Re: immature rubythroats, house finch color morphs

[Helmut Mueller <hmuelle@earthlink.net>]

Juvenile refers to birds in the juvenal plumage (which is of "true
feathers"), which is very short-lived in passerines but lasts a year in most
hawks..an "Immature" Red-tail is actually a juvenile. The first prebasic
molt of the RT Hummingbird occurs in winter..so the young birds you are
seeing are juveniles.
 The red plumage in house finches is due to carotinoids & a yellow bird  did
not get enough precursors in its diet..although other factors may be
involved. The pigment in most red (& yellow birds) is a melanin..which are
also responsible for color in brown & black birds. Blue birds are blue
because their feather structure scatters light..sort of like oil on
water..the underlying pigment is actually brown .

-- Helmut C Mueller

409 Moonridge Road
Chapel Hill, NC 27516
Phone: 919-942-4937

Permanent email address: hmueller@email.unc.edu


> From: "Leah Campbell" <faeriemaiden@hotmail.com>
> Date: Fri, 12 Jul 2002 11:07:36 -0400
> To: carolinabirds@duke.edu
> Subject: immature rubythroats, house finch color morphs
> 
> Carolina Birders,
> 
> I recently spoke with Bob Sargent about immature ruby-throated hummingbird
> plumage. In contrast with adults, immatures have buffy-colored feathers
> scattered about their heads and necks. (Note: I was using the term juvenile
> before; however, juvenile typically refers to a bird that has not developed
> a complete set of true feathers. An immature, on the other hand, has true
> feathers but lacks adult coloration.) Toward the end of the summer, a few
> gorget feathers are visible on immature males.
> 
> On a different topic, I was wondering how common the orange and yellow house
> finch color morphs are. I have an all-orange (tangerine) one at my feeders
> this year, and it is the first I've ever seen. Very pretty.
> 
> Leah
> 
> p.s. Does anyone know of a good online glossary of bird terminology?
> 
> Leah Campbell
> Blackstock, SC
> leahcam@lycos.com
> faeriemaiden@hotmail.com
> 
> 
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