Date: Tue, 30 Jul 2002 13:33:52 -0400
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] Sugar Consumption Amount Formula( Molt discussion)

On 30 Jul 02, at 9:55, Nancy L Newfield wrote:

> I have seen numerous adult Ruby-throateds in heavy body
> molt.

So, it is *not* true that migratory hummers wait until they are in
their winter quarters before molting?

--
Curtis Croulet

Curtis and all:
I suspect that only BODY MOLT occurs in the states and the tail and wing
feathers are replaced on the wintering grounds of Central America and
sometimes in the southern most parts of the United States.  It stands to
reason that a hummer would not want to impair his/her flying skills by
dropping any of these flight feathers.

Of interest to those of you that view your hummers with binoculars and
scopes:  Look closely at the outer primaries (wing feathers) of
Ruby-throated hummingbirds.  If the shafts of those feathers, and the
feathers themselves seem brownish, that is an indication that the bird
being observed is most likely an adult and that it is a migrant.  The old
flight feathers of adults take on this "dead look" before they depart our
area for the tropics.

You might also look at the adult males that are passing through your yard.
Notice at the base of the upper mandible (bill):  On these adult males that
are now in migration and are molting, their head will looked almost
deformed.  The feathers near the base of the bill will be missing and you
will likely see a "hump" that looks like a small oval tumor.  At this
location, will be a lot of tiny bumps that look like brown sesame seeds or
"seed ticks".  These are actually pin feathers that have not yet opened.
Sometimes these adult males will have a cluster of "PVC gray" pin feathers
that look like paint on the forehead as well.  They are pretty trashy
looking creatures as they start this annual body molt of old, worn and
dirty feathers.

Small birds and even smaller details, but it only adds to what we love
about them.

Bob Sargent
Trussville, Alabama

==========================================

Date: Tue, 30 Jul 2002 13:05:53 -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] Molt and migration

My observations agree with Bob's. In highly migratory hummingbirds,
body molt, the less conspicuous and physiologically demanding stage of
the process, does seem to begin before or during migration. In most
individuals, replacement of the tail and outer primaries, which form
the end stage of the process, are "saved" for the wintering grounds
when the bird is under less stress. Less migratory North American
hummingbirds tend to molt the outer primaries and/or tail feathers
much earlier, between late spring and early fall. This can help in
distinguishing Anna's and Costa's from Ruby-throated and
Black-chinned.

Sheri Williamson
Bisbee, AZ
tzunun@mindspring.com
http://tzunun.home.mindspring.com

==============================

Date: Wed, 31 Jul 2002 13:15:50 -0700
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] molt

On 30 Jul 02, at 13:33, RubyThroat@AOL.COM wrote:

> Curtis and all:
> I suspect that only BODY MOLT occurs in the states and the tail and wing
> feathers are replaced on the wintering grounds of Central America and
> sometimes in the southern most parts of the United States. It stands to
> reason that a hummer would not want to impair his/her flying skills by
> dropping any of these flight feathers.

I offer the following:

"Most North American hummingbirds undergo the process in winter
in the tropics, out of sight of northern observers, but a few molt on
different schedules." Annn's, Costa's and Violet-crowned are cited
as exceptions. (Williamson, S. L. 2001. A field guide to
hummingbirds of North America. p.17)

"Often this molt occurs on the winter grounds, e.g., in Mexico, and
in general the molts start with the flight feathers and end with the
head and gorget." (Howell, S. N. G. 2002. Hummingbirds of North
America - the photographic guide. p.2)

Thus it appears we have a difference of opinion, not only as to
where the molt occurs geographically for most species, but also as
to the order of molting of the feather groups.
--
Curtis Croulet
Temecula, California

==============================

Date: Wed, 31 Jul 2002 20:06:48 -0400
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] molt

Curtis and Humnetters
My OPINIONS were based on having banded many thousands of Ruby-throated
Hummingbirds in summer and fall.  One piece of data that I record on every
bird I capture is the location and degree of molt.  All of the banders that
I have trained are encouraged to gather this same information on the birds
that they band as well, if their time permits them to do so.

I was discussiing the molt patterns in Ruby-throated Hummingbirds and will
stack that up against anyone who wishes to challenge the data.  By the way,
I captured a dozen birds today, only two of which were not molting at all.
Both were very young, not too long out of the nest.  Among the birds that
were molting, all but one were molting in the head and all but three were
molting in the gorget.  It was a mostly male hummer day at my house, again.

My observations were made using live, in-the-hands-birds, and not from
museum skins.  All were made in the United States in summer and fall.

In Spring, at our banding station at Fort Morgan, Alabama on the Gulf Coast
we regularly see the tail end of the winter molting scheme in
Ruby-throated.  The last of the old feathers that we see in April are
rectrices (tail feathers), throat feathers (not yet reflective gorget
feathers) and finally the outside two primaries on the wings.

I hope this helps.  I cannot address the molt sequence in winter except for
those species that we encounter that spend the winter in the eastern United
States.  I'll bet Nancy can answer questions on almost any of those
species.

Bob Sargent
Trussville, Alabama