Location Code: KEN3
Rufous Hummingbird (Selasphorus rufus), immature female
December 29, 2011. First
observed by homeowner (Sue McLelland) in late September 2011 and last
observed on 11 January 2012. I arrived around 9:15 a.m. and waited only a
few minutes before the bird made an appearance, and it was obviously a Selasphorus
based on the peach color evident on the birdís flanks.
I set up my trap at 9:30 a.m. and caught the bird at 9:42 a.m. The
bird was banded and released at 9:55 a.m. under Federal Bird Banding
Permit No. 23156, and Michigan Scientific Collectors Permit No. SC 1303.
At the home of Sue McLelland in
All data and observations in this report were made by Allen
Chartier. Also present were the homeowner (Sue McLelland), and Nancy
Photographed in-hand with digital camera (photos 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 with
light snow, and the temperature was 30 degrees. The bird was banded,
measured, weighed, and photographed outdoors.
When the bird first made an appearance in a spruce tree in the
backyard, it was apparent that it was a Rufous or Allenís Hummingbird,
based on peach-rufous on the flanks, and a small spot of iridescent throat
feathers This observation was made with 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 hatch-year (immature) based on the presence of
shallow groovings or corrugations on about 80% of 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 rectrices (r1) was restricted to about the basal
25%, and was completely covered by the green upper tail coverts. These
characters suggested this bird was a female. The wing measurement of 44.27
mm was longer than any age of male Rufous or Allenís given in Stiles
(1972), so this measurement is a very strong indication that the bird was
female. The bill measurement (exposed culmen) can sometimes be helpful for
determining sex. This birdís exposed culmen measurement of 17.79 mm was
longer than adult and immature males of nominate (S. s. sasin) Allenís Hummingbird, but within range of immature
males of the sedentarius
subspecies* of Allenís and shorter than the range of adult females of sedentarius. So, the bill measurement supports the sex as female.
The pattern of iridescent gorget feathers on the throat can sometimes be
helpful in determining the sex of Selasphorus
hummingbirds. This bird had only two in the bottom center of the throat
(see photos), which tends to be more frequent in males than females. There
is a tendency for immature males and immature females to have fewer
iridescent feathers, but this is extremely variable with almost complete
overlap, so this birdís throat pattern cannot really be used to support
aging the bird.
Given that the bird was a hatch-year (immature) female, using
Stiles (1972) 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.
The r2ís of this individual showed only very subtle emargination
(see photos), which is diagnostic for Rufous. Using Figure 3 in Stiles
(1972), the shape most closely matched figure Cb for Rufous, which would
be difficult to see in photos of the free living bird, provided it spread
its tail which they rarely do unless defending food sources from other
hummingbirds. Additional support for the identification can be obtained by
measurements of the widths of two other tail feathers. In cases where r2
shows little or no notching or emagination, the measured widths of the
central rectrix (r1) and the outermost rectrix (r5) are the primary means
to confirm identification. One central tail feather (r1) was measured as
8.52 mm. This is around the mid-range for immature female Rufous (7.8-9.5
mm) given in Stiles (1972), and above the upper end of the range for
immature female of nominate (S. s.
sasin) Allenís (6.9-8.2 mm). It is also above the range for immature
females of the sedentarius subspecies of Allenís (7.3-8.4 mm). So, the width of
the central rectrix provides conclusive and diagnostic support to the
identification as Rufous Hummingbird. One outer rectrix (r5) was measured
as 3.75 mm. This is below the mid-range for immature female Rufous
(3.2-4.7 mm) and broader than the maximum range for immature female
Allenís (max. 3.3 mm) for both subspecies, and so provides conclusive
and diagnostic support to the identification as Rufous. Tail measurements
are often not very useful. This
birdís tail measurement of 27.2 mm is above the maximum for immature
females of the nominate subspecies of Allenís (Stiles gives no
corresponding measurement for immature female S.
s. sedentarius), and is near the maximum given for immature female
Rufous. So tail length is also useful in this case. The wing measurement
of 44.27 mm is near the maximum for immature females of nominate
Allenís, but is within the range for immature females of the sedentarius
subspecies of Allenís (42.1-45.0 mm), so does not support the
identification as Rufous Hummingbird.
There was no body molt evident on this bird.
The outer 3 primaries (p8-p10) were old and worn and the inner
primaries (p1-p7) were recently replaced and contrasting shiny black. All
the rectrices were fresh and unworn.
The bird had a fat code of 1 (0-3 scale) and weighed 3.56 grams, about
average for an immature female planning to overwinter.
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 subtle emargination of the second rectrix
provided support for the identification as Rufous. But the widths of both
the central (r1) and outer (r5) rectrices provided diagnostic and
conclusive support for the identification as Rufous. The tail measurement
also provided additional support for the identification.
I have seen hundreds of Rufous
Hummingbirds in several states, banded more than 60 in Michigan, Ohio,
Indiana, and Ontario, and handled ~35 in Louisiana in February 2003 with
Nancy Newfield, and handled about a dozen in Arizona in July 2006 helping
other banders. I have seen
several Allenís Hummingbirds on two trips to
report was written:
This report was written on January 14, 2012 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
*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.
Condor 74: 25-32.