Thanks to Nate Dias of the Cape Romain Bird Observatory, McClellanville,
SC, for this commentary in response to the recent r.f.i. on King Rails at
Blackwater N.W.R., MD.  Let the dialog continue!. - Harry Armistead.


Hi, Harry, Nate Dias here.

My opinion is that using habitat to ID King versus Clapper rails is a
mistake.  In coastal SC, I have seen pure King Rails in pure salt 
(spartina alterniflora) marshes and pure clapper rails in vegetation in a
freshwater waterfowl impoundment (which is next to a salt marsh).

Please forward the following note to VA-birds and to Sean Flint.

Thanks and happy naturalizing,

Nate Dias
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Separating King Versus Clapper Rails by voice is not hard - the 
"Charleston School of Birding" has been doing it and teaching it for years.

Even hybrids can be called with a fair degree of certainty.  As with all
bird calls, the closer you are to the calling bird, the easier the ID.

King Rails - noticeably deeper, lower tone, markedly slower sequence of
call notes, more grinding individual "grunt" notes (more of a "rrrek"
versus the more monosyllabic, crisp "kek" notes of a Clapper Rail).

Clapper Rail - higher pitch, MUCH more rapid sequence, a sort of 
hyperactive, "goony" sequence of call notes.  Individual notes are 
quick, crisp "kek" sounds, without the more drawn-out raspy undertones of a
King Rail.

Hybrids can have a cadence like Clapper (faster and slightly "hyper") but a
pitch that's lower and call notes that are not quite as crisp as a classic
Clapper.
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Nathan Wescoat Dias
Executive Director
Cape Romain Bird Observatory
PO Box 362
McClellanville, SC 29458
http://www.crbo.net/