Location Code: SAG3
Rufous Hummingbird (Selasphorus rufus), adult female
Time: November 17, 2008.
First observed by homeowner on 12 November 2008 and last observed
on 5 December 2008. I arrived around 9:00 a.m. and waited about 15
minutes before the bird made an appearance.
I then set up my trap at 9:30 a.m. and caught the bird at 9:33
a.m. The bird was banded and
released at 9:42 a.m. under Federal permit No. 23156, and
At the home of Bernie Coleman in Shields, Saginaw Co.
Photographed in-hand with digital camera (attached to this document).
All measurements were made using digital calipers.
Bill corrugations were determined by viewing through a 10x loupe,
as they are impossible to accurately determine any other way.
conditions: The sky was overcast
and the light diffuse. The bird was banded, measured, weighed, and
When the bird first made an appearance at the feeder, it was
apparent that it was a Rufous or Allenís Hummingbird, based on peach-rufous
on the flanks, and an irregular blotch of iridescent throat feathers.
This observation was made with my 10x Swarovski binoculars from a
distance of about 30-feet. The bird was then captured for banding, and
it was aged, sexed, and identified in that order.
The proper use of Stiles (1972) for banders requires that an
individual Rufous/Allenís Hummingbird in-hand be correctly aged and
sexed before a species determination can be made (B. Sargent and N.
Newfield, pers. comm.).
The bird was aged as after hatch-year (adult) based on the
absence of shallow groovings or corrugations on the upper mandible. This
is universally recognized as the most reliable method for age
determination in hummingbirds (Ortiz-Crespo, 1972).
The upper tail coverts and rump were entirely green. The rufous
on the base of the central rectrix (r1) was restricted to about the
basal 25%, and was completely covered by the green upper tail coverts.
As the bill corrugations indicated the bird was adult, plumage alone is
enough to confirm the bird was a female, but these additional plumage
characters support that this bird was a female.
wing measurement of 42.93 mm was at the short end of the range given for
adult and immature female Rufous given in Stiles (1972). It is also near
the large end of the range for immature males, so the wing chord
measurement weakly supports the sex of this bird as female.
bill measurement (exposed culmen) can sometimes be helpful for
determining sex as indicated in Table 1 in Stiles (1972). This birdís
exposed culmen measurement of 17.05 mm was near the middle of the range
given for adult and immature females Rufous. It is also near the large
end of the range for immature males, so the exposed culmen measurement
supports the sex of this bird as female.
pattern of iridescent gorget feathers on the throat can sometimes be
helpful in determining the sex of Selasphorus
hummingbirds. This bird had 17 clustered together in the center of the
throat (see photos). This
pattern is more indicative of females than males, though the number of
iridescent feathers varies considerably and is not particularly useful
for supporting an age determination.
Given that the bird was an after hatch-year (adult) female, using
Stiles we can determine whether this bird was a Rufous or Allenís
Hummingbird using several additional measurements and observations.
The presence of notching and/or emargination on the second
rectrix from the center (r2) is one feature that can often be observed
in the field to confirm Rufous, and is considered diagnostic. This
individual had noticeable notching and emargination on both webs of the
second rectrix (see photos), which confirms that this bird was a Rufous
Hummingbird. Using Figure 3
in Stiles (1972), the shape most closely matched figure Aa.
additional support for the identification, the widths of two other tail
feathers, the central rectrix (r1) and the outermost rectrix (r5) were
measured. The width of the central rectrix (r1) was measured as 7.67 mm.
This is at the narrow end of the range for adult female Rufous and at
the wide end of the range for both subspecies of Allenís Hummingbird*
given in Stiles (1972) so is only suggestive of Rufous.
width of the outer rectrix (r5) was measured as 3.48 mm.
This is broader than the maximum range for immature female
Allenís (max. 3.3 mm for both subspecies given in Stiles 1972) and so
provides additional conclusive and diagnostic support to the
identification as Rufous.
measurements are often not very useful.
This birdís tail measurement of 28.5 mm is above the maximum
for adult females of both subspecies of Allenís (Stiles 1972) and is
at the upper end of the range for adult female Rufous. So tail length is
somewhat useful in this case.
There was no body molt evident on this bird.
The outer 4 primaries (p7-p10) were old and worn, and the inner
primaries (p1-p6) were recently replaced and contrastingly shiny black.
Rectrices 3 and 4 were worn while r1, r2, and r5 were fresh and probably
The bird had a fat code of 1 (0-3 scale) and weighed 3.41 grams, about
average for an adult female planning an extended stay.
Brief, sharp chip note when
the bird was released. More strident than Ruby-throated gives.
Allenís Hummingbird is the species most similar to Rufous
Hummingbird. On this bird, the diagnostic ďnotched and emarginatedĒ
second rectrix (r2), measured width of the outer (r5) rectrices were the
primary characters confirming the identification, with tail length and
to a lesser extent the width of the central (r1) rectrix supporting the
I have seen dozens of Rufous
Hummingbirds in several states, banded more than 50 in Michigan, Ohio,
Indiana, and Ontario since 2001, handled ~35 in Louisiana in February
2003 with Nancy Newfield, and handled about a dozen in Arizona in 2006
helping other banders. I
have seen several Allenís Hummingbirds on two trips to
report was written:
This report was written on December 19, 2008 based on data and
photos taken during the banding process.
None were consulted while observing the bird in the field, nor
were any used to write notes in the field or to write this report.
Stiles (1972) and Pyle (1997) were available during the banding
of the bird.
There are two subspecies of Allen's Hummingbird.
One is the widespread and migratory nominate subspecies (Selasphorus
sasin sasin) breeding from coastal northern
A new method to separate immature and adult hummingbirds. Auk
Identification Guide to North
American Birds: Part 1. Slate
Creek Press, CA.
FStiles, F.G. 1972.
Age and Sex Determination in Rufous and Allen Hummingbirds.
The Condor 74: 25-32.