male Rufous Hummingbird
(Photo © HBSG, Inc.)
by Bob Sargent
the official poop sheet
Hummer/Bird Study Group)
This is the first installment in a series on hummingbirds
that we have encountered in the Southeastern United States as part
of our study of this wonderful family of birds. We will be giving some
opinions based on our work and observation both in the hand and in
the field. As with any scientific endeavor, the truth is constantly
revealing itself to those that systematically search for it. We are
engaged in that search, thanks to the generosity of our members. What
you will read here will surely be refined and updated in the future
by other qualified researchers, including current members of our staff.
To tell you about Rufous hummingbirds is a labor of
love. Starting from the time that Martha Gail and I would regularly
drive 600 or 700 miles to investigate a single reported brownish hummer
in the late 80s, till now where we get 500 such reports annually,
it never grows old. There simply is not enough time to check out all
of the reports, but we try. I remember the first Rufous we captured
and banded, an adult male in Mountain Brook, Alabama, in August 1987.
The Banding Laboratory in Laurel, Maryland, wanted to know how we could
have captured and banded a bird in an area so completely out of range.
They wanted measurements and weight and photographs. We had all of
that and more. I also remember the hordes of people that visited the
home of Ellen Cunningham to see this very special bird. Although we
certainly find Rufous to be a regular winter resident of the Southeast
each year, they are no less special. It seems appropriate that one
of our first Rufous of the winter season of 1995/96 was
at the new residence of now Life Member Ellen Cunningham.
Rufous hummingbird is probably the most hardy of all
the hummer species that nest in the United States and Canada. They
are beautiful and hateful, real junk yard dogs. They are
by far the most common of all the winter hummers that we encounter.
The bulk of the Rufous population spends the winter in Mexico. Their
known nesting range includes Northern California, Washington, Oregon,
Central Idaho, Western Montana, Southwestern Alberta, British Columbia
and as far north as Southeastern Alaska in the area around Seward.
I would not be surprised to learn that Rufous nesting had been documented
in other areas of the United States. The very fact that we have documented
Rufous in the Southeast in every month except June gives us pause to
speculate about the accuracy of what we now know as their nesting grounds.
In the state of Georgia in May, we have had adult males and adult females
on site within three miles of each other.
On birding trips to the port city of Seward, Alaska,
we have observed adult males on breeding territory and females flying
with nesting materials in June. The commitment to complete their nesting
must be accomplished before the snow flies. As soon as
the young have fledged, there appears to be a mass exodus back
to the warmer climate of Mexico. Sounds like Im quoting here
from your friendly field guide. Enter the role of amateurs in ornithology.
First, our good friend and mentor, Nancy Newfield of Louisiana, started
the furor with her pioneering work that located hundreds of Rufous
wintering in her home state. Our own HBSG studies have now painted
an even broader picture of where these birds live in winter. This winter
alone we have captured and banded over 100 Rufous in our study area.
A new assumption is now suggested. It would appear to us that a part
of the Rufous hummingbird population is composed of birds that are
no longer tropical birds. This is supported by 22 individual
return birds being recaptured at or near there original winter banding
location this season (winter 1997/98). Many of these individuals have
returned 3, 4 and even 5 years in a row.
This phenomena of a separate population of Rufous
might even suggest that now or in the future these individuals might
be considered a separate race. There is precedent in other species
of hummingbirds for separate races. Part of our study is to accurately
record and photograph those Rufous that we encounter in an effort to
determine if there are plumage or structural differences that would
support such a hypothesis. What cannot be denied is that the Rufous
that we do encounter year after year are
not vagrant birds. These hummers that we are now calling non-tropical
birds have been generally referred to by the ornithological community
and writers as vagrants, wanderers, lost, off course, sick or genetically
impaired. It is our belief that although their ancestors may well have
been genetically altered some untold number of generations ago, that
defect in the gene that controls migration is now normal for this U.S.
population. The fact that we have some very localized areas all over
the Southeast, not just on the Gulf coast, where new Rufous occur year
after year would appear to take the element of chance out of the equation
in their selection of wintering sites. It is, in our opinion, a decision
over which these non-tropical Rufous have no control. They are directed
to these wintering sites by the genes of ancestors that have wintered
there successfully. It is not known in our proposed scenario about
the timing and merging of these separate populations of Rufous at a
breeding site. However, if these Rufous are confined to a particular
breeding area where they will encounter others with a similar genetic
disposition, the prospects for a wintering population of Rufous may
be on the verge of an explosive expansion. It may have already occurred
and we are just beginning to document the fact. Wouldnt it be
neat to know that if you hung out your feeder in winter, Rufous would
be as dependable as White-throated sparrows, Juncos and other winter
residents? Tiny numbered bands on tiny hummer legs have given us a
very special window into the life of these Rufous. We have long advocated
that Rufous could not simply be dismissed as vagrants. But, it was
not until we had accumulated mountains of evidence to the contrary
did most ornithologists take any notice. This is as it should be in
the scientific community.
A few details about Rufous. Females are larger than
males, this is true in many hummingbird species. Females, adults in
particular, have many irridescent feathers in the throat, unlike our
more common female Ruby-throated who are plain-throated.
Males as young birds have white tips on their outer tail feathers (rectrices),
as do adult females. Only when they molt into their adult male plumage
will they get the all dark tail feathers. After fledging, young males
soon start to molt their all-green feathers of the back. These new
feathers will be rufous colored (or commonly called brown). A brown-backed hummingbird
at your feeder in winter will be a male Rufous. Some very young male
Rufous may show little or no brownish feathers in the back.
Normally, male Rufous will show considerable rufous
color in the area of the rump and in the tail feathers themselves.
The outside tail feathers in males will be 2/3 to 3/4 rufous colored
at the basal end where they go into the body. Females of all ages will
normally be rufous only 1/3 to 1/2 the length of these same tail feathers
(Stiles 1972). The shorter wings of males beat faster than females
and have a higher pitch that is noticeable in flight. Males tend to
be a bit brighter in those areas of rufous coloring than females. The
area of iridescence on the individual gorget feathers is much wider
in males than in females and the color that you perceive will be much
more shimmering. In our experience, if a Rufous has shiny gorget feathers
on the sides of the throat, it is a male.
The first molt of any feathers that we normally see
is on the underparts. In very young wintering Rufous, the loosely textured
feathers of the breast and belly are easily dislodged. The feathers
of the wing molt symmetrically from the body sides outward. Normally,
when we see a Rufous with all new wing feathers except the outside
two on each side, they are subject to leave almost any time. Even though
the brilliant gorget feathers will continue to erupt from their sheathing
during the winter months, the back of a male Rufous will be essentially
all-brown before the gorget color is complete.
Males tend to have a much harsher tone to all their
vocalizations. In addition, males are much more active vocally than
females. Even as very young birds, males in winter begin to hone the
intimidation skills that they will employ on their breeding grounds
to dominate a breeding territory. Like other hummingbird species, young
wintering Rufous males appear to do their version of a territorial
morning song, in effect a declaration of territory. With experience,
you can tell whether a bird is a male or female simply by their voice
and how and when they use it.
Rufous hummingbirds are very cold hardy. They are
hatched in a cold climate, they spend nights on nesting grounds where
the temperatures are near freezing. They migrate down mountain corridors
where the temperatures are cold. Finally, these U.S. Rufous are continually
being refined by the genes of cold hardy ancestors that have endured
severe winters. We regularly have Rufous in the Southeast that seem
little effected by nighttime temperatures of 0 to 20 degrees F. The
presence of Rufous going about their daily routine in times of severe
cold requires rethinking our impression of hummingbirds in general.
Unfortunately, in many cases much of the information
about Rufous available to the public is both incomplete and inaccurate.
The very nature of birding field guides will always have them playing catch-up to
the facts. Revisions and new editions are never far behind. In my opinion,
the single best paper on Rufous hummingbird is the new species account
by our friend, Dr. William Calder of the University of Arizona. This
booklet is part of the new Birds of North America series being published
by the American Ornithologists Union and The Academy of Natural
Sciences, Philadelphia. We hope to have some exciting news about making
these booklets available to our members later as they are published.