[Birdnet] Plover pictures

[Mark Stackhouse]

David Wheeler and I went out to the causeway today and located the 
Pacific Golden-Plover without trouble in the previously reported 
location. Seeing the bird in the field, if I were on the west coast, I 
wouldn't hesitate to call it a Pacific Golden-Plover. That is good, 
since I had already reached the same conclusion after reviewing Paul's 
excellent photos. I also posted a query to the i.d. frontiers group, 
and (I think the first time I've seen this happen with that group) 
received a unanimous reply from ten experts that this is a Pacific 
Golden-Plover. For the record, I'm certain that this is a different 
bird than the one posted last week with the photo by Keith Evans - look 
at the difference in the facial markings and the partially molted back 
as opposed to the Higgins bird which has its back still in breeding 
plumage.

There are many features visible in Paul's photos that favor Pacific 
Golden-Plover, several of which have been pointed out in other posts or 
which you could infer by reading my earlier post on the Evans bird. I 
was impressed by how  worn the outer primaries are, and wondered 
whether the short primary extension could just be an artifact of wear. 
The worn outer primaries are decisive in this i.d., but not for that 
reason. Although there are a number of coloration features that favor 
Pacific, including the facial markings and spotting on the back (two 
pairs of gold spots on the edge of each of the mantle feathers as 
opposed to only one pair in breeding plumaged American), many of you 
know that I'm not a big fan of coloration in tough identification 
problems like this. Structural features, and things like molt sequence, 
are much more secure as field marks.

If you look at the third of Paul's photos (the one with the wings 
spread), you can see that the worn outer primaries contrast with the 
inner primaries, which are fresh, even-tipped and unworn. The 
outer-most of these fresh inner primaries is obviously longer than the 
next outer primary, which is worn (if it they were fresh each primary 
would be a little longer as you move out the wing). This bird appears 
to be about halfway through molting its primaries. Neither the Pacific 
nor the American Golden-Plovers molt their flight feathers during 
migration. However, the Pacific starts its molt on the breeding 
grounds, and finishes on the winter grounds after the migration. 
Americans don't start molting their flight feathers until they reach 
the winter grounds. A recent paper by Al Jaramillo states that, "...an 
autumn golden-plover in wing molt in California, and probably anywhere 
in North America, is almost certainly a Pacific." Because of the severe 
wear on the outer primaries, this bird is probably a second-year bird, 
since these primaries would be from the juvenile plumage acquired last 
summer rather than a pre-basic molt last winter and thus older by 
several months.

An interesting bird and a great, well-documented, state-first record.

Good birding!

Mark Stackhouse
mark at westwings.com
801-487-9453 (Salt Lake City, Utah, USA)
011-52-323-285-1243 (San Blas, Nayarit, Mexico)

On Sep 4, 2006, at 10:50 AM, Utah Birds wrote:

>
> Paul Higgin's photos have been posted on the Hotline Photo page along 
> with a picture of a Pacific Golden Plover taken in Hawaii by Pomera 
> Fronce for comparison.
>
> Here's the link:
> http://utahbirds.org/hotlinephotos/2006/PloverAug2006.htm
>
> P.S.  The webmaster was out of state until last night resulting in the 
> delay in posting the photos.  Sorry about that.
>
>
>
>
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