgment, not based on any published infomation.
I appreciate John Lowry pointing out Sibley's corrections, but I'm not sure
it helps us much with this bird! Perhaps the fact that our bird has black
legs, instead of olive-colored, is suggestive of Western since it's not yet
"late fall". The correction for Semipalmated to "upperside relatively
uniform scaly, usually little rufous" states what most of us already know,
and affirms what Sibley has actually portrayed in his book, but it isn't
definitive as rufous on the scapulars of Semipalmated's do turn up from time to time, though it is perhaps not as richly colored as in Western.
it helps us much with this bird! Perhaps the fact that our bird has black
legs, instead of olive-colored, is suggestive of Western since it's not yet
"late fall". The correction for Semipalmated to "upperside relatively
uniform scaly, usually little rufous" states what most of us already know,
and affirms what Sibley has actually portrayed in his book, but it isn't
definitive as rufous on the scapulars of Semipalmated's do turn up from time to time, though it is perhaps not as richly colored as in Western.
I also wish to thank BLZWIEBEL@AOL.com (sorry, I'd prefer to call you by
name, but you didn't sign your posting), for sending me an excellent photo of an apparent juvenile of a definite Western Sandpiper taken "earlier this summer" at Ottawa NWR, Ohio. If this photo is posted on a website somewhere, I'd like to point this group to it. That bird shows a longer bill than the Washtenaw bird, shows some solid centers and some
anchor-shaped centers on the upper rufous-edged scapulars (!), and
anchor-shapes on some of the lower scapulars.
name, but you didn't sign your posting), for sending me an excellent photo of an apparent juvenile of a definite Western Sandpiper taken "earlier this summer" at Ottawa NWR, Ohio. If this photo is posted on a website somewhere, I'd like to point this group to it. That bird shows a longer bill than the Washtenaw bird, shows some solid centers and some
anchor-shaped centers on the upper rufous-edged scapulars (!), and
anchor-shapes on some of the lower scapulars.
Allen Chartier
amazilia1@comcast.net
1442 West River Park Drive
Inkster, MI 48141
Website: http://www.amazilia.net
Michigan HummerNet: http://www.amazilia.net/MIHummerNet/index.htm
amazilia1@comcast.net
1442 West River Park Drive
Inkster, MI 48141
Website: http://www.amazilia.net
Michigan HummerNet: http://www.amazilia.net/MIHummerNet/index.htm
Birders,
The beautifully photographed Western Sandpiper at Ottawa NWR taken in August, 2004 by Brian Zwiebel, that I referenced in my last message on the Washtenaw County bird, has now been posted on a website for your viewing pleasure. It is at:
http://www.rarebird.org/forum/forum_posts.asp?TID=394&PN=1&TPN=1
The beautifully photographed Western Sandpiper at Ottawa NWR taken in August, 2004 by Brian Zwiebel, that I referenced in my last message on the Washtenaw County bird, has now been posted on a website for your viewing pleasure. It is at:
http://www.rarebird.org/forum/forum_posts.asp?TID=394&PN=1&TPN=1
Allen Chartier
amazilia1@comcast.net
1442 West River Park Drive
Inkster, MI 48141
Website: http://www.amazilia.net
Michigan HummerNet: http://www.amazilia.net/MIHummerNet/index.htm
amazilia1@comcast.net
1442 West River Park Drive
Inkster, MI 48141
Website: http://www.amazilia.net
Michigan HummerNet: http://www.amazilia.net/MIHummerNet/index.htm
