Date: Mon, 22 Jul 2002 14:15:25 -0700
Reply-To: Sheri Williamson <tzunun@MINDSPRING.COM>
From: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@LISTSERV.LSU.EDU>
Subject: Re: [HUMNET-L] Rufous vs. Allen ID
To the excellent comments that
have already been made on this thorny
issue, I would only add the following:
- On an adult male Rufous/Allen's,
a back that's more than 50% green,
regardless of the uniformity thereof, is my first cue to begin
considering the possibility of Allen's. With such birds, I only
feel
comfortable assigning a bird to one species or the other if I
get a
good look at the tail; otherwise, they remain "Rufous/Allen's."
- "Rufous/Allen's"
is being used more and more often outside the
hummingbird community as a more precise generic term for this
challenging species pair, while the older and less precise term
"Selasphorus sp." is still perfectly appropriate when
Broad-tailed has
not been eliminated from consideration.
Sheri Williamson
Bisbee, AZ
tzunun@mindspring.com
http://tzunun.home.mindspring.com
====================================
Date: Sat, 20 Jul 2002 15:01:30
-0500
Reply-To: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@LISTSERV.LSU.EDU>
From: BB for Hummingbirds and Gardening for them in the Southeast
<HUMNET-L@LISTSERV.LSU.EDU>
Subject: Re: [HUMNET-L] Rufous vs. Allen ID
Haji,
At 03:56 AM 7/20/2002 -0700, Haji Warf wrote:
>I thought if you aren't able
to detect any green at
>all, it's likely Rufous, whereas Allen's have some
>green intermingled on its back?
Welcome to the greatest hummer
ID challenge in North America. If an adult
male Selasphorus has a completely rusty back, it is a Rufous.
If an adult
male Selasphorus has a green back with rusty feathers intermingled,
it is a
Rufous. If an adult male Selasphorus [not Broad-tailed] has a
completely
green back, it is very likely to be an Allen's, but a small percentage
of
adult male Rufous have completely green backs, so there is always
the
outside chance that a green-backed adult male Selasphorus is not
an
Allen's. In my somewhat limited experience with Allen's [almost
50,
including all ages and both sexes] the quality of green on an
adult male
Allen's back is darker and more "contrasty" to the rusty
parts of the
plumage than green-backed Rufous [a few]. However, this is not
the kind of
field mark that I would give to the inexperienced hummer-identifier
because
it is somewhat subjective and because I have not had the opportunity
to
test this conclusion extensively.
Immature male Selasphorus [not
Broad-tailed] with any rusty feathers on
their upper backs are clearly Rufous. All others, [and that would
be many
or most this early in the season] should go through a "tail
feather test"
to be identified to species.
As for females, I have seen female
Selasphorus that I thought to be Allen's
because of their small stature and fairly skimpy tail. And, in
most cases
[but not all cases], these birds are identifiable as Allen's once
they are
captured and measured. However, I have seen enough female Rufous
that were
small that I would not recommend considering an identification
absolute
unless the measurements could be taken. Therefore, I would recommend
leaving some Selasphorus identified simply as generic Selasphorus
- however
unsatisfying that may be.
NLN
***************************
Nancy L Newfield
Casa Colibrí
Metairie, Louisiana USA
<colibri@webdsi.com>
***************************
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