Birds, possible species splits

Why can't they leave things alone??
The following is copied from Oregon Birders Online

Possible new species splits under consideration by AOU:

New World Snowy Plover (Charadrius nivosus) and the Old World Kentish Plover (Charadrius alexandrinus)

Split Mountain Chickadee Poecile gambeli into two species:
A). Gambel’s Chickadee P. gambeli including subspecies P.g. gambeli, P.g. grinelli, P.g. inyoensis, P.g. wasatchensis.
B). Bailey’s Chickadee Poecile baileyae – the coastal California, Sierra Nevada, and Cascade populations, including subspecies: P.b. baileyae, P.b. abbreviatus, P.b. atratus.

Split the Common Moorhen (or Gallinule) Gallinula chloropus into:
A). Old World species Common Moorhen Gallinula chloropus
B). New World species Common Gallinule Gallinula galeata. An alternative English name suggested is Laughing Gallinule due to its distinctive call.

Split Yellow-rumped Warbler Dendroica coronata into two, three, or four species. You read that right! This one is really up in the air. If any of the proposed splits are accepted, our local subspecies D.c. auduboni will again be classified a full species, D.auduboni, probably again known as Audubon’s Warbler (the name which some of us have never stopped using).

Snowy / Kentish, the Moorhens, and Myrtle / Audubon's splits already accepted by IOC and also here on BirdFiles .

Have to check up on the Mountain Chickadee one, that's new!

Resin

Checked; yep, the Mountain Chickadee split hasn't been accepted by IOC (yet), I'll leave it as it is on BirdFiles until the AOU produce their formal report

Resin

They like to make things more confusing tiger. ^_^

When you've seen everything, it's the only way left to make your list longer . . . ;-)

I got one new, as I've seen both Audubon's and Myrtle Warblers. Never saw Common Gallinule or Snowy Plover on my American trips, so don't get to add those.

For the real answer – it's all determined by the results of genetic analysis, which wasn't available in the past of course. To take the Kentish Plover / Snowy Plover example, the two look quite similar to each other, but on testing, they discovered that Kentish Plover (Europe, Africa, Asia) is actually more closely related to White-fronted Plover (from Madagascar), than it is to Snowy Plover (N America). So if you're keeping Kentish Plover and White-fronted Plover as separate species, then Snowy Plover also has to be a separate species. This wasn't clear from appearance of the birds, but is from their DNA.

Resin