An Apparent Hybrid

Dunlin X White-rumped Sandpiper

South Beach, Chatham, Massachusetts: 28 June 2012

Blair Nikula

The following four images are of a presumed Dunlin X White-rumped Sandpiper in a basic-like (but perhaps a first alternate?) plumage present on South Beach in Chatham, MA, on 28 June 2012. The bird was rather Dunlin-like in general appearance, but compared with several similarly plumaged Dunlin present in close proximity (see the 5th image below), this bird was a bit smaller; with a slightly shorter, straighter bill; more pattern in the dorsal plumage; more fine streaking on the flanks; a tail pattern intermediate between the two presumed parent species; and a high pitched call that was more like a White-rumped than a Dunlin.

This bird was remarkably similar to one of two presumed hybrids present in the same location in 2008 (see the last three images below). The 2012 images were taken with a Canon 7D and a 300mm Canon lens w/1.4 teleconverter; they have been cropped with some exposure adjustment.

This flight shot shows the tail pattern, which is intermediate between the two presumed parent species. When the bird flushed I heard it call once: a high pitched call somewhat like a White-rumped, but not as short or thin. However, much more reminiscent of White-rumped than Dunlin. I'm unsure about the plumage/age of this bird. It shows relatively little wear, but I get the impression from this flight shot that the outer two primaries are older and worn, which, if true, would suggest it's a one year old bird completing the first molt of its flight feathers. (And is there a tail feather missing?)


For comparison, the next image is of a similarly plumaged, basic-type Dunlin, taken on the same day and location. Note the plainer dorsal plumage (much narrower central shaft streaks) and the somewhat longer bill.

 

Below are two presumed Dunlin X White-rumped Sandpiper hybrids present on South Beach on 21 June 2008, a basic-plumaged (1st alternate?) bird on the right and an alternate-plumaged bird 2nd from right, with two Dunlin on the left. Additonal images of these birds can be seen here.

The 2008 basic-type plumaged bird on South Beach (very similar to the 2012 bird; could it be the same individual?)

The 2008 basic-type bird taking off, giving a side view of the tail pattern (tough to be sure from this angle, but seems virtually identical to the 2012 bird).