ML616645732

Age

Not specified

Sex

Not specified

Observation details

Logan's comments: Putative pipl. Per expert commentary, seems to be an ad female piping plover in basic, not a leucistic semipalm as originally postulated. Details to come. Seen here (37.4944897, -122.1498799). Seen from here (37.4945740, -122.1492375). My comments: This was a small plover, about the same size as nearby Semipalmated Plovers, but differed most apparently in its pale, sandy color that allowed it to be easily spotted from a distance. The bird was generally pure white below, and a sandy brown above, with a brown cap, back, and wings, and a collar extending down from the “shoulders” that I carefully noted was incomplete, and of a relatively uniform width throughout. The bill was short, blunt, and mostly or all dark; it was not muddied for the majority of my observation. The leg coloration was difficult to discern, and I was not quite sure why, but the leg observation appeared a dull gray most of the time, as did the leg color of all surrounding Semipalmated Plovers. Only in a couple specific moments did I notice the legs were a bright, traffic-cone orange. I am not sure how the circumstances in which I was able to notice leg color differed from the times I could not. The face patterning was relatively analogous to that of a Semipalmated Plover, including dark lores. I noticed the couple times that the bird took flight from within my scope view that the leading edge of the wing (primary coverts?) appeared dark or black, and that there was a broad wing stripe. This wing stripe seemed more prominent than in the Semipalmated Plovers, and I remember seeing the same in the field on back of camera photos of this feature. At the time of observation, I was aware that Semipalmated and Piping Plovers differed in shape, although I was not sure how. I decided to try and make an honest appraisal of any differences I noticed without consulting references to know to look for specific features. I thought that from far off that the shape of this bird was quite similar to Semipalmated Plover, and seemed different than Snowy, although no Snowy Plovers were present at the time for comparison. When the bird came closer and was running around amidst Semipalmated Plovers, I thought that the body was perhaps more “horizontally compressed,” if that makes sense. I.e. the bird was about the same length as the Semipalmated, but perhaps the wing made up proportionally more length? Or perhaps the body was heftier towards the center? To my eyes, the bill was noticeably thicker/taller than on nearby Semipalmated, and this was not because of caked mud. In length the bill was similar to the Semipalmated around it. I also thought the head and neck appeared thicker than Semipalmated when viewed from head on but less so in profile. In profile, perhaps the head was more rounded, but I wouldn’t commit to this. I also mentioned that I thought the legs were thicker, particularly in the knees. I didn’t notice any difference in leg/tibia length, and perhaps I might have if I’d known to look, or perhaps I wouldn’t have! I do wish I had known to look for this in retrospect. Discussion: The following was written after a consultation of field guides, photos, etc.: Caveat re. shape: I wrote the following after the fact in an email to several observers, and I think is especially important to consider when it comes to differences in shape I noticed and did not notice: “Of course, the problem here is that I’ve never seen an alive Piping Plover before, only photos and a couple dead ones, so I don’t have a good sense of their shape. I felt this bird was differently shaped from the Semipalmated Plovers around it… but I’m sure you’re all very familiar with how helpful seeing even one bird of a species can be in providing a comparative baseline for things like structure. And I didn’t have that baseline. That makes me less inclined to trust my own perceptions of shape here to tell this to species. If that makes any sense!!” The wing: In the field after my observation of a dark leading edge to the wing and a broad wing stripe, Lucas Stephenson independently noticed this, and commented that he thought the wing stripe and tail/rump pattern was different from Semipalmated Plovers. An “in the field a review” of Sibley and some online photos confirmed that this was a consistent difference between the two species. While this feature remained difficult to see in the field, photos were taken of the bird in flight and confirmed that the leading edge of the wing was mostly black/dark, the wing stripe of the bird was broader than on Semipalmated Plovers, and that at the base of the tail existed a solid, black dot, connected to the back by a white to very pale beige rump/uppertail coverts. This pattern meshes well with what is expected in a Piping Plover, however I am not sure that it is enough to eliminate a “dilute” Semipalmated Plover. For instance (hypothetical stretch), if the gene affecting pigmentation in such a bird only affected areas of brown coloration, and black coloration was controlled by another gene or set of genes that went unaffected, then perhaps a “dilute” Semipalmated Plover could be expected to show a pattern just like this. A number of analogous situations may exist. So it seems important to ask: are there photos that exist of “dilute” Semipalmated Plovers in flight, and how do features such as wing stripe and tail/uppertail coverts/rump appear in these birds? And it would be prudent for the CBRC to do their due diligence and double check this. In review of my own and others photos, and browsing the Macaulay library, there are a couple differences between the two species that appear consistent. One of these features, as pointed out by Louis Bevier, is that the tertials on Piping Plovers are appreciably darker than the “back” e.g. scapulars whereas that is not the case in Semipalmated. That seems to hold true for this bird, and photos of “dilute” Semipalmated Plovers do not show this feature. Another feature that I came across that I greatly liked, is that in Piping Plovers the three innermost secondaries appear to be mostly all white, and in Semipalmated Plovers they appear to be always or almost always mostly dark. This is a rather drastic difference, and seems easily noticeable on birds in flight. The most variation I could find in Macaulay in regards to this feature was in Piping Plovers where the wing was not fully extended and the inner secondaries were hidden. Photos of the Ravenswood bird show three white innermost secondaries when in flight. This seems to add some objectivity to otherwise subjective thinking about wingstripe width.

Technical information

Model

NIKON D500

Lens

150.0-600.0 mm f/5.0-6.3

ISO

2000

Focal length

600 mm

Flash

Flash did not fire

f-stop

f/6.3

Shutter speed

1/2000 sec

Dimensions

1410 pixels x 940 pixels

Original file size

882.45 KB