I could only find one Willet thread, and it focused on convergent evolution in Tringa, so I am making a new one that is Willet-specific. I have a question about the Willet and the potential split of that species into two. Almost five years ago, David Sibley listed them (Eastern and Western Willet) as the most splittable of his 10 potential splits (http://www.sibleyguides.com/2010/04/the-next-10-north-american-bird-splits/). What is the status of any sort of taxonomic work on these two taxa? Has the AOU ever faced a proposal to split them? Does anyone have information on why they are still considered conspecific?
I have pasted some information below from BNA about the two groups, and it sounds good to me.
Information copied from BNA:
“
Two disjunct groups of breeding populations that differ in size (wing length, bill length and thickness, leg length, and body mass), plumage (especially Alternate plumage), vocalizations, breeding ecology, and to a large extent, winter ranges. These 2 groups are recognized as separate subspecies, C. s. semipalmatus and C. s. inornatus, referred to as Eastern and Western willet, respectively (see below). Both plumage and size appear to be more variable among Western Willets.
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Eastern Willets discriminate between Eastern and Western songs, suggesting behaviorally facilitated reproductive isolation (Douglas 1998).
“
I have pasted some information below from BNA about the two groups, and it sounds good to me.
Information copied from BNA:
“
Two disjunct groups of breeding populations that differ in size (wing length, bill length and thickness, leg length, and body mass), plumage (especially Alternate plumage), vocalizations, breeding ecology, and to a large extent, winter ranges. These 2 groups are recognized as separate subspecies, C. s. semipalmatus and C. s. inornatus, referred to as Eastern and Western willet, respectively (see below). Both plumage and size appear to be more variable among Western Willets.
…
Eastern Willets discriminate between Eastern and Western songs, suggesting behaviorally facilitated reproductive isolation (Douglas 1998).
“