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Bird morphs



Hi Carolinabirders,

Just to answer Karen Bearden's question, I'm pretty sure my first bird of 
2002 was the big raft of American Coots on Lake Murray.

The Virginia birding listserv has a report of a Barnacle Goose in a large 
flock of Canadas at Dyke Marsh. No evidence yet that's it's an escaped 
captive... And for those of us who missed the Broad-billed Hummingbird in 
New Bern last fall, there's apparently one in Macon, GA according to that 
state's listserv. The Floridabirds list mentions a Saw-whet Owl from Fort 
Lauderdale, hard to believe there's one down there but nobody's found one 
up here!

On Mon, 7 Jan 2002 THam9281@aol.com wrote:
> 
> I suspect some of you veteran birders may know about morphs and may 
> even know of these specific ones, and can tell me if I've encountered 
> something truly freaky or not.

Morph is kind of a hazy term. The definition is (as I understand it) a 
distinct, regularly occurring color pattern within a bird species that 
isn't associated with what subspecies, age, or gender the individual bird 
is. Good examples might be the white morph of the Reddish Egret, the 
light and dark morphs of many pelagic birds like jaegers and petrels, the 
light and dark morphs of many hawks like Short-tailed and Rough-legged 
Hawks and Gyrfalcon, the red and grey morphs of Eastern Screech-Owl, etc. 
The term gets tossed around a lot though, and there's confusion in some 
cases. For instance, with Red-tailed Hawks there are both subspecies that 
differ in color tendencies, and color morphs, and there is a great deal 
of variation between extremes such that it's hard to tell with some birds 
whether they belong to one morph or another, or even one subspecies or 
another, so people use the terminology pretty loosely.

The pink ibis, as the ranger told Terry, is not really a "morph" 
(whatever that is), but a hybrid. They've been in south Florida for 
years in various locations; I've tried but failed to find them at one 
former Scarlet Ibis (and pink ibis) location, Greynolds Park in Miami. 
There's some debate, of course, as to whether any of the Scarlet Ibis 
might have been natural vagrants or whether all were releases/escapes 
(the Greynolds Park birds were imported from Trinidad). John James 
Audubon claimed to have seen Scarlet Ibis in Louisiana, well before there 
were any captive waterbird collections in this country...

As for the Great White Heron, it was at one point considered a separate 
species from the Great Blue. Who knows, they're splitting enough bird 
species now, it may be separated again in the future. At the moment, I 
think it is considered a subspecies, Ardea herodias occidentalis, and so 
isn't really a "morph" either. It's almost exclusively limited in range 
to the Florida Keys and adjacent areas, but occasional vagrants stray 
northwards; I seem to recall one in western North Carolina a year or two 
ago, and one on Cape Cod, Massachusetts before that. The subspecies is 
listed as an accidental on the Pea Island NWR and Cape Hatteras NS bird 
checklists too; see
http://www.npwrc.usgs.gov/resource/othrdata/chekbird/chekbird.htm

Good birding,

Josh


Joshua S. Rose
Duke University
Department of Biology (Zoology, R.I.P.)

jsr6@duke.edu
http://www.duke.edu/~jsr6/